Zhou Tieming, Sheng Xingwang
School of Civil Engineering, Central South University, Changsha 410075, China.
National Engineering Research Center of High-Speed Railway Construction Technology, Changsha 410075, China.
Materials (Basel). 2022 Apr 1;15(7):2605. doi: 10.3390/ma15072605.
In recent decades, reinforced-concrete bridges have experienced premature deterioration and other problems during service due to severe environmental effects such as fire and corrosion. Previous studies have shown that the use of ultra-high-performance concrete (UHPC) can improve the durability of bridge structures. In this study, four-point bending tests were conducted on twelve UHPC-NC laminated beams with different UHPC-layer heights and at different temperatures in order to evaluate their flexural performance under fire conditions. The test variables were the UHPC heights (20 mm, 50 mm, 80 mm) and temperatures (20 °C, 200 °C, 400 °C, 600 °C), and the effects on the flexural load capacity of UHPC-NC laminated beams under the influence of these factors were investigated. The test results show that the increase in temperature causes the concrete color to change from grayish blue to white and leads to a significant decrease in the flexural load capacity of the stacked beams. The height of the UHPC layer has an important effect on the stiffness of the stacked beams and delays the formation of local cracks, thus improving the durability of the stacked beams.
近几十年来，由于火灾和腐蚀等恶劣环境影响，钢筋混凝土桥梁在服役期间出现了过早劣化等问题。先前的研究表明，使用超高性能混凝土（UHPC）可以提高桥梁结构的耐久性。在本研究中，对12根不同UHPC层高度且处于不同温度的UHPC-NC叠合梁进行了四点弯曲试验，以评估其在火灾条件下的抗弯性能。试验变量为UHPC高度（20mm、50mm、80mm）和温度（20℃、200℃、400℃、600℃），研究了这些因素对UHPC-NC叠合梁抗弯承载能力的影响。试验结果表明，温度升高会使混凝土颜色从灰蓝色变为白色，并导致叠合梁的抗弯承载能力显著降低。UHPC层的高度对叠合梁的刚度有重要影响，并延缓局部裂缝的形成，从而提高叠合梁的耐久性。
