الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Scrap tyres are among the most troublesome waste products in the world. Using recycled tyre rubber as a replacement of sand in concrete mixes is an approach to improve the ductility of concrete. The use of rubberized concrete has gained a lot of attention in the past decade to utilize the enhanced ductility in seismic resistance. The properties of the equivalent compressive stress block exposed to combined flexural and compressive stresses are used to design reinforced concrete components. The design parameters of the equivalent compressive stress block for rubberized concrete are not well established. This article presents an experimental investigation of the behavior of rubberized concrete, with the focus on identifying the stress block parameters.
Two concrete groups were studied during this investigation with two different design strengths. Four different mixes were prepared for each group, with crumb rubber replacing fine aggregate by 0, 10%, 15%, and 20% of the volume. The mixes properties, such as slump, compressive strength, tensile strength, and stress-strain relationship were experimentally assessed and compared. Cubes and cylinders were used the test the compressive, tensile strengths, modulus of elasticity and stress strain relationship. To investigate the stress-strain distribution of rubberized concrete, 16 concrete specimens were examined under combined flexure and axial compression. Equivalent rectangular stress block properties and the ultimate compressive strain for those members were obtained by the experimental examination. The values were compared with those stated in different international design codes.
The compressive strength reduction of rubberized was within acceptable limits, which expands the use of rubberized concrete in Egypt’s building industry. The fresh properties also showed acceptable workability. The values of the equivalent rectangular stress block parameters had no change with the increase in the rubber content. The stress-strain distributions showed that the strain at peak stress improved and approached 0.003 strain. The stress-strain relationship for rubberized concrete obtained from tested specimens indicated that the strain at maximum stress and ultimate strain increase with increasing rubber content, indicating that rubberized concrete was more ductile than conventional concrete which could help improve impact resistance and damping ratio, so rubberized concrete can be used at high seismic regions.