Abstract
The use of recycled materials in roadway construction and rehabilitation can achieve significant benefits in saving natural resources, reducing energy, greenhouse gas emissions and costs. Construction and demolition waste (CDW) recycled aggregate as an alternative to natural one can enhance sustainability benefits in roadway infrastructure. The objective of this study was to quantitatively assess the life cycle economic and environmental benefits when alternative stabilized-CDW aggregates are used in pavement construction. Comparative analysis was conducted on a pavement project representative of typical construction practices in northern Italy so as to quantify such benefits. The proposed alternative sustainable construction strategies considered CDW aggregates stabilized with both cement and cement kiln dust (CKD) for the base layer of the roadway. The life cycle assessment results indicate that using CDW aggregate stabilized with CKD results in considerable cost savings and environmental benefits due to (i) lower energy consumption and emissions generation during material processing and (ii) reduction in landfill disposal. The benefits illustrated in this analysis should encourage the wider adoption of stabilized CDW aggregate in roadway construction and rehabilitation. In terms of transferability, the analysis approach suggested in this study can be used to assess the economic and environmental benefits of these and other recycled materials in roadway infrastructure elsewhere.
Highlights
The construction and rehabilitation of road pavements involve large amounts of natural resources such as raw materials, and energy [1,2,3]
Alternatives B and C have the same base layers (i.e., construction and demolition waste (CDW) aggregate with 10% cement kiln dust (CKD)), alternative C presents a 5% lower cost, in relation to B, since 20% Reclaimed asphalt pavement (RAP) is used in the surface Hot-mix asphalt (HMA) layer
This study examined the life cycle cost savings and environmental benefits of using stabilized CDW recycled aggregates for base layers of roadway pavements
Summary
The construction and rehabilitation of road pavements involve large amounts of natural resources such as raw materials, and energy [1,2,3]. A remarkable variety of studies have investigated several recycled materials to be used in road pavements: recycled aggregates (from different sources), clayey materials, industrial by-products (slags, pulverized fuel ash, etc.), plastic and rubber wastes [14,15,16,17,18,19,20,21,22,23,24]. Among these materials, aggregates recycled from the debris of construction and demolition waste (CDW) play a key role in the sustainability of road infrastructure [25,26,27]. Several studies on engineering properties of CDW aggregates and their potential use in base and subbase have shown that they can be utilized in pavements structures of low to intermediate traffic volumes [36,38,39,40]
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