The rock tailings in the quarries are one troublesome problem need to solve all the time. Recently, there are many customers asking us can rock tailings sand be used to produce concrete, the answer is absolutely yes. However, because of it has more difference from the natural sand, it should do some adjustment in concrete production formula.
The original rock tailings manufacturing sand contains many course particles with a worse grain gradation, but when we add fine sand in an appropriate proportion, its gradation can get an improvement so that it can be used to produce concrete. According to some existing experiments, putting tailings sand into concrete raw components will increase the water demand, but when we use the superplasticizer under the condition of same water consumption as using natural sand, it can also produce qualified concrete with the (180+20) mm slump and get the same construction performance as natural sand concrete. When the mixed tailings sand ratio is 7∶3 ( tailings sand : fine sand ), it can produce the C30 concrete and its compressive stress at 28 days increases by 8.7%. And the shrinkage value of the concrete made of rock tailings sand is larger than natural sand, however, with the improvement of mixed tailings sand in gradation and fineness modulus, mixed tailing sand’s influence on concrete shrinkage value will gradually decrease.