This main aim of this study is evaluate wide range of fresh and hardened properties of sustainable self-compacting concrete containing various types of Cement Replacement Materials with optimum contents of Polyethylene Terephthalate PET waste plastic as fibers and fine aggregate replacement. This is to evaluate effect of the two forms of PET and to determine the best CRMs could be used with sustainable SCC. such as limestone, glass powder and fly ash with high replacement rate of 70% by weight of cement were used while fourth one (kaolin) was used with replacement rate of 20%. PET fibers were added to SCC with an aspect ratio of 24.4 and 0.7% volume fraction whereas fine aggregate partially replaced by 4% of waste plastic. Four reference mixtures contained FA, LP, GP and KA only, same four mixtures contained 0.7% PET fibers by volume, and the other same four mixtures contained 4% PET fine aggregate by volume. The obtained results all tested fresh properties, which include slump flow, T500, L-Box and segregation resistance were within the limits of the specification reported in EFNERC guidelines. Further, the forms PET have an adverse effect fresh properties of SCC. As for hardened properties (compressive strength, splitting tensile strength, flexural strength and impact strength). Further, this produced type of SCC showed an range of compressive strength (15.2-31.64 MPa) at 28 days. It can be from the current study the best CRMs to be used in SCC containing PET wastes was FA in terms of most tested properties.
This study was conducted to examine the impact of plastic fibers (WPFs) in an effort to improve some of the features of self-compacting concrete (SCC) using Iraqi raw materials. Waste polyethylene terephthalate fibers (waste PET fibers) from used beverage bottles were added. Some tests were carried out to determine the effects of adding WPFs on the fresh properties of new concrete, while additional tests examined the mechanical properties of hardened concrete. Because of this, self-compacting concrete blends were created with a constant water-to-binder ratio of 0.32 and a binder content of 525 kg/m3. The designated plastic fiber percentages contents were 0%, 0.5%, 0.75%, and 1% of mix volume. Self-compacting concrete mixtures' fresh characteristics were assessed for slump flow diameter, T50 slump flow concurrently, V-funnel flow concurrently, and L-box height ratio. The 28-day density, compressive strengths and flexural strength of self-compacting concretes were also measured. The use of plastic waste fibers had a slight effect on reducing the density of the produced concrete and a negative effect on the fresh properties. The compressive strengths were improved by using WPFs, with the maximum improvement equal to (11.065%) when compared to those made from the reference mix
Adding fibers to the shotcrete concrete mixes is very important to increase the load carrying capacity, toughness, and reducing crack propagations by bridging the cracks. On the other hand, this fiber has an effect on the fresh and hardened properties of shotcrete. In this study, fresh properties evaluated by using slump flow, , and segregation resistance tests. Hardened properties included testing of air voids, dry density, water absorption, ultrasonic pulse velocity (UPV), compressive strength, and flexural strength. This works including two types of fibers in three forms (waste plastic (PET)fibers only, polypropylene fibers (PP) only, and hybrid fiber (PET and PP)), each form added by three percentages (0.35%, 0.7%, and 1%) by volume.The results showed that the addition of 1% of all types of fiber has a negative impact on fresh properties. Especially in shotcrete containing waste plastic fiber. Also, all specimens containing fibers showed a decrease in the ultrasonic pulse velocity (UPV) and an increase in air voids and water absorption compared to the reference specimens. Also, the results clarify that the addition of waste plastic fiber to shotcrete led to a slight decrease in dry density. The highest increasing in compressive strength of shotcrete recorded by about 8.2% with using 0.35% PP fiber and highest decreasing was 20.9% with using 1% waste plastic fiber. the highest increasing in flexural strength was 62 with using 1% PP fibers.
This paper presents and discuses some properties of self-compacting concrete SCC containing optimum contents of different types of cement replacement materials CRMs like fly ah, silica fume and limestone powder. The purpose is to evaluate the performance of SCC mixtures to choose the best one for strengthening purposes of corroded reinforcement concrete beams. In a preliminary work, the theoretical optimum contents of the above materials were specified using statistical program (Minitab) and they were verified experimentally. This verification based on checking fresh properties such as slump flow, T500, L-box and segregation resistance as well as compressive strength. The optimum contents of CRMs: 14% fly ash, 19% limestone, 18% silica fume plus fly ash and 11% silica fume were selected and studied. Compressive, tensile, and flexural strengths were examined, as well as the modulus of elasticity, water absorption and porosity (which reflect the related durability properties) were examined. Test results show that the optimum verified theoretical percentage of a combination of fly ash and silica fume, at 18% by weight of cement with a fixed water-binder ratio of 0.33 showed the best overall performance. It was deduced that this SCC mix gave the highest mechanical properties and the lowest porosity and water absorption. For example, the compressive strength increased by 36.25% as compared to SCC mix containing limestone powder. Further, the porosity and water absorption decreased by 120.8% and 164% respectively as compared to the above same SCC mix. Thus, it could be used for strengthening purpose of corroded RC beams.
The aim of this study is to develop Lightweight self-compacting concrete (LWSCC) mixtures using locally sourced waste materials such as Expanded Polystyrene Beads (EPS) and Waste Plastic Fibers (WPFs) which are all available abundantly available in Republic of Iraq at little or no cost. The fresh, hardened and mechanical properties of these LWSCC were studied, followed by results analysis. Five different mixes of LWSCC were prepared in term of WPF content (0.25, 0.5, 0.75, 1.0, and 1.25 %), in addition to the control mix (R mix) and lightweight concrete (E mix) made of EPS content as a replacement of coarse aggregate. The study showed that the LWSCC produced with these waste materials were decreased the density (lightweight) of the concrete mixes as EPS tend to form more clumps, absorb water and make the mix dry. Therefore, concrete mixtures were adjusted accordingly to be able to offset the workability caused by the addition of EPS. The increase in WPF content decreased the workability due to clumping that occurred in the mixing phase. The analysis of mechanical properties of the LWSCFRC specimens revealed that there was not much improvement. While LWSCC with 100% of EPS replacement as coarse aggregates and 1.25% WPFs provides the best flexural toughness performance
AbstractThere is no doubt that the type and properties of cement extremely affect the general properties of produced concrete .Cement is one of the main ingredients of cement past phase in concrete. In present study chemical and physical properties of four types of Portland cement available in Iraqi local market were studied ,these types as follow : two types of ordinary Portland cement Kubaisa (Iraqi cement) and Ismnta (Jordanian cement) and the others of sulfate resisting cement Torab alsabia (Lebanese cement ) and Al-qaim (Iraqi cement).Chemical analysis of the four types of cement were conducted in Baghdad central laboratory in National Center for Constructional Laboratories and Researches (NCCLR) and Al-qaim factory laboratory .The physical tests were conducted in the concrete laboratory of Al_anbar university-college of engineering including standard cement paste ,initial and final setting and compressive strength of cement mortars.The results indicate that the local cement (Kubaisa and Al-qaim) showed better performance than imported cement (Ismnta and Torab alsabia) in most tested chemical and physical properties .Kubaisa cement showed 34.1 % , 35.5 % higher compressive strength compared with Ismnta cement at 3 and 7 day respectively and lower loss on ignition and insoluble residue . The major compounds of Kubaisa cement were nearest to those in typical cement. For sulfate resisting cement , Al-qaim cement showed 13.3 % higher compressive strength at 7 day and lower percentage of C3A (1.95%) . Torab alsabia cement exceed the limits of Iraqi standard I.O.S No.5 1984.
Polyethylene terephthalate (PET) fiber is a green-friendly fiber that is capable of enhancing the mechanical properties of wet-mixing shotcrete. The main purpose of this study is to see how varied volumes of waste plastic fibers (WPF) affect the flowability and mechanical properties of wet-mix shotcrete. For this aim, a variety of experimental tests based on WPF content were chosen. Fresh and mechanical tests included slump, T500, density, compressive strength, and splitting strength were applied. The results shown a improved in shotcrete performance as the WPF content increased. Among all fitting correlations, density and compressive strength revealed the strongest linear ship association. Due to greater interlocking between WPF and concrete matrix, WPF was a major use in enhancing splitting tensile strength. WPF had the most influence on splitting strength, with 23–31 percent, 7–23 percent, and 6–38 percent for 7, 14, and 28-day, respectively.
The researches in Iraq has expanded in the field of material technology involving the properties of the light weight concrete using natural aggregate aviable in westran of Iraq. Researches work on porcelinite concrete has been carried out in several Iraqi Universities. The study is deals with mechanical properties of porcelinite aggregate concrete by casting (273) different specimens. These properties are, compressive strength, flexurale strength, splitting strength, static modulus of elasticity and absorption. The results indicated that the structural light weight aggregate concrete produced from local porcelinite aggregate is suitable to used as a structural concrete, it can produce structural light weight concrete of compressive strength varies from (23.0 to 29.8) MPa with the density ranges from (1745 to 1855) kg/m3, by using cement content about (550 and 650) kg/m3.Such concrete exhibited good mechanical properties. It gave the values of splitting tensile strength, modulus of rupture and modulus of elasticity, 75%, 90% and 60% from those of normal weight concrete respectively owning the same compressive strength and meeting the requirement of ACI-213
In this paper, the laboratory experiments works were conducted to study the effect of adding recycle waste plastic as polyethene terephthalate PET fibers on the fresh properties as the slump test and hardened properties as a compressive strength, splitting strength, elastic modulus, ultrasonic pulse velocity (UPV), density, absorption, voids, flexural toughness and flexural rupture for the normal concrete. The parameter of this paper included percentage of fibers content (0%, 0.5%, 1%, and 1.5%). The geometric design of the PET fibers was a strip with dimensions 4mm width, 70mm length, and 0.035mm thickness. The aspect ratio of the PET fibers in this work was about 50. The results showed that the PET fibers improving the most properties of the normal concrete and on the other hand there is negative effect on some properties of concrete. There is a significant increase in flexural toughness, about 21.2%, while the compressive strength and splitting were increased by 5% and 18.8%, respectively. Besides this improving, using PET fibers conform to the principle of sustainability, which is reducing the pollution and the cost of waste plastic disposal. It’s observed that properties of concrete as a static modulus of Elasticity and density were decreased with the fiber percentage increased
Nonlinear numerical analysis of nine reinforced concrete beams with dimensions (150 x 200 x 1200) width, height and length, respectively, was carried out through the finite element theory using the ANSYS software (version 15) to know the effect of different properties of layers in the one beam on the flexural behavior of reinforced concrete beams. The beams are consisting from two layers for the one cross-section. three beams are similar properties layers and the other six are with different properties layers. The beams differ among them depending on the percentage of Polyethylene terephthalate (PET) fibers added, the location of the fibrous concrete layer as well as the thickness of the layer. PET fibers were added in proportions (0%,0.5%, and 1%) from volume of the one layer, with dimension (50 x 4 x 0.3) mm length, width, and thickness respectively. All beams are reinforced with steel reinforcement (6 mm diameter at the top, 10 mm diameter for reinforcement against shear and 12 mm diameter in the tension area). The mechanical properties of each type of mixture have been studied. It was found that the different properties of the layers significantly affected the flexural behavior of reinforced concrete beams. Also the results of the numerical modeling were very close to the laboratory results obtained from the practical study, where the largest difference between the two studies was 8% and 11% for the load and deflection respectively at the ultimate point
Fresh and hardened properties of self-compacting concrete was experimentally examined by replacing different percentages of cement by soft clay powder, which resulting from crushing the wastes of clay bricks. Three percentages (5%, 10%, and 15%) of cement were replaced with clay powder to study their effect on the properties of cement mortar and concrete of Grade (C35) in both fresh and hardened states. It was found that development rates of the compressive and tensile strengths for the mortar between ages of 7 to 28 days, decreased with increasing the percentage of the clay powder. Compared to the mix without clay powder, it was found that replacing (5%) from the cement causes a significant increase in the workability of the self-compacting concrete and the properties of the resulting hardened concrete such as compressive strength, tensile strength, and modulus of elasticity. While using (10%) and (15%) of the clay powder causes a significant decrease in the workability of the fresh concrete and the properties of the hardened concrete compared to mix without clay powder.
