Research On Basic Mechanical Properties And Durability Of Steel Slag To Replace Part Of The Aggregate Concrete

The steel slag as the steel industrial waste of the steel industry, a lot of accumulation will cause a series of environmental pollution problems. In this paper, we use the different size steel slag to replace part of aggregate in concrete, to study in the same water cement ratio, cement under the condition of different varieties, the replacement rate of steel slag concrete is 10%, 20%, 30%, 40%, 50%, 60% and test them flexural strength and compressive strength of each age, to find out the best replacement rate of steel slag stone and steel slag sand stone. And for the best replacement rate of steel lag concrete were sulfate and magnesium salt Anti erosion test respectively, By means of scanning electron microscopy(SEM), energy spectrum(EDS) observation, analysis of the internal structure and the erosion products of test pieces. Get the following conclusions through the experiment:(1) In the case of constant water cement ratio, the replacement of steel slag increases from 10% to 60%,in the natural curing conditions, the test block can maintain their structural integrity. The optimal replacement rate of steel slag is :the steel slag stone replacement of the coarse aggregate in concrete 30%; steel slag sand replacement of fine aggregate in concrete 50%.(2) In the case of the same water cement ratio, different varieties of cement have great influence on concrete strength and size stability of steel slag concrete. Among them, when the cement use ordinary Portland cement, the early strength of steel slag concrete is low, but later strength increased fast; when the cement selection of sulphoaluminate cement, the early strength of steel slag concrete is high,later stage strength of relatively slow growth.(3) Keep original water cement ratio constant, with coarse and fine steel slag mixed replacement in concrete aggregate, the replacement of coarse aggregate 30%, replacement of fine aggregate 50%, when the cementitious materials using only the ordinary portland cement, slag concrete not only early great strength, post strength is also rising in standard curing condition.(4) To the steel slag stone and steel slag sand optimum substitution rate of concrete,do Anti erosion test of sulfate and magnesium salt, can be found it is a great help in steel slag sand on concrete anti erosion performance; the steel slag stone replaced the coarse aggregate in concrete, with the increase of time,its disadvantages more obvious.(5) In the cement variety, replacement of amount, maintenance and replacement of erosion are the same circumstances, improve the steel slag sand on concrete obviously than the steel slag stone, it is obvious that the finer the potential activity of the larger, more help to improve the strength of concrete.