Influence of Fine Aggregate Types on the Performance of Self - Compacting Concrete

Abstract

Self Compacting Concrete (SCC) was first developed to achieve durable concrete structures and help cast concrete into complex geometries without compromising the quality. Due to self-leveling properties, SCC is found suitable for structures with congested reinforcement and structures that are difficult for mechanical vibration. This research was carried out to understand the making of SCC using locally available fine aggregate types (river sand, quarry dust and offshore sand) and the influence of the different aggregate type on the properties of SCC. It was found that the minimum requirements of fine aggregate expressed as a percentage of the total aggregate content of the mix, were 50%, 55% and 60% for offshore sand, river sand and quarry dust respectively. Based on the above results, 60%, 70% and 80% of fine aggregate from total aggregate content was considered as common fine aggregate percentages to study the influence of fine aggregate types on the properties of SCC. As the particle size distributions of different fine aggregate types are different from one another, a separate series with aggregate sizes manipulated to confirm to a single common particle size distribution was also carried out. The influence of fine aggregate type and proportion, on the hardened properties of concrete is evaluated in terms of compressive strength and shrinkage of concrete whilst water requirement under constant dose of superplacizer is taken to evaluate the performance of the mixes in fresh state. Results of the study indicated that quarry dust as fine aggregate has the highest 28 days compressive strength for all the different water cement ratios considered in the study. All fine aggregate types have recorded higher strength when the proportion of fine aggregate to total aggregate content is 60% of the total aggregate content. Offshore sand mixes recorded the lowest water content required for making SCC whilst river sand recorded the highest. Except for changes in the water demand, SCC mixes of different fine aggregate types manipulated to common particle size distribution showed no significant variation in the strength development to that of their natural particle size distribution mixes.