Properties of crumb rubber hollow concrete block

Several researches have been conducted to determine the fresh and hardened properties of crumb rubber concrete (CRC), concrete containing crumb rubber as partial replacement to fine aggregate. The benefits of outlined from these works include low density, good thermal resistivity, better sound absorption, increase slump values and toughness, and better impact resistivity of the resulting concrete. Reduction in strength, increase in water absorption and are some of the adverse effect of utilizing crumb rubber in concrete. The study reported in this paper is a development of crumb rubber hollow concrete block (CRHCB). For the purpose of this work, sixty-four trial mixes were prepared to produce hollow concrete blocks of dimension 390 mm × 190 mm × 190 mm using 0%, 10%, 25% and 50% crumb rubber (CR) as replacement of fine aggregate. Tests conducted on the hardened concrete include compressive strength, thermal conductivity, electrical resistivity, acoustic absorption and transmission loss, and electrical resistivity. It has been found that CRHCB can be produced as load-bearing hollow blocks as well as lightweight hollow blocks. The CRHCB also has better thermal, acoustic and electrical properties in comparison with conventional hollow block.