This study presents an investigation of the mechanical properties of normal concrete reinforced with discarded steel fibers (DSFs) resulting from tire manufacturing. DSFs were added to concrete in two different volume fractions of (0.25 %, and 0.5 %), and these fibers have dimensions of (40 mm length×0.92 mm diameter). The results showed that the compressive strength of the concrete was enhanced by (8.8%, and 3.3%) by adding of DSFs. However, the workability of concrete decreased at all added ratios. While the density is slightly changed. Also, the results indicate that the modulus of elasticity shows slight increases by (3.06%, and 2.25%). Additionally, the incorporation of DSFs improves the splitting tensile strength and modulus of rupture significantly. For concrete mixes having volume fractions of 0.25% and 0.5%, the splitting tensile increased by (7.89%, and 23.68%), and the modulus of rupture increased by (6.67% and 25.58%), respectively. It was concluded that using this type of discarded fibers can improve the mechanical properties of concrete as an alternative type for other types of industrial fibers.
This study presents an experimental research of Self-Compacting Concrete (SCC) properties containing waste plastic fibers (WPF). Adding waste plastics which resulting from cutting PET bottles as fibers to SCC with aspect ratio (l/d) equal to (28). To illustrate the effects of WPFs on the SCC, the current study was divided into two parts, the first part shows the effect of adding plastic fibers on the properties of fresh SCC, which include the ability flow, spread, passing and resistance to segregation, and the second part to evaluate the properties of hardened (mechanical) destructive and non-destructive, which include compression strength, flexural strength and ultrasonic pulse velocity test. One reference concrete mix was conducted and eight mixes contain WPF has been producing self-compacting concrete mixers containing a different volumetric ratio of plastic fibers (Vf) % percentages (0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75, 2) %. Three cubes samples were prepared for testing the compressive strength, three prisms were prepared for the test modules of rupture, one cylinder were prepared testing the modulus of elasticity. The experiments show that adding plastic fibers to SCC leads to an increase in the compression strength and modulus of rupture at 28-day as follows (42.30)% and (73.12)% respectively for mix ratio (1.5)% in comparison with the reference mix, which represent the best ratio of fibers, as such the results of testing the fresh concrete containing waste fibers showed that adding these fibers led a reduction in workability for SCC.
AbstractThis study aims to investigate the properties of SCC produced by locally availablematerials , and attempts have been made to increase the range of grading of fineaggregate, with fineness modulus ranging from (1.5 to 4.1) , and to study the effect of themaximum size of coarse aggregate . It also aims to study the influence of High ReactivityMetakaolin (HRM) as a partial replacement by weight of cement on the properties of freshand hardened SCC, 24 different mixes of SCC are prepared .8 mixes are considered asReference mixes which are used for comparison purposes. To determine the workability,different test methods were adopted such as slump flow, V-funnel, and L-box tests. Whenfineness modulus of fine aggregate and maximum size of coarse aggregate increase,flowability, passing ability and segregation resistance decrease as compared with smallmaximum size of aggregate and other fineness modulus. Further more, the inclusion of10% HRM as a partial replacement by weight of cement leads to decrease flow ability andincrease of viscosity. The fineness modulus (3.1) of fine aggregate gives better resultsthan other fineness modulus. The results obtained from this study, also show that it ispossible to produce SCC from local available materials which satisfy the requirement ofthis type of concrete. Moreover, the results show the possibility of using different gradingof fine aggregate with fineness modulus ranging from (1.5 to 4.1) and the effect ofchange in fineness modulus is not significant on hardened concrete properties , while it ismore significant on fresh concrete properties .
The main objective of the present study is to maintain clear environment by using natural fibers that not cause pollution. Two types of Jute fibers as mat were used to produce ratting polyester composites after treating these fibers with Iraqi dolomite of 0.2, 0.5, 0.7, and 0.9 percentages % where, eight specimens were prepared. Manual casting used to prepared these specimens by using fibers of 2.8 mm diameter between two layers of Resin for all specimens. Mechanical properties tests includes creep, tensile, and hardness by Shore method where best results of creep and tensile strength reduction are given with 0.9% of Iraqi dolomite. Hardness proportional with concentration of dolomite. Physical properties tests includes color, yellowness of color, were the samples exposed to U.V of 254 nm short length wave for 150 hours. The Jute fibers affected the color while the dolomite effects were inconsiderable, also the absorption of acidic and base solutions were proportionate reversely with increasing of dolomite and fibers' mat percentage. In biological tests, the Fungus growth on composite body decreased with increasing dolomite percentage and no great lost of weight. The present study shown that the Jute fibers in the composite body and concentration of Iraqi dolomite improve the mechanical, physical, and biological properties of polyester Resin composites with Jute fibers.
The problem of discarded tires has received a lot of attention from many authors. Incorporation of rubber aggregate recycled from waste tires is one of the solutions to this issue. This research is based on evaluating fresh and hardened properties such as slump flow, T500, segregation resistance, and L-box tests, compressive strength, impact resistance, and flexural toughness. Rubber aggregate replacements in the self-compact concrete mixes was 10% by volume of fine aggregate. Additionally, both PET and steel fibers are utilized at a volume rate of 0.25%.The outcomes indicate that introducing rubber declines rheological and hardened properties, whereas incorporating hybrid fibers enhances hardened properties such as compressive strength, impact energy, and flexural toughness. The best increase impact energy was obtained at roughly 166.6% when 0.25% hybrid fibers and 10% rubber were used. 74.21 was the greatest increase in flexural toughness when 0.25% hybrid fibers (SCCH3) were used. As for the compressive strength, it was the highest by about 11%.
The performance of the structural materials (concrete and steel reinforcement) and the behavior of the structural members after they were exposed to high temperatures have been considered the main topics of the current literature review. All varieties of concrete mixtures lost their compressive strength after 300˚C, even though there was no discernible strength loss between 150 and 300˚C. It was also discovered that the heating time had no appreciable impact on the strength loss when the exposed to heat less than 300 ˚C. Above 300 ˚C. Concrete begins to lose strength after being exposed for longer than one hour; the greatest loss of strength occurs during the first and second hours of exposure. Both the cured cement paste and the aggregates undergo chemical and physical changes at temperatures ranging from 600 °C to 900 °C. The 5% weighted rice husk ash (RHA) blended concrete still had an advantage in compressive strength, over the concrete when subjected to temperatures up to 700 C for two hours. Adding more recycled glass and ceramic particles to regular concrete increases its overall compressive and tensile strengths. Concrete becomes more durable and has fewer cracks when there is a higher replacement rate for ceramic and glass particles. The splitting tensile strength decreased with increasing temperature, changing from 60% to 70% of its initial strength after 600 °C. In this review, the better performance of concrete than the other concrete in terms of mechanical, physical, and durability properties at both room temperature and high temperature were concrete with 10% waste glass powder (WGP) substitution as a partial of cement and 10%–20% crushed glass (CG) substitution as a partial of aggregate .
The aim of this research is to produce lightweight cement mortar with properties better than reference ordinary cement mortar. Porcelanite stone were utilized as lightweight aggregate with a volumetric partial substitution of fine aggregate. The process includes using different percentages (5, 10, 15 and 20 %) of pre-wetted (24hr.) porcelanite to produce lightweight mortar with internal curing. Water curing was used for reference mortar mixture and air curing for the other mixtures of porcelanite substitution. Compressive strength, flexural strength, density and ultrasonic pulse velocity for different ages (7, 14 and 28 days) have been tested. The results show an improvement in the properties of cement mortar especially in replacement percentage of 10 %.
Abstract: The presented investigation studies the effect of steel fiber content on the dynamic properties of High Performance Steel Fiber Concrete by using non-destructive testes; Vibration tests (Electrodynamics tests) were used to obtain the dynamic modulus of elasticity, dynamic shear modulus (modulus of rigidity), damping capacity, and dynamic Poisson‘s ratio. The results demonstrated in general an improvement in dynamic properties, which were tested for example, the percentage increasing in compressive strength relative to the reference concrete were 2.5%, 6.6%, 5.8% for High Performance Concrete (HPC) with 0.5%, 1%, and 1.5% steel fiber by volume of concrete respectively.
This study concern with a new technology to modified the compressive strength of the thermo brick which have a main role in construction field. This research using a new local cheap additives called (tar) which is available in Iraq (Kirkuk area). The experimental program have include three type of thermo brick available in local market (Iraqi, KSA, and Kuwaiti) and these type are common used in south area of Iraq especially Basrah City. The sample has exposed to the steam of tar in different temperature. Four affecting factor are studied carefully on compressive strength of brick including, tar , brick manufacture type, number of exposing faces of brick, and the age of brick after finishing expose of brick to the tar steam. The result shows maximum compressive strength conducted are 4.4 MPa when two faces expose to tar and two hours’ time of exposing ( one hour for each face) and the modified percentage was 62% compared with reference sample (KSA type). The improvement in compressive strength of Iraqi type and Kuwaiti were 27% and 45% respectively. Furthermore the improvement of compressive strength with same condition aforementioned but for one hour exposing time (half hour on each face) are 37.5%. The chemical properties also has conducted in this study.
