Wo Jiangang, Wang Di, Zhang Ting, Shi Chengfang, Zhou Zhengfa, Wang Aiguo, Wang Wenping
School of Chemistry and Chemical Engineering, Hefei University of Technology Hefei 230009 China
School of Materials and Chemical Engineering, Anhui Jianzhu University Hefei 230009 China.
RSC Adv. 2023 Mar 14;13(12):8398-8408. doi: 10.1039/d3ra00373f. eCollection 2023 Mar 8.
The extensive applications of manufactured sand (AS) in cement-based composites were restricted because of its coarse surface texture, poor gradation and inevitable agglomeration. In this paper, a specifically designed polycarboxylate superplasticizer (PCE) decorated manufactured sand (AS-PCE) composite was synthesized radical polymerization. The AS-PCE composite was characterized by FTIR, TGA, XPS and SEM. The load of PCE on the surface of AS was ∼12 wt%. Our results show that AS-PCE can promote cement hydration reaction and refine the microstructure of a cement-based material, thus, reinforcing its mechanical strength. Meanwhile, the fluidity of cement mortar with 1 wt% AS-PCE particles was increased by 35% after 1 h hydration, due to the steric hindrance effect provided by polycarboxylate superplasticizer affiliated with AS-PCE. The AS-PCE can also significantly enhance the mechanical strength (especially, the flexural strength was about 25% increased after curing for 28 days) of mortar. The excellent improvements result from the synergistic effects of AS-PCE including superb dispersibility, promotion of cement hydration reaction and the repair of interfacial defects between AS particles and the cementitious material. The research provides a promising method for the AS application in cement-based materials.
由于机制砂（AS）表面粗糙、级配差且不可避免地存在团聚现象，其在水泥基复合材料中的广泛应用受到限制。本文通过自由基聚合合成了一种特殊设计的聚羧酸减水剂（PCE）修饰的机制砂（AS-PCE）复合材料。采用傅里叶变换红外光谱（FTIR）、热重分析（TGA）、X射线光电子能谱（XPS）和扫描电子显微镜（SEM）对AS-PCE复合材料进行了表征。PCE在AS表面的负载量约为12 wt%。我们的结果表明，AS-PCE可以促进水泥水化反应，细化水泥基材料的微观结构，从而增强其机械强度。同时，由于AS-PCE所附属的聚羧酸减水剂提供的空间位阻效应，含有1 wt% AS-PCE颗粒的水泥砂浆在水化1 h后的流动性提高了35%。AS-PCE还能显著提高砂浆的机械强度（特别是养护28天后，抗折强度提高了约25%）。这些优异的改善效果源于AS-PCE的协同效应，包括优异的分散性、促进水泥水化反应以及修复AS颗粒与胶凝材料之间的界面缺陷。该研究为机制砂在水泥基材料中的应用提供了一种有前景的方法。
