Concrete is the most prevalent building material on the planet, and though the world would be pretty flat without it (not many tall buildings and structures), it does come at a price – around 5-8 percent of all human-generated atmospheric CO2 comes from the concrete industry. A culprit is Portland cement, the binding agent in concrete. It’s the most widely produced man-made material on earth. Production of Portland cement is currently exceeding 2.6 billion tons per year worldwide and growing at 5 percent annually. To halt these alarming pollution figures, innovative research on geopolymer concrete, along with ways of using a waste byproduct from coal-fired powerplants, is being conducted by Dr Erez Allouche, assistant professor of civil engineering at Louisiana Tech University and associate director of the Trenchless Technology Center.
A greener alternative, inorganic polymer concrete (geopolymer) fits into an emerging class of cementitious materials that utilize ‘fly ash’, one of the most abundant industrial by-products on earth, as a substitute for Portland cement.
Geopolymer concrete has a number of benefits. The first is it has the potential to substantially curb CO2 emissions. It can also produce a more durable infrastructure capable of lasting hundreds of years, instead of tens. And by utilizing the fly ash, it can conserve hundreds of thousands of acres currently used for disposal of coal combustion products, and protect our water ways from fly ash ‘contamination’, too.
In comparison to ordinary Portland cement (OPC), geopolymer concrete (GPC) has better resistance to corrosion and fire (up to 2400°F), high compressive and tensile strengths, a rapid strength gain, and lower shrinkage.
Researchers believe the geopolymer concrete’s greatest appeal could like in its life cycle greenhouse gas reduction potential; as much as 90 percent when compared with OPC.
By Jeff Salton