DURABILITY OF REINFORCED-CONCRETE IN AGGRESSIVE SABKHA ENVIRONMENTS

This paper reports results of a study conducted to evaluate durability of is plain and blended cement concretes exposed to a typical salty s abkha environment (15.7 percent Cl- + 0.55 percent SO4--) The concrete mixtures were designed to assess the influence of C(3)A content water -cementitious materials ratio, and type of supplementary cementing mat erial, such as fly ash, silica fume, and blast furnace sing, on sulfat e attack and reinforcement corrosion in an aggressive sabkha environme nt. The sulfate attack was evaluated by visual inspection and weight c hange. Reinforcement corrosion was monitored by measuring corrosion po tentials and polarization resistance at periodic intervals. Despite th e high sulfate concentration in the test solution, classified as ''agg ressive, '' results of this investigation indicated that sulfate attac k was totally hindered in a sabkha environment. Darn on time to initia tion of reinforcement corrosion and polarization resistance indicated that the main contributing factors for mitigating chloride-induced cor rosion bl sabkha environments,in increasing order of importance, were: C(3)A content of cement, water-cement ratio of plain cements, and inc orporation of mineral admixtures. The most significant improvement was achieved when the water-to-cementitious materials ratio was synchrono usly reduced with addition of silica fume.