Effect of different types of fibers on the microstructure and the mechanical behavior of Ultra-High Performance Fiber-Reinforced Concretes
Effect of different types of fibers on the microstructure and the mechanical behavior of Ultra-High Performance Fiber-Reinforced Concretes
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DOI：
10.1016/j.compositesb.2015.09.059
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发表时间：
2016-02-01
影响因子：
13.1
通讯作者：
Raghavan, Balaji
中科院分区：
文献类型：
--
作者：
Hannawi, Kinda;Bian, Hui;Raghavan, Balaji
本研究探讨加入不同类型的纤维对水泥基复合材料的微观结构和力学行为的影响，特别是对UHPC。这些纤维的区别主要在于它们不同的性质（钢，矿物和合成），它们的尺寸（宏观或微观）和它们的机械性能。通过扫描电镜观察、孔隙度、固有渗透率和纵波速度的测量，对试样的微观结构进行了研究。采用单轴压缩试验结合气体渗透和声发射（AE）测量研究了加载下的力学行为。本工作的重点是在机械载荷下的开裂过程。试验结果表明，钢纤维对混凝土的抗压强度和弹性模量的影响相对较小，但钢纤维因其本身的刚性而提高了混凝土的强度。然而，纤维的加入显著降低了峰值载荷下的侧向应变，并提高了初始开裂阈值（σ（k-ci））和不稳定开裂阈值（σ（k-pi））。因此，纤维对混凝土在机械荷载作用下的开裂过程有明显的抑制作用。(C)2015爱思唯尔有限公司版权所有。
This study investigates the effect of adding different types of fibers on the microstructure and the mechanical behavior of cementitious composites, in particular on UHPC. These fibers were distinguished mainly by their differing nature (steel, mineral and synthetic), their dimensions (macroscopic or microscopic), and their mechanical properties. The microstructure of the specimens was examined by using SEM observation and by measuring the porosity, the intrinsic permeability and the P-wave velocity. The mechanical behavior under loading has been studied using a uni-axial compression test which combines the gas permeability and the acoustic emission (AE) measurement. This work focuses on the cracking process under mechanical loading. The experimental results show that the fiber has a relatively slight influence on the compressive strength and elastic modulus of concrete, except for the steel fiber which improves the strength because of its intrinsic rigidity. However, The addition of fiber significantly reduces the lateral strain at peak loading and increases the threshold of initial cracking (sigma(k-ci)) and that of unstable cracking (sigma(k-pi)). Therefore, the fibers clearly restrain the cracking process in concrete under the mechanic loading. (C) 2015 Elsevier Ltd. All rights reserved.