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.
The use of textile reinforcement made from non-corrosive materials, such as carbon and glass can reduce the required concrete material; this is known as Textile Reinforced Concrete (TRC). This study deals with plate specimens having dimension of 500×500×40mm tested under impact load at 28 and 90 days age under two conditions of ends, simply supported and fixed. Cement mortar with about 60 MPa, 7cm cube compressive strength at 28 days was designed for casting the plates. Plate specimens were divided into four groups, they consist of reference plates (no reinforcement) and plates reinforced with 3D glass fabric having three different thicknesses 6, 10 and 15mm. The results indicate that using 3D textile glass fabric cause an increase in number of blows, reduce in final stage deflection, an improvement in toughness and energy absorption under impact loads. Using 3D textile glass fiber with 10mm thickness gave higher number of blows for 28 and 90 days as compared with 6 and 15 mm. Plates with slice 6mm 3D textile glass fiber in two way reinforced has significantly enhancement in number of blows, the improvement was about (80 - 125%) and (128.5- 114. 3%) for 28 and 90 days respectively. The specimens showed increase in the energy absorption, besides the number and width of cracks was reduced and only few cracks are propagated up to the edge of the plates.
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%).