氯盐冻融作用下粉煤灰混凝土抗渗抗冻性研究

Research on Permeability and Frost Resistance of Fly Ash Concrete Under Chloride and Freeze-Thawing

研究了粉煤灰掺量为0%、15%、30%的混凝土28 d抗压强度、抗氯离子渗透性,以及在浓度为0%、5%、10%的NaCl溶液中的抗冻性。结果表明:混凝土28 d龄期的强度随着粉煤灰掺量的增加而降低;未经冻融的混凝土掺入粉煤灰后抗氯离子渗透能力增强,以15%掺量效果最佳;经50次冻融循环后粉煤灰对抗氯离子渗透能力的作用减弱;混凝土试件在5%的NaCl溶液中冻融后质量损失最大;相对动弹性模量随着盐浓度的增加而降低,掺加15%粉煤灰有利于提高混凝土在盐溶液中的抗冻性能。

28 d compressive strength and resistance to chloride penetration and to freezing and thawing of concrete containing fly ash （ FA） was studied in this paper. Concretes containing FA of 0% ,15% and 30% by weight as partial replacement of Portland cement （ PC） were ex-posed to 0% ,5% and 10% sodium sulfate solution under freezing-thawing cycles. It is found that 28 d compressive strength decreases with FA dosage increasing; FA improves the resistance to chloride penetration and 15% FA has the best results,but the improvement effects de-crease up to 50 freezing-thawing cycles. As for concrete with FA, its relative dynamic elastic modulus decrease with the sodium sulfate solu-tion concentration increasing and the replacement level of 15% FA by weight led to significant improvements in the resistance of concrete a-gainst combined freezing-thawing and sulfate attack.