[论文解读] Autonomous Repair in Cementitous Material by Combination of Superabsorbent Polymers and Polypropylene Fibres: A Step Towards Sustainable Infrastructure

Souradeep Gupta, Harn Wei Kua+1 more|arXiv (Cornell University)|Jun 8, 2017

Microbial Applications in Construction Materials参考文献 6被引用 5

一句话总结

本研究提出一种自愈合胶凝复合材料，结合聚丙烯（PP）纤维与超吸水性聚合物（SAP），可自主封闭裂缝并恢复力学性能与耐久性。该系统在潮湿条件下实现高达90%的耐久性恢复和完全的力学强度恢复，裂缝密封效率达85%，并通过碳酸盐沉淀完全封闭最大330 µm的裂缝。

ABSTRACT

Manual maintenance and repair of cracks in concrete structures are often unsustainable because of associated labor, capital and environmental damage. Introduction of microfibers and superabsorbent polymers is a material solution to restrict crack propagation and enhance self-healing efficiency. Therefore, the study proposes a combination of polypropylene(PP) fibers and superabsorbent polymers (SAP) which would facilitate autonomous healing and recover original mechanical and durability properties of mortar. Mechanical strength, sorptivity and water penetration of healed mortars were compared to that of undamaged mortar at same age to estimate recovery of original properties while crack sealing was investigated by means of optical microscopy. Experimental results show mortar with combination of PP fibers and SAP showed full recovery of mechanical strength after healing while recovery in durability up to 90% was recorded. Microscopic images show that average crack-sealing ratio of 85% could be achieved under moist condition by combination of SAP and PP fibers while sealing under drier air curing condition is also significantly higher than reference samples with only fibers. Crack width up to 330μm has been found to be completely sealed by carbonate crystals. Furthermore, mortar with SAP and PP fibers retain about 70% of their original 28-day strength after three cycles of loading while reference mortar samples were found to retain only about 40-50% of their original strength. Effective crack sealing and high recovery of original properties in mortars with SAP and fibers suggest that this material combination would reduce the need for environmentally damaging and expensive repairs during the service life.

研究动机与目标

• 解决混凝土基础设施人工修复带来的不可持续成本与环境影响。
• 开发一种可自主封闭裂缝、无需外部干预的自愈合胶凝材料。
• 通过PP纤维与SAP的协同作用，提升受损砂浆的力学强度与耐久性恢复。
• 评估该混合系统在不同环境条件（潮湿与干燥养护）下的有效性。

提出的方法

• 在受控掺量下将聚丙烯（PP）纤维与超吸水性聚合物（SAP）掺入砂浆混合物。
• 采用光学显微镜分析裂缝密封效率及愈合区域的形貌。
• 在多次加载循环前后对试样进行力学测试（抗压强度），以评估强度恢复情况。
• 通过测量吸水率与渗水性，评估愈合后耐久性恢复情况。
• 在潮湿与干燥条件下养护试样，以评估环境对愈合性能的影响。
• 通过显微镜观察与化学分析监测愈合裂缝中碳酸盐晶体的形成。

实验结果

研究问题

• RQ1 PP纤维与SAP的结合是否能实现胶凝材料的自主裂缝自愈？
• RQ2 在自愈合后，受损砂浆的力学强度与耐久性可恢复到何种程度？
• RQ3 环境湿度（潮湿与干燥养护）如何影响该混合系统的裂缝密封效率？
• RQ4 该自愈机制可完全封闭的最大裂缝宽度是多少？
• RQ5 与仅含纤维或仅含SAP的系统相比，该混合系统在多次循环加载后的强度保持率如何？

主要发现

• 掺入PP纤维与SAP的砂浆在愈合后实现与未损伤对照试样相当的完整力学强度恢复。
• 耐久性恢复最高达90%，通过吸水率与渗水性测试测得。
• 在潮湿养护条件下，平均裂缝密封率达到85%。
• 通过愈合过程中形成的碳酸盐晶体，最大330 µm的裂缝可被完全封闭。
• 经过三次加载循环后，混合砂浆保留了约原始28天强度的70%，显著优于仅含PP纤维的对照样品（仅保留40–50%）。
• 在干燥养护条件下，裂缝密封效果仍显著高于仅含PP纤维的对照样品，表明该系统在不同环境条件下均具备增强的自愈潜力。