Exploring Sustainable Pavement Rehabilitation: Cold In-place Recycling with Expanded Asphalt Mix

Pavement rehabilitation is a critical component to maintain pavement serviceability and performance. Riding surface of the pavement deteriorates over time due to environment, load, material and construction related distresses. In a society where funding and natural resources are scarce, sustainable pavement rehabilitations become the emerging trend to maximize pavement performance using the available funds. Cold In-Place Recycling with Expanded Asphalt Mix (CIREAM) is a very sustainable pavement rehabilitation technique currently available in the industry. CIREAM is an in-place recycling technique that utilizes expanded asphalt (also known as foamed asphalt) without pulverizing the existing pavement. It works similar to cold in-place recycling (CIR) in terms of milling existing pavement when CIR typically uses emulsified asphalt to provide additional adhesion to the recycled aggregates. Foamed asphalt and emulsified asphalt both use water as an additive to cause asphalt cement to foam. The potential benefit of CIREAM includes savings in asphalt cement, in situ recycling of aggregates, significant money and time savings in transportation cost and disposal cost, and low curing time after rehabilitation for traffic. The paper explores planning, design, construction, quality assurance, and environmental aspect of CIREAM in a qualitative manner. The planning for CIREAM involves identifying potential pavement distresses that can be treated with CIREAM. The CIREAM rehabilitation design considers CIREAM mix design, mill depth design, and overlay design. This paper addresses critical items for construction to ensure a good quality results. Quality assurance tests are also explored to understand the acceptance criteria for CIREAM rehabilitation. Lastly, the environmental evaluation for CIREAM through PaLATE analysis is conducted to demonstrate the environmental impacts of CIREAM compared to conventional mill and overlay. This analysis illustrates the energy use, emissions, and carbon footprint associated with CIREAM rehabilitation.