Study on Proportions and Applications of Concrete with Iron Mine Tailings
|Course||Architecture and Civil Engineering|
|Keywords||Mine tailings Resource utilization Special fine sand Mixed sand Engineering application|
The mine tailings in Beijing locality, industrial by-product from mining iron ore, have been heaped and its stock increasing rapidly. The mine tailings have made threat to the environment. The research interest will take these mine tailings used into aggregates of concrete which is used widely in the world, so that these mine tailings will be consumed in the construction effectively.The results have been as following based on experiment.1) The one of difficulties in the research is to use these mine tailings to fine aggregate to make concrete directly, because of these mine tailings are very fine usually. Thus, the mix design proportioning of concrete is accordance with the theory of gradation, and the workability of fresh concrete is guaranteed by decreasing the ratio of fine aggregate to coarse aggregate, adding AEA and supplementary cements into concrete mixture befittingly. Moreover, the mechanical property of this concrete is desired.2) The mixed fine aggregate made of mine tailings and artificial fine aggregate according to given proportions, could be used fine aggregate to made concrete which that the workability, mechanical property and durability are required. So, the compressive strength of the concrete is depend on the proportions between mine tailings and artificial fine aggregate.3) The relationship between cement to water ratio and compressive strength of concrete made by mine tailings and mixed fine aggregate can be described by Bolomey’s equation, where, n=0.27, A=-4～8.4) The concretes made by cements, mine tailings and mixed fine aggregate, coarse aggregate, admixtures, supplementary cements and water, can use into concrete structures engineering. For instance, the concrete of grade C50 can be used to precast reinforced concrete box girder. Also, the concrete of grade from C10 to C50 can used into construction of civil engineering. 5) The effects powder of limestone from mine tailings on properties of concrete are so different from clay in natural sand.The qualities of mine tailings must be controlled, including content of special fine powder. The research is valuable to produce ready-mix concrete with mine tailings. So far, the mine tailing have been used 300,000 wt to make desired concrete successfully. The utilization of mine tailings to reduce the damage to the environment, alleviate shortages of natural sand for cement concrete industry, also play a positive role in impact on other metal tailing utilization significance.