| Steel slag is a steel enterprises discharge of industrial waste residues, according to statistics, in 2013 China’s steel slag quantity is about 100 million tons, and the national steel slag accumulated stockpiling has amounted to 1 billion tons.But, at present, the comprehensive utilization ratio of steel slag is only 10% in our country. Slag gave rise to a series of questions, such as the occupation of land resources, environmental pollution, and destruction of water quality. Slag has some gelling activity, In addition, slag is similar to the natural sand in robustness, surface morphology, particle size distribution, abrasion resistance, etc. So, slag is an ideal material as admixtures and aggregate. But slag contains a lot of f-CaO, greatly affect the safety and durability of the building. Stability of steel slag has great research value for efficient resource utilization of slag.In this paper, Slag stacked more than a year, will be applied separately to cementitious materials, mortar and concrete according to different size of slag. Research on steel slag effect on the stability of cementitious materials, mortar and concrete. By adding siliceous material and reducing the particle size of the slag to improve the stability of the specimen, using boiling cooking method, autoclave method, hydrothermal comprehensive inspection the stability of slag, and using X-ray diffraction analysis the ore phase of cementitious materials mixed with steel slag powder after hydration.In the study of steel slag powder stability, results show that under the condition of boiling, the stability of cementitious material with 30% steel slag powder is qualified, under the condition of the autoclave, the largest steel slag powder content is 10%. Given the relatively poor stability of steel slag, the stability of slag powder improved by adding fly ash, silica fume, mineral powder and CaCl2. After adding siliceous materials, especially when mixed with fly ash and silica fume, the stability of steel slag has been significantly improved, but the improvement is ineffective for CaCl2. Under pressure steam conditions, by adding the siliceous material, steel slag content can reach to 50%. In order to properly simulate the real environment, In this paper, using 90℃ hydrothermal test the stability of steel slag powder, under the condition, the steel slag powder maximum content is 30%, and the results were consistent boiling method. By X-ray diffraction pattern analysis, the greater the amount of incorporation of slag powder, the more Ca(OH)2 content of cementitious material after hydration.In the study of steel slag mortar stability, results show that, reducing the particle size of the slag sand and adding siliceous material may be improve the stability of steel slag sand. The stability of the steel slag sand deteriorates with steel slag sand particle size increases, maximum diameter of 1.18 mm and 0.6 mm, the biggest dosage of the steel slag sand is 10% and 15%, respectively. Study to improving the stability of slag sand by adding fly ash and silica fume. Siliceous materials to improve the stability of steel slag mortar has a positive effect, In the fly ash content of 25%, the maximum dosage of slag sand is 15%; in the fly ash content of 35%, the largest steel slag sand content of 25%. At 90℃ hydrothermal conditions, f-CaO in the slag sand reacts with water is not sufficient, can not reasonably characterize the stability of steel slag mortar.In the study of steel slag concrete stability, results show that, the influence of siliceous materials improve the stability of steel slag stone is not obvious, by adding siliceous materials and the reasonable adjustment dosage, In the fly ash content of 25%, the biggest single slag stone dosage of 15% in the concrete. After adding steel slag powder and steel slag sand in concrete, its stability has been improved, in this case, the maximum content of slag stone is 35%. At 90℃ hydrothermal conditions reflect the poor stability of slag stone, then the maximum dosage slag stone is 25%. |
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