Development and Demonstration of NDT for Evaluating the Curing Effectiveness of Concrete Pavement Construction

Abstract

Early-age concrete surface moisture evaporation can be a factor during paving of concrete pavement resulting in plastic shrinkage cracking and spalling related delamination. The use of liquid membrane-forming curing compounds is one of the most prevalent methods to protect hydrating concrete surfaces. However, success in the application of curing compounds is not always assured under field conditions; lacking a tool to evaluate the curing effectiveness in terms of the uniformity and the rate of application are main issues. Previous research focused on the measurement of the surface dielectric constant (DC) of concrete as an indicator of the moisture retention capability of a given method of curing; however, the inherent limitations associated with the previous handheld technology prevents the method from being extensively utilized under field conditions. To employ better curing practices and the qualification of the application of different methods of curing, this research considers the use of ground penetrating radar (GPR) technology to measure DC at the surface of a concrete pavement. Analyses of the DC measurements indicated that the GPR system provided a very useful means to rapidly and extensively evaluate the curing effectiveness over a broad extent of a paved surface with great data repeatability; visual observations and statistical analyses validated that the system was able to suggest the uniformity of curing applications and differentiate the effectiveness of various curing applications due to varied rates of application. The research also reinforces the notion that the moisture retention capability of a given method of curing increases with the increase of the rate of application and improvement of curing uniformity.