摘要
为探究桥梁索塔结构内部混凝土的实际性能发展规律,将某长江公路大桥索塔C50大体积混凝土施工时的芯部温度作为混凝土的匹配养护温度,对比研究了标准养护和温度匹配养护对纯水泥、单掺20%粉煤灰、复掺20%粉煤灰和15%矿粉3种C50混凝土试件的强度发展规律、抗氯离子渗透性和水化产物微观形貌的影响。结果表明:温度匹配养护下的高水化温度显著激发了掺有粉煤灰和矿粉的复合胶凝材料的水化活性,复掺粉煤灰和矿粉的混凝土在温度匹配养护下的3 d抗压强度和抗折强度较标准养护分别提高45%和30%以上;温度匹配养护抑制了纯水泥混凝土的后期强度发展,且增大了其脆性,降低了抗氯离子渗透性,而单掺粉煤灰或复掺粉煤灰和矿粉可以改善或消除上述不利影响;无论是标准养护还是温度匹配养护,复掺粉煤灰和矿粉的混凝土具有最高强度、最大折压比和最好的抗氯离子渗透性,适合索塔大体积混凝土结构施工使用。
In order to explore the development law of the actual performance of concrete for the bridge cable tower structure,the core temperature of C50 mass concrete construction of the cable tower of a Yangtze River highway bridge was used as the matching curing temperature of concrete.The effects of standard curing and temperature matching curing on the strength development law,resistance to chloride ion permeability and microstructure of hydration products of three kinds of C50 concrete specimens of pure cement,addition of 20%fly ash(FA),mixed with 20%FA and 15%ground granular blast furnace slag(GGBS)were compared and studied.The results show that the high hydration temperature under the temperature matching curing significantly stimulates the hydration activity of the composite cementitious material mixed with FA and GGBS.The 3 d compressive strength and flexural strength of the concrete mixed with FA and GGBS under temperature matching curing condition are increased by more than 45%and 30%respectively than those under standard curing condition.Temperature matching curing inhibits the later strength development of pure cement concrete,increases its brittleness and reduces its resistance to chloride ion permeability,and the above adverse effects can be improved or eliminated by addition of FA or mixed FA and GGBS.Whether under standard curing or temperature matching curing,the concrete mixed with FA and GGBS has the highest strength,the maximum ratio of folding pressure and the best resistance to chloride ion penetration,which is suitable for the construction of mass concrete structure of cable tower.
作者
杨宏天
李北星
田常兵
钟翔
YANG Hongtian;LI Beixing;TIAN Changbing;ZHONG Xiang(State Key Laboratory of Silicate Materials for Architectures,Wuhan University of Technology,Wuhan 430070,Hubei,China;Hubei Jiayu Yangtze River Highway Bridge Co.,Ltd.,Xianning 430051,Hubei,China)
出处
《建筑科学与工程学报》
CAS
北大核心
2024年第3期26-33,共8页
Journal of Architecture and Civil Engineering
基金
国家重点研发计划项目(2020YFC1909904)。
关键词
养护温度
索塔
矿物掺合料
强度
抗氯离子渗透性
水化
curing temperature
cable tower
mineral admixture
strength
resistance to chloride ion penetration
hydration
