Study on Characteristics of Tensile Strength of Concrete Considering Temperature Dependence in Mass Concrete Structures

Abstract

It is important to grasp mechanical and thermal properties in order to verify the possibility of thermal cracking. In this study, for the purpose of improving the accuracy of analysis in prediction of cracking caused by thermal stress, it was investigated that the direct tensile strength and thermal properties considering temperature history inside concrete member may be applied as a design values for the analysis of prediction of cracking caused by thermal stress. From results of these experiments, in early age, the direct tensile strength under mass curing which is considered temperature history inside concrete member is higher than the splitting tensile strength under standard curing. Which is cured under water of 20°C. However, the direct tensile strength under mass curing is lower than the splitting tensile strength under standard curing after 7 days. At 28 days, the strength of former was about 20% lower than that of latter. In this study, the estimated formula on the strength development of the direct tensile strength was proposed. And the thermal expansion coefficient was estimated using measured values of strain and temperature. In this paper, it was reported that the test method of direct tensile strength considering temperature history inside concrete member was proposed and that the accuracy of analysis for the prediction of thermal cracking by using this method would be improved.

Properties of early-age concrete relevant to cracking in massive concrete

“…This was experimentally confirmed by Zunino et al, who clearly showed that the lower CTE of coarse aggregate produces damage (detaching or shrinkage-restraint cracking) around aggregates and the resultant reduction of Young's modulus and compressive strength of early age concrete exposed to cyclic temperature changes ranging from 31.8 to 75.3 ˚C [127]. Similar trends were found in tension, but there is no information on tensile strength of concrete with direct comparison to compressive strength [128].…”