Mechanical Properties Of Roller Compacted Rubberized Concrete

Rubberized concrete is a new type of concrete receiving much concern of the world recently. Previous studies show that the mechanical strengths of rubberized concrete were reduced due to the incorporation of waste tire rubber, but the toughness, deformability and shock resistance were enhanced significantly, so the composite material had wide application field. With the advantages of small water consumption, stiff mixture, ease of construction and high rate of production, roller compacted concrete (RCC) is very suitable to be used in lathlike structures and thin plate structures, such as dams, highway pavements, seepage control faceplates, and so on. But the applications of RCC in the latter projects are limited. It may be due to that RCC can't meet the high requirements of crack resistance and deformability of these projects. The toughness and deformability of RCC may be improved by adding a portion of rubber particles.The paper is a part of the subject, named Properties of Roller Compacted Concrete (No.50679054), which is financial supported by the National Natural Science Foundation of China. The object of the paper is to investigate the workability and mechanical properties of roller compacted rubberized concrete (RCR), prepared by replacing portion of sand in RCC with the same volume of rubber particles. The workability, compressive strength and splitting strength of RCR were experimentally studied, and a compressive strength formula was derived by regression. Then the effects of rubber content on the axial compressive strength, flexural strength and direct tension strength were studied by keeping the compressive strengths at constant.Based on the test results, the following conclusions may be drawn:(1) The density of RCR decreased with the increase of rubber content;(2) The workability of RCR was slightly influenced by replacing portion of sand with the same volume of rubber particles;(3) Roller compacted concrete (RCC) is a stiff consistence concrete, the tire rubber particles did not flow up during the vibrating compaction, and homogeneous concrete can be achieved;(4) The compressive strength and splitting strength of RCR decreased significantly with the increase of rubber content;(5) Cement strength, water/cement ratio and rubber content were three dominant factors determining the strength of RCR, and the compressive strength formula of RCR, developed by regression, had a unsatisfied precision;(6) Remaining the compressive strengths unchanged, the axial compressive strength, flexural strength and direct tension strength increased with the increase of rubber content, indicating that the crack resistance behavior of RCC was improved by the incorporation of waste tire rubber;(7) RCR specimen exhibited a ductile failure under compression.