The construction activities in Nigeria generate more than five million tons of construction demolition (C&D) materials each year. Recycling the C&D materials has been identified as one of the measures to reduce the burden on public landfill capacities and deal with environmental and economic implications of land filling. Concrete is the premier construction material in Nigeria and most widely used in all types of civil engineering works, including infrastructure, low and high-rise buildings, environmental protection and domestic/local developments. Recycled concrete aggregate (RCA) is increasingly available and is often an economical alternative to fresh aggregate. In this study, Scheffe's simplex theory was used to optimize the compressive strength of concrete made from recycled concrete aggregate, based on four components, second degree (4, 2) simplex model. The compressive strengths predicted by the model are in good agreement with their corresponding experimentally observed values. With the model developed in this study, any desired strength of hardened concrete produced from any Portland cement, sand, water and RCA mix proportions, is easily evaluated and vice versa.
Compressive strength, Concrete Mix Design, Recycled Concrete Aggregate, Optimization, Scheffe's Simplex Model
