Reduction in environmental pollution using rice-husk ash in concrete

Document Type : Original Article


Department of Civil Engineering, Faculty of Engineering and Islamic Arccheticture Umm Al-Qura University,


The production of cement as a binding component of concrete is costly, consumes high energy,
depletes natural resources and emits huge amounts of greenhouse gases (one ton of cement
production emits about one ton of CO2). Consequently, environmental degradation, serious
pollution and health hazards associated with cement and concrete industries, have come under
intense scrutiny from environmentalists and the governments. Developed and some developing
countries, are already using industrial and agricultural wastes in concrete. These wastes also pose
several environmental problems. Partial inclusion of waste instead of 100% cement has been found
to be environmentally safe, stable, durable as well as economical. Rice husk ash (RHA), rich in
silica content, can be produced from rice husk using appropriate combustion technique for use in
concrete as a supplementary cementitious material. The present study used rice-husk ash (RHA) as
a partial replacement of cement in concrete. X-ray diffraction analysis, scanning electron
microscopic examination, compressive strength (without and with superplasticizers), flexural
strength, resistance to aggressive chemicals and cost analysis were carried out. Concrete and
mortars containing 25% RHA as a replacement of cement, exhibited same or better results
compared to conventional concrete. Moreover, it leads to substantial cost savings not to mention
benefits to the environment.