Effect of local additive (BM2010) on high performance concrete under sulphate attack

Abstract

Many of reinforced concrete structures especially underground and undersea are subjected to aggressive environmental conditions throughout their exploitation. These conditions are represented by the aggressive sodium sulphate attack from surrounding soil or underground water. When based materials of cement are exposed to sodium sulphate attack produce gypsum and ettringite by its chemical reactions. Formation of gypsum plays a very important role within the damage of materials. According to that the actual compressive strength of concrete elements decreases accompanied with large deformations of concrete. Consequently, a higher reduction of the construction durability occurs, so using of effective and economic admixture for concrete elements protection against sulphate attack or the other environmental conditions is needed. The main purpose of this research is to study through an experiment the effect of the local admixture (BM2010) which contained in its composition wastes from petroleum industries, silica fume, Wastes of coke factory and its mechanism effect on the compressive strength of concrete specimens subjected to external sulphate attack. The experimental results showed that Compressive strength of concrete specimens modified with the organic admixtures (BM2010) at age of 128 days hardened in salt solution with concentration (9%NaCl + 12% Na2SO4) increased by about 15% compared to the control specimen with (Addicrete dm2) for sulphate resistance cement (S.R.C) & 3.6% compared to the control specimen (without admixture) for ordinary Portland cement (O.P.C). The absorption of concrete specimens modified with the organic admixture (BM2010) at age of 128 days hardened in salt solution with concentration (9%NaCl + 12% Na2SO4) is less than concrete specimens modified with (Addicrete dm2) by about 29%percent in case of (S.R.C) but in case of (O.P.C) it is more by about 16% percent. The experimental results showed that, the optimum composition of all components of the suggested admixture (BM 2010) was successfully and experimentally achieved.