Semi-rigid pavements have structural properties that are more similar to rigid pavements than flexible pavements. However, testing its bearing weight has evolved more along the lines of methods used for flexible surfaces. Because most of the semi-rigid surfaces crack transversally and systematically, with gaps between the cracks that may range between four and six metres, the road surface appears uneven, with signs of weak spots with low structural capacity that correspond to the crack areas, whereas the rest of the road surface maintains important structural properties that match the rigid pavements almost identically. Traditional testing techniques that were done with evenly-paced deflectographers, normally five metres, entailed random deflection measurement over high bearing zones and occasionally over reduced capacity cracked sections. Data collected in this fashion is scattered and difficult to repeat. For this reason, in Spain, over the last several years, road testing has begun looking into the bearing capacity of semi-rigid surfaces by concentrating on its weak points (cracked zones), with the use of an impact deflectometer, and by examining structural parameters of said weak zones as though they were rigid surfaces. This paper describes these testing methods and presents the results obtained. (A)
Abstract