机制砂中残留的APAM絮凝剂对水泥基材料性能影响研究  

Research on the Effect of APAM Flocculant Residues in Manufactured Sand on the Properties of Cement⁃Based Materials

作　　者：郝迎军[1] HAO Yingjun(China Railway 16th Bureau Group Co.Ltd.,Beijing 100018,China)

机构地区：[1]中铁十六局集团有限公司,北京100018

出　　处：《铁道建筑技术》2023年第12期20-23,45,共5页Railway Construction Technology

基　　金：中铁十六局集团有限公司科技研究开发计划项目(K2021⁃23A)。

摘　　要：通过水泥净浆、水泥胶砂及混凝土试验,研究机制砂残留阴离子聚丙烯酰胺(APAM)浓度对水泥净浆粘度、流动度和凝结时间的影响规律,并深入分析APAM浓度对水泥胶砂强度及新拌混凝土性能的影响。结果表明:随APAM絮凝剂浓度增大,水泥净浆流动度会逐渐降低,相较于不掺外加剂的水泥净浆,掺加外加剂的水泥净浆受APAM影响更大,当浓度大于0.6‰时,流动度下降趋势陡然增大;由于APAM的锁水效应,随APAM絮凝剂浓度升高,水泥净浆粘度均值逐渐增大、凝结时间缩短,且随浓度增加,对水泥净浆凝结时间影响愈发明显。APAM对水泥胶砂抗折和抗压强度均有影响,随APAM浓度提高,水泥胶砂抗折、抗压强度逐渐降低,APAM的掺入对水泥胶砂的3 d抗折及抗压强度无显著影响;7 d龄期后APAM影响加强,随浓度升高,抗折、抗压强度随之减小,当浓度达到0.1‰时,抗折、抗压强度分别减小25%、27%,严重影响水泥胶砂的抗折和抗压强度;当龄期到达28 d,APAM对强度的破坏作用更为明显。This article investigates the influence law of residual anionic polyacrylamide(APAM)concentration in machine⁃made sand on the viscosity,flowability,and setting time of cement paste through experiments on cement paste,cement mortar,and concrete.Furthermore,the influence of APAM concentration on the strength of cement mortar and the performance of fresh concrete is analyzed deeply.The results show that as the concentration of APAM flocculant increases,the flowability of cement slurry gradually decreases.Compared with cement slurry without additives,cement slurry with additives is more affected by APAM.When the concentration is greater than 0.6‰,the flowability decreases sharply;due to the water locking effect of APAM,as the concentration of APAM flocculant increases,the average viscosity of cement paste gradually increases,and the setting time decreases.Moreover,as the concentration increases,the impact on the setting time of cement paste becomes more and more obvious.APAM has an impact on the flexural and compressive strength of cement mortar.As the concentration of APAM increases,the flexural and compressive strength of cement mortar gradually decreases.The addition of APAM has no significant effect on the three⁃dimensional flexural and compressive strength of cement mortar.When the strength reaches 7 days,the influence of APAM strengthens.As the concentration increases,the flexural and compressive strength decreases.When the concentration reaches 0.1‰,the flexural strength decreases by 25%and the compressive strength decreases by 27%,seriously affecting the flexural and compressive strength of cement mortar.When the age reaches 28 days,APAM has a more significant impact on the strength.

关 键 词：机制砂 水泥净浆 APAM浓度 强度 流动度 粘度 

分 类 号：TU521.1[建筑科学—建筑技术科学] TU502