A series of concrete mixes were cast to assess the effect of coarse RCA on ceiling strength. The conventional mix design method [15] for normal concrete was used for NA concrete mix proportioning. RCA concrete mixes were proportioned using NA and RCA blends, with up to 100% coarse RCA. Using the mix proportions for NA concrete with 0.45 w/c ratio (50Nflnm2), given in Table 2, the NA mixes were developed to give a full range ofw/c ratios (0.45 to 0.23) by altering the cement content in increments of 40 kg/m 3.