A study of the sand-patch and outflow meter methods of pavement surface texture measurement was completed. Included in this study were repeatability testing and testing to determine the degree to which pavement surface texture, as measured by these procedures, correlates with pavement coefficient of friction, skid number, and skid number speed gradient. Test locations were selected on open-graded and dense-graded asphalt concrete, chip-sealed and fog-sealed asphalt concrete, and new, polished, and grooved portland cement concrete (PCC) pavements. The results of the testing indicated that the repeatability of the sand patch test procedures studied was poor to fair and that the outflow meter test results were independent of water temperature. A general trend toward higher skid numbers and coefficients of friction was evident with increasing texture depth, as measured with both the modified sand patch and the outflow meter procedures. However, neither relationship was considered definitive enough to use as a basis for a minimum texture depth construction specification requirement for pavement surfaces. Also, neither method provided a definitive measure of skid number speed gradient.

Bearing Capacity of Roads, Railways and Airfields includes the contributions to the 10th International Conference on the Bearing Capacity of Roads, Railways and Airfields (BCRRA 2017, 28-30 June 2017, Athens, Greece). The papers cover aspects related to materials, laboratory testing, design, construction, maintenance and management systems of transport infrastructure, and focus on roads, railways and airfields. Additional aspects that concern new materials and characterization, alternative rehabilitation techniques, technological advances as well as pavement and railway track substructure sustainability are included. The contributions discuss new concepts and innovative solutions, and are concentrated but not limited on the following topics: · Unbound aggregate materials and soil properties · Bound materials characteritics, mechanical properties and testing · Effect of traffic loading · In-situ measurements techniques and monitoring · Structural evaluation · Pavement serviceability condition · Rehabilitation and maintenance issues · Geophysical assessment · Stabilization and reinforcement · Performance modeling · Environmental challenges · Life cycle assessment and sustainability Bearing Capacity of Roads, Railways and Airfields is essential reading for academics and professionals involved or interested in transport infrastructure systems, in particular roads, railways and airfields.

This report contains guidelines and recommendations for managing and designing for friction on highway pavements. The contents of this report will be of interest to highway materials, construction, pavement management, safety, design, and research engineers, as well as others concerned with the friction and related surface characteristics of highway pavements.