干旱大风环境下不同养护措施对桥梁混凝土性能的影响  

Effect of Different Curing Measures on the Performance of Bridge Concrete Under Arid Wind Environment

作　　者：安明喆 张洪发[2] 王月 张瑜 余自若[2] An Mingzhe;Zhang Hongfa;Wang Yue;Zhang Yu;Yu Ziruo(Engineering Research Center of Railway Industry of ConstructionTechnology for LongSpan Bridge in Special and Complex Environment,China Railway Major Bridge Reconnaissance&Design Institute Co.,Ltd.,Wuhan,Hubei 430050,China;School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China)

机构地区：[1]中铁大桥勘测设计院集团有限公司特殊复杂环境下长大桥梁建造技术铁路行业工程研究中心,湖北武汉430000 [2]北京交通大学土木建筑工程学院,北京100044

出　　处：《铁道技术标准（中英文）》2023年第3期10-17,共8页Railway Technical Standard(Chinese & English)

摘　　要：干旱风环境作用加速桥梁结构混凝土内部水分传输与相对湿度的降低,使得混凝土在凝结硬化过程中易产生性能的劣化。本文通过试验研究模拟干旱多风环境下C50塔柱混凝土内养护及内外协同养护方式对结构混凝土内部湿度、强度与抗裂性的影响,并提出干旱大风环境下养护建议。①掺入15%的不同粒径沸石粉混凝土,5 d保湿养护后在20℃、相对湿度30%环境下继续放置至28 d,随着龄期的增长混凝土的内部相对湿度均呈现下降趋势,0~28 d龄期范围的掺入沸石粉内部湿度明显高于高比未掺入沸石粉混凝土,5 m/s风速下混凝土内部湿度进一步降低,而保湿养护5 d后表面喷涂养护剂协同养护可有效提高内部湿度;②掺入沸石粉对抗压强度有一定的降低,且随沸石粉平均粒径的减小,28 d强度呈降低趋势,劈裂抗拉强度的变化规律与抗压强度相同;掺入沸石粉可以降低5 m/s的风作用混凝土的28 d强度的损失,表面喷涂养护剂协同养护可有效提高28 d混凝土的抗压与抗拉强度;③圆环抗裂性能试验表明,干燥环境与风作用下未掺沸石粉混凝土收缩应力大,在11 d时产生裂缝释放应力,而掺入沸石粉、采取内掺沸石粉和表面涂刷养护剂协同养护可以有效降低混凝土内部收缩应力,未发生开裂现象,且采取内掺外涂刷协同养护的混凝土收缩应力更小。干旱多风环境下采取沸石粉内养护与外涂养护剂协同养护措施,可以在保证混凝土的强度的基础上,抑制结构混凝土的早期开裂。The action of dry and windy environment accelerates the water transmission and reduces relative humidity in the concrete of bridge structure,which makes the concrete easy to deteriorate in the process of setting and hardening.The effects of internal curing and internal and external synergistic curing methods on the internal humidity,strength and crack resistance of C50 tower column concrete under simulated dry and windy environment were studied through experiments,and the curing suggestions under dry and windy environment were put forward.①Add 15%zeolite powder concrete of different particle sizes,after 5 d of moisture curing,continue to place it to 28 d at 20℃and a relative humidity of 30%.With the increase of age,the internal relative humidity of concrete shows a downward trend.The internal humidity of zeolite powder concrete in the range of 0~28 d is significantly higher than that of highratio zeolite powder concrete.The internal humidity of concrete is further reduced at 5 m/s wind speed,and the surface spray curing agent after moisture curing for 5 d can effectively improve the internal humidity.②The addition of zeolite powder results in a certain reduction in compressive strength,and with the decrease of the average particle size of zeolite powder,the 28 d strength decreases,and the variation of splitting tensile strength is the same as that of compressive strength.The incorporation of zeolite powder can reduce the 28 d strength loss of 5 m/s windaffected concrete,and the surface spraying curing agent can effectively improve the compressive and tensile strength of 28 d concrete.③The ring anticracking performance test shows that the shrinkage stress of concrete without zeolite powder is large under the action of dry environment and wind,and the crack release stress is generated at 11 d.The addition of zeolite powder,the use of zeolite powder and surface coating curing agent can effectively reduce the internal shrinkage of concrete.

关 键 词：干旱多风 内外协同养护 沸石粉 养护剂 内部相对湿度 抗裂性能 

分 类 号：U24[交通运输工程—道路与铁道工程]