缓凝剂对脱硫石膏性能的影响

Effect of Retarder on Performance of Desulfurized Gypsum

研究了DF、PF两种复合缓凝剂对脱硫石膏凝结时间、水化进程、力学强度及耐水性能的影响。研究结果表明:两种缓凝剂都能明显延长脱硫石膏的初、终凝时间和养护峰值温度出现的时间,且养护峰值温度皆出现在石膏终凝以后的一段时间,DF缓凝剂对脱硫石膏的缓凝效果大于PF缓凝剂。两种缓凝剂随掺量增加,脱硫石膏的抗折强度呈下降趋势,但抗压强度则呈先小幅度提高后下降的趋势,掺量越大,下降幅度越大。DF、PF两种复合缓凝剂对脱硫石膏的耐水性都有不同程度的提高,随掺量的增加呈先提高后降低的趋势,其下降拐点掺量为脱硫石膏质量的0.020%。

The effects of DF and PF composite retarders on the setting time,hydration process,mechanical strength and water resistance of desulfurized gypsum were studied.The research results illustrate that both retarders can significantly prolong the initial and final setting time and the time for the peak value of the curing temperature.the peak value of the curing temperature occurs during a period of time after the final setting of the plaster.The effect of DF retarder is much better than that of PF retarder.The flexural strength of the desulfurized gypsum decreases with the increasing amount of the two retarders.However,the compressive strength increases a little and then decreases with increasing amount of the two retarders.The more the adding amount is,the greater the decrease of compressive strength is.The two kinds of composite retarders(DF and PF)can improve water resistance of desulfurized gypsum with different degrees.With the amount of the retarder increasing,the drop inflection point of the quality of the desulfurized gypsum is 0.020%.