保坍型聚羧酸减水剂的吸附-分散机理  

Adsorption-dispersion mechanism of polycarboxylate admixture for slump retention(PCA)

作　　者：赵越[1] 蒋亚清[1] 张敏杰[1] 

机构地区：[1]河海大学力学与材料学院,江苏南京210098

出　　处：《新型建筑材料》2016年第6期57-59,74,共4页New Building Materials

基　　金：国家"十二五"科技支撑计划项目(2012BAB03B02)

摘　　要：分析了保坍型聚羧酸减水剂(PCA)的等温吸附特性,利用XRD研究了PCA在C3A水化产物中的插层行为,基于TGDSC定量了掺与不掺减水剂的水泥浆体中的钙矾石(AFt)和单硫型水化硫铝酸钙(AFm)。结果表明,PCA可在水化铝酸钙中插层,形成的有机金属矿物相在水泥水化体系中逐步转化为AFm,加之PCA促进了水泥水化初期AFt和AFm形成,使1 h吸附量降低。促进水化硫铝酸钙形成及提高溶液经时平衡浓度是保坍型聚羧酸减水剂的主要作用机制。Isothermal adsorption characteristic of polyearboxylate admixture for slump retention （PCA） was analyzed,and interealation behavior of PCA into layered hydrate of C3A was investigated by XRD. Ettringite （AFt） and monosulfoaluminate （AFm） were quantified based on TG-DSC. It is indicated that PCA may intercalate into aluminum hydrate to form organic metal minerals. Gradually, it conversion to AFm in cement hydration system. Adsorption amount at 1 hour is decreased for both the transformation process and the acceleration of initial AFt and AFm formation. The main mechanism of polyearboxylate admixture for slump retention is the more hydrated ealcium aluminate sulfate formation and the increase of equilibrium concentration with time.

关 键 词：混凝土 减水剂 聚羧酸减水剂 适应性 吸附 钙矾石 

分 类 号：TU528.042.2[建筑科学—建筑技术科学]