MECHANICAL PROPERTIES FOR ORDINARY CONCRETE CONTAINING WASTE PLASTIC FIBERS

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).


Introduction
Buildings made from reinforced concrete for all structural elements like slabs, beams, columns and shear walls still number one in the whole world because of safety, long life and fire resistance. In case of high rise buildings, the concrete structure not recommended because of the effects of wind and seismic loading and since concrete is a brittle material, so that become weak against these types of loading. The sources of waste plastic fiber classified in two types, first, due to production scrap and second after used plastic (post). The benefit of waste plastic fiber concrete not only enhanced some mechanical properties of concrete up to specific percentage, but also, make the environmental very fresh and clear because of removing all waste that make air pollutions. In 2013, R. N. Nibudey et al (1), studied the performance of concrete in presence of WPF. The experimental works that adopted included tests of cube and cylinder specimens. The WPF that added to the concrete was ranged from( 0 to 0.3 %).The specimens was cured at twenty eight days and after that tested to investigate compressive and tensile strength. The results indicated that at (1%) of WPF there was improved the mechanical properties of concrete as compared with control specimen. In 2013, Al-Hadithi Abdulkader Ismail and Shilan (2) , investigated the effects of presence waste plastic chips on the mechanical properties of the new concrete. Various percentages by volume was adopted as (1.6 and 3.25 %), with Styrene Butadiene Rubber SBR polymer (10 %) from cement weight to the mix.
The tests result indicated that there was improved in mechanical properties of new concrete with increasing of fibers. The increasing in c strength was (4.1 %) and modulus of rupture (24.4 %). In 2014, Al-Rawi (3) , investigated the flexural behavior of reinforced concrete beams contained waste plastic fiber. The ratio of (WPF) that looked out was (0,0.5,1,1.5 and 2 %) by volume According to tests result, the conclusions as follow, there was reduced in deflection when the percentage of WPF increased, and up to (1%) of WPF the compressive strength increased. In 2014, Alani Mahmood Fawzi (4) , studied the possible way to use waste plastic material as fine aggregate in structural elements by evaluate the mechanical properties of concrete. Various ratio of waste plastic was considered (2.5%,5% and 7.5% ) by volume with ten percent of silica fume. Tests result indicated that the presence of waste plastic reduce concrete workability and decreased in compressive strength and modulus of elasticity compared with fresh concrete. In 2015, P. Ganesh et al (5) ,investigated t h e increasing in compressive strength of concrete by replace percentage of fine aggregate by waste plastic. Total of twenty seven specimens included cube and cylinder tests and compared with the reference specimen without replacements. The ratio used in the work was (0. 5,1 and 1. 5 %) of waste plastic by volume. The results indicated that the ratio of waste plastic one percent give good result for compressive and tensile strength. In 2016, J. M. Irwan and Mohd Haziman (6) , investigated the effects of r i n g shaped of waste plastic bottle on the flexural toughness. The width that looked out was (5mm and 10 mm) with applied loading at the third point of specimen. By tested results, there was increased in the toughness around (23%) in case of (5 mm) width and (40%) in case of (l0 mm)width.

Materials 2.1 Cement
Ordinary Portland Cement (OPC -Type I) produced by Al-Mass company was used to cast all specimens as cubes, cylinders, prism and RC slabs. Its physical properties and chemical composition are given in Tables (1) and (2), respectively. Test results indicate that the adopted cement conforms to the Iraqi specifications (IQS No.5/ 1984) ( 7 ) .

2.2Fine aggregates
Natural fine aggregate that used in present work from local Al_ Akhadir area has properties as free of organic, clay and deleterious, so it clean. Table(

Coarse aggregate
The maximum size of coarse aggregate is (10 mm), Crushed gravel from AL-Nibaey zone was washed and submerged in to water for about two hours and dry in air to get saturated surface dry (SSD). Table (5) and (6)  Test results

Lower limits
Upper limits properties of coarse aggregate respectively and the limit specified by Iraqi Specification No 45 / 1984 ) (8) . Figure (2) show the full sieve analysis behavior with lower and upper limits.

Waste plastic Fibers
This type of plastic fiber used is conforming to (ASTM -A 820, 2002) (9) . The geometrical characteristics of plastic fibers throughout the experimental work are illustrated in Table (7) and resulting from cutting by hand. Fibers were added to the mixes as a ratio by volume of mixture of (0.5, 0.75, 1.00, 1.25, 1.50, 1.75 and 2%) respectively show plate(1) plastic waste cutting.

Water
Fresh water was used to produce concrete without any admixture.

