Skid resistance and mechanical performance comparison between in-place and in-plant cold-mix recycling 100​% RAP: A sustainable design for bicycle lanes

Technological advancements have produced sustainable approaches to pavement preservation and reconstruction procedures. Specific recycling processes are being developed to reuse the asphalt concrete guaranteeing costs and environmental effects reduction. Reclaimed asphalt pavement (RAP) is the material worldwide used in the road construction sector to ensure the sustainability of asphalt pavement. RAP employment percentages in asphalt concrete layers are increasing. The development of cold mix asphalt (CMA) recycling technique including high amount of RAP is becoming popular especially for localized patching and potholes. Wearing course layers designed for bicycle lanes realized with 100% RAP and CMA technologies are presented in this research. Two cycle paths rehabilitated with different construction technologies in-plant and in-place recycling techniques are compared by performing a trial field and laboratory analysis on compacted and cored samples. An innovative rejuvenator used as additive specifically designed for CMAs is added as rejuvenator in both RAPs. The main goal is to determine the frictional, physical and mechanical characteristics of solutions produced by using high quantity of recycled materials. British pendulum tester (BPT) and Micro GripTester are applied to assess skid performance and indirect tensile strength test (ITS) and Marshall stability is performed to analyse the mechanical behaviour. RAPs skid resistance and physical-mechanical properties provide positive outcomes with viable characteristics for urban soft-mobility solutions. The innovative machine used in the in-place technique demonstrated excellent performance in terms of milling and mixing, representing a valid alternative for repaving applications in the urban context.