The reduced availability of natural sands, particularly along the east coast of India, and the need to better utilise sand-size material generated in the aggregate crushing process, has combined to encourage the development of ‘Manufactured Sand’. The crushed rock fine should be processed to have fines content close to the optimum fines content or within a certain recommended range encompassing the optimum fines content. Such knowledge of the optimum fines content would help the quarry operators process the crushed rock fine to produce manufactured sand. With manufactured sand marketed as a material complying with certain recognized specifications, it is then up to the design engineers or concrete producers to specify ordinary crushed rock fine, which is cheaper and should be good enough for normal concrete, or manufactured sand, which is more expensive but should be a better choice for high strength concrete.
“The key idea is to develop admixtures with enhanced water reduction capacity to compensate for the increase in water demand and rheology modification to improve the pumpability and finishability of concrete mixes with manufactured sand so that they work just as well as concrete with natural sand.”