Characteristics of recycled aggregate concretes produced in Kuwait : a case study

Thirty one concrete mixes made of various combinations of coarse and fine recycled aggregates (produced in Kuwait from demolition waste) were cast and tested. The possibility of producing structural grade concrete using the recycled concrete aggregates (RCA) produced in Kuwait has been investigated in this study. The cube compressive strength of these concretes was in the range from 26 to 51 MPa. The concretes produced exhibited good workability, due to the use of a proprietary superplasticizer. ASTM Type I Portland cement, without any supplementary cementitious material, in the range of 295 to 509 kg/m³ of concrete has been used. The water – cement ratio of these concretes varied between 0.3 to 0.67. The 28-day experimentally determined modulus of elasticity of the concretes ranged from 26 to 39 GPa, which is indicative of good quality concrete. The flexural strength of these concretes was found to be as high as 6.2 MPa. Strength development of these concretes, up to a period of 91 days, was monitored under continuous curing in tap water, in seawater and under air curing. The engineering characteristics of the concretes derived from this study suggest that the recycled concrete aggregates (RCA) produced from the demolition waste in Kuwait are capable of making good quality structural concrete.