Mu Ru, Soro Dogniman Landry, Wang Xiaowei, Qing Longbang, Cao Guorui, Mei Shaolin, Liu Yongshuai
School of Civil and Transportation Engineering, Hebei University of Technology, Tianjin 300401, China.
Materials (Basel). 2021 Oct 18;14(20):6162. doi: 10.3390/ma14206162.
From the perspective of improving the self-healing method in construction, a tubular healing fiber was adopted as a container to improve the encapsulation capacity, which was available using a micro-capsule as a container. Knowing the direction of the stresses to which structure members are subjected, this research investigated the influence of aligning tubular healing fibers parallel to intended stress into a cementitious composite to increase the self-healing capability. For that, a healing agent was encapsulated into a tubular healing fiber made with polyvinylidene of fluoride resin (PVDF). Then, the healing fiber was combined with steel fibers to align both fibers together parallel to the direction of an intended splitting tensile stress when subjected to a magnetic field in a cylindrical cementitious composite. The alignment method and the key point through which the alignment of the healing fibers could efficiently improve autonomic self-healing were investigated. Since the magnetic field is known to be able to drag steel to an expected direction, steel fibers were combined with the healing fibers to form a hybrid fiber that aligned both fibers together. The required mixture workability was investigated to avoid the sinking of the healing fibers into the mixture. The healing efficiency, according to the orientation of the healing fibers in the composite matrix, was evaluated through a permeability test and a repetitive splitting tensile test. The aligned healing fibers performed better than the randomly distributed healing fibers. However, according to the healing efficiency with aligned healing fibers, it was deduced that the observed decreasing effect of the container's alignment on the specimen's mechanical properties was low enough to be neglected.
从改进建筑中自修复方法的角度出发，采用管状愈合纤维作为容器来提高封装能力，此前是使用微胶囊作为容器。了解结构构件所承受应力的方向后，本研究调查了将管状愈合纤维与预期应力方向平行排列在水泥基复合材料中对提高自愈合能力的影响。为此，将愈合剂封装到由聚偏二氟乙烯树脂（PVDF）制成的管状愈合纤维中。然后，在圆柱形水泥基复合材料中施加磁场时，将愈合纤维与钢纤维结合，使两种纤维一起沿预期劈裂拉伸应力方向排列。研究了愈合纤维排列的方法以及通过该排列能够有效提高自主自愈合能力的关键点。由于已知磁场能够将钢拉向预期方向，因此将钢纤维与愈合纤维结合形成混合纤维，使两种纤维一起排列。研究了所需的混合料工作性，以避免愈合纤维沉入混合料中。通过渗透性试验和重复劈裂拉伸试验，评估了愈合纤维在复合基体中的取向对愈合效率的影响。排列的愈合纤维比随机分布的愈合纤维表现更好。然而，根据排列的愈合纤维的愈合效率推断，观察到的容器排列对试件力学性能的降低影响足够小，可以忽略不计。
