A highy topical subject in the contribution of road construction to sustainable development is the production of asphalt mixtures at lower temperatures (reduced-temperature asphalt, RTA), because of the advantages from the energy, environmental and engineering points of view. Within a project on European test methods for bituminous mixtures and binders that was initiated by the Belgian Bureau for Standardization (NBN) and aims among other things at improvements with a view to sustainable development, BRRC has undertaken to closely monitor the recent developments and achievements in the field of RTA, both in Belgium and abroad. This includes the following aspects:
This four-year project (July 2006 – June 2010) was funded by the Belgian Bureau for Standardization (NBN). Its objective was:
to improve the procedures for the extraction (with a continuous flux centrifuge) and recovery (with a rotary evaporator) of binders from bituminous mixtures prepared with polymer-modified bitumens (PmBs) (EN 12967-1 and -3);
to study and improve the procedure for the determination of binder content by ignition (EN 12697-39).
Ever since CEN/TC 227 Road Materials was formed in the late eighties, that is, before there were any plans to reorganize the standardization landscape in Belgium, BRRC has been a pioneer and an active participant in this committee. The main focus at the time was on the activities of WG1 Bituminous Mixtures and WG2 Surface Dressing, Sprays and Slurry Surfacing (incorporating Microsurfacing).
This test method describes how the defects in a surface dressing can be visually assessed. These defects include fatting up, tracking, bleeding, scabbing, tearing, fretting, and streaking (more information on these various forms of distress can be found in BRRC’s code of good practice R71/01 “Code de bonne pratique pour les enduits superficiels”).
Damage can be assessed in two ways: qualitatively and quantitatively.
A qualitative method will assess the rate of damage by simple rules. The quantitative method will measure the defects in much more detail.