This study program has been conducted to investigate the influence of adding waste plastic fibers (WPF) resulting from manual cutting for bottles used in the conservation gassy beverage on different characteristics of ordinary concrete. Cutting plastic waste by volumetric rates ranging between (0.5%) to (2%) was approved. Reference mix was produced for comparison. Tests were conducted on the models produced from waste plastic fiber concrete like compressive strength, flexural strength and splitting tensile strength. The analysis of the results showed that the use of plastic waste fibers (1%) has led to improve the properties of flexural strength and splitting tensile strength compared with reference concrete .When the( 0.75%)WPF ratio improved the compressive strength as compared with the control specimen . Compressive strength in (28 days) with fiber ratio (0.75%) WPF is higher than equal (5.1%) from compressive strength in (28 days) of reference concrete. Volumetric ratio (1%) WPF can be also observed that each of the flexural strength and splitting tensile strength increases equal (12.5 and 12.5%) respectively, from flexural strength and splitting tensile strength for the reference mix at(28day).
This research includes producing compacted concrete by rolling method and the possibility for using in highway construction field with studying the influence of adding waste plastic fiber resulting from manual cutting for bottles used in the conservation gassy beverage on different characteristics of this type of concrete. For the purpose of selecting mix proportions appropriate for rolling compacted concrete (RCC). Approved design method for ACI-committee (5R-207 .1980) was selected for this research. Destroying plastic waste by volumetric rates ranging between (0.5%) to (2%) was approved. Reference mix was produced for comparison. Tests were conducted on the models produced from rolling compacted concrete like compressive strength, flexural strength and split tensile strength. The analysis of the results showed that the use of plastic waste fibers (1%) has led to improve the properties of each of the compressive strength and flexural strength and split tensile strength compared with reference concrete. Compressive strength in 28 days with fiber ratio (1%) is higher than (52.15%) from compressive strength in 28 days of reference concrete. It can be also observed that each of the flexural strength and split tensile strength increases by (17.86, 25.61)%, respectively, from flexural strength and split tensile strength for the reference mix
This research include the study of flexural behavior of polymer modified concrete beams containing waste plastic fiber (WPF). Fifteen reinforced concrete beams are moulded of (100*150*1300) mm dimension with different steel reinforcement ratio (ρ). These steel reinforcement ratio were (0.0038, 0.0207 & 0.0262). Styrene Butadine Rubber (SBR) was added as cement replacement by weight equal to (5%). Reinforced concrete beams classified in to five groups, each contains three beams with different (ρ) value. The first group conducted of reference concrete mix , the second group made with SBR modified concrete, while the three remaining groups were make by PMC containing (WPF) with volumetric ratio equal to (0.75, 1.25 & 1.75)%. This study includes compressive and flexural tests for concrete which was used in this research, load deflection relationships, the moment at mid-span with deflection and ductility were established. The results prove that, polymer modified concrete wich content waste plastic fiber has compressive and flexural strengths more than reference mixes as well as the PMC beams wich content waste plastic fiber have a stiffer response in terms of structural behaviour, more ductility and lower cracking deflection than those made by reference concretes and that refer to good role of styrene Butadiene Rubber (SBR) polymer and plastic fiber on the properties and behaviour of reinforced concrete beams.
The concept of sustainability was developed in the last years and included the construction industry to solve the issues that pertaining by high consumption of natural sources, environmental pollution and high amount production of solid wastes. On the other hand, the plastics generation is growing exponentially every year, especially, types of Polyethylene Terephthalate (PET) that are used to produce soft drinks bottles, this study attempts to apply the concept of sustainability and reduce the environmental pollution by cutting the plastic bottles (PET) as small fibers added to the ordinary concrete to improve the shear and tensile strength of reinforced concrete beams. For this purpose, the experimental work was carried out to study the effect of waste plastic fibers (PET) on the shear behavior of seven reinforced concrete beams with dimensions of (100×150×1200) mm that were designed to fail in shear, the fibers percentages that were used in this study are (0.25, 0.5, 0.75, 1, 1.25 and 1.5%). Also, the influence of Polyethylene Terephthalate (PET) fibers on the mechanical properties of concrete was studied such as: workability, compressive strength, splitting tensile strength, static modulus of elasticity and ultrasonic pulse velocity.
Abstract :- For improving the properties of asphaltic cement several materials such as sulfur, rubber, carbon black, polymers….etc. are used for this purposes. In this study low density Polyethylene (LDPE) used at different percentage (0%, 1%, 3%, 5% and 7%) by weight of the asphaltic cement and then the changes in the properties are evaluated by pentration test (ASTM D-5), softening point test (ASTM D-2398), and Kinematics viscosity test (ASTM D-2170). Temperature susceptibility was evaluated by using Penetration vescosity number ( P.V.N ). In addition to that stiffness modulus of asphalt cement was predectied by using van der pole’s nomograph. The study showed that the LDPE increase the hardening of asphalt cement at different percentage except at (1%), and decrease the susceptibility of asphaltic cement to temperature.
Foamed concrete (FC) is a type of lightweight concrete characterized by a high void space ratio and cementitious binders. In this research, the fresh and mechanical properties of fiber-reinforced modified foamed concrete (made with fly ash, silica fume, and superplasticizer) with a density of 1300 kg/m³ were studied. Carbon fibers of different lengths (12 mm, 20 mm, and 28 mm) were introduced in two ways: as single fibers (12 mm) and as hybrid fibers combining lengths of 20 mm and 28 mm.
The results showed that the compressive and split tensile strengths increased by approximately 43% compared to the control mix (modified with additives) when using a single fiber of 12 mm at a volume proportion of 0.4%. In contrast, using hybrid fibers resulted in increases of about 65% and 66% in compressive and split tensile strengths, respectively. When compared to the single fiber method, the hybrid approach improved compressive and split tensile strengths by about 15% and 16%, respectively.
The gypseous soils are distributed in many locations in Iraq. The Engineering properties of such soil will be changed when it is wetted and it leads to failure which causes danger on the structures built on. This reason needs to study its properties and to find the way to treat it. In this study, natural properties of soil prepared from Samarra-Salah al deen governorate were studied. The gypsum content of soil is about 32%. To improve this soil, many trials were carried out on the soil by additive of Portland cement and calcium chloride. For the importance of the compressibility of the soil, the effect of the additives were studied and it is found that addition of 3% of cement or 5% of calcium chloride will improve the soil compressibility.
SUMMARY This research work includes three main experimental stages. The first stage includes the production of foamed concrete. It is divided into two parts; in the first, mixing design (determination of the proportions of the raw materials) according to the required density was presented and in the second part, the mixing procedure has been illustrated. The second stage includes preparation of samples,(i.e. molding, finishing surface, removal from molds and curing). The third stage includes several tests to estimate properties of the final product and factors influencing them . These properties include density , compressive strength , splitting tensile strength and flexural strength. For foamed concrete with 800 kg/m3 density, the 28-day compressive strength is from (1.334 MPa) to (2.323 MPa), while with 1600 kg/m3 density, the strength is from (7.015 MPa) to (9.591 MPa). For 1600 kg/m3 density foamed concrete, the 28-day flexural strength range is from (1.08 MPa) to (2.205 MPa).
This study is the second stage of the paper “Study the Effect of Rubber Silicon on Physical Properties of Asphalt Cement”. This study took the effect of additives on asphalt mixture performance. Asphalt mixture has been designed by Marshall method for determining the optimum asphalt content and geophysics properties of mix according to ASTM (D- 1559 ). Rubber silicon at different percentage (1%, 2%, 3% and 5%) was added to asphalt binder and three specimens of asphalt rubber silicon mixture (ARSM) are prepared and evaluating according to Marshall method. Diametric tensile creep test ASTM (D-1075) at 60 Co used to evaluating permanent deformation and modulus of elasticity for ARSM. The study shown that the Rubber-Silicon has more effects increasing the marshal stability, air voids, and reducing the flow and bulk density compared with the original mix.. Increase the flexibility properties of the mix and this appear from reducing the permeate deformation at test temperature (60C), the reduction percent is about (30 to 70)%
1-AbstractThis research includes the variation effect of (W/C) water: cement ratio on the properties as compressive strength , flxural strength , density and workability of concrete contains low Polymer SBR ratio.1:2:4 (cement: sand :gravel) by weight mixes were used . The polymer was added as percentages of cement weight and it was 2%. Reference mix was made. Water cement ratio (w/c) were used are 0.2 , 0.3 , 0.4 , 0.5 and 0.6 respectively and 0.35 (w/c) was used for reference mix . The density of concrete varied between 2030 kg/m3 and 2360 kg/m3.
The super fine materials constitute that portion of mineral filler finer than 10 microns. The effectiveness of these materials comes from their relation with asphalt film thickness. Asphalt cement grade (40-50) has been used. Nibaay course aggregate and Thmail fine aggregate were combined to achieve the aggregate gradation confirms with the Iraqi Standard Specifications for dense graded mix. Six different types of filler from five locally different sources in Iraq had used and subjected to grain size distribution, specific gravity and chemical composition tests. To study the effect of super fine materials on the performance of HMA mixture, Marshall stiffness, Indirect tensile strength, Moisture susceptibility and Creep tests have been made. Statistical analysis for results has been made. The conclusions referred to the importance of super fine materials due to their effect on HMA concrete properties.
Extracted asphalt from the sulphate asphalt springs in Heet area was prepared to study its properties and its also involve the study of UV and IR spectra of the natural samples and compared to the spectra of similar petroleum samples taken from Al-DORA Refinery .The study shows that the properties of natural asphalt have a great similitude with the asphalt samples resulting from refining Iraqi petroleum. Analysis of UV and IR for the asphalt sample show the existence of heavy organic compounds, that’s found in asphalt extracted from refineries that used for building and construction and for road pavements.
