Sustainable asphalt mixes: Use of additives and recycled materials

To respect and conserve the environment, many companies are trying to improve their plants and production processes to reduce contaminant generation. In this regard, asphalt mix industries are also making their contribution to reducing greenhouse gas (GHG) emissions, polycyclic aromatic hydrocarbons (PAHs) and benzene during the manufacturing and laying processes of bituminous mixes, as well as reducing waste generation when eliminating aged pavements or manufacturing surplus. In order to achieve this objective, mixes that can be produced and compacted at lower temperatures are becoming increasingly popular to bring about a reduction in gas emissions and obtain improvements in working conditions for employees in contact with them, without losing the mechanical characteristics of the conventional asphalt mixes (manufactured and compacted at 160 °C and 130 °C, respectively). This article summarizes the main techniques currently existing in the manufacture and placement of bituminous mixtures at lower temperatures, as well as the techniques applicable in the reuse of aged pavement, and introduces the use of some methods to assess the choice between different types of mixes, such as analysis of the life cycle and its economic variants.This paper is based on the initial literature review for the Fenix Project. The development of the Fenix Project (www.proyectofenix.es) has been possible thanks to the financial contribution of the Center for Technological and Industrial Development (CDTI) within the framework of the Ingenio 2010 programme, through the CENIT Programme. The companies and research centers involved in the project wish to express their gratitude for the contribution. The authors are grateful to all organizations and companies participating in the Fenix Project: Centro de Investigación Elpidio Sánchez Marcos (CIESM), Centro Zaragoza, Construcciones y Obras Llorente (Collosa), Ditecpesa, Asfaltos y Construcciones Elsan, Intrame, Pavasal, Repsol YPF, Sacyr, Serviá Cantó, Sorigué, CARTIF, CEDEX, CIDAUT, CSIC (IIQAB), GIASA, Intromac, Labein, Universidad de Alcalá de Henares, Universidad Carlos III de Madrid, Universidad de Castilla La Mancha, Universidad de Huelva, Universidad de Cantabria, Universidad Politécnica de Cataluña, Universidad Politécnica de Madrid, and our many partners whose work capacity and effectiveness have enabled the development of this project in an environment of cooperation