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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。
Pumice lightweight aggregate concrete with two strength grades (LC30, LC35) was formulated by incorporating polypropylene fibers, superplasticizers, air entraining agents and mineral admixtures. Compared with salt solution (5% Na2SO4) and water frost resistance test, it was found that the freeze-thaw lightweight aggregate concrete in salt solution degraded more than water. The incorporation of lightweight aggregate concrete into fiber can improve its resistance to freeze-thaw damage. The higher the dosage, the more obvious its effect on the improvement of lightweight aggregate performance. SEM observation showed that with the erosion of salt solution and the increase of the number of freeze-thaw cycles, the structure of hydration products became loose gradually from dense to dense. The adhesion between polypropylene fiber and cement paste was strong, which could restrain the freeze-thaw of concrete damage.