María Carmen Rubio Gámez

The main goal of this study is to evaluate the feasibility of designing high-performance MASAI mixtures produced at ambient temperature. For this purpose, the impacts of certain variables, such as the type and amount of asphalt emulsion and the use or non-use of RAP, on its performance are evaluated. Subsequently, its stiffness modulus, tensile strength, permanent deformation, and resistance to thermal cracking were evaluated and compared against a conventional dense-graded asphalt concrete (AC 16) and an open-graded (BBTM11B) hot-mix asphalt used for wearing courses. The results showed that these materials could represent more sustainable and good solutions for the rehabilitation of some types of pavements.

Growing environmental awareness of the depletion of finite natural resources (gas, fuel, etc.) and the continuous rise in greenhouse gas emissions (NOx, CO, CO2, etc.) has driven the road engineering industry to develop technologies for producing asphalt mixes at lower temperatures than traditional hot mix asphalt (HMA). Warm mix asphalts (WMAs) offer a viable alternative to conventional mixes, maintaining both mechanical performance and durability while providing a positive ecological impact. This paper presents an investigative study aimed at analyzing the reuse of waste by-products in the production of WMAs at 140°C. To achieve this, three different waste materials (a zeolite by-product from the petrochemical industry, charred acacia splinters, and charred plastic) were characterized and analyzed as additives for the indirect foaming of WMA. Their mechanical performance was then compared to a reference HMA. The results showed that the zeolite by-product exhibited similar workability and compaction to traditional HMA produced at 160°C, while also demonstrating comparable stiffness modulus, resistance to plastic deformation, and water resistance.

The granular bases commonly used in the construction of road infrastructure projects often require a high consumption of raw materials. The potential utilization of recycled materials, specifically Reclaimed Asphalt Pavement (RAP) derived from road asphalt pavement demolition, emerges as a promising sustainable advantage for infrastructure projects, considering its potential environmental and cost benefits in other layers of the structure. In this context, this research proposes a feasibility study on the use of RAP as a granular base layer, supported by an advanced laboratory analysis that includes a range of tests simulating the in-service conditions as well as a full-scale demonstration of the material behavior under static and dynamic loads. Various design variables, such as different gradations and binder content, are considered. The results demonstrate that, despite having discontinuous gradation and smaller aggregate sizes than those commonly applied in natural base layers, the evaluated recycled materials exhibit a higher load-bearing capacity and resistance to permanent deformation than the reference materials commonly used as granular bases. Notable enhancements of up to 30% in elastic modulus, coupled with reductions of around 20% in permanent deformations, have been documented using the asphalt cement potential in the old pavement.