Study on Evaluating the Hardness of the Sidewalk Pavement

In Japan, some laws for the pavement, which took into consideration physically handicapped people and senior citizens, were established. In those relevant laws, it is recommended that safety and comfort for all users should be considered when the sidewalks are designed. But the evaluation method of safety and comfort is not established when the sidewalk pavement are constructed. Therefore, the objective of this study is to establish� the� simple� evaluation� method� of� the� pavement's� hardness� that take into consideration safety and comfort of users, especially for handicapped people. Moreover, the SB/GB test and the Portable Falling Weight Deflectometer (PFWD) test were carried out in this study. In SB/GB test, 1 inch steel ball in diameter and a golf ball were used to measure SB/GB coefficients that were calculated from the bounce height of each ball. The PFWD was used to measure elastic moduli of pavement. In the previous study, Takeuchi et al. pointed out that the range of an elastic modulus took into consideration safety and comfort of users that is 25-80MPa. However it is hard to obtain PFWD because of an expensive device. By contrast, SB/GB test can be conducted easily by using a golf ball and a steel ball, moreover, it is widely used in Japan. Hence, to simplify the hardness evaluation of sidewalk pavement, SB/GB coefficients were compared with the elastic modulus. As the result, it was found that the range of SB/GB coefficients corresponding to the range of 25-80 MPa in the elastic modulus were around 20-35% in SB coefficient and around 45-65% in GB coefficient. The range can be used to evaluate a road surface by cheap, easy and convenient equipment.