超高强混凝土用降粘型外加剂复配技术研究  

Research on Compounding Technology of Viscosity-reducing Admixtures for Ultra-high Strength Concrete

作　　者：王林 魏子程 杜艮坤 郭宏[2] 刘东红[2] 荆学亚[2] 

机构地区：[1]北京建筑大学土木与交通工程学院,北京102616 [2]中铁十七局集团有限公司,山西太原030006

出　　处：《混凝土世界》2023年第9期30-36,共7页China Concrete

基　　金：山西省2021年度重点研发计划项目“C100及以上强度等级自密实混凝土配合比研究”。

摘　　要：超高强混凝土胶凝材料用量大、水胶比低,导致其粘度较高、工作性能较差、泵送困难。本文以聚羧酸高适应性减水剂母液为基础,采用“先消后引”的方法,进行单组分试验及正交试验,探究不同引气剂和流变剂掺量对水泥净浆粘度、流动度以及胶砂的3 d和28 d抗折、抗压强度的影响规律,确定降粘型外加剂的最终配合比,为复配降粘型外加剂提供理论参考。结果表明:掺入适量的引气剂能有效降低水泥净浆的粘度,提高其流动度,是关键的降粘组分;掺入适量的流变剂能小幅度降低水泥净浆的粘度,提高其流动度,可以解决由于引气过多而导致水泥净浆粘聚性较差的问题;降粘型外加剂的最佳配合比为聚羧酸高适应性减水剂母液∶消泡剂∶引气剂∶流变剂=1000∶0.4∶0.4∶15。The high dosage of cementitious materials and low water-cement ratio of ultra-high strength concrete lead to higher viscosity,poorer working performance and pumping difficulties.In this paper,bases on the polycarboxylic acid highly adaptable water reducing agent mother liquor,adopting the method of"eliminating first and then inducing",single-component test and orthogonal test carries out to investigate the influence of different airentraining agent and rheological agent dosage on the viscosity,fluidity of the cement slurry,as well as the flexural strength and compressive strength of the mastic sand at 3 d and 28 d.It also uses to determine the final mixing ratio of the viscosity-reducing admixture,and to provide theoretical references for the compounding of viscosity-reducing additives.The results show that mixing appropriate amount of air-entraining agent can effectively reduce the viscosity of cement slurry,improve its fluidity,is the key viscosity-reducing component;mixing appropriate amount of rheological agent can reduce the viscosity of cement slurry in a small amount,improve its fluidity,can solve the problem of excessive air-entraining leading to the poor cohesion of the cement slurry;the optimal ratio of viscosityreducing admixture is polycarboxylic acid highly adaptable water reducing agent mother liquor∶defoamer∶airentraining agent∶rheological agent=1000∶0.4∶0.4∶15.

关 键 词：超高强混凝土 降粘型减水剂 引气剂 流变剂 

分 类 号：TU528[建筑科学—建筑技术科学]