Reliability of british pendulum test on macrotextured surfaces

The British pendulum test is a common laboratory test for measurement low-speed friction of pavement surface which is related to surface microtexture of road surface. Transverse or longitudinal grooving is used to improve skid resistance on concrete pavements. In this study, experiments were made on different size and shape of transverse and longitudinal grooved surfaces by using British pendulum tester to find their skid resistances. The experimental results presented in this paper showed that the British pendulum test is also affected by macrotexture. Although some experimental studies have been made on determining the effect of macrotexture on BPN value, this paper implies that the microtexture must also be taken into account when examining macrotexture effect on skid resistance while using British pendulum tester. The importance of microtexture effect on British pendulum test is different if there is a penetration of rubber into gaps. This penetration has a big effect on skid resistance and different amount of penetration can be obtained when the first horizontal contact point between the rubber and the testing surface is changed. The results demonstrated that when there is any macrotextured surface, there are too many parameters to be considered to investigate the reliability of BPN values.