Flow and Early Strength Properties of Controlled Low-Strength Material Made from Cup Lump Rubber

Abstract

At present, the production of natural rubber is increasing but the consumption of rubber and the export of rubber are decreased, resulting in a price drop. The use of cup lump rubber as a material in the mixture of controlled low-strength materials (CLSM) is a possible alternative to apply rubber in a variety of usages and to reduce natural resource depletion. In this study, the mechanical properties of CLSM and the possibility of using cup lump rubber as a mixture of CLSM are studied. The material mixtures include cement, fly ash, water, natural sand, and cup lump rubber, in which, the cup lump rubber is used to replace the natural sand by 20, 30, and 40% by the volume of fine aggregate. The experiments consist of the slump flow and unconfined compressive strength at the curing age of 7 and 14 days. The results showed that flowability and early unconfined compressive strength decrease as the amount of used cup lump rubber increases. However, the properties are still within the criterion of ACI 229R, hence, the employment of cup lump rubber as a mixture of CLSM is valid.