Preparation And Basic Performance Studies Of Iron Tailings-Expansive Perlite Concrete

As infrastructure construction in our country continuing,the yield of concrete has increased year by year.At the same time,natural sand-gravel reserves have been gradually reduced,and concrete raw material crisis has gradually emerged.In order to cope with the current lack of sand-gravel resources,the idea of using various types of industrial solid wastes instead of sands and gravels as concrete aggregates has been widely recognized.Iron tailings as common industrial solid wastes have been widely used in the building material industry,but the added value is relatively low when they are directly used for the preparation of ordinary cement concrete.Therefore,it is of great significance to use iron tailings instead of natural sands as fine aggregates to prepare iron tailings-expanded perlites concrete and simultaneously exert the advantages of iron tailings(high strength)and expanded perlite(excellent thermal insulation properties),accordingly achieving the collaborative optimization of basic performance,mechanical properties and thermal insulation performance of concrete.This project focuses on the preparation of iron tailings-expanded perlite concrete and its basic properties,mechanical properties,and thermal insulation properties.The experimental research and results obtained are as follows:(1)The basic performance tests of iron tailings-expanded perlite concrete with different iron tailings and expanded perlite replacement rates were conducted based on the completion of mix ratio design and preparation,testing slump,water absorption and dry bulk density of iron tailings-expanded perlite concrete.The testing results show that with the increase of the replacement rate of expanded perlite,the dry bulk density decreases and the water absorption increases;with the diameter of the expanded perlite increases,the slump and water absorption increase but the dry bulk density decreases;with the replacement rate of iron tailings increases,the slump and water absorption of iron tailings-expanded perlite concrete decrease.(2)The mechanical tests of iron tailings-expanded perlite concrete were conducted to test the compressive strengths of iron tailings-expanded perlite concrete at 7d,28 d,and 56 d.The test results show that the compressive strength of expanded perlite concrete decreases in the fluctuations with the increase of the replacement rateof expanded perlite.Compared with the other groups of fineness,the expanded perlite concrete has the largest compressive strength when the particle size of the expanded perlite is 0.6mm-1.15 mm.When the replacement rate of expanded perlite is 100%,with the increase of the replacement rate of iron tailings,concrete compressive strength decreases.(3)The thermal insulation performance test of iron tailings-expanded perlite concrete was conducted to test its thermal conductivity.The experimental results show that as the replacement rate of expanded perlite increases,the thermal conductivity of concrete decreases;with the increase of the particle size of expanded perlite,the thermal conductivity of the expanded perlite concrete increases.When the replacement rate of the expanded perlite is 60%,with the increase of the replacement rate of the iron tailings,the thermal conductivity of concrete increases.