Although the fact that foam asphalt, i.e. the material produced by injecting cold water into the hot bitumen, is known for almost five decades, only in the last few years it is gaining acceptance worldwide.
Nowadays, technological development has led to the cost-effective production of foamed asphalt mixes by mixing foamed asphalt with aggregate at ambient conditions. Foamed asphalt can be used as a stabilizing agent with a variety of pavement materials. The use of foamed asphalt technology in the rehabilitation of road pavements, as well as new pavement construction, was given a boost in the 1990s through the incorporation of the technology in cold recycling machines.
Technology development has created, especially in the last few years, research needs, in terms of modeling of the specific material, laboratory testing or even in situ characterization for quality control needs or pavement performance evaluation purposes.
The present publication is initiated by the International Working Group (WG-01) on Foam Asphalt, in the framework of the scientific activities of the Technical Committee (TC) on Constitutive Modelling of Asphaltic Materials of the International Society of Asphalt Pavements (ISAP), with the aim to provide insight on the existing experience and motivation to explore new aspects concerning the scientific area of foamed asphalt for pavements.
This special issue, by the International Journal of Pavement Engineering is a peer–reviewed publication, dedicated to foamed asphalt for pavements and includes high quality scientific or technical contributions devoted to several topics related with the mechanical properties and laboratory testing of foamed asphalt mixes, modelling of the material used, pavement recycling and rehabilitation aspects, structural monitoring and deterioration aspects and mechanisms, performance assessment aspects, in situ characterization of the material, case studies, as well as economical aspects related with foamed asphalt for pavements.
Closing this preface, I would like to express my sincere thanks to the IJPE Chief Editors, Tom Scarpas and Imad Al-Qadi and the Taylor & Francis Publisher for their willing support. Many thanks are also addressed to all international authors who contributed to this special publication. A special thanks also to the reviewers for their time and effort in improving each paper.