Colorado Public Works Journal, Summer 2022

54| ColoradoPublic Works Journal ACPA COLORADO/WYOMING CHAPTER Angela Folkestad, PE How Colorado’s Concrete Paving Industry is Reducing Greenhouse Gas Emissions Colorado’s concrete paving industry is committed to reducing Greenhouse Gas (GHG) Emissions in Colorado and around the world. The concrete paving industry has identified three Stages of Opportunities for Reducing Greenhouse Gas (GHG) Emissions: Before Construction, During Construction, After Construction. Reducing GHG Emissions Before Construction… Optimizing pavement design and materials selection begins the process of reducing GHG emissions in the beginning stages of any pavement’s life. Designing with concrete means designing for longevity and longevity of pavement life is the primary opportunity for the reduction of GHG emissions as it allows for less frequent reconstruction. The production of cement is often the most referenced item in regard to CO2 output. One way the concrete pavement and cement industries have begun addressing this issue is by producing and using Portland Limestone Cement (PLC) or Type IL. Blending limestone into the cement reduces the amount of energy required as well as the amount of CO2 produced. Alternative fuels are also being used in these plants which burn cleaner than coal and renewable energy options are being pursued. Requiring Supplemental Cementitious materials such as Flyash and Slag Cement utilizes byproducts from coal fire power and steel production while increasing the durability of concrete pavements. Specifying optimized gradations reduces the amount of cement required and the use of recycled concrete can also greatly improve the opportunity for reduced GHG emissions. Reducing GHG Emissions During Construction… Sourcing locally available materials is one of most effective ways to prioritize sustainability during the construction process. The use of mobile batch plants decreases the number of trucks hauling long distances. Angela Folkestad is the executive director of ACPA, Colorado/Wyoming Chapter. She can be reached at Having onsite mining operations, 5,200 truck trips can be avoided when producing 120,000 tons of sand. When recycling pavement that is removed into 50,000 CY of base 4,200 truck trips can be saved. All of these contribute to the reduction of GHG Emissions. By optimizing phasing of projects, identifying concrete mixtures for specific situations, and performing nondestructive testing construc- tion can be accelerated which reduces congestion. Reducing GHG Emissions After Construction… During its long lifespan, concrete reabsorbs a significant amount of CO2 through a naturally occurring process called recarbonation. Pavement preservations and restoration serves the main purpose of extending the life of the pavement and minimizing disruptions to the traveling public while maximizing the efficiency of resources. Diamond grinding is a practice that is often combined with other Concrete Pavement Repair (CPR) procedures. Diamond grinding can extend a pavement’s life by 14-17 years per a study performed by Caltrans. Improved smoothness, texture and reduced noise can all be anticipated as a result of Diamond Grinding. Concrete Overlays contribute greatly to pavement preservation and are a great opportunity for reduced GHG Emissions after initial construction. Concrete overlays efficiently utilize resources and eliminate the need for disposal of existing pavements. They are cost effective and are constructed quickly while simultaneously extending the life of the pavement. It is imperative to consider all aspects of “use phase” of road construction and identify the areas before, during and after construction where improvements can be made to create the most sustainable and reliable roadways possible.