Sustainable Construction—Use of Stone Dust as Plasticiser in High Strength SCC with Blended Cement

Abstract

Extensive growth in the developing countries due to infrastructure development is resulting into massive consumption of concrete thereby increasing the demand on concrete materials. Quite large amounts of fine aggregates are required for concrete in developing countries thus shortages of quality river sand is putting pressure on availability of fine aggregates. To fulfill the high demand of fine aggregates, a search for alternative materials is in process. Stone crushing and processing industry is a large industry which generates large amounts of stone dust and slurry which is a waste produced from this process. Tons of such waste generated has no useful purpose except as landfill material. Some preliminary studies have been conducted into use of marble/ limestone waste for use in concrete [1] [2]. This study aims at using stone dust as partial replacement of sand in concrete to observe its effects on workability and other mechanical properties. This would result in useful consumption of this waste product thereby eliminating environmental issues related to its disposal. Partial replacement of 10% and 20% sand replacement with stone dust is carried out with the use of self-compacting concrete with blended cement. Blended cement used contains 50% rice husk ash and 50% Portland cement. Such high strength SCC with blended cement containing 50% rice husk ash and 50% Portland cement has already been tested to provide better quality concrete [3]. Wide ranging investigations covering most aspects of mechanical behavior and permeability were carried out for various mixes for compressive strengths of 60 MPa & 80 MPa. Compressive strengths of high strength SCC with blended cements and 10% and 20% replacement of sand with stone dust for 60 MPa and 80 MPa were observed to be higher by about 10% to 13% than the control specimen. Higher elastic moduli and reduced permeability were observed along with better sulphate and acid resistance. Better strengths and improved durability of such high strength SCC make it a more acceptable material for major construction projects thereby reducing the burden on environment and use of such waste product for a useful purpose promoting sustainable construction.