Partial Replacement of Ordinary Portland Cement (OPC) with Natural Pozzolanas (Jebel Marrah) Volcanic Ash in concrete

Abstract

Considering the need for low-cost construction materials in the rural areas in Sudan, especially in Darfur, this paper examines ordinary Portland cement (OPC). The use of as a replacement of Jebel Marrah volcanic ash in concrete. The ash is obtained from Jebel Marrah (mountains), west of Sudan. These materials have been chemically and physically characterized. Concrete cubes measuring 150mm*150mm*150mm were made from four different concrete mixes prepared by using pozzolana to replace 0%, 10%, 20% and 30% of OPC by weight. The workability of the fresh concrete mixes were evaluated using the slump test and compacting factor test while compressive strengths of concrete cubes were evaluated at 7, 28, and 90 days. The maximum compressive strength at all ages of testing was obtained at 20% replacement. Workability increased with an increase in replacement percentage and the strength of cement/ash concrete increased with curing period but decreased with increasing ash percentage. The results obtained showed that Pozzolana can be used to partially replace up to 20% of OPC in the production of concrete without compromising strength