New Performance-Based Approach for Assessment of Curing Effectiveness

Ensuring sufficient water availability in hydrating concrete is of great importance for quality curing relative to both short-term and long- term performance of concrete pavement. Excessive early-age evaporation from the concrete pavement surface can cause high porosity, and low strength at the top part of concrete with a deeper moisture gradient, which ultimately leads for some aggregates to a greater potential of surface distress and warping induced delamination. Application of liquid curing compounds on newly built concrete pavement surfaces has been widely used to minimize evaporation. However, the availability of a reliable test method to assess the efficacy of a curing compound relative to the amount of expected evaporation is still lacking. Therefore, advancements are needed to facilitate the evaluation of curing effectiveness in terms of their expected performance under field conditions. This paper presents a laboratory-based procedure, which bridges laboratory measured parameters to performance in the field, in terms of qualifying the effectiveness of a curing compound membrane relative to the factors that control it. The curing monitor system, a device capable of accurately recording relative humidity and temperature readings at three critical locations along with wind speed and solar radiation is used as part of a laboratory test procedure to assess the efficacy of a curing compound. A compound curing effectiveness parameter, i.e., effective curing thickness or an evaluation index, as defined in this paper, is then calculated based on the above measured parameters. The curing effectiveness parameter is useful to rank the curing compound relative to specific lab conditions. From the limited field application studies, it has been observed that the proposed test procedure has good potential to evaluate the curing effectiveness under field conditions.