Hilti

GSA Cuts the Carbon in Asphalt and Concrete

    The U.S. General Services Administration is one of the nation’s biggest landlords. As part of its sweeping mandate, the agency maintains thousands of government properties and constructs federal court houses, office buildings, border stations, and other structures nationwide. So when GSA adopts new construction standards — usually after exhaustive study and participation by the private sector — the building industry as a whole takes notice.

    In March, GSA announced new standards for asphalt and concrete used in construction. Why target building materials? And why these two in particular? Construction materials can account for more than half of a building’s lifetime carbon emissions. And concrete and asphalt are among the most heavily used: The U.S. produces more than 500 million tons of concrete and 420 million tons of asphalt per year, according to GSA.

    The new low embodied carbon concrete standard requires GSA project contractors to provide environmental product declarations (EPD), where available. An EPD is a standard, third-party-verified summary of the primary environmental impacts – including greenhouse gas (GHG) emissions – from a product’s extraction, transportation, and manufacturing. GSA also now asks its contractors to provide concrete that meets specific numeric limits for the amount of GHG emissions, or “embodied carbon,” associated with its production. GSA’s standard reflects a 20% reduction from national concrete GHG limits.

    The new asphalt standard requires EPDs and at least two environmentally preferable techniques or practices to be used during the material’s manufacture or installation. Input directly from the asphalt industry helped shape a menu of widely-available practices to improve this material’s environmental footprint. These options include bio-based or alternative binders, recycled content, and reduced mix temperatures. Both standards will evolve as GSA and its partners build implementation experience.

    — U.S. General Services Administration

    More than 130 businesses provided information in the lead-up to the announcement. Among them, more than half said that the lower-carbon carbon approach cost the same or less than the earlier methods.