INFLUENCE OF MIXTURE COMPOSITION ON WASHOUT RESISTANCE, FRESH PROPERTIES AND RELATIVE STRENGTH OF SELF COMPACTING UNDERWATER CONCRETE

Abstract

Successful design of underwater concrete mixtures must fulfill two basic requirements: adequate flowability to spread into the placing forms without consolidation, and viscosity in order to resist the washing out. In this paper an investigation was carried out to determine the effect of the dosage of anti washout admixture (AWA), water cementitious materials ratio (w/cm),sand to total aggregate ratio(s/a), and the supplementary cementitious materials on the washout resistance, fresh properties and the relative compressive strength of self-compacting underwater concrete (SCUWC). Therefore five groups were prepared for this study. First group studied the effect of the supplementary cementitious materials, second group dealt with the effect of the AWA ratios, third group is concerning with the effect of w/cm ratio, fourth group take into account the effect of s/a ratio and finally fifth group included the effect of cementitious materials. Test results indicate that the concentrations of antiwashout admixture (AWA) have direct effect on washout resistance and relative compressive strength. The washout mass loss can be reduced by using 10% silica fume replacement. Also it can be reduced by decreasing the w/cm and increasing the cement content and that result in greater relative strength.