Cold In-place Recycling for road rehabilitation was introduced in Eastern Canada in 1989 when Miller Paving Ltd. acquired a recycling train. The Regional Municipality of Ottawa-Carleton was the first road agency to utilize Cold In-place Recycling. More than 5 million square metres of pavement have been rehabilitated with this process since 1989 throughout Eastern Canada. The standard pavement structure in the Eastern Canada consists of an unbound granular base overlaid by one or more courses of bituminous concrete. The primary cause of pavement distress and failure in Eastern Canada is thermal cracking. Before the introduction of Cold In-place Recycling, the only effective treatment for cracked pavements was the total removal of the bituminous concrete layers. Cold In-Place Recycling uses the in-place bituminous pavement as a source of materials. The existing bituminous concrete pavement is reclaimed, transformed into a bituminous aggregate which is then mixed with a new binder and laid down in-place. Cold In-place Recycling also restores the longitudinal and transverse profile of the roadway. Recycled bituminous mixtures obtained from Cold In-place Recycling have mechanical properties that differ significantly from those of standard hot bituminous mixtures. The mechanical properties of cold in-place recycled bituminous mixtures improve with time, unlike those of standard hot bituminous mixtures. Recycled bituminous mixtures provide more fatigue resistance but less stiffness than regular standard hot bituminous mixtures. In addition, recycled bituminous mixtures offer improved mitigation of reflective cracking. Cold In-place Recycling is a cost effective rehabilitation alternative to traditional methods for aged cracked pavements in a cold and wet environment. This paper presents a brief overview of Cold In-place Recycling and a discussion of project selection, design practices, process equipment, construction procedures and the performance of recycled bituminous mixtures. (A)
Abstract