纤维素纤维及混杂纤维混凝土的弯曲韧性

研究了纤维素纤维UF500增强混凝土的抗弯韧性,同时进行了合成纤维、钢纤维及混杂纤维混凝土的弯曲韧性试验,测定了纤维混凝土梁的荷载一挠度全曲线.基于美国ASTM方法,分析了纤维素纤维、合成纤维、钢纤维及其混杂纤维增强混凝土的弯曲韧性.研究表明,纤维素纤维可提高混凝土抗弯韧性和变形能力,韧性指数I_5、J_(10)分别比素混凝土提高了3.0和5.8倍;在纤维体积率相同情况下,纤维素纤维混凝土抗弯韧性高于聚丙烯纤维混凝土;纤维素纤维和钢纤维混杂使用显著改善了混凝土的韧性和变形性能,使混凝土由脆性破坏变为延性破坏.

Flexural Toughness of Cellulose and Hybrid Fiber Reinforced Concrete Beams

The cellulose fiber(ultra-fiber 500)is a new type natural cellulose fiber.In order to study the flexural toughness of cellulose fiber reinforced concrete,the flexural toughness experiments of concrete with synthetic,steel fibers,and hybrid fiber are made at the same time,and the load-deflection curve of all beams are obtained.Based on the ASTM method,the flexural toughness of concrete with cellulose,synthetic,steel fibers and hybrid fibers are all analyzed.The experimental results indicate that the cellulose fiber can improve the flexural toughness and the deformation ability of concrete beams.The flexural toughness index I_5 and I_(10) of concrete with cellulose fiber are 3.0 and 5.8 times higher than that of the plain concrete respectively.For the same ratio of volume of fibers,the flexural toughness index of cellulose fiber reinforced concrete is higher than that of concrete with PP fiber.Cellulose and steel hybrid fibers can improve the toughness and deformation ability of concrete remarkably,and the failure mode changes from brittle to ductile fracture.