Use of recycled aggregate and fly ash in the development of concrete composite

Continuous economic growth poses severe problems of waste disposal for civil engineering construction and demolition works. In this research work, recycled aggregate (RCA) and fly ash in concrete composites for pavements are presented. The approach adopted here is to replace a large amount of normal aggregates (NA) with recycled aggregate, obtained from various crushed concrete and partial substitution of Portland cement by fly ash to develop rigid pavement concrete. A preliminary test is conducted on the materials which are used in the development of concrete pavement. Results have satisfactory results as per Indian standard guidelines. The compressive strength is determined at a proportion of fly ash varying from 0 to 40%, which gives a wide range of adding fly ash and recycled aggregate to achieve the aggregate's better mechanical property. It also determines the concrete's long-term flexural strength by partially replacing the RCA and fly ash, an important parameter in rigid pavement design. At 28 days and 56 days, the compressive strength is determined for different fly ash and recycled aggregate proportions, and concrete having more fly ash shows better results at 56 days’ compressive strength.