钢纤维混凝土层裂强度的实验研究  

Experimental Study of Spall Strength of Steel Fiber Reinforced Concrete

作　　者：郝龙[1,2] 张磊[2] 高伟亮[2] 吴建华[2] 

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,河海大学安全与防灾工程研究所,江苏南京210098 [2]总参工程兵科研三所,河南洛阳471023

出　　处：《实验力学》2013年第1期94-100,共7页Journal of Experimental Mechanics

基　　金：国家自然科学基金资助项目(10802098)

摘　　要：钢纤维能显著提高混凝土抵抗层裂破坏的能力,但纤维含量、长细比和形状对高应变率下钢纤维混凝土层裂强度的影响仍缺少系统研究。本文利用大直径Hopkinson杆对混凝土细长杆件进行冲击加载,通过放置在试件后方的空心铝合金杆上应变波形确定试件的层裂强度,系统研究了钢纤维含量、长细比和形状对钢纤维混凝土层裂强度的影响。实验结果表明钢纤维混凝土层裂强度具有应变率效应,即应变率越高层裂强度越高。钢纤维对混凝土层裂强度的增加与纤维影响系数α、纤维长细比和纤维含量三者之乘积具有线性关系。动态加载条件下的系数α高于静态,其原因主要是动态加载时纤维快速从基体拔出时动态剪应力增加。波浪形纤维混凝土的系数α比扁头型纤维高。根据实验结果建立了钢纤维混凝土层裂强度经验公式,公式预测结果能与实验结果较好吻合。Steel fiber can detailed study about the improve evidently concrete ability to prevent spall fracture. But there is little effect of the fiber content, the fiber length and diameter ratio and the fiber shape on the spall strength of steel fiber reinforced concrete under high strain rate condition. A large diameter Hopkinson bar equipment was used to impact the slender concrete rod. The strain pulse in a hollow aluminum alloy bar mounted behind the specimen was used to examine the spall strength of concrete specimen. The effect of the fiber content, slenderness ratio and shaper on the spall strength was detected in detail,respectively. Experimental results indicate that the spall strength of steel fiber reinforced concrete （SFRC） has strain rate effect. In other words, the higher the strain rate is, the higher the spall strength. The improvement of spall strength due to steel fibers presents a linear relation with the product of the fiber influence coefficient a, the ratio of slenderness and the fiber content. The fiber influence coefficient a is higher under dynamic loading condition than that in the static loading due to the improvement of the dynamic shear stress between the fiber and the concrete bulk material when fiber is extracted quickly from bulk material. The undulated fiber concrete has higher influence coefficient a than that of dumbbell-shaper fiber concrete. An empirical formula to predict the spall strength of SFRC is presented based on the experimental results, which is well consistent with experimental results.

关 键 词：HOPKINSON杆 钢纤维混凝土 层裂 层裂强度 纤维影响系数 

分 类 号：O347[理学—固体力学]