ABSTRACT

Building materials are often the largest component of costs for housing construction in developing countries, accounting for up to 70% of standard low-cost housing unit (Erguden 2001).

2 BACKGROUND

Strength is one of the main properties of hardened concrete. Concrete without adequate strength is of no use. With clay in the mix, the amount of water required for good workability can be considerably higher than that needed for hydration. Therefore, once the clay-concrete is cured and a portion of the water is chemically bound by hydration, a greater remainder of it evaporates, leaving an increased content of voids leading to lower strength (Neville 1987).