Public Policy is Slowing Down Mainstream Adoption of Sustainable Concrete
By Matthew P. Adams, Associate Professor of Civil & Environmental Engineering at New Jersey Institute of Technology (NJIT)
Concrete is the world’s most pervasive man-made material, and it has a colossal impact on global consumption of energy and natural resources. Traditionally, concrete has almost entirely been produced with newly mined minerals; and the production of concrete’s core ingredient – cement – is estimated to be responsible for about 8% of global CO2 emissions. The lifecycle of concrete typically ends at a landfill, and in the U.S. alone, more than 134 million tons of concrete waste are sent from demolition to landfills every year.
Scientists have been researching and developing a broad array of technologies that can significantly cut CO2 emissions associated with the production of concrete globally. Sustainable design techniques, such as reusing demolished concrete or using waste materials to replace cement, already exist and can reduce energy use, ecosystem destruction, landfill usage and the massive financial costs associated with the mining and shipping of fresh stone. Yet despite significant advancements in the industry’s technical knowledge, public policy has yet to catch up and instead hinders mainstream adoption of these techniques.
How can we leverage the industry’s technical understanding to recycle the rubble of old sidewalks and demolished building slabs to produce a net benefit to the environment? As an engineer, educator, and sustainable construction policy expert, I am working to bridge the knowledge gap between industry and policymakers.
One major barrier to the mainstream adoption of sustainable concrete is the lack of accessible, easily digestible information about how these new technologies perform, how best to specify them, and what materials are locally available. We need to develop education campaigns that inform officials and construction engineers about up-to-date research, testing and real-world case studies, while emphasizing that there is no one-size-fits-all solution to the greening of concrete – no single mixture that works in every scenario. Recycled concrete mixtures that are sturdy enough for a house foundation or a sidewalk, for example, might not be suitable for a bridge deck.
As a civil engineer focused on sustainable materials, I work on creating technical solutions at the Materials and Structures Laboratory at New Jersey Institute of Technology. Inside the lab, which looks more like a miniature construction site, other researchers and I develop and test new types of concrete that include novel materials such as recycled concrete aggregate, waste from the coal and steel industries and pulverized recycled glass. We squeeze, pull, and bend the concrete until it breaks to assess how strong it is; we freeze, heat, and dry it, then spray it with de-icing salts and other corrosive chemicals to see how resistant it is to environmental degradation. Our goal is to reduce the embodied carbon content of concrete without compromising its ability to withstand heavy loading, natural disasters and long-term wear.
However, industry advancements have led to limited real-world adoption and use. Building codes at the local, state, and national level are slow to permit the use of new technologies in building materials, despite extensive strength and durability testing. Local agencies also lack the resources to develop regulations to support the use of novel, sustainable products. Many public agencies and engineering companies are afraid to embrace new methods without strong proof of their long-term durability and performance in real-world applications, and rightfully so.
The state agencies that write and control materials specifications need to know what happens when we use low-carbon cement combinations with locally available rock in new concrete. An official in New Jersey familiar with local granite is rightly skeptical, for example, about research performed on limestone in Texas. To address these challenges, we need to develop design tools that help engineers decide which sustainable materials are best suited to their construction projects. Easily accessible documents with ready to follow guidance – such as those available for structural calculations or durability guidance from the American Concrete Institute – need to be produced to support sustainable design practices.
While national-level sustainability policies are hampered by countless political and legislative complexities, regional-level changes can be, at least comparatively, easier to maneuver. Since a significant amount of concrete is purchased using state and local tax dollars, states and municipalities hold the power to directly encourage the use of approved sustainable construction materials. Local legislative bodies can advance sustainability policies by directing their agencies to include more sustainable construction materials and practices for local infrastructure.
Communities like Hastings-on-Hudson in New York showcase what a successful coordinated campaign between scientific communities and municipalities can achieve. In 2020, the Board of Trustees of the Village of Hastings-on-Hudson passed a resolution committing the government to promote the use of low-carbon concrete materials in building and infrastructure projects. Notably, a key component of the resolution required the municipality to provide education and support regarding low-embodied carbon concrete. These efforts later proved critical to securing local stakeholder and construction company support, leading to a range of completed local projects, including sidewalks and even the new Hillside Elementary School. Other local municipalities soon passed similar resolutions of their own, and in turn, the New York State legislature passed the Low Embodied Carbon Concrete Leadership Act. It’s a prime example of small-scale projects at the local level that can fuel widespread adoption.
Engineers are tirelessly working to develop the next generation of durable and green construction materials. But ushering in the era of sustainable construction will require meaningful local community support. When enough municipalities decide to demand that local infrastructure designs be held to higher standards, the larger state agencies in turn are more likely to adopt them. Scientific advancements and sustainable communities will have to work hand-in-hand to see significant improvements in the sustainability of our concrete infrastructure.
Matthew P. Adams is an Associate Professor of Civil & Environmental Engineering and the Co-Director of the Materials and Structures Laboratory at New Jersey Institute of Technology (NJIT).
The views and opinions expressed herein are the views and opinions of the author and do not necessarily reflect those of Nasdaq, Inc.