Volume III: High-Volume Recycled Materials for Sustainable Pavement Construction

Project Details









Jeffery S. Volz, Julie Ann Hartell, Lexis Allen, Jonathan Drury, Rex McLauchlin, Mohammad Zare Banadkoki




Fly ash, Greenhouse gases, Rigid pavements, Slag, Sustainable development

Project description

Concrete production uses a considerable amount of non-renewable natural resources and generates a significant amount of greenhouse gases. To obtain a more sustainable solution requires examining the two main components of concrete – aggregates and cement. Recycling concrete as aggregate for new concrete reduces construction waste, diverts material from already over-burdened landfills, and lowers demand for virgin aggregate. Using supplementary cementitious materials – such as fly ash, blast furnace slag, and glass powder – also diverts material from landfills and reduces the carbon footprint of concrete. The Federal Highway Administration (FHWA) estimates that two billion tons of new aggregate are produced each year in the U.S. Aggregate demand is anticipated to increase to two and a half billion tons per year by 2020. With such a high demand for new aggregates, concern arises about the depletion of current sources of natural aggregates and the availability of new sources. Similarly, construction waste produced in the U.S. is expected to continue increasing. From building demolition alone, the annual production of construction waste is estimated to be 123 million tons, with concrete accounting for up to two-thirds of the total weight. Currently, this waste is most commonly disposed of in landfills. To address both the increasing demand for new aggregates and the increasing production of waste, many states have begun to recognize that more sustainable solutions exist in recycling waste concrete for use as aggregate in new concrete – recycled concrete aggregate (RCA). RCA helps address the question of how to sustain modern construction demands for aggregates and reduce the amount of waste entering already overburdened landfills. Many states have begun to implement RCA in new construction. For instance, 41 states have recognized the many uses of RCA as a raw material for riprap, soil stabilization, pipe bedding, and even landscape materials. Of these, 38 states have gone a step further in taking the additional step of integrating RCA into roadway systems for use as aggregate base course material.