面板混凝土在高低温循环作用下的性能演化及老化评估

Properties evolution and aging assessment of panel concrete under high and low temperature cycles

摘要

为了探究高低温循环条件下堆石坝混凝土面板性能演化及老化程度，研究了5~85℃条件下面板混凝土的力学性能演化，同时为了提高其抗裂性，使用钢纤维进行了增强。此外，还对面板混凝土劣化后的老化等级进行了评估。结果表明，高低温循环作用下，掺钢纤维能减小混凝土的抗压和抗拉强度的损失。相比于普通(O型)面板混凝土，450次高低温循环作用后，钢纤维增强(S型)面板混凝土的抗压和抗拉强度损失率减小了3.89%和9.32%。O型面板混凝土在450次高低温循环作用后抗压强度老化等级可达4级，S型面板混凝土仅达3级；在360次高低温循环作用后O型面板混凝土抗拉强度老化等级已达4级，而S型面板混凝土的老化等级在450次高低温循环作用后才达到4级，表明高低温循环作用对抗拉强度的劣化影响更显著。长期高低温循环作用引起的老化问题会使面板混凝土无法承担设计荷载而可能产生开裂并引发渗漏等安全问题。

Abstract

To investigate the performance evolution and aging of concrete panels of rockfill dams under high and low temperature cycles, the mechanical property evolution of panel concrete under 5~85℃ was investigated, while it was reinforced with steel fibers to improve its cracking resistance. In addition, the aging level of panel concrete after deterioration was evaluated. The result show that the incorporation of steel fibers reduces the loss of compressive and tensile strength of concrete under high and low temperature cycles. Compared to normal(Type O) panel concrete, the rate of loss of compressive and tensile strength of steel fiber reinforced(Type S) panel concrete was reduced by 3.89% and 9.32% after 450 cycles of high and low temperature cycles. The compressive strength aging grade of O-type panel concrete after 450 cycles of high and low temperatures could reach grade 4, while that of S-type panel concrete only reached grade 3. The aging level of tensile strength of O-type panel concrete after 360 cycles of high and low temperature cycles have reached 4, and the aging level of S-type panel concrete after 450 cycles of high and low temperature cycles has also reached 4, indicating that the degradation of tensile strength caused by high and low temperature cycles is more significant. The aging problem caused by long-term high and low temperature cycles will make the panel concrete unable to bear the design load and may cause building safety problems.

关键词

面板混凝土 / 高低温循环 / 钢纤维 / 性能演化 / 老化评估

Key words

panel concrete / high and low temperature cycles / steel fiber / property evolution / aging assessment

Author summay

林文华(1973—), 男, 高级工程师, 硕士, 主要从事水利研究。E-mail: [e-mail]

基金资助

国网新源集团有限公司科技项目(SGXYKJ-2022-023)