A study of the fresh properties of controlled low-strength rubber lightweight aggregate concrete (CLSRLC)

Controlled low strength material (CLSM) is most used as a backfill in situ and its fresh properties influence the convenient for construction. The fresh properties and 1 day-aged compressive strength of controlled low-strength rubber concrete (CLSRC) and controlled low-strength rubber lightweight aggregate concrete (CLSRLC) with five waste-tire rubber replacement of 0%, 10%, 20%, 30% and 40% are studied, respectively. Experimental results show that the slump, slump flow and tube flow value of each mix proportions is greater than 190, 400 and 150 mm, respectively. The fresh properties of CLSRLC are slightly better than CLSRC. The unit weight and initial setting time are affected by the amount of rubber particles that have been substituted for natural aggregate. An average 10% increase in the amount of rubber particles decreased the unit weight by approximately 69 kg/m(3), while the initial setting time was approximately 35 min. The compressive strength of CLSRC and CLSRLC decrease while the amount of rubber replacement increases, respectively. Before the rubber replacement reaches 20%, the early-stage (1d) compressive strength of CLSRC and CLSRLC is greater than 0.7 MPa and achieves ASTM standard requirement. The optimal rubber replacement of 20% is suggested for concerning about construction and safety in situ. By comparison with CLSRC, CLSRLC has the number of advantages such as the workability, low cost and environment-friendly. (C) 2012 Elsevier Ltd. All rights reserved.