Energy, Emissions, Material Conservation, and Prices Associated with Construction, Rehabilitation, and Material Alternatives for Flexible Pavement

Abstract

Today, public agencies responsible for roads, streets, and highways are experiencing significant increases in the price of construction operations and asphalt binder availability; they are also experiencing limited available funds and the uncertainty of inflation. Those concerns are coupled with significant pressure to build, maintain, and rehabilitate “green,” and agencies must look to alternative construction, rehabilitation, and maintenance methods as well as alternative materials that deliver on both of these seemingly different forces. Life-cycle assessment was used to evaluate roadway construction activities. Life-cycle assessment is similar to life-cycle cost analysis, except that environmental impact is considered over the analysis period. Life-cycle assessment includes energy consumption, emissions generation, and natural resource consumption in addition to price of the activity. All activities evaluated were compared with conventional materials and means of construction. Materials evaluated specific to hot-mix asphalt included reclaimed asphalt pavement, asphalt shingles, and warm-mix asphalt. Aggregate base stabilization and subgrade treatments were evaluated as part of a low- and high-traffic-volume facility. The final evaluation considered rehabilitation and maintenance activities that focused on in-place recycling, such as hot in-place and cold in-place recycling. In most instances, these activities can reduce energy consumption and emissions generation and can conserve natural resources (aggregate and asphalt binder), plus offer the benefit of reducing the price of construction. These materials and technologies show promise in helping agencies meet the rising price of construction while addressing public concern for the environment.