实验参数对固废基发泡混凝土试块性能的影响研究

以超细粉煤灰和钢渣超微粉为主要原料,配加少量水泥和铝粉发泡剂制备发泡混凝土试块.实验系统考察了不同水灰比、发泡剂掺量、发泡温度对发泡混凝土试块的绝干密度、抗压强度、吸水率和孔隙率的影响.结果表明,铝粉发泡剂掺量从1‰增加到7‰,所得试块的绝干密度和抗压强度分别降低36％和84％;而对应的吸水率和孔隙率增加幅度分别高达79％和30％.水灰比从0.65增加到0.95,所得试块的绝干密度和抗压强度分别降低26％和82％;而对应的吸水率和孔隙率均出现"先增后减"趋势,其中吸水率增加幅度为34％,降低幅度为24％;孔隙率增加幅度为18％,降低幅度为9％.发泡温度从25 ℃增加到90 ℃时,试块的绝干密度和抗压强度整体上呈"先降后升"趋势,绝干密度降幅约为30％,升幅约为60％;抗压强度降幅为50％,升幅高达140％.优化后的实验条件为:铝粉掺量1‰～3‰、水灰比65％～75％、发泡温度40 ℃左右.试块抗压强度与绝干密度随制备条件变化幅度不一致,这说明有可能通过制备工艺优化获得"高强度、低密度"的发泡混凝土产品.

Effect of Experimental Parameters on the Performance of Solid Waste Foamed Concrete

Solid waste foamed concrete was prepared by using the ultrafine fly ash and the steel slag as the main raw material with amount of cement and a little of aluminum powder.The influence of some factors including water-solid ratio,aluminum powder content and foaming temperature on the product properties such as dry density,compressive strength,water absorption and porosity were investigated.The results show that with the content of aluminum powder varying from 1‰ to 7‰,the change rate of dry density and compressive strength decrease by about 36％and 84％respectively,while the decreasing rate of water absorption and porosity are about 79％and 30％respectively;when the water-solid ratio increases from 0.65 to 0.95,the change rate of dry density and compressive strength decrease by about 26％and 82％;while,it showes a trend of increasing first and then decreasing for water absorption and porosity,the increasing rate of 34％at first and then with a decrease of 24％for water absorption,the increasing rate of 18％at first and then with the decreasing rate about 9％for the porosity.With the foaming temperature increasing from 25 ℃ to 90 ℃,it showes a trend of decreasing first and then increasing for dry density and compressive strength,the decreasing rate by about 30％at first and then with increasing rate of 60％for the dry density,the decreasing extent by about 50％at first and then with the increasing extent of up to 140％.The optimized conditions: the content of aluminum powder of 1‰-3‰,the water-solid ratio of 65％-75％,the foaming temperature is about 40 ℃.The otherness of the change rate between the compressive strength and the dry density with preparation conditions indicate that it is possible to obtain the foamed concrete products with higher strength and lower density by optimization the preparing condition.