ANALYSIS OF TEMPERATURE INFLUENCE ON SKID RESULTS

1. ANALYSIS OF TEMPERATURE INFLUENCE ON SKID RESULTS Authors: Marta Pagola and Oscar Giovanon Argentina 3rd International Surface Friction Conference Gold Coast, Australia, 2011 National University of Rosario, Argentina

2. 3rd International Surface Friction Conference Gold Coast, Australia, 2011 SOUTH AMERICA ARGENTINA ROSARIO IMAE ROAD LABORATORY NATIONAL UNIVERSITY OF ROSARIO ARGENTINA Dedicated to research, to teach and to give technical solutions since 1963 In aspects related with structural pavement design, road materials, surface deterioration, and pavement management system National University of Rosario, Argentina

3. Skid resistance vs. Time • Temperature, • Surface dirty, • Rain • Tire condition, • ….. Periodic Cycle Permanent decreasing 3rd International Surface Friction Conference Gold Coast, Australia, 2011 National University of Rosario, Argentina

4. Parameters and variations Each one of them have transitory and permanent variations. Permanent are because of traffic and wear of surface and test tyre. Transitory are related with surface contamination and temperature. The objective of study was to analyze temperature influence on results. 3rd International Surface Friction Conference Gold Coast, Australia, 2011 National University of Rosario, Argentina

5. Objective of measurements 1. Know the value at certain moment (airports) 2. Know the minimum (pavement management systems) 3. Quality control. (results are compared with technical specifications) 3rd International Surface Friction Conference Gold Coast, Australia, 2011 National University of Rosario, Argentina

6. Temperature influence analysis Influence in considered and results are expressed at reference temperature of 20ºC. Correction factor is 1 point each 3ºC. British Pendulum Correction factor TemperatureºC 3rd International Surface Friction Conference Gold Coast, Australia, 2011 National University of Rosario, Argentina

7. Equipments 3rd International Surface Friction Conference Gold Coast, Australia, 2011 National University of Rosario, Argentina

8. Mu meter Mu meter equipment does not have temperature sensor incorporated, then at the end of measurement were taken the possible temperatures: air, water, pavement and water on pavement surface. Water on pavement surface temperature is the same that is indicated in British Pendulum methodology, and it is a combination between surface and water temperature. Were measured 4 sections of 4 Km of length approximately, sections have different characteristic of texture depth, and air temperature was between 8 ºC and 32 ºC. 3rd International Surface Friction Conference Gold Coast, Australia, 2011 National University of Rosario, Argentina

9. Tendency shows that influence is 1 point of Mu Meter each 3 ºC or 0.33 points each 1 ºC, the same that TRRL Pendulum, and considering the same temperature parameter, water on pavement surface. The graph also shows that when temperature increases skid resistance coefficient decreases. 3rd International Surface Friction Conference Gold Coast, Australia, 2011 National University of Rosario, Argentina

10. Scrim tex This equipment has two sensors incorporated, one measure air temperature and another dry pavement surface temperature. Tendencies with both temperatures were analyzed, and one additional analysis was made between results and average temperature between both available temperature results. The objective here was to use available results without incorporate additional temperature measurements. Were measured 2 sections of 2 Km of length approximately, sections have different characteristic of texture depth and air temperature was between 8 ºC and 18 ºC. 3rd International Surface Friction Conference Gold Coast, Australia, 2011 National University of Rosario, Argentina

11. The tendency obtained indicates that when temperature increases skid resistance result (CFT) decreases, but it influence was really low. 1 point Scrim each 12ºC with average air-surface temperature, and 1 point each 11ºC with air temperature. 3rd International Surface Friction Conference Gold Coast, Australia, 2011 National University of Rosario, Argentina

12. Conclusions 1/2 • Was analyzed temperature influence on results obtained with Mu meter and Scrim Tex in Argentina. • For Mu Meter from all temperatures present during measurement the one that presented a reasonable tendency is water on pavement surface. • For Mu meter equipment the temperature influence obtained is 1 point each 3 ºC or 0.33 points each 1 ºC, considering the temperature of water on pavement surface. 3rd International Surface Friction Conference Gold Coast, Australia, 2011 National University of Rosario, Argentina

13. Conclusions 2/2 • It is recommended to correct Mu meter results to a reference temperature of 20 ºC like is made with TRRL Pendulum results using the factor presented here. It is the recommendation for National Road Administration. • To correct Scrim Tex results it is recommended to make an additional measurement of water on pavement surface temperature like is made on Mu meter measurements, and analyze this influence with more experiences. • The correction presented here does not pretend correct seasonal variations; it only corrects results to a reference temperature and reduces results dispersions. 3rd International Surface Friction Conference Gold Coast, Australia, 2011 National University of Rosario, Argentina

14. THANK YOU 3rd International Surface Friction Conference Gold Coast, Australia, 2011 National University of Rosario, Argentina