用巴塞罗那试验法分析混凝土中钢纤维的分布规律

为研究混凝土基体中钢纤维的空间分布情况,利用巴塞罗那(BCN)试验所推荐的局部受压法对钢纤维掺量分别为20,35,50kg/m~3的混凝土立方体试件在局部受压时的开裂后韧性进行了测试;根据钢纤维混凝土试件在不同方向上局部受压的荷载-位移全曲线,对钢纤维在试件中的分布情况进行了分析及预测,并与利用电磁感应法测得的钢纤维空间分布情况进行了对比.研究表明:在BCN立方体局部受压试验中,混凝土的开裂后韧性随着钢纤维掺量的增加而显著提高;测试方向不同时,钢纤维掺量相同的混凝土立方体试件中纤维限制裂缝扩展的作用不同,从而表现出不同的力学性能,进而可以预测不同方向上的纤维分布情况;采用BCN试验与采用电磁感应法所测得的纤维分布规律相近.

Investigation on the Spatial Distribution of Steel Fiber in Concrete Matrix Using Barcelona Test

In order to study the spatial distribution of steel fibers in concrete matrix, the concrete cube specimens with different contents of steel fiber (20, 35, 50kg/m3) were prepared and the spatial distribution was investigated using Barcelona(BCN) test. For analyzing the effect of the fibers distribution, the whole load displacement curves of cube specimens loaded under different directions were measured. The cosine ratio was used in comparatively analyzing the results of inductive method. It is demonstrated that the toughness of steel fiber reinforced concrete(SFRC) increases with the increment of fiber content in the BCN local bearing test. Different mechanical and toughness behaviors of SFRC are obtained when the loading direction is changed. Considering that the fibers are able to limit the crack propagation, the fibers distribution can be estimated. Besides, the results of the fiber distribution measured by inductive method appear similar to those from the BCN test.