Nondestructive Testing for Crack Width and Variability on Continuously Reinforced Concrete Pavements

Abstract

Previous research has shown that the main failure mode in continuously reinforced concrete pavements (CRCP) is the punchout, a distress associated with the loss of load transfer capacity across transverse cracks. Despite the fact that crack width is widely recognized as one of the most important factors in CRCP punchout development, little research has been focused on effectively quantifying this variable. This paper presents results of crack width determined by measuring the crack closing movement under the action of vertical loads. The CRCP crack width data were acquired by using a rolling wheel load and a falling weight deflectometer (FWD) measuring technique. Crack width was successfully determined with an FWD, which enables future use of this device and technique to determine field CRCP crack widths. Crack width distribution is difficult to assess initially on CRCP test sections because the zero-crack width temperature needs to be known and the average pavement temperature must be less than this value during the testing. The data gathered from this study consisted of crack width from 31 transverse cracks on a uniform section, measured at the surface, when the pavement temperature was 9.5°C (average top and bottom) and the temperature differential was 0.5°C. In this case, the average width was 59 microns, and the standard deviation was 11.6 microns. On the basis of the measured crack width data, a Weibull distribution of the crack width was proposed with shape parameters related to the minimum, maximum, mean, and standard deviation of the crack width data.