LAUSR

Abstract In order to prevent damage to concrete due to early age freezing, it is very important to monitor the microstructure formation process and strength development of early-age concrete in winter construction. A resistivity method is presented in this study to assess the freezing process of early age concrete at different negative ambient temperatures. The results show that the freezing temperature leads to a sharp rise in resistivity of concrete. The evolution of resistivity can be divided into three stages, which are cooling and nucleuses formation stage, rapid crystallization stage and crystallization finish stage. In addition, some characteristic values, such as blocking time t1, maximum ice content time t2 and freezing rate α, are extracted from the resistivity-time relationship curve and further clarify the freezing process of concrete. There is a good log-linear relationship between resistivity and compressive strength, which can be used to predict the extent of frost damage to concrete. Moreover, the monitoring results of outdoor concrete resistivity confirm that this method is suitable for the evaluation of concrete frost damage on site during winter construction.