Citation

Bonnot J, Ray M. Transp. Res. Rec. 1977; 624: 72-81.

Copyright

(Copyright © 1977, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

The highways built in France in the 1960-1970 period with a cement concrete pavement have now very low friction coefficients, mainly because they had received only a very inefficient burlap surface treatment. This leads to an abnormal decrease of safety on wet conditions, characterised by a high value of the ratio "number of wet pavement accidents/total number of accidents". A research has been made by L.C.P.C. to compare different methods of skid resistance improvements, in order to prepare a program of improvement work on this network. 25 experimental stretches on highways have been made, including transversal (diamond sawing and percussion) and longitudinal (diamond sawing) grooving with different grooving patterns, and surface dressings. The main conclusions are: For longitudinal grooving, narrow and close-set grooves are more efficient than wide and far apart grooves. As for braking force coefficient, longitudinal grooving leads to surfacings equivalent to a poor asphaltic concrete, but as for sideways force coefficient its efficiency is much better. The influence of grooves depth is not high, provided this depth is more than 2 mm. For the same quantity of concrete removed by grooving, the braking force coefficients obtained with longitudinal and transversal grooving are the same, but the sideways force coefficient is much higher with longitudinal grooving. It is possible to use surface dressings on a highly trafficked concrete motorway (40,000 veh/day) with hard stone chippings and a polymer modified asphaltic binder. This process is cheaper than grooving on concretes made with flint aggregates; after four years the skid resistance is still good.