Novel methods of quantifying curing influence and freeze thaw cycles in the field

Abstract

This work developed a flexible resistivity sensor that provides a novel perspective to develop a deep understanding of two important problems for concrete, i.e. curing influence on concrete hydration and freeze-thaw cycles of concrete in the field. First, the resistivity sensor is designed to quantify the influence of different curing methods on hydration and subsequent related properties of the fresh concrete. A correlation between resistivity and degree of saturation (DOS), tensile strength, and porosity was established based on measured data. The work also provides guidance on the allowable delay in applying the wet curing before the properties of the concrete are compromised. The same resistivity sensor network is modified to measure the DOS, temperature, and the ice formation of concrete in the field condition. A series of samples were sent out to different field sites with various weather conditions. An equation for calculating the temperature when ice forms and thaws for samples with different DOS was obtained. The designed sensor was proven to provide a practical approach to making widespread measurements of the number of effective freeze-thaw cycles of concrete in the field. These new electrical observations offer powerful insights into liquid water movement, chemical bonding in hydration products, and the phase change with temperature.