AbstractThis study deals with establishing high-velocity impact properties of polymer –modified concrete (PMC) including Styrene-Butadiene rubber (SBR), with different weight ratios of polymer to cement: 4%, 8% and 12%. Steel fibers were also included. Sixteen (500mm) diameter, (50mm) thick discs for high-velocity impact tests were used. In addition compressive strength, splitting tensile strength, and flexural strength (modulus of rupture) were companionly recorded. In all the tests, concrete was with and without crimped steel fibers of ratio 1% by volume.In investigating high-velocity impact strength, the decrease in projectile penetration depth was (5-17%) and the scabbing area reduced (15-35%) over reference concrete.In studying PMC including 1% by volume steel fibers, an additional increase was observed in all properties. The increases were quite significant in high-velocity impact strengths. Further reduction was recorded in scabbing area of (64-95%) and penetration depth reduced (28-39%) over control specimens. The fragmentations were reduced also. The range of corresponding compressive was (48-64)MPa ,of splitting tensile strength (4.2-7.8) MPa, and of flexural strength (5-8) MP
This study addressed some important tests for concrete including thermal, acoustic insulation and some mechanical behaviour of concrete containing granular Polyvinyl Chloride (PVC) waste as a sand replacement. The PVC waste was collected from a plant of manufacturing PVC doors and windows, was used to replace some of fine aggregate at ratios of 2.5%, 5%, 7.5%, 10%, 12.5% and 15% by weight Properties that studied are thermal conductivity, acoustic insulation slump, fresh density, dry density, compressive strength, flexural strength, and splitting tensile strength. Curing ages of 7, 28, and 56 days for the concrete mixtures were applied in this work. From the results of this study, it is suggested that using of 12.5% fine PVC as a sand replacement by weight can improve thermal insulation to about 82.48% more than concrete without plastic waste Acoustic insulation is about 43.09% more than reference mix and it satisfies the requirement of ACI 213R 2014 for structural lightweight concrete.
To preserve the natural materials, applying the principles of sustainable engineering, to approach the principle of zero waste and to contribute the solution of the negative environmental impact of two decades, which is caused by excessive use of bottles of polyethylene terephthalate (PET) in packaging, has led to the approach of alternative, clean and innovative technologies aimed at recycling and reuse to address this environmental problem. Proposed re-use empty bottles as a way to get rid of them and benefit from them at the same time the way, this method through which the empty bottles cutting into fibres using these fibres made of PET to improve the properties of concrete. Percentage of fiber that has been used are 1%, 1.5%, 2%, 3%, 4%, and 5%. Suitable tests were performed to measure properties of concrete reinforcement by recycle PET fibre such as compressive strength, splitting tensile strength, four-point bending strength, modulus of elasticity and toughness index. Flexural toughness tests were performed to measure the ductility capacities of reinforced concrete members with recycled PET fibre reinforced concrete. The results obtained indicate Toughness index was enhanced by using PET fibre reinforced concrete specimens, compared to no ductility performance of concrete specimens without fibre reinforcement. A significant change in ductility was when observed PET used fibre with 3%.
Microbial-induced carbonate precipitation (MICP) is a fast-evolving technology for cementing sandy soils, improving ground, repairing concrete cracks, and remediating contaminated land. The current work thoroughly reviews various factors that can impact the effect of the MICP technology on geomaterials. These factors include the type and strain of the microbes, concentration of bacterial solution, cementation solution composition and concentration, environmental factors (temperature, pH level, and oxygen dissolved), and soil properties. It was found that the type and strain of bacteria, concentration of bacterial suspension, pH value, temperature, and the reaction solution properties are the most affecting factors in controlling the characteristics of the produced calcium carbonate, which in turn affects the degree of bonding between geomaterials particles. For an optimal implementation of the MICP in soils treatment, it appeared that for the most commonly used bacterial strains a temperature between 20 and 40 °C, a pH between 6.5 and 9.5, and a cementation solution concentration of 0.5 mol/L, are typically recommended.
The current research’s purpose is to examine how Ultra-High Performance Fiber Concrete (UHPFC) holds up in terms of strength and durability for strengthening purposes. For this reason, the experimental and the theoretical studies in this research attempted to assess different fresh and hardened properties of a variety of ultra-high performance combinations. Steel fibers were utilized to differentiate all of the program's combinations at percentages of 0.25 %, 0.5 %, 0.75 %, 1%, and 1.25 % by volume. Mini flow slump, compressive and flexural strength, ultrasonic pulse velocity, water absorption, and porosity tests were all used to examine the performance of the strength and durability of the material. The findings of this study's trials showed that steel fibers increased the strength of UHPFC. The steel fiber ratio of 1% gave the maximum compressive strength, whereas 1.25 percent yielded the highest flexural strength. Because the fibers function as a bridge, preventing internal breaking, the tensile test results were improved as the proportion of steel fiber rises. Through the use of the multi-objective optimization approach, the optimal ratio of fibers was chosen at the end of the laboratory work since it has the best durability and strength characteristics. Statistical software (Minitab 2018) was used to find the optimal combination of UHPFC that meets all of the requirements. The theoretical selected optimum ratio of 0.77% of fibers obtained from the optimization was evaluated and validated experimentally. The optimized mix provided 90.28 MPa, 14.6 MPa, and 20.2 MPa for compressive, splitting tensile and flexural tests respectively with better durability performance compared to other mixes prepared in this investigation.
The paper shows the final findings of the effect of metakaolin on the strengths properties of concrete exposed to crude oil. Sulfate resistance Portland cement of V type was used and specimens of concrete were adjusted and subjected to a solution of concentrated crude oil. However, the samples are cured in a control media at immersion ages of (28, 56 & 120 days) with ambient temperature, then samples have been kept in curing water for comparisons purpose as well. The results explain that the use of metakaolin reinforces compressive, flexural and splitting resistance of concrete which is exposed to crude oil. The compressive strength reduction increased from 8.0% at (28 days) to 37.7% at (120 days) curing for normal weight concrete (NW) whereas the concrete incorporating metakaolin (MC) has a reduction of 6.0% at (28 days) & 29.3% at (120 days). .
Slurry infiltrated fiber concrete (SIFCON) is a relatively new high performance material and can be considered a special type of fiber concrete (FRC) with high fiber content. The matrix consists of a flowing mortar or cement slurry that must penetrate well through the network of fibers placed in the mold. SIFCON has excellent mechanical properties combined with high ductility and toughness values. SIFCON a relatively new material, is composed of mud (cement or cement and sand), water, a plasticizer (water reducer), and fibers. All previous studies have used waste steel fibers, steel fibers and other fibers, but in this study, plastic fibers were made from polyethylene terephthalate (PET) by cutting carbonated beverage bottles. The main objectives of this study are: Determination the effect of the waste plastic fiber volume ratio on the strength and deformation of (SIFCON) samples under the influence of bending loads. Both flexural strength and toughness properties were determined by testing samples (100×100×400) mm at 28 and 56 days of age. The results obtained from these tests were compared with those performed on conventional tests. Aspect Ratio equal to (36.8) and three volume ratios (3%, 5% and 7%) of the total volume of the concrete mixture were used to add fibers with different volume ratios. A conventional concrete mix was created as a reference for comparison. Bending strength and fresh concrete tests were performed. And compared with the reference mixture and according to the analysis of the results. The results showed an improvement in bending strength .It was found through the flexural examination that the flexural strength of the mixture containing fiber percentage (7%) achieved the highest strength compared to the rest of the ratios used, compared with the reference mixture (Ref.) by (32.25, 27.5)% for ages (28, 56), respectively.
AbstractA geophysical study using seismic wave velocities data, including compressional and shear wave velocity (Vp and Vs) values, for 14 sites has been carried out. These sites are located within the Mesopotamian plain and surroundings. Both seismic and geotechnical data have been conducted by the National Center for Construction Laboratories and Research (NCCLR) in Iraq. Some geotechnical parameters have been deduced from seismic velocities either from Vp or Vs. Correlations between seismic velocities (Vp and Vs) and geotechnical properties have been derived. These relations show direct proportionalities between Vp and Vs with standard penetration test (SPT-N value). LiuefyPro software has been utilized for two selected Iraqi sites to investigate the liquefaction potential. Input data of the program will be based on those derived from the compressional and shear wave velocities. The application shows a total settlement for saturated and dry sand of 32 mm for the first site while no settlement has been indicated for the second site. It was found that the high value of both wave velocities for a cohesionless fully saturated soil gives an indication that this soil is unable to liquefy and settle under earthquake excitation and vice versa.
The accumulation of wastes, especially plastic and car tires, has become a major problem facing society today. Therefore, through this research, these wastes were recycled and used to improve some properties of concrete. Recycled crumb rubber from car tires was used instead of sand as a partial replacement of 10%. The substitution was done by two methods: random and equivalent size substitution. As well, 1%polyethylene terephthalate (PET) fiber was added by the volume of concrete to improve some properties of rubberized concrete. Compressive strength, ultrasonic pulse velocity test (UPV) were conducted in this study to investigate the efficiency of PET rubberized concrete, as well the impact resistance test was also conducted to investigated the ability of PET rubberized concrete in term of energy absorption. Slabs of size (50cm×50cm×5cm) were utilized for low velocity impact test. The results indicated there were a reduction in compressive strength and UPV results were observed in PET fiber rubberized concrete the reduction were (37.47% and 5.4%) respectively as compared with PETC mixture and the result of dynamic modulus of elasticity show the same pattern of UPV result , in contrast there was an improvement in the impact resistance when PET fiber and crumb rubber were used it increased by(117.63% and 52.9% ) for random and equivalent replacement respectively as compared with PETC.
Research in Iraq has expanded in the field of material technology involving the properties of the light-weight concrete using natural aggregate. Research work on porcelinite concrete has been carried out in several Iraqi Universities. However , despite the great practical importance of such concrete in construction fields ,very limited amount of work has been carried out to investigate the (shear strength) of structural light-weight aggregate concrete , therefore it is important to study the properties and their structural behavior. In this work an attempt is made to study shear strength of porcelinite reinforced concrete beams without (stirrups). The results have been compared with the results predicted by the equations of International codes, such as ACI 318M-02, BS-8110 codes and with some authors' equations as for, Hanson. The experimental results also have been compared with results obtained from normal weight concrete specimens that had been prepared for this purpose. The study mainly deals with the structural behavior of porcelinite reinforced concrete beams without stirrups, especially the shear strength, besides, the short-term deflection, strain and cracks. The variables are, compressive strength ranging between (23.0-29.8) MPa and reinforcement percentages ranging between (0.0174-0.0307). A total of 12 beams are tested; (9) are light weight concrete beams without stirrups and (3) are normal weight concrete beams, also without stirrups. The dimensions of all those beams are 135 * 260 * 1800 mm. The structural results more often, give values 2.9 times more than that of (ACI-02)
The research aims at revealing the morphometric characteristics of wadi Jbab Basin, which include areal ,relief characteristics, and the shapes of cross- sections of the valley. The hydrological properties of Jbab basin were studied to estimate the amount of water received by its catchment area during rain falls, thus, the appropriate places for the construction of dams and reservoirs for use in water harvesting can be determined. The area under study is located in Iraqi western plateau , between the latitudes of 33º 55' 45"N to 34 º 27' 50" N, and longitudes 41º 24' 30" E to 41º 43' 00" E. Remote sensing technology (RS) and geographic information systems (GIS) were used to reach the objectives of this research, so Digital Elevation model (DEM) for the year 2009 was brought to program (Arc GIS 9.3) and detected the basin and valley of Jbab automatically by using the hydrological analysis method. The area under study is characterized by the drought with a deficit of water in all months of the year where the highest in the month of July, amounting to 324.5 mm and the lowest in January, 10.92 mm. The geological formations prevail formations limestone, with sandy soil to sand-clay mixture, with lack of density in the vegetation. The average slope in basin of Wadi Jbab is 0.25 degree. There are five ranks of river, the sum of their tributaries 676 tributary within an area of 986.6 km ², and its perimeter is 214.3 km , it is also noticed the form of the basin tends to form a rectangle, with three places suitable for the construction of dams and reservoirs depending on the morphometric and hydrologic information that related to the area of research.
