Influence of Cooling Ways on the Structure and Hydraulic Activity of Blast Furnace Slag

摘要

Using the industrial limestone, fly ash and pure chemical reagents as raw materials, the blast furnace slag was prepared in the simulation condition of the actual slag-making process by three different cooling ways, including air cooling, water cooling and liquid nitrogen cooling. Combined with different test methods such as XRD, SEM, IR, the influence of cooling ways on the structure and hydraulic activity of blast fumace slag was studied in the present in investigation. The relationship between glass content, compressive strength and the phase compositions of blast furnace slag has been obtained. The results showed that, the glass content of water cooling slag or liquid nitrogen cooling slag was slightly higher than that of air cooling slag, there was obviously gehlenite crystal phase in air cooling slag. The 7D and 28D compressive strength of three slags did not present positive correlation with vitreous content, the sequence of 28D compressive strength of three slags was water cooling slag > air cooling slag > liquid nitrogen cooling slag. SEM observation found that crystallization phases in water cooling slag had a small grain and uniform distribution, this kind of structure was advantageous to the latter hydration reaction and strength development of blast furnace slag.