Prof. Gamal Elsayed Abdelaziz :: Publications:

This paper presents some experimental investigation to characterize the fresh and mechanical properties of self-compacting concrete (SCC). The effect of concrete mix proportions on the main parameters of fresh SCC is studied. Seventeen OPC concrete mixes, made with different mix proportions of self-compacting admixture (SCA), high range water-reducing admixtures, cement content and fine/coarse aggregate ratio, were prepared and immediately subjected to Slump Flow, L-flow Deformability and Air Content tests. The main parameters of fresh SCC (deformability, flowability, filling capacity, speed of flow and air content) have then been evaluated. These parameters were also assessed at different elapsed time from mixing, 30, 60 and 90 minutes for studying the losses in SCC’s parameters occurred during such elapsed periods. On the other hand, cubical concrete specimens (15x15x15 cm) were taken from these mixes, left in water curing tanks for various periods, 3, 7, 14 and 28 days and then subjected to non-destructive and destructive test means, to investigate the early-age strength development and surface hardness of SCC. Using of SCA has led to a remarkable improvement in the main parameters of SCC, when compared to the use of high range water-reducing admixtures. The amount of improvements in SCC’s parameters increases with increasing SCA content and fine/coarse aggregate ratio. However, these improvements are dramatically diminished with increasing the elapsed time. Such diminishing effect is found to increase with increasing SCA content. The results also show that both SCC and normal concrete have similar mechanical properties (early-age strength development and surface hardness), regardless the amount of SCA utilized in the concrete mix.