Abstract: This work investigates some properties of chopped worn-out tires concrete (Ch.W.T.conc.). It is a type of concrete characterized by the incorporating of Ch.W.T into the mixes as a partial replacement of volume of aggregate (sand and gravel of equal proportion). Three mixes of Ch.W.T conc. In addition to the reference mixes were selected, using Partial Replacement Ratio (PRR)of 30%, 40%, and 50%.The tests which were used in this study were: compressive strength, modulus of elasticity (static and dynamic), and impact resistance (low and high velocity). It was found that incorporating Ch.W.T in concrete effect on the properties of concrete, for example the percentage decreases in compressive strength were 41%, 46.7%, and 52.4% for concrete with 30, 40, and 50% Ch.W.T. PRR by volume of aggregate (50% sand, 50% gravel) respectively. However, it gave good indicator to be utilized as a new construction material in many applications.
ABSTRACT: Many of researchers study the uses of chopped worn-out tires as a replacement material to production special types of concrete. In presented work, the worn-out tires were used as fibers which have dimensions of 1×1×3 cm. The fibers used as a partial replacement from volume of coarse aggregate. Two mixes of fiber worn-out tires (F.W.T.) concrete in addition to reference mix were selected, using Partial Replacement Ratio (PRR) of 20% and 30%. The tests which were used in this study were: compressive strength, splitting tensile strength and flexural strength. It was found that incorporating of F.W.T. in concrete effected negatively on most properties of concrete, for example the percentage decreases in compressive strength relative to reference mix at 28 day were 20% and 27.3% for concrete with 20% and 30% F.W.T. by volume of coarse aggregate respectively. However, it gave good indicator to be utilized as a new construction material in many applications.
One of the most popular non- destructive techniques is ultrasonic pulse velocity (UPV) which used in assessment of concrete properties. A statistical experimental program was carried out in the present study to establish an accurate relation between the UPV and the concrete compressive strength. The program involved testing of concrete cubes cast with specified test variables. The variables are the age and density of concrete. In this research, all the samples were tested by direct ultrasonic pulse velocity (DUPV) and surface ultrasonic pulse velocity (SUPV) to measure the wave velocity in concrete and the compressive strength for each sample. An experimental study was conducted to compare between the velocities of ultrasonic waves that transmitted along the two paths; direct and indirect. A total of more than 150 cubes having dimensions of 150 mm side were prepared to conduct both non-destructive and the compressive strength (destructive testing). The results from experimental program were used as input data in a statistical program (SPSS) to predict the best equation, which can represent the relation between the UPV (direct, indirect), and compressive strength, a linear equation is proposed for this purpose. The UPV measurement and compressive strength tests were carried out at the concrete age of 7, 28, 56 days. A relationship curves were drawn between DUPV, SUPV, compressive strength and density. The mixes composition in this study consists of ordinary Portland cement, fine sand, gravel, super-plasticizer, and water. All the specimens were under (20) Cº. The statistical analysis revealed that the possibility in evaluating the properties of the concrete by using direct and indirect wave velocities
A series of experimental tests were carried out to investigate the behavior of high strength concrete filled double skin steel tubular (HSCFDST) columns. Fourteen column specimens were tested in the present study, taking into account the effects of the shape of column cross section (circular or square), the hollowness ratio, and the slenderness ratio. For comparison, two of the tested specimens were filled with normal strength concrete. It was seen that the ultimate axial strength of the square HSCFDST columns is greater than that for circular ones, in spite of that the sectional properties were approximately equal. Also, it was found that for both circular and square column specimens, the ultimate axial strength of HSCFDST columns was inversely proportional to their hollowness and slenderness ratios. CFDST column specimens filled with high strength concrete compared with those filled with normal strength concrete increased stiffness and ultimate axial strength, but give unexpected results for the ultimate axial strength, therefore the suitable choice for the section properties of the inner steel tube is required. The experimental results and analytical approach that developed by other researchers shown good agreement.
This work study the effect of partial replacement of cement by hydrated cement on some properties of cement paste and cement mortar such as normal consistency, initial and final setting time, compressive strength, and length change. The results show that pastes containing hydrated cement require more water than reference paste to give normal consistency. The results also show that the replacement by hydrated cement delay the initial and final setting time of cement paste. The delay in setting time increased with increasing the partial replacement by hydrated cement. Compressive strength test was carried out on (54) cubes of (50) mm side dimensions of mortars containing (5, 10, 15, 20, and 25%) of hydrated cement at (3, 7, and 28) days. They were then compared with reference mortar. The compressive strength results show that the compressive strength decreases with increasing the replacement percentage by hydrated cement at all ages. The decreases in compressive strength reached (23.05 %) when (25%) of cement was replaced by hydrated cement in (28) days. The results also show that the replacement of cement by hydrated cement increases the length change of mortars compared with reference mortar.
Concrete is by far the most widely used construction material now today. Foamed concrete is light building material with good strength as well as low thermal conductivity and easy workability; it is produced by either Mix Foam Method or Preformed Foam Method. Ultrasonic Pulse Velocity(UPV) is a non destructive technique involve measuring the speed of sound through concrete in order to predict concrete strength and to detect the presence of cracking, voids, decay and other damages. This research includes three main experimental stages:- The first stage includes the production of foamed concrete and it was divided into two parts, the first part, mixing design(determination the proportions of the raw materials) was presented in the second part, the mixing procedure has been illustrated. The second stage includes preparation of samples,(i.e. molding, finishing surface, removal from molds, and curing). The third stage includes several teste to estimate properties the final product and factors influencing them, these properties include density, compressive strength, and the ultrasonic pulse velocity. From the experimental work and at the same test's age, the compressive strength and the ultrasonic pulse velocity for foamed concrete with 800 kg/m3 density were respectively (2.38 MPa,1.56 km/s)and the compressive strength and the ultrasonic pulse velocity for foamed concrete with 1200 kg/m3 density were respectively (3.7 MPa,1.96 km/s) while it were (7.8 MPa and 2.12 km/s) for foamed concrete with 1600 kg/m3 density
Extracted asphalt from the sulphate asphalt springs in Heet area was prepared to study its properties and its also involve the study of UV and IR spectra of the natural samples and compared to the spectra of similar petroleum samples taken from Al-DORA Refinery .The study shows that the properties of natural asphalt have a great similitude with the asphalt samples resulting from refining Iraqi petroleum. Analysis of UV and IR for the asphalt sample show the existence of heavy organic compounds, that’s found in asphalt extracted from refineries that used for building and construction and for road pavements.
The problem of solid waste is being emerged increasingly due to the increased quantity of solid waste as a result of population’s increase .From the point of view of environmental and energy concerns, it is preferable to reuse the organic and inorganic components of solid waste in order to minimize the cost. In this investigation, the possibility of using solid waste ash (SWA) as a partial replacement of cement and its effect on the mechanical properties of concrete was studied. Samples of municipal solid wastes were collected were burring and changed to ash. A total of 50 cubes, 15 small cubes, and 30 cylinders, as well as 5 prisms were prepared .Various properties of solid waste ash are added to the cement mistures with percent's of 5, 10, 15 and 20 percent by weight of solid waste ash. A concrete mix with a percent solid waste ash was used as reference. Pozzolanic activities of all mortars, and setting times of all pastes, and workability of all mixes were investigated .Compressive strength, splitting tensile strength, absorption, and drying shrinkage for reference for reference and solid waste concrete specimens were investigated at various ages. Results demonstrate that the pozzolanic activity was within ASTM requirements for the cases of 5% and 10% ash replacement. For 15 and 20 percent replacement this activity was only slightly less than the ASTM value. The 90-day compressive strength rose, in comparison with control specimens, with 5 percent replacement and was only slightly lower at 10 percent replacement. In splitting tensile strength was at least equal to reference specimens for all replacement ratios. The rise in these values, over the reference specimens, ranged between 0 to 21 percent for the case of 20 and 5 percent replacement, respectively.
This research work includes production of new type of light weight concrete and studies the mechanical and thermal properties. Several proportions of raw materials were used to produce this type of concrete. This study is intended to produce light weight concrete with low thermal conductivity so that it can be used for concrete masonry units. Polystyrene aggregate was added as percentages by weight of cement to improve the thermal properties of this type of concrete .Mechanical , and thermal tests with difference ages were made in this work .For polystyrene concrete with polystyrene cement ratio (p/c) of (2.67 – 6 )% , the28-day compressive strength range is from (4.31 – 2.67)MPa, flexural strength range is from (3.05-1.719 ) MPa , density range is from ( 1493-1213 ) kg/m 3 ,and thermal conductivity range is from ( 0.91-0.782)% as a percentage by that of reference mix. The study show suitability of this type of concrete to be used in concrete masonry units of non-bearing walls.
In this study, the structural behaviour of RC-deep beams of glass fibre-reinforced polymer (GFRP) rubberized concrete is investigated. Rubberized concrete is manufactured by replacing fine sand aggregate with rubber crumbs in volumetric replacement ratios. The main variables were the crumb rubber content (0%, 10%, and 20%) and the main reinforcement ratio. Tested Six samples of deep beams with different dimensions (b = 150, h = 300 mm, L= 1400 mm) were under a four-point load until failure. The parameters under investigation were the mechanical properties of mixtures, load-midspan deflection curves, toughness, and the load-strain relationship. The results indicate that the increased crumb rubber content led to a decrease in the mechanical properties of rubberized concrete mixtures. It was found that the behaviour of all samples of rubberized concrete affected the deflection load curve, the ultimate load, and the increase in deflection. The sample R2-10% Rub showed the highest toughness among the tested samples, with an increase of 301.6% compared to the reference.
