Innovative 100% RAP cold in-situ recycling of wearing course layers: laboratory and field characterisation and environmental impact assessment

Abstract

In the last decade, research is pushing forward the use of innovative techniques and environmentally friendly materials aiming at sustainable development in the road sector. In the present paper, a 100% RAP mixture is proposed through an innovative cold recycling in-situ technique for road pavement maintenance of small damaged sections and repairing distresses. The localized patching is developed through an innovative milling machine that is capable of directly and simultaneously milling and mixing the RAP produced. The innovative machine develops repairs that guarantee the safety and comfort of users. For obtaining the final mixture, RAP is combined with cement and a chemical additive. The experimental program was divided into a laboratory study of the milled material and a trial field campaign. After these phases, the environmental impacts that affect the repaired road sections are also evaluated through Life Cycle Assessment (LCA) tool. Tests from the laboratory and field phase highlighted positive results and downsides that need to be optimized to obtain a good quality intervention. The LCA analysis showed a positive impact in terms of global warming potential. Thanks to the use of this innovative machine, it is possible to mitigate the negative environmental impact associated with road pavement maintenance.