ASSESSMENT OF CRACKING IN CONCRETE DUE TO HYDRATION HEAT AND AUTOGENOUS SHRINKAGE
This paper presents the results of an experimental study conducted to simulate thegeneration of thermal stresses due to hydration heat considering various restraint conditionsby using thermal stress measuring device (TSD). It was found that influence of early-ageproperties of concrete on generation of thermal stresses such as elastic modulus; thermaldilation coefficient; and transitional thermal creep can be incorporated using TSD due to thesimultaneous development of temperature and the corresponding stress in restrained specimenfrom the very beginning. Moreover,additional tests were conducted to study the effect oftemperature rise due to early hydration on measurement of early-age autogenous shrinkage(AS). Early-age Autogenous shrinkage of specimens obtained with (semi-adiabatic condition)and without any temperature change (isothermal condition) was quite different. Therefore,itis suggested to control the isothermal conditions while measuring AS. Underestimation ofearly-age AS would cause serious errors while predicting the time of shrinkage inducedcracking especially in HPC. Basic creep model was evaluated with respect to AS. It wasfound that for low w/c concrete,as well as at an early age of normal strength concrete,asignificant difference exist between apparent (including AS) and real basic creep (excludingAS). It is recommended to modify the current basic creep model with respect to AS in orderto prevent from possible errors and some other computational problems.
autogenous shrinkage early age hydration heat thermal stress basic creep
Jin-Keun Kim Muhammad Nasir Amin Jeong-Su Kim
Department of Civil and Environmental Engineering,Korea Advanced Institute of Science and Technology (KAIST),373-1 Guseong-dong,Yuseong-gu,Taejon 305-701,R.O.Korea
国际会议
The International Conference on Durability of Concrete Structures(2008年混凝土结构耐久性国际学术会议)
杭州
英文
99-108
2008-11-01（万方平台首次上网日期，不代表论文的发表时间）