Construction waste accounts for about 40% of total urban solid waste , mainly containing waste concrete , waste bricks, mortar waste , waste ceramics , glass and so on. Of concrete garbage in 2010 reached 2.39 × 109 t, is expected in 2020 will reach 6.38 × 109 t, with an average of 8 % of the amount of annual growth . If you press the stacking height of 5m , 10,000 t of construction waste will be an area of ​​2 acres , construction waste not only occupy the land , but also pollute the air and water quality , the impact of the human living environment . The crushing of construction waste recycled aggregate for the building materials industry is efficient use of the method . Research presented by : recycled aggregate should be divided into recycled coarse aggregate and recycled fine aggregate , and take measure of mixing warehouse , not to use recycled aggregate gradation of the whole concept and related technology roadmap . At present, the recycling of construction waste coarse aggregate more research , but relatively little research on recycled fine aggregate .
   Ordinary concrete sand fineness modulus range of 3.7 to 1.6 . In the sand fineness modulus between 1.5 to 0.7 for the special sand was not suitable for mixing concrete . The rich reserves of extra fine sand , the majority of the Yangtze River, Yellow River and the desert areas and the lack of equal distribution of wealth produced in special sand grit resources. Sand, stone and other aggregates resource with the weight of a large amount of more features , suitable for long distance transport , the need to meet the economic requirements of local materials . Thus , the bulk of research and development in areas of special sand method using local resources , with better economic benefits. The construction waste in the waste concrete , crushed brick waste is recycled fine aggregate sand mixed with Kaifeng local special use , get mixed construction waste recycling sand , used in the preparation of concrete . Research on the impact of construction waste regeneration of mixed sand and mechanical properties of fresh concrete hardened concrete and ordinary concrete properties were compared .