STRENGTH AND CHLORIDE RESISTANCE OF RECYCLED AGGREGATE CONCRETE CONTAINING GROUND RICE HUSK ASH

Abstract

The aim of this study is to investigate the utilization of rice husk ash, a by-product from thermal power plant, as a cement replacement for improving the compressive strength and chloride resistance of recycled aggregate concrete. Rice husk ash was ground until the particles retained on a sieve No. 325 were 51% by weight. Portland cement type I was replaced by ground rice husk ash at the rates of 20, 35, and 50% by weight of binder to cast concrete specimens. The concrete specimens were divided into 2 groups. The first group was made from recycled coarse aggregate and river sand. The second group was made from coarse and fine recycled aggregates. Compressive strengths of the concretes were determined at 7, 28, 60, and 90 days. Rapid permeability of chloride of concrete was determined at 28 and 90 days and chloride penetration depth of concrete was also investigated at 90 and 180 days. The results revealed that the recycled aggregate concretes with and without ground rice husk ash had compressive strength lower than that of conventional concrete. However, the use of ground rice husk ash at 20% by weight of binder in recycled aggregate concrete gave higher compressive strength than the one without ground rice husk ash at 60 days. In addition, the use of 20 to 50% of ground rice husk ash in recycled aggregate concrete could increase chloride resistance of the recycled aggregate concrete.