A novel method of self-healing cement paste by using gel microparticles encapsulating phosphate
A novel method of self-healing cement paste by using gel microparticles encapsulating phosphate
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DOI：
10.1016/j.conbuildmat.2021.122439
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发表时间：
2021-02-04
影响因子：
7.4
通讯作者：
Chen，Wanyu
中科院分区：
文献类型：
--
作者：
Zhang，Heng;Qi，Chenjie;Chen，Wanyu
混凝土的抗拉强度有限，容易产生裂缝，这促使研究人员提出了自愈的概念。受生物骨骼自愈合的启发，本文利用羟基磷灰石作为水泥基材料的愈合物质，设计了聚丙烯酰胺(PAM)凝胶微粒作为水泥浆体自愈合系统的磷酸盐载体。研究了PAM凝胶微粒的形态和性能、羟基磷灰石作为愈合剂的可行性和愈合效率。结果表明，PAM的三维交联结构可以包埋磷酸盐，交联剂的含量可以控制磷酸盐的释放速率和累积释放量。与普通水泥浆体相比，掺有PAM和磷酸盐的水泥浆体自愈后的氯离子渗透性降低。自愈水泥基材料养护28d后，抗压强度修复率达81.9%，抗渗水修复率达93.2%。多种分析技术证明修复部位的白色反应产物为羟基磷灰石。
Concrete is liable to form cracks owing to the limited tensile strength, which prompts researchers to propose a concept of self-healing. Inspired by the biological bones self-healing, this paper utilized hydroxyapatite as healing substances of cement-based materials and designed polyacrylamide (PAM) gel microparticles as carriers of phosphate for cement paste self-healing system. Morphology and properties of PAM gel microparticles, feasibility of hydroxyapatite as healing agents and healing efficiency were studied. The results showed that the three-dimensional crosslinked structure of PAM can encapsulate phosphate and the content of crosslinking agent can control the release rate and cumulative release of phosphate. Chloride permeability of cement paste containing PAM with phosphate is reduced after self-healing compared with plain cement paste. The healing efficiency of self-healing cement-based materials can reach 81.9% for compressive strength repair ratio and 93.2% for resistance to water penetration repair ratio after curing for 28 days. The white reaction products at the repairing section are proved to be hydroxyapatite according to multiple analytical techniques.