恒定低温下环境湿度对混凝土抗压强度的影响分析  

Influence of ambient humidity on compressive strength of concrete at constant low temperature

作　　者：蒋平江[1] 王起才[2] JIANG Pingjiang;WANG Qicai(Shanxi Railway Institute,Weinan 714000,China;Lanzhou Jiaotong University,Lanzhou 730070,China)

机构地区：[1]陕西铁路工程职业技术学院,陕西渭南714000 [2]兰州交通大学,甘肃兰州730070

出　　处：《混凝土》2019年第8期17-19,23,共4页Concrete

基　　金：国家自然科学基金(51768033);长江学者和创新团队发展计划滚动资助项目(IRT_15R9);陕西省渭南市科研计划项目(2016KYJ-1-3)

摘　　要：恒定低温下环境湿度和龄期关系到混凝土内部水含量的变化,进而影响着水泥的水化进程和混凝土的抗压强度。试验研究了恒定低温下保湿养护和空气养护中不同配合比混凝土抗压强度的变化规律。通过分析水泥水化反应进程和混凝土抗压强度增长机理,得出恒定低温下,空气养护和保湿养护下同一水胶比混凝土的抗压强度在前3 d内差异很小,之后随着龄期的增加差异变大,混凝土保湿养护56 d的抗压强度是其空气养护的1.15~1.2倍,128 d的抗压强度是其空气养护的1.17~1.23倍;保湿养护下,不同配合比混凝土28 d的抗压强度达到设计强度的86%~87.6%,128 d时都达到设计强度,高水胶比混凝土最先达到设计强度,低水胶比混凝土后期强度增长速率较大;空气养护下不同配合比混凝土128 d的抗压强度只达到设计强度的81.3%~86%,低水胶比混凝土前期强度增长较快,高水胶比混凝土后期强度增长较快。Ambient humidity and age are related to the change of water content in concrete when curing in constant low temperature,thereby affect the hydration process of cement and concrete compressive strength.The ongoing paper studies the changing law of compressive strength of concrete with different mix proportion in constant low temperature when keeping moisture or curing in air.Conclusions are drawn by analyzing the hydration process of cement and mechanism of the development of concrete compressive strength,that the difference of the compressive strength of concrete with identical water-binder ratio is rarely small within the first 3 d when keeping moisture or curing in air under constant low temperature,then the difference amplifies as the age goes further.When cured for 56 d and 128 d,the compressive strength of the concrete curing by keeping moisture is 1.15~1.20 and 1.17~1.23 times of the concrete with air curing.The strength of the concrete with different mix proportion can reach 86%~87.6%of the design strength when curing by keeping moisture for 28 d,and reach design strength when cured for 128 d,the concrete with higher water-binder ratio reaches the design strength at first,and the development of later strength of the concrete with relatively lower water-binder ratio appears to be faster.However,the strength only reaches 81.3%~86%of design strength when curing in air for 128 d,the development of the strength of the concrete with lower water-binder ratio appears to be faster in early stage,and the later strength of the concrete with higher water-binder ratio develops faster.

关 键 词：低温 保湿养护 空气养护 水胶比 抗压强度 

分 类 号：TU528.01[建筑科学—建筑技术科学]