Étude de faisabilité et développement d'une procédure de récupération et de réhabilitation des abrasifs routiers en vue de leur utilisation

Abstract

This experimental thesis identifies and validates a practical and economic alternative to the disposition of valuable abrasives after one winter cycle use by recycling them for another or more cycles. The quantities disposed of after each winter account to over a million tons every year in Quebec. The solution proposed complies with the Quebec Residual Materials Management Policy, which would herein apply to materials from natural resources. While the thesis does summarize a rather modest state of the art on the above mentioned topic, it has for the first time highlighted and compared physical and chemical characteristics of abrasives before and after a winter cycle. It has also innovated in identifying a guide-valid and convenient solution to decontaminate recovered abrasives after one winter cycle, making them fully suitable for reuse on the provincial and municipal levels. The thesis evaluates the abrasives nature and degree of contamination in the road environment. As such, the chemical characterization of samples taken from two different administrative and geological regions of Quebec on the provincial and municipal levels, shows a high degree of similarity. This additional finding justifies the assumption that reuse may be extended to possibly other jurisdictions. Indeed, it appears from the experimental analysis that exposure of these abrasives to the pavement environment induced contamination with C10-C50 hydrocarbons and certain metals, primarily zinc, copper and lead. This pioneering experimental study also found that the distribution of the metals affected all granular fractions of residuals but still with a prominent prevalence for the fines <80 microns and the 630 microns and 2.5 mm fuseau. In a second phase, this study assesses the evolution of the intrinsic and mechanical properties of the abrasives after their cleaning. The abrasives behavior shows a deterioration of their intrinsic properties, mainly due to a transformation or shrinking of their grain size distribution as a result of mainly compression stress between the traffic and the pavement, particularly under the combined effect of the vehicles wheel passage and of several other parameters such as water and the contact with other materials. Nonetheless, they conserve their mechanical properties that put them in Category 1 of fine material for the standard NQ 2560-114 / 2002. The granularity of the washed abrasives allow them to be ranked into the grain size AB-10 of the NQ-2560-114 VI / 2002 standard and are thereby adapted to be possibly reused as compound abrasives of crushed aggregates for another winter cycle . Moreover, the results of the carried out experiments allow the ranking of the abrasives in the category 3 "Guidelines of the management of concrete, brick, asphalt and stone." This classification opens up to a number of opportunities of reusing, especially that it comes out from this experimental analysis that their leaching potential is low, which however had been established in the state of the art. In third place, this study sought finally, the different possibilities of abrasives reusing in agreement with the laws, standards and regulations in force in Quebec. To date, two applications in the coated are achieved. The first bituminous mixture is formulated and produced successfully; given a coated 10 EB-S with an input of up to 60% of abrasives. The second produced mixture is a coated GB 20 with an input of 35% of abrasives. Although both formulations have passed the standard requirements associated with the gyratory compactor, the second formulation failed the requirements of the standard associated with the rutting. The fact remains that with lower concentrations and a better optimization of the formulations, the reusing in the coated remains a higher economically alternative and a lot more beneficial than landfilling.

Date	29 Feb 2016
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Gabriel J. Assaf (Supervisor)