特种喷射混凝土用多元胶凝体系缓凝特性研究

Study on retardation of a quaternary cementitious materials system for special shotconcrete

研究了常温状态下,不同缓凝剂对复合快硬早强型水泥净浆凝结时间的影响。通过复配复合缓凝剂延缓水泥水化,通过对水泥凝结时间、水化温峰、X射线晶体衍射和扫描电镜分析不同龄期水泥水化产物Ca(OH)_(2)和AFt等生成量的影响,探讨了复合缓凝组分对快硬早强型水泥净浆的缓凝作用机理。结果表明,柠檬酸-硼酸-β-环糊精缓凝体系可以大幅抑制早期C_(3)S水化,由于协同效应,Ca(OH)_(2)生成量的减少和吸附量的增加使水泥浆体中Ca(OH)_(2)浓度大幅降低,有效降低了早期水化速率,具有很好的缓凝效果。

The effect of different retarders on the setting time of composite quick-hardening and early-strength cement paste at room temperature was studied.The hydration of cement was delayed by compounding a composite retarder.The products of ce ment hydration at different ages like Ca(OH)_(2) and AFt were analyzed by the setting time,hydration temperature peak,XRD and SEM.The effect of composite retarder components on the retardation mechanism of cement paste was discussed.The results show that the "citric acid-boric acid-β-cyclodextrin" retarder system can greatly inhibit the early C_(3S) hydration.The reduction of Ca(OH)_(2) generation and the increase of adsorption amount make the Ca(OH)_(2) in the cement paste due to the synergistic effect.The concentration of Ca(OH)_(2) was greatly reduced,which early hydration rate was effectively reduced and has a good retarding effect.