高性能粉煤灰混凝土抗冻性试验分析

Experimental Analysis of Frost Resistance on High Performance Fly Ash Concrete

为研究粉煤灰对高性能混凝土抗冻性能的影响,利用冻融循环试验分析粉煤灰掺量、冻融循环次数、含气量及结构气泡特征与抗冻性之间的关系。结果表明:质量损失率随着粉煤灰掺量增加与冻融循环次数增加均呈显著增加趋势,相对动弹性模量呈逐渐下降趋势,二者均对抗冻性能产生劣化效果;随着内部结构含气量增加,质量损失率呈逐渐下降趋势,且随冻融循环次数的增加,不同含气量之间的质量损失率指标差异愈加显著;随着粉煤灰掺量增加,混凝土结构中的气泡数量显著下降,耐久性系数也呈下降趋势;粉煤灰对混凝土抗冻性能的宏观影响与气泡特征微观结构变化基本相一致。

In order to study the effect of fly ash on the frost resistance of high-strength concrete,freeze-thaw cycle test was used to analyze the relationship between fly ash content,freeze-thaw cycle times,air content,structural bubble characteristics,and frost resistance.The results show that the quality loss rate shows a significant increasing trend with the addition of fly ash and the increase of freeze-thaw cycles,while the relative dynamic elastic modulus gradually decreases.Both of them have a deterioration effect on the frost resistance performance;as the internal structure gas content increases,the mass loss rate gradually decreases,and as the number of freeze-thaw cycles increases,the difference in mass loss rate indicators between different gas contents becomes more significant;with the increase of fly ash content,the number of bubbles in the concrete structure significantly decreases,and the durability coefficient also shows a downward trend;the macroscopic effect of fly ash on the frost resistance of concrete is basically consistent with the microstructure changes of bubble characteristics.