The Applications of Manufactured Sand in Concrete Production
According to the stable and adjustable grain gradation characteristics of manufactured sand, compared with natural sand under the same proportion design and the same forming and curing conditions of other materials, the concrete made of m-sand has the features of decreasing slump and increasing 28d concrete strength; if the slump is kept invariant, the water demand will increase, but under this premise of not adding the cement content but increasing the water-cement ratio, which actually have no effect on the concrete measured strength under the normal circumstances. According to the principle of using natural sand to produce concrete, water demand of manufactured sand is larger and the workability is slightly worse and it is easy to occur bleeding phenomenon, especially in low-strength concrete with low cement content. However, if we follow the features of manufactured sand and adjust its sand ratio by using m-sand crushed dust content to produce concrete, which can fully produce the high quality concrete with good workability. The proportion design of ordinary concrete is fully applicable to artificial sand. And the best m-sand fineness modulus is 2.6-3.0, and the gradation zone is 2. When artificial sand is used in concrete that should add some admixtures, it is more sensitive to admixtures than natural sand.
The high-strength pumping concrete made of machine-made sand is not easy to block during the pumping process. And the concrete made of m-sand with a proper proportion has the advantages of high density, good anti-permeability and anti-freezing performance. Its physical and mechanical properties and long-term durability can all meet the construction requirements. Manufactured sand is especially suitable for the production of high strength concrete, high performance concrete and pump concrete.
Manufactured sand can be used as one important component in concrete, mortar, and concrete and mortar products production. At present, China's largest Three Gorges Project(TGP), the Yellow River Xiaolangdi Project had used manufactured sand to produce concrete. Additionally, according to existing engineering projects, C10-C70 strength ordinary concrete and pump concrete made of m-sand can reach the maximum pumping height of 400m; It also has produced prestressed concrete beam with 64m span. In laboratory experiment, C100 concrete has a actual 155Mpa compressive stress at 90 days.Above all, m-sand will have more and more applications in construction industry both for economic and environment benefits.