A full-scale experiment was constructed on the Windover to Funtley section of M27 and opened to traffic in 1976. The experiment comprised twelve sections, each 150 m long, containing a variety of concretes chosen to study the effect of using a range of qualities of limestone coarse aggregate and also to determine the effect of using different proportions of limestone or shell in the fine aggregate. Measurements of Sideway Force Coefficient have been made annually and after 10 years these have been analysed to determine the influence of various aggregate and concrete properties tested in the laboratory. The factor having the most effect on skid resistance was the acid-soluble content of the fine aggregate. Results of the Polished Mortar Value test correlated with both the acid-soluble content and the Sideway Force Coefficient on two of the three lanes but were relatively insensitive to changes in material quality. The Polished Stone Value of the coarse aggregate was a significant factor but, as previous studies also have shown, its effect on skid resistance was limited. The results of the Accelerated Wear Test were inconsistent with the fine aggregate properties and in general did not relate to skid resistance as well as individual aggregate properties. (A)

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