Water absorption of acid attacked specimens at 28, 56 and
84 days did not follow the trend of the control mix. When we
observe Figs. 6 and 7, the top layer of the concrete specimens with
0% crumb rubber was completely removed (100%) by the action of
sulphuric acid. In the case of the mix with 20% crumb rubber, less
than 100% top surface were attacked by acid. The rubber particles
and the cementitious layer surrounding the rubber particles were
unaffected by acid and have projected outwards by providing extra