| Lack of a quantitative methodology for assessing the benefits that can be achieved through application of sustainability strategies is a barrier to the promotion of sustainable construction. For this reason, a quantitative methodology was developed that allows rating of the relative benefits of alternative construction designs, in which sustainability strategies are employed, compared to conventional designs. The methodology incorporates pairing of environmental and economic life-cycle analyses in a rating system: the Building Environmentally and Economically Sustainable Transportation Infrastructure-Highways(TM) (BE2ST-in-Highways(TM)). A pairing method was used to quantify the benefits of using recycled materials in highway pavements by conducting life-cycle assessment and life-cycle cost analysis on pavements constructed with conventional and recycled materials. Results of the analysis indicate that using recycled materials primarily in the base and subbase layers can result in reductions in global warming potential, energy and water consumption, and hazardous waste generation while also extending the service life of the pavement. In addition, using recycled materials can result in life-cycle cost savings. The BE2ST-in-Highways(TM) system is grounded in quantitative metrics so that a transparent linkage exists between the project rating and the sustainable practices employed in design and construction. The system requires a method of estimating the number of rehabilitations needed during a given analysis period using the international roughness index (IRI). The application of the system in the pilot project evaluations indicates that replacement of conventional natural materials with recycled materials in highway construction results in lower consumption of energy and water and CO 2 emissions, thus resulting in higher sustainability scores. The superior material properties of some recycled materials reduce material quantities and also extend the service life of the highway structure, a decisive factor affecting the sustainability rating. The rating system proposed can be used to promote reuse and recycling of materials and assess the benefits of sustainable construction practices in a quantifiable manner. This is expected to promote more sustainable construction and sustainable growth. |
