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| Influence of temperature history on crack resistance of early age concrete |
| 1.Nanjing Hydraulic Research Institute, Nanjing, Jiangsu 210029, China; 2. State Key Laboratory of HydrologyWater Resources and Hydraulic Engineering, Nanjing, Jiangsu 210029, China; 3.School of Materials Science and Engineering, Southeast University, Nanjing, Jiangsu 211189, China) |
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Abstract The complex crack resistance of dam concretes cured by three modes, i.e. adiabatic curing, temperature matched curing (TMC) and 20 ℃ constant temperature curing, were studied through the temperature stress testing machine. Based on the maturity of concrete under adiabatic mode, the start time of cooling and cooling rate (i.e. 0.5~1.0 ℃/h) of other two curing modes were determined. Two kinds of aggregates combination were used in the tested dam concretes. Different to the test results of concretes under the curing modes of constant temperature and TMC, the tensile stress of concrete develops faster and the cracking temperature of concrete is higher under the adiabatic curing mode. Meanwhile, the crack resistance of concrete can be easily distinguished and evaluated under the adiabatic curing mode than under other two curing modes. However, the beginning point of cooling is overestimated and the crack resistance of concrete is underestimated under the adiabatic curing mode. Moreover, the influence of precompressive stress on the crack resistance of concrete cured under the constant temperature can not be obviously evaluated, and the cracking temperature of concrete is lower than true value under this curing condition. The test results show that the influence of the temperature history on the stress development and crack resistance of concrete could be reasonably investigated only under TMC condition.
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2011, Vol. 32 
