New Performance-Based Approach to Ensure Quality Curing during Construction

Ensuring sufficient water availability in hydrating concrete is a key to achieving quality curing that protects the fresh concrete in the short term and develops the potential properties of the mixture for long-term performance of concrete pavement. Excessive early-age evaporation from the concrete pavement surface can potentially result in plastic shrinkage cracking, high porosity, and low strength at the concrete surface leading to a variety of surface distresses. Application of liquid curing compounds on newly placed concrete pavement surfaces has been widely used to minimize evaporation. However, the availability of a test method to assess the efficacy of a curing compound relative to the actual environmental conditions encountered in the field is still lacking. Therefore, advancements are needed to further facilitate the evaluation of curing effectiveness (CE). This paper presents a laboratory-based procedure, which bridges laboratory measured parameters to performance in the field, as part of a process to qualifying the effectiveness of a curing compound membrane. The curing monitor system, a device capable of accurately recording relative humidity and temperature at three critical locations along with wind speed and solar radiation, is used as part of a test procedure to assess the efficacy of a curing compound. A compound curing evaluation index (EI) is defined in terms of the effective curing thickness concept and moisture loss at 24 h after placement. The EI is useful to rank the curing compound relative to laboratory test conditions. From the limited field application studies, it has been observed that the proposed test procedure has good potential to be an effective tool to assess CE and quality under field conditions.