混杂纤维高性能混凝土的收缩抗裂性能

试验研究了聚丙烯纤维(PPF)和碳纤维(CBF)及其混杂后对高性能混凝土的早期抗塑性收缩开裂性能及干缩性能的影响。结果表明,聚丙烯纤维、碳纤维及其混杂使用对高性能混凝土早期塑性收缩开裂及干燥收缩都具有较好的抑制作用,但其作用大小不同。单独使用纤维时,聚丙烯纤维抑制早期塑性收缩开裂效果优于碳纤维,而碳纤维抑制干燥收缩的效果优于聚丙烯纤维。混杂使用纤维时,存在纤维之间的搭配优势,当两种纤维按体积比1∶1混杂使用时,纤维总用量为0.2 Vol.%的高性能混凝土的抗早期塑性收缩性能最好,其抑制干缩的效果也较好。为了同时抑制高性能混凝土的早期塑性收缩和长期干燥收缩,试验所用纤维采用纤维总用量为0.2 Vol.%,聚丙烯纤维和碳纤维以体积比为1∶1的混杂使用最佳。

Shrinkage and anti-cracking properties of high performance concrete with hybrid fibers

The effects of polypropylene fiber,carbon fiber as well as their combination on shrinkage and anti-cracking properties of high performance concrete were investigated.Results show that polypropylene fiber,carbon fiber and their combination all have a better inhibitory effect on the early plastic shrinkage cracking and drying shrinkage of high performance concrete,and their inhibitory effects are in different degrees.When used alone fibers,polypropylene fibers inhibiting effect of an early plastic shrinkage cracking is superior to carbon fiber,while carbon fiber is better than the effect of inhibiting drying shrinkage of polypropylene fiber.Mixed use of fibers,there is mix of strengths between the fibers,when the two kinds of fiber in the volume ratio of 1∶1,mixed use,the fibers of the total volume of 0.2 Vol.% of high-performance concrete has the best performance against the early plastic shrinkage,and their inhibition shrinkage effects are also good.In order to suppress the same time,the early plastic shrinkage and long-term drying shrinkage of high performance concrete,experimental use of fiber used in fiber to the total volume of 0.2 Vol.%,polypropylene fiber and carbon fiber to volume ratio of 1∶1 mixed use is of the best.