中文摘要：

为了研究受冻融腐蚀的混凝土抗冻性能，分别制作了素混凝土块和约束钢筋混凝土柱两批不同试件，两批试件根据水灰比高低和粉煤灰的掺量不同设计为四种不同材料配合比。对上述试件进行0、20、40、60、100、120次的冻融循环试验，分别从冻融循环后约束混凝土抗冻性能、素混凝土的抗冻性能以及两者抗冻性能差异三方面进行研究。本研究作为第一部分，主要研究内容为约束混凝土的抗冻性能，主要分析约束混凝土强度和刚度随冻融循环次数退化规律和不同材料配合比对试件抗冻性能影响。研究结果表明：在O一一120次的冻融循环过程中，随着冻融循环次数增加，约束混凝土极限强度经历冻融初期陡降，冻融中期平缓，冻融后期再次陡降三个阶段，曲线呈现平台效应，冻融循环120次时，极限承载力降低约50％，但延性相对提高2～3倍。水灰比相同，掺15％粉煤灰约束混凝土柱的极限承载力比不掺粉煤灰混凝土柱降低约30％~40％，掺15％粉煤灰并不能提高抗冻性能；粉煤灰掺量相同时，水灰比越高，极限承载力越大；不掺粉煤灰时宜采用低水灰比。本研究对寒冷地区受冻融作用的钢筋混凝土结构的承载力评估和设计具有重要的指导意义。

英文摘要：

In order to study the anti-freeze performance of concrete, respectively making two group of different specimens which were plain concrete blocks and reinforced concrete columns.The two groups of specimens were designed into four different materials, according to the water cement ratio and dosage of fly ash.They were also tested under freeze-thaw cycle of different numbers as 0,20,40,60,100 and 120 to study the antifreeze performance of plain concrete and reinforced concrete, also with contrast.As the first part, this paper mainly described the antifreeze performance of confined concrete, analyzing degradation rule of strength and stiffness of confined concrete with freeze-thaw cycles and the impact of different ratio of materials on the antifreeze performance of specimens.Research shows that in 0-120 times freeze-thaw cycle,with the increase of freeze-thaw cycles,ultimate strength of confined concrete was steeply falling in the early cycle,gently in mid freeze-thaw cycle and again sharply fall in the last stages,the curve of ultimate strength had a platform,at the freeze-thaw cycle of 120 times, ultimate bearing capacity reduced about 50%, but the ductility relatively increase 2~3 cycles.As the same water-cement ratio, the ultimate bearing capacity of 15% fly ash confined concrete column less than the concrete columns without mixing fly ash, reducing about 30%-50%, so mixing 15% fly ash does not improve anti-freeze performance;as the same dosage of fly ash, the higher the water-cement ratio,the greater the ultimate bearing capacity;concerte with no fly ash should use low water cement ratio.In this paper,we study the bearing capacity of reinforced concrete structures in cold areas subjected to freezing and thawing,which has an important guiding significance to the evaluation and design of confined concrete.