Concrete Mixes
Six trail mixes was used in present experimental work by using normal concrete mixing different proportions, upon to arrival the required compressive strength. Seven ratios from (%WPF) and add them to the mixture volumetric ratios as (0.5, 0.75, 1, 1.25, 1.5%, 1.75 and 2%) then selected three percentage that gives higher compressive and tensile strength (0.5, 0.75 and1%). The trail mixes with waste plastic fiber at (0.75%) give increased in compressive strength and at (1%) give enhanced in tensile strength. The variation of compressive and tensile strength of concrete with (%WPF) at 28 days as shown in Figure (3a) and (3b), respectively.

Normal weight concrete
The normal weight mix was prepared and then mixed mechanically and steering until all components becomes uniform. In case of presence waste plastic material to produce waste plastic concrete (WPC), the waste plastic was added to the dry mix and put all materials in the mixer and then turned on without water until the mixing become uniform and then the water required that calculated before was added and then remixed all components together.

Curing
All specimens before tested was cured under ideal conditions in water tank that contained fresh water and keep the specimens to the specific and required time to make the concrete complete the hydration processes, see plate (2). The temperature degrees for the water about 20±5 C o Plate 2. curing the specimens

Experimental works 6.1 Slump Test
The slump tests was adopted before any other tests like compressive strength, tensile strength and modulus of elasticity to ensure the adequacy of concrete that used in tests. Slump test different in values based on the percentages of waste plastic fiber that added to the concrete according to ASTM C143 / C143M -5a (10) Plate (3) show the slump test method and Table (9) show slump values decries with increase the (WPF) percentage.

Compressive strength
Two kind of molds were used to determine the compressive strength and these molds were cube (150x150x150 mm) according to BS 1881 -119 -2011 ( 11 ) , and cylinder (300 mm) in height and (150 mm) in diameter according to ASTM C39 / C39M-14 ( 12) . The machine used in tests by BESMAK, have capacity (2000 KN) for compression, as shown in plate (4a). Three specimens were tested for each type of mix for cube and cylinder. All test results was listed in Table (9).

Splitting tensile strength
Splitting tensile strength tested by traditional testing method according to C 496 -96 (13) , that cast standard cylinder. The loads applied gradually and continuously without shock and after that record the breaking load. Plate (4c) show the specimen rest on the machine test. Three specimens were tested for each type of mix .All test results was listed in Table(10).

Flexural strength(modulus of rupture)
Flexural strength or modules of rupture test define the stress in a concrete before yield in flexure this test was conducted according to ASTM C 293 (14) (center-point loading). The dimension of prism is (400x100x100 mm) and the machine used in tests by BESMAK, have capacity (200 KN) was used to determine the flexural strength of concrete in different percentages of WPF and normal concrete with different ages. Plate (4b) show the specimens which were testing. Three specimens were tested for each type of mix the flexural strength. All test results was listed in Table (

Compressive strength tests
Test results listed in Table (10) at ages (7, 14 and 28) days for (0, 0.5, 0.75 and 1%) from (WPF) by total volume. The compressive strength increased as compared with the reference mix without (WPF) up to (0.75%) because of the ductility and elongation of (WPF) through cracks Also, the compressive strength increased with age because of with age the concrete become stiffer and strength due to complete of hydration processes and reduces in porosity and after that there was dropped in result, the increased percentages (5.1 %) and (2.9%) for (0.75 and 0. 5%) respectively. Plate (5) shows the specimens after and before tests.

Flexural strength and splitting strength tests
All test results for flexural and splitting tensile strength of concrete with (%WPF) listed in Tables (  11) and (12) respectively and plotted in Figures (5) and (6) respectively at (7, 14 and 28 days) for (0, 0.5, 0.75 and 1%) from (WPF) by total volume. Flexural and splitting tensile strength increased when (%WPF) increased and also increased with time, that is mean there was enhancement in tensile strength of concrete due to the presence of (WPF) because the presence of (WPF) make tight the microscopic coracles to propagate and reinforced the concrete matrix. The percentages increasing of flexural as compared with the reference specimen was (6%), (10.3%), (12.5%), respectively. Plate (6and7) shows the specimens after and before tests.

Conclusions
Based on the experimental work and results obtained in this study, the following conclusions can be presented: 1. Addition of waste fiber with different ratios (0.5% and0.75%) increases the compressive strength at ages 28 compared with the original mix. The value of increasing is about (2.9% and 5%) respectively for 28 days. 2. Addition of waste fiber with different ratios increases the flexural and splitting strength at ages 28, and compared with the original mix. The max. value of increasing is (12.5%) and (12.5%) respectively for 28 days for the mix with (1%) (waste fiber to concrete) percentages. 3. Take advantage of the industrial waste of plastic used in the empty bottled water bottles of soft drink and turn them into plastic fibers after manual cutting appropriate and added to concrete as well environmental effect good at cleaning up the environment from the waste.