This paper presents the findings of a study conducted to investigate the quantitative role played by small-scale surface texture (microtexture) in determining the skid resistance of a pavement. Specific objectives were to understand better the microtexture's influenceon skid resistance and to determine if optimal dimensions of microtexture exist that should be sought when designing a pavement or selecting aggregate materials. Measurements of microtexture profiles were obtained on a series of pavement cores using a noncontact image analysis system in the laboratory. Correlations were determined between these measurements and british portable tester numbers (bpns), obtained on the same cores. (Bpns are friction measurements believed tobe closely related to microtexture.) Finally, the microtexture measurements were combined with estimated tire-contact area measurements(representing macrotexture) and the results correlated with skid resistance measurements taken on the same pavements. Correlation coefficients of up to 0.70 Were attained. Examination of the data indicates that some improvement in this correlation may be possible. It is concluded that pavement microtexture can be characterized by one profile parameter. Additionally, pavement macrotexture can be characterized by estimating the percent contact a vehicle tire would have on the pavement surface in question. A combination of these two measurements shows a good correlation with skid measurements and should be further investigated. This paper appears in transportation research record no. 1215, Pavement management and rehabilitation.
Abstract