基于玄武岩纤维的大体积混凝土自愈合性能研究

Study on the Self-Healing Performance of Mass Concrete Based on Basalt Fiber

地铁工程建造过程中常采用的大体积混凝土,早期易出现收缩、温度裂缝,影响混凝土的耐久性,引发渗漏,存在巨大的工程隐患。针对此类问题,以玄武岩纤维的体积分数与纤维长度为变量,开展对大体积混凝土自愈合性能的研究。结果显示:玄武岩纤维的加入导致混凝土的流动性下降,施工和易性变差;玄武岩纤维具有抑制混凝土开裂的作用,且在混凝土开裂后能够为其中未水化反应的胶凝材料提供成核点,促进混凝土自愈合行为的发生;当玄武岩纤维体积分数为0.1%、纤维长度为18 mm时,混凝土的抗压强度最大,抗渗性能、自愈合效果最好。

Mass concrete is often used in the construction process of subway engineering,which is prone to shrinkage and temperature cracks in the early stage,which affects the durability of concrete and causes leakage,and there are huge hidden dangers in the project.To solve these problems,the self-healing properties of mass concrete were studied by taking the volume fraction and fiber length of basalt fiber as variables.The results show that the addition of basalt fibers leads to the decrease of concrete fluidity and the deterioration of construction workability.Basalt fibers can inhibit the cracking of concrete,and can provide nucleation point for the cementitious material without hydration reaction after concrete cracking,and promote the self-healing behavior of concrete.When the basalt fibers volume fraction is 0.1%and the fiber length is 18mm,the compressive strength,impermeability and self-healing effect of concrete are the best.