Experimental study of deformation of early age concrete suffering from frost damage

摘要

In winter construction, early age concrete is easily threatened by frost damage. In order to explore whether early concrete freeze occurred and its freezing degree, the deformation of early age concrete suffering from frost damage was investigated. Firstly, a test device for high-precision non-contact deformation for sub-zero temperature use was designed. By using this device the effects of different sub-zero temperatures, various frequently-used antifreeze agents, and different pre-curing time on the deformation characteristic of early age concrete were studied. Besides, to understand the relationship between the deformations and the frost damage level, the compressive strength and pore structure of concrete were examined. The results showed that the deformation laws of early age concrete suffered from frost damage was consistent and six stages could be divided. They were settlement and contraction, frost heaving, deformation stabilization, positive temperature settlement, positive temperature expansion and re stabilization, respectively. In addition, the characteristic values of the deformation were significantly affected by different sub-zero temperatures, types of antifreeze agent and pre-curing time. Moreover, the characteristic values such as frost heaving deformation and residual deformation can represent the extent of frost heaving and frost damage for early age concrete. (C) 2019 Elsevier Ltd. All rights reserved.