Experimental Research On Fracture Performance Of Steel Slag Concrete

The application of new materials in concrete has become an important subject of properties of concrete and utilization of waste and environmental protection, adding to new materials in the concrete may be necessary to enhance performance of concrete. The research content of this paper is a new type of environmentally friendly high-performance concrete material-steel slag concrete (SSC). This new concrete material is mainly made of waste slag. The use of steel slag’s high strength, high water absorption characteristics can improve the mechanical properties of concrete, this paper studies the fracture properties of steel slag concrete (including fracture energy, fracture stress intensity factor, double-K fracture parameters). We study the steel slag concrete notched beam with size of 150mm×150mm× 550mm by three-point bending test, and acquire the data from the experiment. There are three following aspects of our research content of this article:(1) By using steel slag as coarse aggregate incorporated into the ordinary concrete and rubber concrete which rubber replace 10% fine aggregate, then materials could be formulated into steel slag coarse aggregate concrete and steel slag rubber concrete(content of 20%,40%,60%,80%,100%), the experimental data were measured by three-point bending test which could be calculated and we can get load-deflection curves, load-crack mouth opening displacement curve and load-strain curve, then we can get fracture energy and stress intensity factor of steel slag coarse aggregate concrete and steel slag rubber concrete from it. The results show that with the increase of content of steel slag, The fracture energy of steel slag aggregate concrete increased at first and then decline with the growth trend and the lowest energy is under 60% content of steel slag, the highest energy is under 40% and 80%. The regularity of stress intensity factor、double-K fracture parameters and fracture energy is substantially the same as the maximum content at 100%. Incorporation of rubber will reduce the anti-breaking strength of steel slag concrete、the peak load which is much smaller than NC, and the regularity of fracture properties keeps the same with steel slag concrete.(2) By using steel slag as fine aggregate incorporated into the ordinary concrete (content of 20%,40%,60%,80%,100%), measuring the experimental data by three-point bending test,then calculate the curves and fracture properties by the formula. The test results show that the fracture energy increased at first and then declined with the growth of the content of steel slag, and the maximum value is reached at the 60% content. Stress intensity factor and double-K fracture parameters increases with growth of the content, but it dropped to the lowest value of stress intensity factor at 80%.(3)Steel slag powder concrete (content of 5%% 、10%、15%、20%) is made by steel slag powder instead of cement added to the concrete. Measuring the experimental data by three-point bending test, then calculate curves and fracture properties. The test results show that the fracture energy、stress intensity factor、double-K fracture parameters is improved at content of 5%,but it declined with the growth of content, some other fracture properties also declined with the growth of content.