Thermal Effect of Braking on Pavements during Heat Waves in Ouagadougou

Abstract

Flexible pavements, whose surface layers are made from hot mix asphalt, may show rutting in some of these infrastructures during the first months of life. In the city of Ouagadougou, this rutting phenomenon is sometimes observed. The objective of this article is to quantify the thermal response of the wearing course of national roads 1 and 2, when they are subjected to the braking of heavy trucks of 13 tons and 20 tons per axle. The meteorological conditions retained are those of the Burkinabe climate. The evaluation of the temperature was carried out by numerical simulation using the Comsol Multiphysics 5.2 software. This study showed that the thermal response of the pavement to the combined effects of surface temperature, overloading by a 20 tons heavy truck and braking during a heat wave increase in pavement surface temperature ranging from 1.09% for National Road 1 to 0.91% for National Road 2, particularly in the braking zone. This made it possible to establish the diagnosis according to which the nature of the bitumen used on the wearing course can reduce rigidity modulus. In predictive terms, they allowed us to deduce that an under-dimensioning of the wearing course, even if the bitumen was used is adequate.