Influence des conditions de cure en laboratoire sur les propriétés physiques et mécaniques des matériaux traités au ciment et au bitume formulés avec de l’émulsion ou de la mousse de bitume

Abstract

Full-depth reclamation (FDR) is an asphalt pavement rehabilitation technique that offers significant technical, economic, and environmental advantages, particularly when hydraulic and/or bituminous binders are added. This approach allows the reuse of all existing materials in situ, without heating, thereby reducing costs, greenhouse gas emissions (GHG), and the consumption of natural resources, while enhancing the load-bearing capacity and durability of road infrastructures. The addition of binders (stabilization process) modifies the behavior of recycled materials over time, a process influenced by the curing rate of these binders. In turn, curing depends on environmental conditions, which play a crucial role in the long-term performance of rehabilitated pavements. However, in Quebec, current laboratory curing methods do not adequately account for climatic conditions and the specific characteristics of recycled pavement layers. Additionally, few studies have compared the effect of bitumen emulsion and foamed bitumen on the properties of stabilized recycled materials. These gaps limit the potential adoption of this technique and highlight the need for an adequate methodology to better characterize laboratory mixtures and improve the simulation of in situ conditions. In this context, an experimental program was developed to evaluate the effect of curing conditions on the evolving properties of cement-bitumen treated materials (CBTM). These materials were produced in the laboratory using either bitumen emulsion or foamed bitumen while maintaining an identical volumetric composition to ensure a fair comparison. Three curing regimes simulating combinations of temperature and relative humidity representative of Quebec’s climate and industry practices were studied over 28 days. An extended curing, up to 90-100 days, period was also conducted to analyze the long-term properties of CBTM. The results showed that curing at high temperature and low relative humidity accelerates water loss and promotes rapid mechanical development, while curing under high humidity slows this process. A cyclic variation between ambient ≈ 30 %) and high ≈ 100 %) humidity slows short-term property development but enables continuous long-term progression. Regarding binder selection, materials produced with foamed bitumen demonstrated superior mechanical properties in the short-term. However, these differences disappeared after 28 days. Furthermore, the materials with foamed bitumen proved to be less sensitive to variations in relative humidity. The findings of this study offer new perspectives for optimizing pavement rehabilitation practices in Quebec. By proposing an experimental methodology adapted to local climatic conditions, this research provides valuable data for designers, particularly regarding the longXII term behavior of recycled material layers and the influence of climatic variations on their properties on field.

Date	2 Apr 2025
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Éric Lachance-Tremblay (Supervisor)