混凝土中的慢动力学：温度、强度变化和微裂缝损伤的影响
Slow dynamics in concrete: Effects of temperature, strength variation, and microcracking damage
- University of Nebraska-Lincoln（内布拉斯加大学林肯分校）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过压缩加载和尾波干涉法监测混凝土慢动力学，发现恢复速率随强度增加而加快，ASR损伤导致恢复时间延长，展示了慢动力学在评估强度和检测微裂缝方面的潜力。
AI中文摘要：
在本研究中，我们探讨了具有不同抗压强度（$f'_c = 32\sim56$ MPa）和碱-硅酸反应（ASR）损伤的混凝土的慢动力学行为。混凝土棱柱体通过压缩加载进行调理，并通过尾波干涉法（CWI）监测恢复过程。采用自参考温度校正技术以最小化环境温度变化的影响，突显了仔细的温度控制和校正的重要性。对于完整试件，恢复速率 $m_v$ 和速度下降幅度 $|c|$ 通常随抗压强度增加而增大。根据拟合参数计算了恢复时间，发现较高强度的试件恢复更快（$f'_c = 32$ MPa 时为 9.9 小时，$f'_c = 56$ MPa 时为 6.6 小时）。当施加相同应力时，ASR 损伤试件表现出增加的软化和更快的恢复速率，但恢复时间更长（长达 458 小时）。这些发现证明了慢动力学在混凝土表征中的潜力，通过其评估完整试件强度的能力及其对损伤试件中微裂缝的敏感性。
英文摘要：
In this study, we investigated the slow dynamic behavior of concrete with varying compressive strengths ($f'_c = 32\sim56$ MPa) and alkali-silica reaction (ASR) damage. Concrete prisms were conditioned by compressive loading and recovery was monitored by coda wave interferometry (CWI). A self-referencing temperature correction technique was used to minimize the effect of ambient temperature changes, demonstrating the importance of careful temperature control and correction. For intact specimens, both the recovery rate, $m_v$, and velocity drop magnitude, $|c|$, generally increased with compressive strength. Recovery times were calculated from the fit parameters, and higher strength specimens were found to recover faster (9.9 h for $f'_c = 32$ MPa, 6.6 h for $f'_c = 56$ MPa). When the same stress was applied, ASR-damaged specimens had increased softening and faster recovery rates, but longer recovery times (up to 458 h). These findings demonstrate the potential of slow dynamics in concrete characterization, through its ability to evaluate the strength of intact samples and its sensitivity to microcracking in damaged samples.
