纳米SiO_2粉煤灰轻骨料混凝土抗离析性能的试验研究  

Segregation Resistance of Nano SiO_2 Fly Ash Lightweight Aggregate Concrete

作　　者：高英力[1] 邹超[1] 陈家宝[1] 

机构地区：[1]长沙理工大学交通运输工程学院,长沙410114

出　　处：《硅酸盐通报》2015年第6期1513-1519,共7页Bulletin of the Chinese Ceramic Society

基　　金：湖南省自然科学基金(13JJ3070);湖南省教育厅资助科研项目(11A005)联合资助

摘　　要：掺加不同比例的粉煤灰和纳米SiO2,制备了强度等级为LC40~LC50的轻骨料混凝土。通过坍落度和分层度试验研究了轻骨料混凝土的抗离析性能。结果表明：单掺细度较高的粉煤灰能够增强轻骨料混凝土的流动性,使坍落度变大,同时随粉煤灰掺量增加,混凝土分层度变小,轻骨料上浮有所缓解,但依然存在;单掺纳米SiO2可以在一定程度上提高轻骨料混凝土的抗离析性能,但同时也会使混凝土拌合物流动性变差;复掺纳米SiO2和粉煤灰不仅可以增大轻骨料混凝土的坍落度,而且可以提高其抗离析性能,阻止轻骨料的上浮。研究表明,复掺2%纳米Si O2和18%粉煤灰的轻骨料混凝土工作性最佳。力学性能试验表明：复掺纳米SiO2和粉煤灰,可以提高轻骨料混凝土的抗压强度。Lightweight aggregate concretes of strength grade raging from LC40 to LC50 were prepared by adding different proportions of fly ash and nano SiO2. Segregation resistance of lightweight aggregate concrete was studied by slump and segregation degree tests. The results indicate that adding of finer fly ash can enhance the liquidity of lightweight aggregate concrete and enlarge the slump, meanwhile, with the increasing of fly ash content, segregation degree of concrete is decreased and floating of lightweight aggregate is somewhat alleviative but still exists, adding of nano SiO2 can improve the segregation resistance of lightweight aggregate concrete to a certain extent, meanwhile, deteriorate the fluidity of concrete mixture, combined admixture of nano SiO2 and fly ash can not only increase the slump of lightweight aggregate concrete, but also improve its segregation resistance, prevent the floating of lightweight aggregate. Studies indicate that lightweight aggregate concrete containing 2% nano SiO2 and 18% fly ash has the best workability. Mechanical property tests indicate that combined admixture of nano SiO2 and fly ash can improve the compressive strength of lightweight aggregate concrete.

关 键 词：轻骨料混凝土 纳米SIO2 粉煤灰 离析 强度 

分 类 号：TU528[建筑科学—建筑技术科学]