The most concerning issue confronting the planet these days is the ascent in Carbon dioxide (CO2) levels to record levels. The cement industries are answerable to between 6-8 % of worldwide CO2 emitting. In construction sectors, researchers tried to contribute in decreasing of CO2 in atmosphere produced by industry and using that was released in air. Accelerated CO2 curing is one of the methods used to get benefit from CO2 in the air. In this paper, CO2 concentration in addition to pressure, relative humidity and period of curing all had a significant influence upon the features of Cement – Based Composites. Results showed that using CO2 curing with different and specific properties of fibers (types, quantities, circumstances and lengths) improved the most mechanical properties and enhanced durability such as: strength, stiffness, ductility, toughness, porosity, and absorption.
In this study remote sensing was employed with Geographical Information System (GIS) for study the hydrochemistry properties for Habania Lake that is located on Euphrates river, where the use of traditional methods are not fulfill the demands for study quality and situation of water of great areas which need enough time and money . Analytic study was performed on hydrochemical aspect through samples of store water and make physical and chemical water tests with GIS to product layers represent place distribution nature of these elements on the whole area of reservoir through the use of satellite image. The present study concluded that the use of remote sensing , geographic information system and analytic study for samples was employed to study quality and situation of water .
Organic soils are problematic soil for various engineering applications due to their high compressibility and low shear strength which need to be improved. For many soil improvement techniques, using waste materials, such as fly ash (FA), is a practical and sustainable process. In this research, FA and geopolymer were used e used to reduce organic soil's compressibility. A one-dimensional consolidation test was performed to evaluate the organic soil's consolidation and compressibility properties. The geopolymer was prepared using 20% FA and of sodium hydroxide ratio and sodium silicate alkali solutions. The geopolymer specimens were first cured for 2 hours at 45 and 65 oC, then cured for further 28 days at room temperature. The consolidation test results showed that FA-based geopolymer is effective in stabilizing organic soils due to the observed improvement in the compressibility, consolidation, and permeability characteristics. The compression index decreased by 98.16%, and the permeability decreased by 95%.
The earth-fill dams are simple structures which are able to prevent the sliding and overturning because of their self-weight. Due to lack of suitable clay materials, the dams may be designed as zoned core which is composed of three vertical zones contains central impermeable core and two permeable shells on their two sides of the core. Impervious core is used in zoned earth dam to reduce the quantity of seepage through the body of the dam and to relief part of risk of piping and erosion in the downstream side. This study aims to study the soil properties that is used as a core of earth dam through a series of laboratory experiments that were carried out a several soil samples mixed with both lime and silica fume, in order to stabilize the soil. The process of stabilization aims to increase the soil strength and reducing its permeability and compressibility. Test results show that adding lime and silica fume to the soil decreases the permeability of soil with different cases of study, the percentage of decreases in case of standard compaction about (21%-90%) while in modified compaction test the permeability decreases in range (41.7%-91.3%). Also the unconfined compressive strength of the soil increasing significantly in both cases of compaction which were standard and modified. When add the materials, these values were increased in range (76%-90%) for samples from standard compaction test, while it being (0.21%-42%) in modified compaction test.
AbstractSolid waste data survey for the period from 1977 and 2002 has been collected andanalyzed, while the solid waste generated in six regions in Baghdad, which were selectedand estimated to be 1435 houses and 28643 households for the period 2000-2005 wasstudied. The growth of Baghdad's population, increasing urbanization and rising standardsof living have all contributed to an increase in both the amount and the variety of soliddomestic wastes.The amounts of waste generated and their sources, the type of materials in eachwaste stream, their properties, potential toxicity, and the hazards were evaluated. The lackof reliable time series on solid waste streams and rapid changes in the composition ofwaste streams are a serious impediment to setting priorities in solid waste management inBaghdad. The basic conclusions from this study are:-- The waste generated per capita in Rusafa, Kerkh and Baghdad increased from 0.32,0.46 and 0.354 kg/day in 1977 to 0.98, 1.37 and 1.11 kg/day respectively in 2002.- Municipal wastes in Baghdad have a higher proportion of organic matter and ash,higher moisture content and lower paper content. Organic matter and ash may account for between 76-89% of all wastes in low income settlements. Thepercentage of organic waste decreased from 91.17% in 1977 to 64% in 2002, whileplastic, paper, textile, metal, wood and glass wastes increased slightly at the sameperiod.- Collected solid wastes amounts were less than evaluated solid wastes amountsduring the period from 1977 to 2005 because of war and economic sanction.Keyword: SolidWaste management, Waste composition and characteristics, Baghdad city
This study describes the results of tests carried out in order to investigate the structural behavior of reinforced concrete beams containing Expanded Polystyrene (EPS) stabilized Polystyrene beads. Three concrete mixtures were used with densities 350kg/m3, 500 kg/m3 and 600 kg/m3. A total of 12 beams, with control specimens were tested after 28 days of curing immersion in water. Four types of steel reinforcement were utilized: Two ratios of tensile steel reinforcement without compression steel and the same two ratios of tensile reinforcement with compression steel and stirrups. The beams were tested under 4- points loading up to failure. The main variables considered in this study were: different types of Izocrete densities and types of reinforcement steel bars. The results indicated that the amount of polystyrene beads significantly affects the strength of the concrete produced. In general, it can be observed that the compression, tensile and flexure strengths decreased as the EPS beads contents increased, and the moment capacity of the beams reduced with the increase of the beads ratio.The load deflection behavior of the Izocrete beams were similar to other lightweight concrete beams .The failure in most of the beams was initiated at the compression region undergoing large deformation due to the high compressibility of the material.
This research includes study the effect of fineness upon physical properties of cement mortar where use ordinary Portland cement with fineness (300 m2/kg) as reference mixture which denoted by symbol (M1), and then produce with flowing fineness (350,400,450 and 500 m2/kg) which denoted by ( M2, M3, M4, M5 ) respectively . The results of study show that increasing in fineness makes an increase in water quantity that requires for consistence of standard paste and the ratio of above mixes with reference mixture (2%,5%,7%,11%)respectively, although the increasing in density for all ages and increasing in compressive strength in early age, the increasing ratio in 3 days age was ( 45% , 50% , 60% , 70%)respectively .this increasing in fineness makes increasing in ratio of flow as compared with reference mix(16%, 25%, 50%, 66%) respectively
A study examined the ductility and toughness properties of beams made of reinforced concrete, including foamed, normal, and hybrid beams. Nine reinforced concrete beams were produced: three foamed concrete beams, three normal concrete beams, and three hybrid concrete beams. Each beam possessed identical rectangular cross-sectional dimensions of 1500 mm × 250 mm × 150 mm. The flexural parameters (ultimate load, ductility, deflection, and durability) were assessed for each type of concrete utilized. The study's results showed that the load-bearing capacity of hybrid concrete beams was comparable to that of normal concrete beams, whereas foamed concrete beams exhibited slight improvement in their ability to carry loads. The ductility of reinforced foamed concrete beams was lesser than that of normal concrete. For over-reinforced beams, the ductility of hybrid concrete beams showed a significant improvement of 61% compared to foamed beams and an even more significant increase of 91.7% compared to normal beams. Furthermore, the hybrid concrete beam with over-reinforcement had a flexural toughness of 18.7% greater than the normal concrete beam. Suggested that a hybrid section comprising conventional and foamed concrete be utilized to decrease ductility and improve stiffness.
This research includes the study of improving impact resistance of concrete using styrene butadiene rubber (SBR) with different weight ratios of polymer to cement 3%, 5% and 10%. Two series of polymer modified concrete (PMC) were produced the first level I with moderate compressive strength and the other level II with higher compressive strength. Cubes, prisms and panels were made as follows: Results showed an improvement in impact resistance of polymer modified concrete (PMC) over reference concrete in low-velocity and high-velocity impact properties. In conducting low-velocity impact tests, method of repeated falling mass was used: 1300gm steel ball falling freely from three heights 2400mm, 1200mm and 830mm. In high-velocity impact tests, shooting of 7.62mm bullets was applied to slab specimens from distance of 15m. The improvements were significant in low velocity impact resistance. The maximum increases were (33.33%, 75% and 83.33%) at ultimate failure for falling mass heights 2400mm, 1200mm and 830mm respectively. In high-velocity impact strength tests, maximum reductions recorded in spalling area were (18.5% and 27%) for polymer modified concrete (level I) with moderate compressive strength and polymer modified concrete (level II) with higher compressive strength.Maximum reductions recorded in scabbing area were (11.42% and 35.6%) for polymer modified concrete (level I) with moderate compressive strength and polymer modified concrete (level II) with higher compressive strength, respectively.
Determining building materials and their types and determining their effect on concrete properties are consistent with the technical and design variables of buildings. From this point of view, the research came to include theoretical studies and empirical tests for some materials, focusing on the aggregate as a basic material involved in the formation of concrete. The first part includes the introduction, research problem, assumptions, importance, and purpose of the research. the second part was to conduct practical experiments by designing different concrete mixtures in the mixing ratios and the type of aggregate until results were reached regarding the resistance of the concrete that was produced as a result of the difference in densities between ordinary aggregate concrete and lightweight aggregate concrete. Through that, for example, the lightweight aggregate with an age of (7) days and a mixing ratio of (1: 2: 4) gave strength to the models used (19.58) Mpa, and for the same mixing ratio and at an age of (28) days, it gave durability ( 22.83) Mpa. When the mixing ratio was changed to (1: 1.5: 3), it was (25.74) MPa and (32.34) MPa at the age of (7) days and (28) days, respectively. These results give an accurate indication that the aggregate is light in weight with similarity to the ordinary aggregate in obtaining concrete with a bearing strength within the approved specifications without guaranteeing the environmental treatments and the resulting loads
This paper presents a new and improved design procedure in shear for reinforced concrete normal members without shear reinforcement (stirrups) using the techniques of dimensional analysis and multiple regression analysis. A total of 334 data sets have been obtained from existing sources of reinforced concrete shear test results covering a wide range of beam properties and test methods. The proposed equation is applied to existing test data for these reinforced concrete normal beams (shear span to depth ratio (a/d) greater than or equals to 2.0) and the results are compared with those predicated by ACI and BS codes. It can be also noted that the test results are in better agreement with the proposed cracking shear strength equation because of the excellent correlation between experimental results and theoretical values.
