自修复混凝土修复效果影响因素的试验研究

Influencing Factors of Self-healing Performance of Concrete

为探究外界环境条件、裂缝初始宽度大小、玻璃纤维管的放置方式这3种因素对内置玻璃纤维管自修复混凝土修复效果的影响,以长城717为修复胶黏剂,以玻璃纤维管为载体制备自修复混凝土试件进行自修复试验.用修复后试件的抗折强度f1与对照组试件初始抗折强度f的比值η来表征修复效果,分析了3种因素与修复效果之间的关系.结果表明:修复效果随着外界环境条件(温度)的升高而增加,在特定的玻璃纤维管放置方式和预压荷载条件下,温度为30℃时的修复效果比-15℃时的修复效果最高提高了13.3%;在一定裂缝宽度范围内,裂缝初始宽度越小,修复效果越好,自修复混凝土能够修复裂缝初始宽度为1.0mm及以下范围内的微裂缝;玻璃纤维管的放置方式为梯形时的修复效果高于放置方式为菱形时的修复效果;当裂缝初始宽度达到约2.0mm时,玻璃纤维管的放置方式对自修复效果起主导作用.

The performance of self-healing concrete can be affected by various factors.In order to explore how the factors like external environmental conditions,initial width of crack and placement method of fiberglass tubes affect the performance of self-healing concrete,the self-repairing test was conducted by using the self-healing concrete specimens with the Great Wall 717 as the repairing adhesives and the fiberglass tubes as carriers.The rateηof the flexural strength after being repaired(f 1)and the initial flexural strength of the control group(f)was used to characterize the repairing performance,through which the relationship between these three factors and the performance were analyzed.Results show that the repairing effect increases as the external environmental conditions(temperature)increase,under the condition of special fiberglass tube placement method and initial width of the crack,the performance at 30℃is 13.3%higher than that at-15℃;the smaller the initial width of the crack is,the better the repairing effect will be.The microcrack with initial width of cracks of 1.0 mm or below can be repaired by the self-healing concrete.When fiberglass tube is placed in a shape of trapezoid,the performance will be better than that of the rhombus.The placement method of fiberglass tubes plays a dominant role in the self-healing process when the intial width of the crack is up to about 2.0 mm.