考虑尺寸效应的大尺寸混凝土干燥收缩预测方法研究  

Prediction model for drying shrinkage of large-size concrete considering size effects

作　　者：王庆贺 董国明[1] 杨金胜 张信龙 王全 刘庆东[3] WANG Qinghe;DONG Guoming;YANG Jinsheng;ZHANG Xinlong;WANG Quan;LIU Qingdong(School of Civil Engineering,Shenyang Jianzhu University,Shenyang 110168,China;Key Lab of Structures Dynamic Behaviour and Control of the Ministry of Education,Harbin Institute of Technology,Harbin 150090,China;China Northeast Architectural Design&Research Institute Co.,Ltd.,Shenyang 110006,China)

机构地区：[1]沈阳建筑大学土木工程学院,辽宁沈阳110168 [2]哈尔滨工业大学结构工程灾变与控制教育部重点实验室,黑龙江哈尔滨150090 [3]中国建筑东北设计研究院有限公司,辽宁沈阳110006

出　　处：《混凝土》2023年第3期1-6,共6页Concrete

基　　金：国家自然科学基金(51808351);住房和城乡建设部科学技术计划项目(2019-K-054);辽宁省博士科研启动项目(2019-BS-193);辽宁省教育厅(lnjc202007,lnqn202024);沈阳市科技局项目(RC200143)。

摘　　要：国内外规范均基于小尺寸试件的实测数据提出混凝土的干燥收缩模型,未充分考虑试件尺寸效应的影响,因而其对大尺寸混凝土的干燥收缩的预测精度较低。基于此,首先对典型的混凝土干燥收缩模型(EC2模型及B3模型)的特点进行评述,明晰构件截面形式与尺寸效应对干燥收缩的影响规律;基于收集的15组混凝土收缩试验结果评价规范模型的可靠性,进而提出考虑尺寸效应的大尺寸混凝土干燥收缩模型。研究结果表明,现有的规范模型可有效预测小尺寸混凝土的干燥收缩变形,但会低估大尺寸混凝土的干燥收缩终值,理论厚度大于100 mm(200 mm)时,EC2模型(B3模型)的预测结果平均低于试验结果 33.2%(40.5%);通过引入理论厚度调整系数,得到修正的EC2模型和B3模型,可以有效预测大尺寸混凝土的干燥收缩变形,预测结果与试验结果平均相差15.5%和2.0%。Current specifi cations propose drying shrinkage models based on measurements from small-size concrete specimens.These models could not provide reasonable predictions for large-size concrete specimens as size effects are not fully considered in these models.In this context,the characteristics of typical drying shrinkage models(i.e.EC 2 model and B3 model)were first summarized and evaluated,and the effects of cross-section form and specimen size on the drying shrinkage were obtained.The reliability of the drying shrinkage models were benchmarked against test data on 15 concrete specimens from literature,based on which the modified drying shrinkage models were proposed accounting for the size effects.The results show that the existing drying shrinkage models can effectively predict the dry shrinkage of small-size concrete,but underestimate the final dry shrinkage of large-size concrete.When the theoretical thickness is greater than 100 mm(200 mm),EC2 model(B3 model)underestimated the drying shrinkage of concrete by 33.2%(40.5%).By introducing the theoretical thickness adjustment coefficient,the modified EC2 model and B3 model can effectively predict the dry shrinkage of large-size concrete,with the average difference between the predicted and measured results of 15.5%and 2.0%,respectively.

关 键 词：大尺寸混凝土 干燥收缩 尺寸效应 收缩模型 

分 类 号：TU528.01[建筑科学—建筑技术科学]