| By the end of 2015, Anhui iron and steel production capacity reached 3000-3500 million tons, if by 10% estimates, the province’s steel slag production in 2015 was about 300-350 million tons. The discharge of steel slag not only takes up a lot of land resources, but also brings bad effects on the environment and human health. Steel slag in the chemical composition and mineral composition similar to Portland cement clinker, with certain agglutinability, but steel slag volume stability problem has become limit its application in cement concrete in the main reason. If the content of free calcium oxide in steel slag can be reduced, the volume stability of steel slag applied to cement concrete materials can be improved, which can save resources, reduce cost, and protect environment and reduce the waste of land.According to Anhui province Maanshan Steel slag powder mineral composition, microstructure and physical properties of basic research. Analysis of chemical composition and mineral Maanshan Steel Slag Powder by means of fluorescence analysis, XRD. The volume stability test and mechanical property test of steel slag powder were carried out, and the effect of free calcium oxide on the volume stability of cement based materials was explored. The coal gangue as a modifier, according to different proportion optimization design, through Si O2 and Al2O3 in the component under high temperature of 800 DEG C for physical and chemical reaction of f-Ca O in steel slag absorption and to heat treatment of free calcium oxide mixture titration analysis, determine the best formulation of steel slag and coal gangue. This study for improving the heat treatment of steel slag powder mixture in the application of cement concrete were system test of mixture on Soundness of cement, volume stability of cement mortar, mechanical properties, by scanning electron microscope(SEM) mechanism of. Analysis of mixed material influence on the properties of cement based materials.The results show that the mechanical properties of cement-based materials decreases with the increase of the effect of steel slag powder content, especially the early strength decreased obviously, but later improved to some extent. The effect of steel slag powder effect on the volume stability of cement-based materials obviously, the same age with the increase of the dosage of steel slag free expansion rate increased. The analysis shows that f-Ca O is the root cause of the volume expansion of the cement base material. For steel slag heat of raw materials before and after the treatment, the content of free calcium oxide in no obvious change; along with the modifier dosage of coal gangue from 10% to 50%, by heat treatment process, the content of free calcium oxide reduction rate is 8.24 percent from up to 50%. When the mixture of coal gangue is accounted for 40%, the mixture of free calcium oxide content is 1.12%, meet the requirements of the content of free calcium oxide in cement clinker. The quality of steel slag and coal gangue was compared with 6:4 mixture for heat treatment, and the new type of composite material was prepared, and its effect on the properties of cement base materials was studied. Results show that as the mixed expected increase in dosage, cement-based material volume shrinkage compensating effect is improved obviously, mechanical properties with content decreases with increasing, but increased at the late; when adding 20% modified mixed material in the middle of the flexural strength did not decrease, the compressive strength than the single doped steel slag powder has significantly improved. Were observed by scanning electron microscope(SEM), mixed with slag mixture and blank sample of cement-based materials compared, the gel content changed little, but with the age growth, adding modified slag mixture of cement stone density has increased, flaky crystal filling the voids may is located on the causes for the volume shrinkage compensating of cement based materials. |
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