The evaluation of asphalt mix surface rejuvenators in South Africa

Abstract

Ageing of a seal or asphalt surfacing increases the stiffness of the layer, resulting in a decreased ability to resist cracking. Asphalt surface rejuvenators have been used traditionally as an economical maintenance technique to extend the binder lifetime, thereby postponing eventual costly rehabilitation. Rejuvenators vary in nature, whether they are emulsion-based or solvent-based, making it very difficult to have national specifications for rejuvenators. This class of materials are, therefore, ideal candidates for certification by Agrément South Africa. A guideline for the evaluation of rejuvenators has been proposed for the roads industry by Agrément South Africa (O’Connell, 2017). The guideline defines asphalt rejuvenators as a proprietary product with suitable properties to extend the lifetime of an asphalt mix layer (or seal); by delaying the appearance of fatigue-related distresses such as cracking and potholing, without increasing the risk of skid-related accidents. The paper discusses the guideline evaluation techniques and the results obtained for one commercial rejuvenator evaluated to date. The paper serves to fulfil the need for knowledge dissemination on rejuvenators in the South African transportation industry.