This paper deals with the potential reuse of coal mine waste rocks (CMWR) as an alternative material for road construction to conserve the natural resources and sustainable management of mining waste. The investigation was conducted through the determination of the chemical, mineralogical, geotechnical properties, and acid mine drainage formulation of CMWR as well as economic feasibility. This waste was used either alone for embankments and mixed with stabilizing agents fly ash (FA) and hydraulic road binder (HRB) for pavement applications. The experimental results confirmed that weathered CMWR can be successfully used alone as a sustainable alternative material for the embankment. Furthermore, the use of stabilizing agents in the following ratio CMWR:FA:HRB = 80:20:5 allow the use of CMWR in road sub-base layers for high-traffic pavements. Also, the environmental investigations showed that CMWR does not present any potential contaminating risk on the surrounding environment and most of the pyrite particles were already oxidized. Therefore, the environmental impact of acid mine drainage produced by pyritic waste throughout its life cycle can be neglected. Finally, an economic case study confirmed the workability of CMWR reuse in a radius of 29 km around their dumps by resulting in a lower cost compared with conventional materials.

This paper presents numerical investigations into the mechanical behaviour of hot mix asphalt (HMA) through the use of finite element modelling simulations. HMA is a well-known composite medium containing a highly complex microstructure. The X-ray computed tomography images (CTI) method can lead to a numerical model that closely represents the actual internal HMA microstructure. Unfortunately, this technology is not available to most researchers in the field of composite materials. It is therefore preferable to seek other techniques that enable researchers to simulate the actual internal microstructure. The aim of this study is to examine a heterogeneous generation (HG) method capable of generating an artificial microstructure of complex materials, as opposed to the X-ray CTI method. Several numerical HMA models are derived based on both these methods. A comparison of the mechanical behaviour output at the global and local scales from the X-ray CTI and HG digital models shows good agreement, thus indicating that the HG method has proven its effectiveness in reproducing the actual internal HMA microstructure and in predicting the material mechanical properties at these two scales.

This work focuses on the use of a heterogeneous generation method in order to develop a micromechanical model of Hot Mix Asphalt (HMA) that takes into account the effects of characteristics at the interfacial zone (IZ), where aggregate surfaces come into contact with the mortar matrix. Numerical calculations are conducted to investigate the effect of IZ mechanical characteristics on both the overall viscoelastic response of HMA and the local scale behavior. First of all, the HMA is treated as a biphasic material composed of mortar and granular inclusions. Next, a third phase is added between these two at each point of aggregate/mortar contact. Elastic and viscoelastic behaviors are assigned to the aggregates and mortar, respectively. The mechanical behavior of IZ varies between that of the inclusions and the matrix. At the global scale, these numerical results demonstrate that the use of triphasic micromechanical models improves the predictive accuracy of the dynamic modulus. At the local scale, a significant strain variation was found in each model. These results justify our triphasic modeling approach whenever local zone characteristics are the subject of interest.