Synergic Effect of Pozzolanic Materials on the Structural Properties of Self-Compacting Concrete

Presently, ternary-blended concrete is widely accepted as a building material, which is obtained from two well-known materials. It can be used for enhancing the structural properties (mechanical and durability properties) of the concrete as well as increasing the total quantity of the replacement level of cement. It is also useful to eliminate the drawbacks of the particular supplementary cementitious materials through combining with other superior quality material and reducing the overall cost of the concrete production. In this paper, the mechanical and permeability properties of self-compacting concrete (SCC) containing metakaolin (MK), rice husk ash (RHA), and a combination of MK and RHA (1:1 ratio) were evaluated and their interrelationships discussed. For this purpose, different mixtures were prepared with different amounts of MK and RHA and ordinary Portland cement (OPC) was replaced by 5 to 40 % of MK and RHA. As a result of increasing the percentage of MK, RHA, and MK + RHA, the mechanical and permeability properties of SCC improved considerably. One interesting point is observed that the sample incorporating the ternary blend of cement with 15 % MK and 15 % RHA showed better workability and mechanical and permeability properties than that of the normal SCC sample without MK or RHA. This blend was proven to be the optimum combination for achieving maximum synergistic effect. In addition, the linear relationship between chloride penetration in terms of total charge passed and the (SiO2 + Al2O3 + Fe2O3)/CaO ratio was studied.