Concrete mix was designed as per IS: 10262-2010 and IS: 456-2000 with water-cement ratio 0.4. Water-cement ratios of 0.45 and 0.5 were also studied to study the variations in different properties. Crumb rubber was replaced for natural fine aggregates from 0% to 20% in multiple of 2.5%. The mixture proportions are given in Table 1. Super plasticizer was used as the admixture to arrive at the desired workability (above 0.91). In these mixes, nine cube specimens of size 100 mm were casted for 7, 28 and 90 days compressive strength test. Three concrete cube specimens each were casted for water absorption test, sulphate attack test and carbonation test. Nine concrete beams of size 100 mm 100 mm 500 mm were casted for 7, 28, and 90 days flexural tensile strength test. The mixtures were prepared and casted at indoor temperature of 25e30 C. Moulds were covered with plastic sheets, soon after casting and de-moulded after 24 h. Curing was done for 28e90 days in water tank, with controlled temperature of 25e27 C.