聚丙烯腈纤维增强水泥混凝土的抗弯性能

Flexural Behaviour of Cement Concrete Reinforced with Polyacrylonitrile Fiber

为了研究将体积掺率 0 .0 85%～ 0 .17%的聚丙烯腈纤维 (PAN)掺入水泥混凝土后 ,对硬化混凝土力学性能的效用 ,试验研究了新拌纤维混凝土的坍落度和容重 ,测定了纤维混凝土的抗压强度、弹性模量、抗劈裂强度 ;基于美国 ASTM及日本 JCI方法 ,用四点弯曲梁测得了抗弯初裂强度、抗弯拉强度和抗弯韧性等。试验证明 :聚丙烯腈纤维能够均匀地分散在混凝土中 ,纤维混凝土无离析现象 ;该纤维对混凝土具有良好的增韧效应和一定的增强效应。腈纶纤维使混凝土由脆性破坏变为有较好的延展性 ,可用于修建高等级水泥混凝土路面、桥梁面板、机场道面、堆石坝面板和抗震防爆结构等。

The polyacrylonitrile fiber concentrations of cement co ncrete are 0 085% and 0 17% by volume in this test The concrete properties suc h as slump and unit weight are measured For the hardened concrete, the compres sive str ength, static moduli,split strength, first-crack strength and modulus of ruptur e are measured Load-deflection curves are plotted from the data obtained in the mo dulus of rupture test to determine the toughness indexes by the ASTM method, and the flexural toughness factor and equivalent flexural strength by the Japanese Standard method using third-point bending beam The test results showed that t here is no balling of fiber during mixing and placing for all the concretes T here is less bleeding in the fiber concretes compared with the plain concrete This kind of fiber has dual efforts of increasing strength and increasing toughn ess on concrete There is a significant increase in the flexure strength,spilt strength and toughness indexes with the addition of fibers The addition of pol yacrylonitrile fibers have changed the failure mode of concrete from a brittlens s to a ductility Polyacrylonitrile fiber reinfo rced concrete is an ideal material for structuring airport and highway pavements , bridge deck overlays, curtain dams, cavitations/earthquake resistant structur es and so on