Abrasion resistance of concrete containing marginal aggregates

The main aim of the present study was to recommend ways and means to upgrade abrasion resistance of concrete made of low quality aggregates to acceptable levels on the basis of laboratory experimental investigations. The variables of the study were grade of concrete, type & quantity of pozzolana, type of aggregate, cement type and age of concrete. Various mixtures of concrete were designed and cast using different cements and pozzolanas. Three types of aggregates with three different Los Angeles (L.A.) values (less than 30%, between 30% and 50% and more than 50%) were employed in the study. A total of 90 cylindrical specimens were tested as per ASTM C 1138 procedure in this study to evaluate the abrasion resistance of concrete. Several companion cubes were also tested for evaluating the compressive strength of various mixes. The results indicate that while the abrasion resistance of concrete depends upon the properties of aggregates, no direct correlation exists between the L.A. abrasion of aggregates and the abrasion resistance of resulting concrete. The abrasion resistance of concrete degrades considerably once the L.A. value of aggregates goes beyond 30%. Incorporation of pozzolanic admixtures in concrete mix improves the abrasion resistance of resulting concrete with maximum benefits being observed in case of silica fume. Important observations have also been made about the influence of age of concrete and type of cement.