OUR WORK: Aligned With National priority in “Environmental Sustainability”
"We are what we repeatedly do. Excellence, then, is not an act, but a habit." - Aristotle
The “Highways of the Future – A Strategic Plan for the FHWA’s Infrastructure R& D Program” (2010) identified research priorities such as: Accelerated Highway Construction; Environmentally Sensitive Highway Infrastructure; and Comprehensive and Integrated Infrastructure Asset Management.
LASCM is an active player in the Center for Environmentally Sustainable Transportation in Cold Climates (CESTiCC).
Why the Need for Sustainable Cementitious Materials?
The production of cement is an energy-intensive process that constitutes a significant portion of anthropogenic carbon dioxide emissions and other greenhouse gases. Concrete is the most widely used man-made building material in the world, and its annual global production is approximately 5.3 billion cubic meters. Cement is the most common binder in concrete, and its annual global production “has reached 2.8 billion tons (t), and is expected to increase to some 4 billion t”.
Durability and sustainability are two increasingly important characteristics for concrete infrastructure, and more research is needed to enable expanded use of industrial wastes as supplementary cementitious materials (SCMs) in concrete without sacrificing its long-term performance and reliability.
EXAMPLE: Up-Cycling Coal Fly Ashes
Coal fly ashes (CFAs) are the main by-products of coal combustion for electrical energy production. They are considered as a type of solid waste with high levels of contaminants, and thus pose a substantial environmental risk unless being solidified in concrete or mortar. The U.S. generates approximately 70 million t of CFAs, of which only 27 percent (~19 million t) are recycled and the rest are landfilled. Currently, about 12 million t of CFAs in the U.S. are utilized in concretes and mortars each year, as SCM or as replacement of fine aggregate.
The last decade has seen the complete replacement of cement by CFAs in mortars or concretes to garner considerable interest. The vast majority of studies in this field have focused on alkali activated binder materials such as geopolymer and alkali activated fly ash. Novel uses of CFAs as cementitious binder can produce cost and energy savings and reduce greenhouse gas emissions and landfill waste. For instance, our recent work reports an environmentally friendly cementitious binder material made from only the class C coal fly ash (as-received from supplier, without further treatment), water, and a very small amount of borax, at room temperature and without direct alkali activation.
EXAMPLE: "Greener" Pervious Concrete
Pervious concrete is considered a successful Low Impact Development (LID)/Green Infrastructure technology and has been increasingly used as a stormwater Best Management Practice (BMP) for parking lots, sidewalks, and other applications. It also has other environmental benefits such as traffic noise reduction, urban heat-island mitigation, and groundwater recharging. Pervious concrete pavements have an open network of pores to allow infiltration through the pavement with a subsequent reduction in the quantity of stormwater runoff and an improvement in water quality, thus protecting aquatic resources from urban and transportation developments. In place of impervious surfaces, pervious concrete pavement reduces stormwater runoff, distributes infiltration, and recharges the groundwater.
Our approach is to develop “greener” pervious concretes made from recycled materials and nano-/micro-sized materials. The innovation is inherent in the use of multi-scale modified “green” cementitious binder and low-cost materials and waste materials in a synergistic manner.
We are seeking continued funding and partners in both up-cycling of locally available by-products and pilot deployment of "greener" concrete pavements. Please contact Dr. Shi at 509-335-7088 or email@example.com for more information.