缓凝剂和高效减水剂对硫铝酸盐水泥流动性和强度的影响及其机理研究

发布时间：2018-01-29 22:54

本文关键词： 硫铝酸盐水泥高效减水剂缓凝剂流动性强度吸附　出处：《西安建筑科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：复合掺入缓凝剂与高效减水剂,被认为是改善水泥浆体流动性和降低浆体流动性经时损失的常用方法之一。针对硫铝酸盐水泥混凝土坍落度损失大和凝结时间不易控制等问题,本文选择了两种缓凝剂—柠檬酸(CA)和葡萄糖酸钠(SG),将它们分别与萘系高效减水剂(BNS)、氨基磺酸盐高效减水剂(AS)及聚羧酸高效减水剂(PC)复合掺入到硫铝酸盐水泥浆体和胶砂中,研究了缓凝剂对掺高效减水剂硫铝酸盐水泥塑化浆体流动性、凝结时间及胶砂试件各龄期强度的影响。测试结果表明:单掺高效减水剂时,水泥浆体流动度均随减水剂掺量的增加而增大;两种缓凝剂的掺量为0.03%~0.15%时,均使水泥浆体流动度有很大提高,并降低了经时损失,且SG的作用效果更好一些;缓凝剂的掺量越大,浆体的凝结时间越长,胶砂强度越低。对于上述现象,采用紫外分光光度计、Zeta电位仪、X-射线衍射仪(XRD)及扫描电子显微镜(SEM)对硫铝酸盐水泥浆体中高效减水剂的吸附量、浆体的Zeta电位、水化产物中钙矾石的生成量及其形貌进行了测试分析。实验结果表明:(1)随着高效减水剂掺量的增加和水化时间的延长,水泥浆体对高效减水剂的吸附量也增加;(2)水泥浆体的Zeta电位测试结果与流动性的结果很好地吻合;(3)XRD测试的结果表明CA和SG分别与以上三种不同高效减水剂掺入到水泥浆体中,均使水泥浆体中的钙矾石略有降低;(4)SEM测试结果表明三种高效减水剂掺入使得硫铝酸盐水泥浆体7d的水化产物钙矾石呈针状结构,而当两种缓凝剂分别掺入到三种高效减水剂塑化水泥浆体时,CA和SG则均抑制了水泥浆体中钙矾石的生长与结晶,且在7d时呈柱状结构。
[Abstract]:Mixed with retarder and superplasticizer. It is considered to be one of the common methods to improve the fluidity of cement paste and to reduce the loss of slurry fluidity in time, aiming at the problems of large slump loss of sulphoaluminate cement concrete and difficult control of setting time, etc. In this paper, two kinds of retarders, citric acid (CA) and sodium gluconate (SGN), were selected and used as naphthalene superplasticizers (BNSs). Amino sulfonate superplasticizer (ASA) and polycarboxylic acid superplasticizer (PCP) were mixed into sulphoaluminate cement paste and mortar. The effects of retarder on the fluidity, setting time and strength of cement plasticized paste with high efficiency water reducer were studied. The fluidity of cement paste increases with the increase of water reducer content. When the content of two retarders is 0.03 ~ 0.15, the fluidity of cement paste is greatly improved, and the loss of time is reduced, and the effect of SG is better. The larger the content of retarder, the longer the setting time of slurry and the lower the strength of cemented sand. For the above phenomena, the ultraviolet spectrophotometer and Zeta potentiometer are used. X- ray diffractometer (XRD) and scanning electron microscope (SEM) were used to study the adsorption of sulphoaluminate cement paste with superplasticizer and the Zeta potential of the slurry. The formation amount and morphology of ettringite in hydration products were tested and analyzed. The experimental results show that the content of water reducer increases and the hydration time increases with the increase of water reducer content. The adsorption capacity of the cement paste to the superplasticizer is also increased. (2) the Zeta potential of cement paste is in good agreement with that of fluidity. The results of XRD test showed that CA and SG were mixed with the above three kinds of superplasticizer into the cement paste, and the ettringite content in the cement paste decreased slightly. The SEM results show that the hydration product ettringite of sulphoaluminate cement paste has a needle-like structure after the addition of three superplasticizers. When the two retarders were added into the plasticized cement paste, CA and SG both inhibited the growth and crystallization of ettringite in the cement paste, and showed a columnar structure at 7 days.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528.042.2

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