海水(清水)与冻融对持续承载钢筋引气混凝土梁的影响  

Effect of seawater(water)and freeze-thaw cycles on reinforced air-entrained concrete beams with persistent loads

作　　者：张健[1] 刁波[2] 叶英华[2] 郑晓宁[2] 

机构地区：[1]国家知识产权局专利局专利审查协作北京中心,北京100083 [2]北京航空航天大学土木工程系,北京100191

出　　处：《混凝土》2013年第9期46-50,55,共6页Concrete

基　　金：国家自然科学基金(51078015);北京市自然科学基金(8092020);华南理工大学重点开放基金(2009KA03)

摘　　要：寒冷地区的钢筋混凝土结构会受到持续荷载与冻融循环作用,在沿海和内陆环境还会有不同侵蚀介质作用。试验比较了在冻融循环与海水或清水浸泡交替作用下,持续承载的钢筋引气混凝土梁的力学性能差异。试验结果表明,含气量为6.1%的引气混凝土,经历冻融循环和海水(清水)浸泡交替作用后,抗压强度均随着冻融循环次数增加而降低,其中冻融与海水浸泡的混凝土降低幅度更大;对于持续承载的钢筋引气混凝土梁,经历300次冻融循环和100次海水(清水)浸泡后,冻融与海水浸泡梁中混凝土用扫描电镜检测出更多的晶体和微裂缝;梁的承载力和延性性能均降低,冻融与海水浸泡梁的屈服荷载、极限荷载以及延性的降幅均大于冻融与清水浸泡梁。Reinforced concrete structures in cold regions are always subjected to freeze-thaw cycles and persistent loading, and the cor- rosion media are different in coastal and non-coastal areas.Under the alternating action of freeze-thaw cycles and seawater or water immer- sion,the mechanical properties of reinforced air-entrained concrete beams with persistent loads were experimentally compared.Results showed that, under alternating actions of freeze-thaw cycles and immersion in seawater （water）, the compressive strength of concrete with 6.1% air content decreased with the increase of freeze-thaw cycles, concrete specimens immersed in seawater showed larger reduction in compressive strength.After 300 cycles of freeze-thaw and 100 cycles of immersions in seawater（water）, more acicular crystals and micro cracks were found in beams suffered by freeze-thaw cycles and seawater immersion The deterioration of bearing capacity and ductility of reinforced air-entrained concrete beams were obvious, the reduction of yield load, ultimate load and ductility of beams immersed in seawa- ter was larger than that of beams immersed in water.

关 键 词：冻融循环 海水浸泡 引气混凝土 持续荷载 耐久性 

分 类 号：TU528.01[建筑科学—建筑技术科学]