Evaluation of Calibration Procedures of British Pendulum Tester

Like all test devices, a British pendulum tester has to be calibrated to ensure that its measurements are correct and accurate within acceptable limits. The ASTM E303 and BS EN 13036-4 standards present two established and widely followed calibration procedures for the British pendulum tester. Though similar in most aspects, there are some differences in the two calibration procedures. This study examines the impacts on British pendulum test (BPT) results of the calibration requirements of the two standards by means of a finite element BPT simulation model developed based on theories of mechanics. The simulation model is applied to analyze the range of variations in the test values of BPT devices with different operating parameter values within the allowable limits of the two standard procedures. It is found that two BPT devices both satisfying the ASTM E303 calibration requirements could produce measurements with a difference of more than 60 % of their mean test value, and for BS EN 13036-4 it is more than 25 %. It means that different BPT devices, all meeting necessary calibration and precision requirements of either of the two standards, could give different test values that might lead to different skid resistance assessments of the pavement tested. This is unsatisfactory for practical applications in skid resistance evaluation of pavements. Based on analyses of the simulation model, this study proposed revised calibration limits to achieve more acceptable magnitudes of differences between the measurements made by different BPT devices.