The fracture energy of the high-performance fiber-reinforced cement-based composite (HPFRCC) can be modified within wide limits by the variation of the amount of steel fibers added to the fresh mix. First of all, considering the actual engineering conditions in Qingdao, the materials commonly used in Qingdao were selected. The optimal reference mix proportion of the HPFRCC cementing material was proposed through determination of fluidity and flexural strength. Based on the optimal mix proportion, the uniaxial tensile, fracture, and dry shrinkage properties of HPFRCC with different steel fibers are systematically studied. Stress-strain diagrams of the different samples were measured under the uniaxial tensile test, wedge splitting test, and three-point bending test. The steel fiber content was varied between 0 and 200 kg/m³. The load bearing capacity and the fracture energy were determined experimentally. In addition, moisture loss as a function of time and shrinkage was determined in an environment of 20°C and 50% RH (relative humidity). The results indicate that the maximum load increases significantly in the HPFRCC series reinforced by 150 and 200 kg/m³ of steel fibers. Both have a hardening branch developed after the first crack deflection due to the high percentage of fibers bridging the crack surfaces. The load bearing capacity and fracture energy increased almost linearly with the steel fiber content. It was found that the three-point bending test is more applicable in measuring the fracture energy of HPFRCC than the wedge splitting test. The addition of steel fibers decreased the moisture diffusion and consequently the drying shrinkage of HPFRCC, and there was minimum weight loss and deformation when the steel fiber content was 150 kg/m³. The results obtained will be presented and discussed.

中文翻译：

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钢纤维用量对HPFRCC断裂能和干缩的影响

高性能纤维增强水泥基复合材料（HPFRCC）的断裂能可通过改变添加到新鲜混合物中的钢纤维的数量来在较大范围内进行调整。首先，考虑到青岛市的实际工程条件，选择了青岛市常用的材料。通过确定流动性和抗弯强度，提出了HPFRCC胶结材料的最佳参考混合比。根据最佳混合比，系统研究了不同钢纤维的HPFRCC的单轴拉伸，断裂和干缩性能。在单轴拉伸试验，楔形劈裂试验和三点弯曲试验下测量了不同样品的应力-应变图。钢纤维含量在0至200 kg / m ³之间变化。实验确定了承载力和断裂能。另外，在20℃和50％RH（相对湿度）的环境中确定了水分损失随时间和收缩的函数。结果表明，以150和200 kg / m ³增强的HPFRCC系列的最大载荷显着增加钢纤维。两者都具有在第一次裂纹挠曲后形成的硬化分支，这是由于高百分比的纤维桥接裂纹表面。承载能力和断裂能几乎随钢纤维含量线性增加。发现三点弯曲测试比楔形劈裂测试更适用于测量HPFRCC的断裂能。钢纤维的添加降低了HPFRCC的水分扩散并因此降低了其干燥收缩率，并且当钢纤维含量为150kg / m ³时，重量损失和变形最小。将介绍和讨论获得的结果。