This paper includes an analysis to asses the behavior of stone columns using the finite element method and to provide bases and information helping geotechnical engineers to design foundations resting on weak soils reinforced with stone column. The axisymmetric quadrilateral element is adopted in the finite element program to simulate the soft soil and the stone column while the one-dimensional element is used to simulate the soft soil and the stone column-soil interface. The nonlinear inelastic stress-dependent model is used to simulate the behavior of the soil and the interface throughout the incremental loading stages adopting nonlinear parameters obtained from triaxial and direct shear stress. The analysis is carried first on a selected basic problem, to clarify the nonlinear of the column, in which a selected geometry, boundary condition, and material properties for both soil and interface as chosen. The rest of the analysis is grouped into the effect of some of the parameters concerning the geometry of the stone column and the material of column and adjacent soil are investigated. It was found that the increase in stone column length and in relative stiffness of stone column material to soil play an important role in increasing ultimate capacity of the stone column and in reducing settlements.
Abstract:Many of researchers study the uses of chopped worn-out tires as a replacementmaterial to production special types of concrete. In presented work, the worn-out tireswere used as fibers which have dimensions of 1×1×3 cm. The fibers used as a partialreplacement from volume of coarse aggregate. Two mixes of fiber worn-out tires(F.W.T.) concrete in addition to reference mix were selected, using PartialReplacement Ratio (PRR) of 20% and 30%. The tests which were used in this studywere: compressive strength, splitting tensile strength and flexural strength. It wasfound that incorporating of F.W.T. in concrete effected negatively on most propertiesof concrete, for example the percentage decreases in compressive strength relative toreference mix at 28 day were 20% and 27.3% for concrete with 20% and 30% F.W.T.by volume of coarse aggregate respectively. However, it gave good indicator to beutilized as a new construction material in many applications.
ABSTRACT: In this study an attempt is made to derive governing equations satisfying equilibrium and compatibility, for multi-layer composite beams with different layers, materials properties and dimensions for linear material and shear connector behavior in which the slip (horizontal displacement) and uplift force (vertical displacement) are taken into consideration. The analysis led to a set of number differential equations containing derivatives of the fourth and third order, number of these equations depending on number of layers forming the beam section. The theory developed for three, four, and five layers. A general formula were derived to find the governing equations (compatibility and equilibrium equations) for any layered composite beam.
This research includes study of the of effect of adding sulphur, which is obtained from Samrraa factory on the properties of concrete like compressive strength, flexural strength and splitting tensile strength. The concrete mixes were: (1:8.5:8.5:7), (1:8.5:8.5:9), (1:8.5:8.5:12) and (1:1.5:3:0) (cement: sand: gravel: sulphur) respectively. The results refer to increasing of compressive strength , flexural strength and splitting tensile strength with increasing of sulphur ratio but increasing decreased at age (28)day with respect to ordinary concrete (sulphur ratio=0%).
The main rule of this search is determining the effect adding various types of fiber to normal concrete mixes on performance normal strength concrete ,it has been used three types of fibers (glass, short steel fibers& long steel fibers)with different contents in mixes(0.5,1.0&1.5%) respectively. It had been cast (210) cubes with dimensions (100×100×100m) mm,(160) cylinders with dimensions (100×200) mm , All concrete specimens heated under different temperatures (100,200,300,400,500 &600 C°) at age 28 days, so that it had been stayed under specified temperatures about two hours then , cooled in naturally in room temperatures and tested in compressive for cubes &splitting strength for cylinders. The results stated that the fiber improve the compressive strength under fire temperatures about (87%) compare with reference mixes, and the fiber glass take little differences than steel fiber in splitting strength when its content reach (1.0,1.5%) respectively and using this types of fibers improved the properties of concrete against the fire.
Abstract: This research is devoted to investigate the behavior of steel fiber reinforced concrete members subjected to blast loading. Material nonlinearity due to nonlinear response of concrete in compression, tensile cracking, strain softening after cracking, crushing of concrete and the yielding of steel reinforcement are considered. Three-dimensional finite element is used with eight and twenty-node are hexahedral isoparametric brick element for the spatial discretization. In the idealization of the reinforced concrete structures, the steel reinforcement is incorporated in the concrete brick element as a smeared layer assuming perfect bond. Concrete is modeled as an elasto-viscoplastic model in compression and as a linear elastic strain softening in tension. The steel reinforcement is assumed to have uniaxial properties in the direction of the bars. A classical elasto-viscoplastic model is used to model the reinforcement. Some numerical problems are solved and compared with other studies to verify the applicability and accuracy. Parametric study to investigate the effect of some important parameters has been carried out. The results showed that the use of steel fibers in members subjected to dynamic loading lead to better performance.
A BSTRACT: Leaching effects on permeability and compressibility characteristics of undisturbed sandy gypseous soil were investigated in this study. Time, stress level, strain, leachate condition and flow velocity were considered. The loading, leaching and permeability measurements were carried out utilizing the constant head pereameter with special modifications. Test results show that salt leaching and thereby leaching strain is a time dependent process. Also as leaching strain continued coefficient of permeability decreases.
The spillway is an important structure in the dams, used to pass the flood wave to the downstream safely. In the past decades, Computational fluid dynamics (CFD) has evolved. Research findings have shown the CFD models are a great alternative for laboratory models. According to it, the flow pattern over ogee spillways can be studied in a short time and without paying high expenses. Because the flow over the ogee spillway is turbulent and has a free surface, its properties are complex and often difficult to predict. Therefore, the present paper focuses on the study of turbulence closure models including the standard k-ε, RNG k–ε, k–ω, also, the large-eddy simulation (LES) models, to assess their performance to simulate flow over the spillway. The Flow-3d software with the volume-of-fluid (VOF) algorithm is applied to obtain the free surface for each turbulence model. The results of the analysis show that the LES model yielded better results when compared with laboratory results, while the turbulence closure models result of Reynold average Navier Stocks equations (RANS) was more stable, especially standard k-ɛ and RNG models.
This research investigates the impact resistance of concrete slabs with different volume perecentage replacement ratios of waste plastic fibers (originaly made from soft drink bottles) as follows : 0.5%, 1% and 1.5%. Reference mix produced in order to compare the result. For the selected mixes, cubes with (100×100×100mm) were made to test compressive strength at age of (90) days. Flexural strength (Modulus of Rupture) test was also conducted using prisms sample of (500*100*100 mm) dimensions. The low-velocity impact test was conducted by the method of repeated falling mass where 1400gm steel ball was used. The ball falling freely from height of 2400mm on concrete panels of (500×500×50 mm) having a mesh of waste plastic fiber.The number of blows that caused first crack and final crack (failure) were determined, according to the former obtained results , the total energy was calculated. Results showed an improvement in mechanical properties for mixes containing plastic fibers compared with reference mix. For compressive strength the maximum increase in compressive strength was equal to (3.2%) at age of (90) days. Flexural strengths for mixes containing plastic fiber at ages 28, and 90 days are higher than that of these of reference mix. The maximum value of increaseing was (18%) for 28 days age of test and it was equal to (26%) for 90 days age of test for the mixture with plastic fiber content by volume equal to (1%) . Results showed a significant improvement in low-velocity impact resistance of all mixes contining waste plastic fibers when comparing with reference mix. Results illustrated that mix with (1.5%) waste plastic fibers by volume give the higher impact resistance at failure than the others. The magnitude of an increase over reference mix was equal to (340%).
This research investigates the efficiency of Ultrasonic Pulse Velocity (UPV) method in detecting voids and depth of cracks in concrete. Tests were performed to compare the accuracy between the direct and indirect method of Ultrasonic Pulse Velocity method (UPV) in detecting the location of defects. Three concrete prisms with fabricated void at a known location were used and tested at 28 day. Two other prisms were casted and tested to detect of crack depth in concrete, cracks at depth of 5 and 10 cm perpendicular to axis of beam were induced without actually breaking the beam. Test results indicate that direct and indirect methods can be used to assess the in-situ properties of concrete or for quality control on site, and the first and second method of determining the crack depth gave results with high accuracy while the results of third method were lower than the actual crack depth and for the forth method were higher than it. Therefor, we can use the average of the third and forth results to obtain the crack depth with good accuracy.
Processed and natural clays are widely used to construct impermeable liners in solid waste disposal landfills. The engineering properties of clay liners can be significantly affected by the leachate from the waste mass. In this study, the effect of inorganic salt solutions on consistency and compressibility characteristics of compacted clay was investigated at different concentrations. Two type of inorganic salt MnSO4 and FeCl3 are used at different concentration 2%, 5%, and 10%. The Clay used was the CL- clay (kaolinite). The result shows that the consistency limits increased as the concentration of salts increased, while the compression index (Cc) decreases as the concentration increased from 2% to 5%, after that the Cc is nearly constant. The swelling index (Ce) tends to increase slightly as the concentration of MnSO4 increased, while it decreases as the concentration of FeCl3 increased.
The look for the new water resources and the optimal using of available water is very important because of high change in the climate of the earth, the dry wave in the region as well as the decreases of the water inflow to the Euphrates and the tigress river because of the building of the dams upstream the basin in Turkey and Syria. In the present study, four biggest catchments area in the Iraqi western desert (wadi Horan, wadi AlGhadaf, wadi Ubayiad, wadi Tubul) were selected to study the hydrologic properties to determine the best region for the water harvesting because these areas include the most water harvesting project such as the small dams. Present hydrologic study was depended on the available data to determine the amount of runoff that can be harvested according to measuring data of metrological station in the region with the method of hydrograph for analysis. For the period (1971-1976) the study showed wadi Al-ghdaf is the best region for water harvesting according to the number of floods to the cathment area (44 floods) with water volume (1047*106m3), and the average water harvesting (7098.64 m3/km2). The second is wadi Horan the number of floods to the cathment area (33 floods) with water volume (2033.29*106m3), and the average water harvesting (6115.16 m3/km2). Then wadi al Ubyaid number of floods to the cathment area (21 floods) with water volume (405.197*106m3) and the average water harvesting (2493.52 m3/km2). The last one is wadi Tubul with number of floods to the cathment area (18 floods) with water volume (909.36 and the average water harvesting (2231.6 m3/km2)*106m3)
Pavement rutting as a permanent deformation is a major type of distress in flexible pavements. In Iraq, the rutting in Expressway pavements represents a severe problem due to its widespread, and high severity and distress density levels. Therefore, driving is profoundly dangerous and causes severe damage to the vehicle’s parts and the life of its riders. To date, the number of comprehensive research on pavement rutting has been limited in Iraq, owing to several technical, logistic, and economic considerations. The current research studies the major mechanisms responsible for rutting and evaluates the structure of the Iraqi Expressway No.1 at selected sections. The work encompasses field and laboratory aspects. The field work involved; performing field surveys to investigate the pavement rutting condition and its extension with depth, characterizing pavement layers in terms of geometric material properties, and collecting field samples for lab tests. The laboratory work was detailed and included; performing a set of standard lab tests on samples taken from the asphalt, the subbase, and the subgrade layers as well as the natural ground. In addition, the project’s archive was searched for specific design information and limitations. In order to assess pavement rutting in the selected sections of Expressway No.1/R9 (A and B), two well-established evaluators were considered; The rutting severity levels and the distress density.
