| 摘要: |
| 测试了4种黏土的吸附率、吸水率和膨胀容，测定了蒙脱石的层间距，研究了不同黏土对聚羧酸减水剂(PCE)的吸附作用和吸附方式，分析了黏土吸附PCE后混凝土拌和物固液相体积的变化，探索了黏土对PCE应用性能的抑制机理.结果表明：黏土对PCE的吸附率远大于水泥，其中蒙脱石的吸附作用最强.PCE分子侧链嵌入蒙脱石的层间，使得蒙脱石层间距d(001)由1443nm增加到1863nm.黏土吸附PCE分子，使得产生分散作用的有效PCE含量降低；黏土吸附水后体积膨胀，导致混凝土拌和物中固相体积增大、液相体积减小，最终引起混凝土拌和物工作性能劣化. |
| 关键词: 聚羧酸减水剂 黏土 机理 吸附 |
| DOI：103969/j.issn1007 9629201402009 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目（51208012） |
|
| Inhibition Mechanism of Clays on Applying Performances ofPolycarboxylate Superplasticizer |
|
WANG Ziming1, WU Hao2, XU Ying3, LIU Xiao1
|
|
1.College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China;2.Beijing Oriental Yuhong Waterproof Technology Co. Ltd., Beijing 100025, China;3.Institute of Building Materials, China Academy of Building Research, Beijing 100013, China
|
| Abstract: |
| The adsorption rate, water absorption, volume swelling capacity of 4 kinds of clay, and the interlayer spacing of montmorillonite were tested. The adsorption capacity and mode of polycarboxylate superplasticizer(PCE) on different clays were studied. The volume change of solid and liquid phase in fresh concrete before and after adsorbing PCE by clay was calculated. The inhibition mechanism of clay on applying performance of PCE was explored. The results show that the adsorption of PCE on clay is higher than that on cement, and adsorption capacity of montmorillonite is the strongest of all. The side chain of PCE molecular is adsorbed into interlayers of montmorillonite, which increases the interlayer spacing(d(001)) of montmorillonite from 1443nm to 1863nm. Clay adsorbs more PCE and thus reduces the effective content for dispersing action. The volume of clay expands after absorbing water, increasing the solid phase volume and decreasing the liquid phase volume, and finally worsening the workability of fresh concrete. |
| Key words: polycarboxylate superplasticizer(PCE) clay mechanism adsorption |
