摘要
为研究冻融作用下海工高性能混凝土(Marine High Performance Concrete,简称MHPC)梁性能退化机理及其正截面受弯承载力计算方法,采用水冻水融法对三种配合比的9根MHPC梁和36个试块进行总计100次循环的快速冻融试验;通过微宏观结构、质量、动弹性模量以及抗压强度等指标分析,对MHPC材料的冻损特性进行有效评价,并基于抗压强度的退化提出冻融作用下MHPC适筋梁正截面受弯承载力计算模型。试验与分析结果表明:(1)三种MHPC混凝土的抗冻性能明显优于普通混凝土,其冻损特性可用动弹模损伤度或抗压强度损失率进行评价;(2)冻融作用后MHPC梁受弯过程中截面应变仍符合平截面假定,且混凝土受压区高度随冻融次数的增加而增大;(3)用文章提出的计算模型能很好地预测冻损MHPC梁的正截面受弯承载力;(4)当抗压强度损失率低于40%时,通过已有试验结果和计算模型对比分析,验证了文章计算模型在预测冻融作用后普通和MHPC混凝土梁受弯承载力的有效性。
To explore the performance degradation and calculation method of flexural capacity of MHPC beams suffering from freeze-thaw action,a quick freezing-thawing test with total 100 water freezing-thawing cycles was carried out on nine MHPC beams and 36 block specimens designed with three kinds of concrete mixtures.The micro-and macro-structure,weight,dynamic elastic modulus and compressive strength of block specimens were measured and the inner damage of concrete was elevated.Based on the degradation of concrete compressive strength after freeze-thaw action,the calculation model of flexural capacity of MHPC beams with proper reinforcements was proposed.The test and analysis results show that three kinds of test MHPC specimens all have better frost resistance than the normal concrete and the frost damage can be assessed by damage degree of dynamic elastic modulus or loss ratio of compressive strength.The sectional strains of test MHPC beams after freeze-thaw action still conform to the rule of plane section assumption and the height of concrete compression zone increases with the freeze-thaw cycles.The calculation model proposed in this study can effectively predict the flexural capacity of test MHPC beams after exposure to freeze-thaw environment.Furthermore,by comparing with the existing experimental data and calculation models,the effectiveness of proposed calculation model for predicting the flexural capacity of damaged normal and MHPC concrete beams is verified when the loss ratio of concrete compressive strength after freeze-thawing action is less than 40%.
作者
陆春华
杨钰婷
平安
张菊连
Lu Chunhua;Yang Yuting;Ping An;Zhang Julian(Jiangsu University,Zhenjiang 212013,China;Shanghai Horizon Construction Technology Co,Ltd,Shanghai 201800,China)
出处
《土木工程学报》
EI
CSCD
北大核心
2022年第7期47-56,共10页
China Civil Engineering Journal
基金
国家自然科学基金(51878319)。
关键词
冻融作用
MHPC梁
受弯承载力
计算模型
freeze-thaw action
MHPC beams
flexural capacity
calculation model
