While cement and concrete production are routinely criticized for their contribution to climate change, cement manufacturers are moving in the right direction and the concrete products industry is already both resilient and sustainable, especially when compared with plastics.
On the cement side, manufacturers are committed to reducing their carbon footprint, with some of the largest companies pledging to cut their greenhouse gas emissions by up to 25% in the next decade and reaching net zero by 2050.
While cement is improving, concrete products have always been both sustainable and resilient. Let’s look at precast concrete and reinforced concrete pipe, which are 100% recyclable. When concrete structures are removed from a site, they can be crushed. The crushed concrete is ideal for roadbed. We use it in our yard at Cemcast, in fact. The reinforcing steel is separated out and recycled.
While 7% to 15% of concrete’s mass comes from cement, major portions of the concrete mix consist of regionally sourced natural raw materials. Aggregate, sand and water, which comprise the bulk of a concrete structure, are available locally nearly everywhere. Other factors fall into the sustainable category as well, enabling builders to earn up to 28 LEED points when using concrete in various applications, according to the Ready Mixed Concrete Association’s Green Concrete Website.
Turning the focus to concrete pipe and related structures, we really need to look at lifecycle to get a true picture of sustainability. With a 100-year lifespan for concrete pipe, the total carbon footprint is spread over a century. These structures last a lifetime.
The Problem with Plastic and Galvanized Metal
The plastic industry often criticizes cement’s heavy carbon footprint but ignores the 100% recyclable aspect of concrete and instead takes a lot of credit for plastic’s recyclability. Made from petroleum products, plastic has its own carbon footprint issue, and while it is indeed recyclable, in the real world most plastic is not recycled. To be recycled, plastic components must be separated, cleaned and shipped to a recycling center. Even then, the waste material will be too expensive to recycle relative to using new resins.
It is too labor intensive to recycle for most users, so it is either sent to the landfill or barged overseas where it ends up in massive burn pits. This was documented in a PBS Frontline documentary in 2020. If you want to learn more about how unrecycled plastic is increasing pollution around the world, check it out.
On the resiliency side of the coin, concrete also has a credible edge on plastics. In our industry, we see example after example of roads that wash out in extreme weather events where plastic pipe is involved. What is often left behind is an impassable road where the plastic pipe underneath has floated, buckled or broken, further compounding the problem. Often the only thing remaining undamaged are the concrete headwalls.
In excavations under roads and bridges concrete pipe and box culvert structures lay down and stay down. Roads can be quickly reopened because the structures underneath do not have to be replaced. Unlike plastic, concrete will not float away, or be easily damaged like galvanized pipe.
The Fire Factor
Resistance to fire is another critical resiliency factor that favors concrete structures. Unlike plastic, concrete is fireproof. We’ve all seen the unrelenting damage from wildfires, which are growing in number and intensity seemingly every year. Plastic will melt when exposed to that kind of extreme heat. Even worse, when a plastic pipe system catches fire, that line can burn underground for long distances, leading to an expensive, disruptive replacement. No municipality or residential developer wants to deal with that.
Yes, of course we’re biased toward concrete at Cemcast, but there’s a reason. Like most South Dakotans, we’re practical. We’re cost-conscious. We want to do the best for our customers and our community and build a sustainable, resilient world for our children and grandchildren – with concrete.