A nondestructive evaluation method for semi-rigid base cracking condition of asphalt pavement

The evaluation of semi-rigid base cracking condition is one of the most important elements of project-level pavement evaluation, and has been a key challenge facing pavement engineers for many years. This is because that the semi-rigid base cracking condition cannot be obtained through visual surveys unless the asphalt course is milled off, therefore the nondestructive detection and evaluation method is a better choice. This paper develops a nondestructive FWD-based evaluation model to evaluate the semi-rigid base cracking condition. It was found that the normalized base modulus (ratio between back-calculated and initial modulus) and the semi-rigid base cracking condition had good relationship on log-log scales, therefore the normalized base modulus was considered to be a reasonable indicator for the evaluation of semi-rigid base damage (cracking) condition. Based on the comparison of measured data and back-calculated modulus in freeway pavements, the evaluation criterion is established.