INVESTIGATION ON THE PROPERTY OF SELF-CONSOLIDATING LIGHTWEIGHT CONCRETE USING SCORIA AS COARSE AGGREGATE

Abstract

Concrete is a construction material that consists of a mixture of fine aggregate, coarse aggregate, cement, and water. Now a day, the shortage of conventional concrete material needs a quick solution in the production of concrete mix. Hence this study was aimed to investigate the effects of using scoria as coarse aggregate in the production of self-consolidate lightweight concrete. The study used a purposive method of sampling materials. An experimental research method was used to investigate the partial and full replacement of scoria in the concrete mix based on the concrete mix design method. In order to achieve the objective, concrete was classified in to five groups; a control group, a self-consolidating lightweight concrete(SCLWC) with 25%, 50% ,75% ,100% scoria. The chemical composition analysis indicated the scoria can be classified as a class – N pozzolana. The ratio of ingredients for samples was 1:1.763:1.743 with differing aggregate and scoria content. To determine a fresh property of the mix; slump flow and flow table tests. Also compressive and split tensile strength was conducted on the 7th, 14th, and 28th day. The results of these properties of concrete in this study the suitable SCLWC mixtures for further use in construction projects. It also plays a great role in minimizing the consumption of aggregate in concrete by utilizing scoria.The fresh property test result shows, all the different percentage replacement of scoria fulfilled American Concrete Institute (ACI) specification requirement, which is 600mm diameter. Also, the hardened property of self- consolidates lightweight concrete resulted in better compressive strength than C-25 concrete. The maximum compressive and split tensile strength were obtained with 25% scoria replacement, which is 35.17MPa and 3.72MPa respectively. The percentage replacements of scoria from 25 to 100% in self- consolidate lightweight concrete had a better strength than the control group. The SCLWC with scoria replacement developed better split tensile strength compared to control concrete on the 28th days. The concrete unit weight was decreased as the contents of Scoria increased. The decrease in the unit weight of the concrete shows as the specific gravity of Scoria is less than the specific gravity gravel coarse aggregate. Finally, it can be concluded that scoria can be used either as a full replacement or in combination with gravel coarse aggregates to produce SCLWC structures with a superplasticizer. Further study on durability, economic analysis, with different gradation is recommended.