固化温度对由于ASR而导致混凝土膨胀的影响
Yongfu Yang1,2, Min Deng1,3, Liwu Mo1
1College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009, China.
Materials (Basel, Switzerland)
|July 13, 2024
概括
升高的温度最初会加速混凝土中的-反应 (ASR),但最佳膨胀发生在50-60°C之间. 在孔隙溶液中降低氧化离子度 ([OH-]) 显著影响ASR扩张率.
科学领域:
- 材料科学 材料科学 材料科学
- 土木工程 土木工程是指土木工程.
- 化学工程是化学工程的重要组成部分.
背景情况:
- -反应 (ASR) 是混凝土结构中的关键降解机制.
- 混凝土使用寿命的预测模型通常与高温和低温性能相关,但温度对ASR的复杂影响尚未完全理解.
研究的目的:
- 为了研究固化温度对-反应 (ASR) 诱导混凝土膨胀的影响.
- 阐明孔隙溶液化学,特别是氧化物离子度 ([OH-]) 在温度依赖的ASR膨胀中的作用.
- 为大型横截面混凝土样品的加速测试提供建议.
主要方法:
- 实验室实验涉及在40°C至80°C的温度下固化2级和3级混凝土镜.
- 从混凝土样本中提取孔隙溶液的化学分析,以确定[OH-] 度.
- 在各种热条件下随着时间的推移监测混凝土的膨胀.
主要成果:
- 温度升高最初加速了ASR扩张,但更高的温度 (70°C和80°C) 导致后期阶段的放缓.
- 在50°C和60°C固化的混凝土在实验期间表现出最显著的扩张.
- 由于反应消耗和温度对NaOH (aq) 活性的影响,孔隙溶液[OH-]度下降,与延迟的ASR扩张相关.
结论:
- 固化温度显著影响混凝土中ASR扩张的速度和程度.
- 对于大型截面样本的加速测试,建议固化温度低于60°C,以避免误导性结果.
- 了解ASR的温度依赖性对于开发精确的混凝土耐用性预测模型至关重要.
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