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
ABSTRACT:The resistance of concrete to sulfate attack is considered as one of the important factors for concrete durability.The effect of SBR polymer on sulfate resistance of concrete is investigated. Both internal and external sulfate attack are considered.Internal sulfate attack was made by adding gypsum to raise the sulfate content of sand to that of Ramadi city soil (2.17%), while the external sulfate attack was made by adding chemical materials (MgSO4.7H2O, Na2SO4, CaCl2.2H2O, NaCl) to tap water to convert it into water similar to groundwater of Ramadi city.The laboratory tests were compressive and flexural strength, modulus of elasticity, slump, ultra-sound velocity and total percentage of sulfate after exposing to attack for different ages. It was found that the compressive strength of reinforced normal concrete (RNC) for ages (7,28,90,180) days respectively were (20,28,11.166,7) MPa, the compressive strength of polymer Portland cement concrete( PPCC) with polymer/cement ratio( P/C)=5% (PPCC5) were (21.83,32.666,12.766,8.733) MPa and for PPCC with (P/C)=10% were (24.166,35.866,15.533,11.366)MPa.While the flexural strength of RNC for different ages (7,28,90,180) respectively were (3.953,3.7,1.68,11.305) MPa, the flexural strength of PPCC5 were (4.05,5.025,2.13,1.605) MPa and for PPCC10 were (4.43,6.375,2.43,1.92) MPa.The static modulus of elasticity at age (28) days for (RNC) was (37.4) GPa , for PPCC5 was (9.7) GPa and for PPCC10 was (13.63) GPa.Slump for (RNC) was (155) mm, for PPCC5 was (142) mm and for PPCC10 was (75) mm.T he ultra-sound velocity of RNC for ages (7,28,90,180) respectively were (4.2,4.445,4.203,4.53) Km/sec , for PPCC5 were (4.36,4.646,4.53,4.176) Km/sec and for PPCC10 were (4.437,4.837,4.656,4.52) Km/sec.It was found that (PPCC10) has higher resistance to sulfate attack than (PPCC5) and (NRC). The thesis refers to necessity of polymer to improve the resistance of concrete to sulfate attack although if the sulfate percentage raise to more than (0.5) % which represents the maximum limit of sulfate percentage in I.O.S No. 45-1970.
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.
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.
The present study, concern about an experimental work to study the stress-strain relationship of steel-fiber reinforced polymer modified concrete under compression. Four different mixes with weight proportions of (1:2:4) were used as; normal weight concrete (NC), polymer modified concrete (PMC) with (10%) of cement weight and two mixes of steel-fiber polymer modified concrete with (1%) and (2%) volume fraction of steel fiber, (SMPC). The influences of polymer and fiber addition on peak stress, strain at peak stress and the stress-strain curve were investigated for concrete mixes used. For all selected mixes, cubes (150×150×150mm) were made for compressive strength test at (28) days while stress-strain test was caried out on cylinders (150 mm 300 mm) at the same age. Results showed an improvement in compressive strength of polymer modified concrete (PMC) over reference mix, the maximum increase of it was (13.2 %) at age of (28) days. There is also an increase in compressive strength with increasing of steel fibers content with comparison to normal concrete, the maximum increases of it were (19.6% and 25.2%) of mixes with 1% and 2% fiber content by volume respectively. In terms of modulus of elasticity, the addition of polymer and the presence of fibers cause a significant increase in it. The peak of stress- strain curve for normal strength concrete (Mix No.1) was linear whereas it was more sharp for the other mixes. The behaviour of normal strength concrete (Mix No.1) was linear up to 20 % of ultimate strength, while for the mixes with the higher strength i.e. polymer modified concrete and fibers reinforced concrete (Mixes No.2, 3 and 4) the linear portion increases up to about 50 % of ultimate strength
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
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.
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%.
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.
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.
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.
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 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.
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)%