摘 要
随着基础设施建设的快速发展，混凝土材料的耐久性问题日益受到关注，其中抗冻性能是衡量混凝土在寒冷地区服役能力的重要指标。为探究粉煤灰掺量对混凝土抗冻性能的影响，本研究以不同粉煤灰替代水泥比例（0%、15%、30%、45%和60%）的混凝土为研究对象，通过快速冻融循环试验评估其抗冻性能，并结合孔结构分析探讨微观机理。结果表明，适量掺入粉煤灰可优化混凝土孔结构，减少连通孔数量，从而提高抗冻性能；然而，过高的粉煤灰掺量会导致水化产物减少，强度不足，进而降低抗冻性能。试验发现，当粉煤灰掺量为30%时，混凝土的抗冻性能达到最佳水平，其质量损失率和相对动弹性模量均显著优于其他组别。本研究创新性地结合宏观性能测试与微观结构表征，揭示了粉煤灰掺量与混凝土抗冻性能之间的量化关系，为寒冷地区高性能混凝土的配比设计提供了理论依据和技术支持。
关键词：粉煤灰掺量；混凝土抗冻性能；孔结构优化；快速冻融循环；水化产物
ABSTRACT
With the rapid development of infrastructure construction, the durability of concrete materials has attracted increasing attention, among which freeze-thistance is a critical indicator for evaluating the serviceability of concrete in cold regions. To investigate the effect of fly ash content on the freeze-thistance of concrete, this study examined concrete specimens with different fly ash replacement ratios of cement (0%, 15%, 30%, 45%, and 60%) through rapid freeze-thaw cycle tests. The microstructural mechanism was further explored by analyzing pore structure characteristics. The results indicate that an appropriate amount of fly ash can optimize the pore structure of concrete by reducing the number of interconnected pores, thereby enhancing its freeze-thistance. However, excessive fly ash content may lead to insufficient hydration products and reduced strength, consequently deteriorating the freeze-thistance. Experimental findings reveal that when the fly ash content is 30%, the freeze-thistance of concrete reaches its optimal level, showing significantly lower mass loss rates and higher relative dynamic elastic moduli compared to other groups. This study innovatively integrates macroscopic performance testing with microscopic structural characterization, establishing a quantitative relationship between fly ash content and the freeze-thistance of concrete. Such findings provide theoretical support and technical guidance for the mix design of high-performance concrete in cold regions.
Keywords: Fly Ash Content; Freeze-thaw Resistance Of Concrete; Pore Structure Optimization; Rapid Freeze-thaw Cycles; Hydration Products
目 录
第1章 绪论 1
1.1 粉煤灰掺量研究的背景与意义 1
1.2 混凝土抗冻性能的研究现状分析 1
1.3 本文研究方法与技术路线 2
第2章 粉煤灰掺量对混凝土微观结构的影响 3
2.1 微观结构测试方法的选择 3
2.2 不同掺量下粉煤灰对孔隙率的影响 3
2.3 粉煤灰掺量与界面过渡区的关系 4
第3章 粉煤灰掺量对混凝土抗冻性能的作用机制 5
3.1 抗冻性能评价指标的确定 5
3.2 粉煤灰掺量对抗冻融循环的影响 5
3.3 温度变化对粉煤灰掺量效果的作用 6
第4章 粉煤灰掺量优化及工程应用分析 7
4.1 不同环境条件下的最佳掺量选择 7
4.2 工程案例中粉煤灰掺量的应用效果 7
4.3 粉煤灰掺量经济性与环保效益评估 8
结论 10
参考文献 11
致 谢 12
