纤维尺寸对地下工程防渗抗裂纤维混凝土性能的影响

Influence of fiber size on the performance of anti-seepage and anti-crack fiber reinforced concrete in underground building

针对地下混凝土结构易发生开裂、渗透的现象,研究了纤维尺寸对混凝土工作性能、力学性能、收缩及断裂韧性的影响。试验结果表明:同掺量时纤维越长对混凝土工作性能影响越显著,纤维越短根数越多抗裂塑性开裂效果越明显,长15 mm的聚丙烯纤维对混凝土断裂韧度、断裂能及抗收缩性能提高效果要优于12、19 mm的纤维。鉴于地下建筑群工程C30泵送混凝土,采用粒径为5～25 mm的粗骨料宜选择15 mm长的抗裂纤维,起到较好抗裂效果的同时不影响纤维混凝土的泵送施工性能。

Based on the cracks and penetration of grouped underground basements,the working performance,compressive strength, shrinkage properties and fracture toughness were tested in order to research the effect of fiber size on fiber reinforced concrete.The experi- mental results showed that the fiber longer the more significant influence of concrtet construction performance, and fiber more short crack plastic cracking effect was more obvious under same volume,length of 15mm polypropylene fiber on fracture toughness, fracture energy and resistance to shrinkage performance was better than the 12 mm and 19 mm fiber.Considering the pumping construction performance and crack resistance of polypropylene fiber reinforced concrete,priority selection the length of the 15 mm polypropylene fiber in the particle size of coarse aggregate was 5-25 mm concrete system.For the low strength grade of C30 pump concrete in underground building.