Suitability Of Recycled Concrete And Marble Wastes As Conventional Aggregates For Base Course Material

Abstract

The rate of consumption of natural aggregate increase as the demand for highway construction materials increase and landfills fill up, interest in recycling solid wastes such as demolished concrete and marble waste as conventional aggregate. Using wastes are important to reduce natural aggregate consumption rate and to minimize pollution. Solid wastes that have been considered as aggregate for base course include mineral wastes from mining and mineral processing known as marble waste aggregate and municipal wastes include commercial or household known as recycled concrete aggregate. Using these wastes also enhance some properties of the pavement, hence the aim of this study is to evaluate the suitability of recycled concrete and marble wastes as conventional aggregates for base course material. Sampling population were recycled concrete, marble wastes and suchlike solid wastes materials. Samples of recycled concrete and marble waste were collected from Addis Ababa city, demolished Samsung building and Ethiopian Marble Processing Enterprise, respectively. Purposive sampling techniques and experimental sampling design were used in this study. Laboratory tests were conducted to determine engineering properties such as gradation, specific gravity and water absorption, California bearing ratio (CBR), aggregate crushing value (ACV), aggregate impact value (AIV), loss Angeles abrasion value (LAV), plasticity, angularity, flakiness and elongation index of recycled concrete and marble wastes. To achieve these blend (0:100, 20:80, 50:50, 80:20 and 100:0)RCA and CA as well blend (0:100, 20:80, 50:50, 80:20, and 100:20) MWA and CA were conducted. Blend 80:20 RCA and CA engineering properties obtained are Gs, W, FI, EI, ACV, AIV,LAA and CBR with corresponding values of 2.21, 9.3%, 26.3, 21.8, 22.9, 15.9, and 15.5, 106% respectively with well graded gradation. Blend 80:20 MWA and CA engineering properties obtained are Gs, W, FI, EI, ACV, AIV,LAA and CBR with corresponding values of 2.68, 0.57%, 22.4, 17.4, 24.9, 16.2, and 19.7, 99%, respectively with well graded gradation. The finding of the study shows that both materials can be as conventional aggregates for base course. However, further research has needed particularly on long term field performance of both materials.