Environmental Impact of Concrete Production

Concrete is the widely used material for all infrastructural activities in the world. There is a huge demand for concrete usage nowadays next to water. Around the world, lot of attention have been paid in the last two decades to minimize environmental degradation caused by the concrete .Many studies have been carried out to develop alternative material for concrete in order to reduce its environmental impact. Concrete is produced conventionally by using Ordinary Portland Cement (OPC) as the primary binder. The production of Ordinary Portland Cement (OPC) causes many environmental issues. Due to the calcinations of limestone and fossil fuel combustion during the manufacture of ordinary Portland cement, carbon dioxide is released in the order

Coal-based thermal power generation meets the growing energy demand of the country since coal reserves in India are expected to last for more than 100 years. Coal with an ash content of around 40% is used predominantly in India for thermal power generation. The total production of fly ash is 75 million tons which is almost same as that of cement production.But only 5% of produced fly ash is used effectively. As a result, large amount of fly ash is generated in thermal power plants, leading to several disposal-related problems. Fly ash has been successfully used as a mineral admixture component of Portland cement for nearly 60 years. Effective utilization of Fly ash in making cement concretes extends technical advantages and also controls environmental pollution.

Fly ash reacts with calcium hydroxide when used as a partial replacement of OPC in the presence of water and in ambient temperature to form calcium silicate hydrate (C-S-H) gel during the hydration process of OPC. It has been found that fly ash can effectively replace OPC up to 60% by mass (Malhotra 2002; Malhotra and Mehta