Flexural and cracking behaviors of reinforced UHPC beams with various reinforcement ratios and fiber contents
Flexural and cracking behaviors of reinforced UHPC beams with various reinforcement ratios and fiber contents
复制标题
不同配筋率和纤维含量的增强UHPC梁的弯曲和开裂行为
DOI：
10.1016/j.engstruct.2021.113266
复制
发表时间：
2021-09-27
影响因子：
5.5
通讯作者：
Ke, Lu
中科院分区：
文献类型：
--
作者：
Feng, Zheng;Li, Chuanxi;Ke, Lu
本研究旨在探讨超高性能混凝土梁之受弯及裂缝特性。9个UHPC梁与不同的钢筋率（0，1.0%，2.9%，4.8%，和7.1%）和纤维体积分数（2.0%和3.0%）被认为是弯曲。截面分析也被用来预测UHPC梁的弯曲和开裂性能，并通过试验结果进行了验证。试验结果表明，钢筋和钢纤维可以发挥显着的作用，在限制裂缝的发展。在考虑钢纤维性能的基础上，建立了超高性能混凝土梁平均裂缝间距的高精度计算公式。法国标准NF P 18-710中的公式对于高配筋率（>4%）的UHPC梁的最大裂缝宽度高估了很大幅度。配筋UHPC梁的抗弯刚度随着配筋率的增加而增加，而无筋UHPC梁的初始刚度大于低配筋率（1.0%）时的初始刚度，这是由于UHPC与钢筋之间的粘结界面较弱。UHPC梁的抗弯承载力基本上随配筋率线性增加。截面分析结果表明，随着配筋率的增加，钢纤维对受弯构件抗弯承载力的贡献显著减小。在极限承载力设计中，当配筋率大于4.0%时，UHPC抗拉承载力的贡献仅作为安全储备考虑，当配筋率小于2.9%时，UHPC抗拉承载力的贡献应作为安全储备考虑。
This research is aimed at investigating the flexural and cracking behaviors of ultra-high-performance concrete (UHPC) beams. Nine UHPC beams with different reinforcement ratios (0, 1.0%, 2.9%, 4.8%, and 7.1%) and fiber volume fractions (2.0% and 3.0%) were considered under flexure. A section analysis was also performed to predict the flexural and cracking behaviors of UHPC beams and was verified by experimental results. The test results showed that the reinforcement and steel fibers can play a significant role in limiting crack development. Considering the performance of the steel fibers, a high-precision equation for predicting the average crack spacing of UHPC beams was developed. The formulas in the French standard NF P 18-710 overestimated the maximum crack width by a significant margin for the UHPC beams with a high reinforcement ratio (>4%). The flexural stiffness of the reinforced UHPC beams increased as the reinforcement ratio increased, whereas their initial stiffness without reinforcement was larger than that with a low reinforcement ratio of 1.0% because of the weak bond interface between the UHPC and the reinforcement. The flexural capacity of the UHPC beams basically increased linearly with the reinforcement ratios. The result of the sectional analysis indicated that the contribution of steel fibers to the flexural capacity decreased significantly with the increase in the reinforcement ratio. In the ultimate limit states design, the contribution of UHPC tensile capacity could be considered only as a safety reserve when the reinforcement ratio is greater than 4.0%, whereas its contribution needs to be considered for the UHPC beams with a reinforcement ratio of less than 2.9%.