中文摘要：

对比研究了聚羧酸减水剂（polycarboxylate superplasticizer,PCS）对原生与再生石膏性能的影响,并通过SEM、粒径分析对其作用机理进行分析。结果表明：PCS对再生石膏与原生石膏性能影响差异显著,相同掺量下,PCS对再生石膏具有更强的减水能力;随PCS掺量增加,原生石膏凝结时间延长,而再生石膏的凝结时间却呈先缩短后延长的趋势;原生石膏2h强度与干强分别在0.12%、0.15%掺量下达到峰值,之后强度降低;而随PCS掺量的增加,再生石膏强度不断增加,在掺量0.20%内,并无再生石膏最佳的PCS掺量。分析表明,再生石膏较大的比表面积和较小的粒径是导致PCS对其产生较好减水效果的主要因素,随PCS掺量的增加,再生石膏硬化体致密度增加、晶体搭接更紧密,因此其强度大幅提高。

英文摘要：

The effect of polycarboxylate superplasticizer（PCS）on performances of recycled gypsum is investigated in comparison with raw gypsum.The mechanism is also studied based on SEM observation and particle size and distribution measurements.The results showed a significant difference between the influences of PCS on both recycled plaster（R-P）and plaster of paris（POP）and a higher water reducing capacity of R-P than that of the same dosage of POP.The setting time of POP was prolonged with the increase of PCS,whereas first decreased and then increased for POP.The peak of POP occupied by 2hstrength and dry strength with the addition of PCS was 0.12% and 0.15%,respectively,after which it began to reduce.However,the strength of R-P was increased with the dosages of PCS,and no optimal dosage was found in the dosage of0.20% and below.The analysis provides that the main factor of the good water reducing effect on R-P is due to the large specific surface area and small particle sizes.The density of crystals and lapping closely increasing with the dosages of PCS,improving the strength of R-P dramastically.