Compressive strength and durability of fly ash stabilized dolomitic waste as a lightweight construction material

Abstract

Due to the seriousness of environmental pollution and the production of huge energy consuming building and construction materials, the development of new eco-friendly and energy saving building materials to overcome these issues has been gaining increasing attention. South Africa has largest number of dolomite deposits in Southern Africa, if not in the entire Africa. Nonetheless most of the dolomite in South Africa has some impurities of which they are neglected in dumping site (millions of tons). This paper looked at finding alternative use for this dolomitic waste (DW) by stabilizing this waste with another waste called fly ash (FA), introduction of gypsum as an activator will trigger a pozzolanic reaction in presences of water. As a result of this, the product of this reaction will be a useful material in construction and as well solve the difficulties i.e. environmental, social and cost often associated with storing and handling of this waste. This work went as far as providing an alternative for low-cost construction materials that can help deal with South African housing problems. The waste material was analyzed from geomaterial and geochemistry view point, the chemical reaction between these materials: dolomitic waste and fly ash were illustrated. The XRF, SEM and EDS of the reacted product were looked at, the strength gained by the reaction after sample preparation for 28 days were also shown. However various geotechnical laboratory experiments were conducted ranging from proctor compaction test, compressive strength test and a mathematical model was generated to predict the compressive strength and these results were compared to compressive strength values obtained from the laboratory