Corrosion in steel bars is considered a big problem because corrosion is mainly responsible of decrease virtual age of structures and many risks indicated by deterioration. In addition, corrosion increases the cost of maintenance, particularly structures exposed to harsh environmental condition. FRP bars (Fiber Reinforced Polymer) became an alternative material from traditional steel bars. FRP had properties made it used in civil engineering sectors which are lightweight, non-corrosive, non-conductive made it a preferred alternative from steel bars in aggressive environments. FRP bars don’t have yield made it con not bind outside its linear behavior to make ties, because of the brittle behavior of FRP bars up to failure. So that, the new innovative manner by using CFRP sheets stirrups immerged by sikadur330 for produce beams can resist the harsh condition and purely reinforced with FRP in a new manner can provide stirrups in full different sizes and with lower cost. Twelve beams reinforced with GFRP bars in three different ratios of tension reinforcement (four beams for each ratio). Three control beams with steel stirrups: two beams were designed to fail in shear. Whilst, the residual nine beams with shear reinforcement made from CFRP sheets strips, immerged by sikadur330. The main variable were studied is the change in type and amount of secondary reinforcement and change in amount of primary reinforcement. The test was conduct under four point loading and in simply supported conditions. The result of tested beams illustrated that, beams had a higher percentage of tension reinforcement and shear reinforcement displayed an increasing in ultimate load about 38.1% from related control beam. While, an equivalent amount of shear reinforcement displayed an increasing in carrying load capacity up to 10%. In maximum ratio of CFRP sheets immerged by sikadur330 stirrups convert failure mode from shear to flexural indicated by crushing in cover of concrete. In addition, increased energy absorption, changed cracks orientation, increased energy absorption, decrease principal strain and increased concrete tensile.
Abstract:-This investigation studies the mechanical characteristics of carbon fiber reinforcedlight weight aggregate concrete, containing different percentages of fiber. The effect ofusing high range water reducing agent (SP) with 8% silica fume (SF) and 8% highreactivity Metakaolin (HRM), as a partial replacement by weight of cement, on thebehavior of (LWA) concrete is also studied.This investigation was carried out using several tests. These tests were workability freshand hardened density, compressive strength, splitting tensile strength and modulus ofrupture. Tests were performed for specimens at ages of (7,28,60,90 and 180) days . Thetest results indicated that the inclusion of carbon fiber to the light weight concrete mix didnot affect the compressive strength significantly, while the splitting tensile strength andthe modulus of rupture were improved significantly. The addition of silica fume andmetakaolin improves the compressive, splitting tensile , and modulus of rupture strengthsof carbon fiber light weight concrete. The average improvement was about (26.5%, 71%and 73 %) respectively for carbon fiber LWA concrete containing silica fume and (28%,72% and 75%) respectively for carbon fiber LWA concrete containing high reactivitymetakaolin.
This study program has been arranged to test the behavior of punching shear for concrete slabs reinforced by an embedded glass fiber reinforced polymer (GFRP) reinforcements. However, the shear resistance of concrete members in general and especially punching shear of two-way RC slabs, reinforced by GFRP bars has not yet been fully investigated. Seven decades ago, many researches have been carried out on punching shear resistance of slabs reinforced by conventional steel and several design methods were created. However, these methods can be not easily applied to FRP-reinforced concrete slabs due to the difference in mechanical properties between (FRP) and steel reinforcement. sixteen specimens are to be cast in lab within two categories of reinforcements such as GFRP and equivalent steel reinforcements. In addition, based on experimental data obtained from the author’s study and ACI model, the paper performed an evaluation of accuracy of proposed model. The results from the evaluation show that the ACI-formula gave inaccurate results with a large scatter in comparison with the test results of this study. A new design formula can be proposed for more accurate estimation of punching shear resistance of (GFRP) specimens.
This study was determined specified characteristics of Iraqi silica sand , touse it in the drinking water treatment rapid gravity filters. These properties includes grain size ,uniformity coefficient , grain shape , porosity , density , durability, chemical content and capability of solubility in the acid ..this study explained that the Iraqi silica sand has high degree at mechanical and chemical stabilities .The e filter column was operate for many cycles , the average results of raw water and treatedwater for variable values (turbidity , total suspended solids and total bacterial count) was taken . The study showed that possibility of use the Iraqi silica sand in the westernIraqi desert in the rapid gravity drinking water treatment plant filters . when the raw water has initial turbidity (5.24 NTU) ,the study and the experimental tests showedthat the average removal efficiency of turbidity , T.S.S ,and T.B.C of (82.9%,82.8%and 79.5%) respectively . when the raw water has initial turbidity (9.58 NTU) ,the study and the experimental tests showed that the average removal efficiency of turbidity , T.S.S ,and T.B.C of (79.4%,78.7% and 74.1%) respectively . when the rawwater has initial turbidity (28.35 NTU) ,the study and the experimental tests showedthat the average removal efficiency of turbidity , T.S.S ,and T.B.C of (72.6%,72.7%and 60.9%) respectively
Ferrocement is a type of concrete made of mortar with different wire meshes. It has wide and varied applications in addition to its strength and durability. This research aims to combine ferrocement and sustainability, as over time, the consumption of plastics, especially plastic bottles, has increased and has serious negative effects if buried, burned, or chemically analyzed. Therefore, this research aims to benefit from this plastic waste and introduce it into the construction field by using plastic waste fibers in the concrete mixture instead of cement at a rate of 0.5% and 1% by volume. This research studied the mechanical properties of nine samples of ferrocement beams with dimensions of 1200 × 200 × 150 mm3. A longitudinal hole with a diameter of 50 mm was drilled in different places of the beams and filled with lightweight concrete to facilitate the use of the hole in service passes when drilled, with a study of the initial cracking loads and the resulting deflection in addition to the failure modes and the deflection resulting from the maximum load. The results showed an improvement in load resistance with an improvement in deflection at the maximum load, In addition to an increase in the improvement of Toughness and Stiffness of ferrocement beams.
This research paper is accomplished to study the effect of using waste fibers in properties of concrete . Steel lathe waste fibers are added by percentages of (4, 6 and 8 %) from weight of concrete and a percentages of concrete coarse aggregate are replaced by rubber tires waste fibers in a ratios of (5, 10 and 15%) by volume . Besides to that, the combined fibers are used steel lathe waste fibers by adding (4, 6 and 8 %) with constant replacing of rubber tires waste fibers of (10 %). The results showed that adding of steel lathe waste fibers in plain concrete enhances its strength under compression about (15%) and tension about (20%), while rubber tires waste reduced both of compression about (80 %) and tension about (51%) strengths .Also the compression and tension strengths are reduced (88% and 30%) respectively with using combined fibers . The dry concrete density of lathe waste fibers concrete is (2345-2365kN/m3) , the rubberized concrete density is (2130-2240kN/m3) and for combined fibers concrete density (2025-2180 kN/m3).
ABSTRACT: In this study an attempt is made to develop a method of analysis dealing with a multi-layer composite beam, for linear material and shear connector behavior in which the slip (horizontal displacement) and uplift force (vertical displacement) are taken into consideration. The analysis is based on a approach presented by Roberts[1], which takes into consideration horizontal and vertical displacement in interfaces. The analysis led to a set of eight differential equations contains derivatives of the fourth and third order. A program based on the present analysis is built. Series of three push-out tests were carried out to investigate the capacity of shear stiffness for connectors. From these tests, load-slip curves were obtained. Also, series of multi-layer composite simply supported beams were tested. Each one consists of three layers in different material properties and dimensions. A comparison between the experimental values and numerical analysis is carried out. Close agreement is obtained with experimental values for different materials, layers thickness and shear stiffness.
This paper presents the testing results and numerical results of nine reinforced concrete thick slabs with and without openings. All slab specimens have the same planar dimensions (1000mm×1000mm) with three different thicknesses of (120mm,100mm,and 80mm).The slabs resting on 4 corner steel columns and tested under concentrated static loading up to failure. These slabs were also analyzed using nonlinear finite element method assuming nonlinear material properties. From the experiments, it was found that, The presence of openings in slabs supported on their four corners decreases the strength and rigidity of slabs to about (12-23) % depending on the slab thicknesses and the shape of these openings. The slabs with (circular opening) recorded a reduction in ultimate strength to about(20) % from those with square openings having an equivalent opening areas. The yielding of main steel reinforcement occurred at load about 85% of the slab ultimate load. The ultimate loads predicted by ANSYS model have showed a good agreement with the experimental results.
ABSTRACT: In this study an attempt is made to derive governing equations satisfying equilibrium and compatibility, for multi-layer composite beams with different layers, materials properties and dimensions for linear material and shear connector behavior in which the slip (horizontal displacement) and uplift force (vertical displacement) are taken into consideration. The analysis led to a set of number differential equations containing derivatives of the fourth and third order, number of these equations depending on number of layers forming the beam section. The theory developed for three, four, and five layers. A general formula were derived to find the governing equations (compatibility and equilibrium equations) for any layered composite beam.
AbstractThis research includes the study of the effect of adding steel fibres resulting from cutting chicken wire (which is available in Iraqi markets now) as fibres added to the polymer concrete. These fibres were added with percentages of concrete volumes. These percentages were (0.5%) and (1%). Reference concrete mix was also made for comparative reasons. From the results, it can be noted that the increasing of compressive strength of SFPC1 comparing with RPC at 28 days equal to 9.90%, whereas the increasing of compressive strength of SFPC2 comparing with RPC at 28 days is equal to 15.48%. The increasing of splitting strength of SFPC1 comparing with RPC at 28 days equal to 15.50%, whereas the increasing of SFPC2 comparing with RPC at 28 days is equal to 21.40%. The increasing of flexural strength of SFPC1 comparing with RPC at 28 days equal to 10.80%, whereas the increasing of SFPC2 comparing with RPC at 28 days is equal to 20.63%.Results proved that adding of steel fibres with these percentages lead to improvements in compressive strength, splitting strength and flexural strength of concretes containing steel fibres, but the improvement in flexural strength appeared more clearly. Results proved also an increasing in densities of fibre concrete samples according to these made of reference mix.