Material engineers and scientists are turning their attention to concrete. Their interest was first drawn by the belief that the world’s goal of reducing CO2 could be furthered by developing alternative cementitious materials (ACMs). But their research yielded another discovery: ACMs can help improve concrete’s durability, service life, and strength properties.
ACMs have become the concrete industry’s rising star. The Strategic Development Council, an affiliate of the American Concrete Institute, has identified them as a critical technology and has committed to help promote their development. ACMs were a major topic at its last meeting, and they also will be an important topic at the International Conference on Grand Challenges in Construction Materials next March. Conference leaders hope to further discussions on how a multidisciplinary approach can combine best practices from different fields to revolutionize concrete. And researchers at the MIT Concrete Sustainability Hub have proposed the concept of Gorilla cement, an ACM developed by applying glass science tools to cement that could bring an improved toughness to concrete.
But as concrete practitioners know, there’s a great difference between “labcrete” and concrete.
Fortunately for producers, Dr. Lawrence Sutter has taken a practical approach to introducing ACM concretes to our industry. Sutter is a professor in Materials Science and Engineering at Michigan Technological University, and director of the Michigan DOT Transportation Materials Resource Center.
For almost a decade, Sutter has worked to develop a path by which ACMs can be introduced into the commercial concrete industry. His efforts will have a major influence on the future of concrete production and concrete construction.
Creating better concrete
Sutter first came to the material science of concrete by studying the beneficial effect of hydraulic fly ash. But recently his interests have expanded to other ACMs such as geopolymers, activated slags, activated glassy, and CO2-cured cements. Sutter states that these new materials can be a replacement for the portland cements in a producer’s mix designs, or an addition that creates better concretes.
While there seem to be no limits to opportunities that material science and engineering will be to the future ACMs, there is one key limitation. The design community is very cautious about adopting unproven materials that can lessen the proven service life of concrete made with hydraulic cement.
To solve this, Sutter has led the effort to urge the standards-writing community to develop appropriate testing protocols and guides for ACMs. Not all ACMs meet material specifications like ASTM C1157 and ASTM C1600, or design codes such as ACI 318-14. Sutter and other ACM proponents have worked with the standards-writing organizations to establish the infrastructure that will ensure that ACMs can be specified using commonly referenced test and performance standards. “Once specifiers are assured that the new materials have similar performance attributes as commonly used materials, they will include them in their contracts,” Sutter says.
ASTM committees C01 and C09 have been discussing how to best incorporate ACMs. Once the standard communities unite, ACMs will slowly be adopted by concrete producers, who will first use ACMs in high-performance mixes.
More on Lawrence Sutter.