The Laboratoire Central des Ponts et Chaussées, a French technical administration department, has put forward a laboratory method for characterising polymer-modified binders for surface dressings such as emulsions and fluxed asphalt cements. This method has been applied to the most commonly used polymer-modified binders in France. In consultation with contractors, nine binders have been selected. For comparison purposes, an unmodified binder has been added to the list for each category. All of the binders on the list underwent all known practicable laboratory tests. This exhaustive characterisation had two objectives: to evaluate the degree of modification of each binder compared with the corresponding reference binder and to simplify the characterisation methodology by requiring that only tests that indicate significant aspects of modification be run. To complement the laboratory tests, a traffic simulation test was carried out on a circular traffic simulator to make more lifelike usage comparisons. It has been possible to draw up a classification system and threshold limits, below which binders cannot be considered "modified," for certain specifications.
Abstract