by William C. Holden
The start of a new year and a new decade seems like a good time to take stock. Looking back over a long career in concrete, there’s a lot to consider. This is the industry that has literally built the modern world. It’s also the industry often blamed for it. But as our long history proves, no one stands more ready to face the challenges of the future than we do.
|William Holden has over thirty years of executive and general management construction materials experience in aggregates, ready mixed, masonry products, and building materials and is currently Chairman of the CarbonCure Technologies Industry Advisory Council. He has served as the president of Alabama’s Block USA, one of the leading concrete masonry producers in the country, and president of Couch USA, a major producer of building materials serving the Southeast. Holden was formerly Chairman of the Board of the National Concrete Masonry Association (NCMA) and Alabama Concrete Industries Association, and Chairman of the NCMA’s Long Range Planning Committee.|
Aside from water, concrete is the most-consumed substance in the world. It has formed everything from the Roman Empire’s aqueducts to modern China’s enormous Three Gorges Dam.
But working in the industry day-in-day-out, it can be hard to notice just how much things have changed. When I started in this business, multistory buildings were made with stationary forms constructed onsite by carpenters, then filled with concrete and left to cure for a month. You had to wait 28 days just to move on to the next level; building was a slow-moving process. But progress in admixtures and composition and technique all add up to higher concrete compressive strength and drastically shorter curing times. Solid structures that once took years to erect can now rise at a rate of one floor every six days.
The concrete business, more than any other part of the construction envelope, has embraced change and rapidly improved—perhaps more than any other element of our building systems. And as it evolves, concrete remains more durable and versatile and readily available than any other building material in existence. But because it is so functional and so economical, it’s also used more than any other material, and that takes a toll on the environment.
Global building is booming as people continue to move to cities, and they need housing, office space, roads, and infrastructure. By 2060, global construction will probably add nearly 2.5 trillion square feet of floor space, much of it concrete. Today, the ready-mixed concrete sector alone is valued at $59.8 billion globally, delivering material to the transportation, commercial, residential, and numerous other construction markets—and supplying good work, decent wages, and reliable employment to hundreds of thousands of men and women around the world.
In the U.S., the National Ready Mixed Concrete Association (NRMCA) reports there are about 5,500 ready-mixed concrete production facilities (typically located within a hundred miles of any construction project) and 55,000 mixer trucks in service. Concrete production is a healthy business.
But there’s no denying that being the world’s most useful material impacts the environment. Concrete production is said to account for 4-8 percent of the world’s carbon dioxide emissions. That percentage is just too high.
The concrete industry doesn’t shirk its responsibilities. There’s plenty of support for safer and cleaner production and respect for progress in ASTM standards; ANSI/ISO 14025:2006 principles and procedures; the Leadership in Energy and Environmental Design (LEED) program; the open-access Embodied Carbon in Construction (EC3) tool; and, both academic and industry research. With such a large carbon footprint, we know it’s up to us to make a difference. In my experience, this is an honorable industry noted for owners and operators who live in the places they serve. Meeting your responsibilities and taking pride in your work are core to our community, but we are often cast in the role of ecological villain.
Particularly troubling is the resurgence in timber being promoted as a “green” building alternative. While it might be nice PR for the lumber industry, the simple fact is that wood is wholly unsuitable for mass construction. It lacks the strength, durability, and safety of concrete. And there’s obviously catastrophic potential for more air pollution from more logging and timber manufacture, the destruction of existing forests, and the unavoidable dangers of fire. People need to be reminded of these things.
Even in the harshest criticisms of concrete, there remains a simple truth. To quote civil engineering professor Phil Purnell on concrete: “The raw materials are virtually limitless and it will be in demand for as long as we build roads, bridges, and anything else that needs a foundation. By almost any measure it’s the least energy-hungry of all materials.”
We need concrete. And so it’s up to concrete producers to do what we can where we can to minimize our impact. The industry already repurposes industrial byproducts that would otherwise be considered waste (fly ash, slag, and silica fume). When these materials were introduced a few decades ago, they were met with healthy skepticism. Over time, we came to realize that we could use these materials to save money, reduce emissions, and make better concrete. When it’s a win-win-win scenario, why wouldn’t we do it? As an industry, we need to embrace innovations like these.
My personal passion has turned toward capturing CO2 in concrete products, which is now economical, scalable, and catching on with government bodies, private building developers, and designers. We’ve shown we can put CO2 that would have gone into the atmosphere into our concrete, create a stronger product, and reduce our impact on air pollution. It’s the right thing to do and it makes sense; that’s the type of logic that drives this industry.
The Global Cement and Concrete Association recently announced the formation of Innovandi, a global cement and concrete research network pairing industry with scientific institutions to drive even more progress. It’s another step in the right direction. For us and for our children and grandchildren, we’ll continue to improve our industry, leave the planet cleaner, and build a better place for generations to come. Cleaner, simpler, and stronger makes good business sense for both our products and their continued use—and that’s always how we’ve supplied the world with what it needs to build for the future.
Concrete Innovation in Action
The Hawaii Department of Transportation is testing a concrete mix injected with waste carbon dioxide as part of a sustainable transportation initiative. The test involves a pour of 150 yd. of carbon-injected concrete next to an equivalent pour of standard concrete mix on an access road for the Kapolei Interchange Phase 2. The carbon-injected concrete used in the testing is produced by Island Ready-Mix Concrete using waste carbon dioxide from Hawaii Gas.
The CO2 is mixed into the concrete using CarbonCure technology. The resulting product traps carbon dioxide in mineral form within the concrete and improves the compressive strength. Depending on the final specifications, the use of carbon-injected concrete could reduce embodied carbon by 25 lbs. per cubic yard. A mile of concrete pavement uses roughly 21,000 yd. of concrete. The amount of concrete poured in the HDOT demonstration project will save 1,500 lbs. of CO2, offsetting the related carbon emissions from 1,600 miles of highway driving. — CarbonCure Technologies, Halifax, Nova Scotia, 902/442-4020; www.carboncure.com