THE EXPERIMENT STUDY ON FROST RESISTANCE DURABILITY OF POLYPROPYLENE FIBER REINFORCED LIGHTWEIGHT AGGREGATE CONCRETE
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摘要: 通过掺入聚丙烯纤维、高效减水剂、引气剂及矿物掺合料,配制两种强度等级(LC30,LC35)的浮石轻骨料混凝土。对比盐溶液(5%Na2SO4)和水中抗冻性试验发现,盐溶液中冻融的轻骨料混凝土劣化程度大于水中。轻骨料混凝土掺入纤维后,其抵抗冻融损伤能力得到改善,掺量越高,对轻骨料性能的改善作用越明显。SEM观察发现,随着盐溶液的侵蚀以及冻融循环次数的增加,水化产物的结构由密实逐渐变得疏松;聚丙烯纤维与水泥石浆体的粘结力强,能够抑制混凝土的冻融损伤。Abstract: Pumice lightweight aggregate concrete (LWAC) of LC30, LC35 is prepared with the method of mixing polypropylene fiber, superplasticizer, air?? entraining agent and mineral admixtures. Comparing frost resistance durability of LWAC in salt solution ( 5% Na2SO4) and in water, the degree of LWAC durability deterioration is: freezing??thawing in salt solution freezing??thawing in water. The frost resistance of LWAC is improved by mixing polypropylene fiber. The large volume fraction has tendency of good frost resistance of LWAC. SEM shows that hydrate structure in interfacial transition zone (ITZ) becomes loose gradually with an increase in cycles of freezing thawing and corrosion. Polypropylene fiber has stronger cementing bond with paste and can restraint the damage to concrete by freezing??thawing.
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