For millennia, concrete has been one of humanity’s most basic building materials. Concrete was used in the Egyptian pyramids, the Coliseum and, now, every modern building project. Indeed, concrete is so ubiquitous in construction that the equivalent of 2-4 tons of it are made for each person on earth annually, with significant environmental impacts. Concrete manufacturing creates an enormous carbon footprint, for one thing. Cement production currently contributes 5-8% of the world’s total carbon dioxide emissions. According to the EPA, the cement industry is the third largest industrial source of pollution in the U.S. To cut greenhouse discharges, concrete manufacturers are looking for new, earth-friendly ways to produce this universal building material.
Concrete Manufacturing: Old and New Approaches
For the past 150 years or so, the recipe for concrete has been pretty consistent: Mix sand, water, and crushed rock to make cement. Pour said cement into a desired form, and let it harden into concrete. To boost strength, modern structures include rebar supports as well as additional ingredients, such as alite. Some eco-conscious concrete researchers have suggested replacing high-temperature clinkers such fly ash or slag that would otherwise to go a landfill. However, researchers from Oregon State University, Purdue University, and Solidia Technologies say they have a new, better way to make concrete: With carbonation.
Carbonated Concrete: Environmental and Structural Benefits
Rather than reacting with water, carbonated cement reacts with carbon dioxide and calcium silicate. The resulting product, Carbonated Calcium Silica-based Cement, or CCSC for short, appears like traditional concrete, but with added durability. Moreover, as liquid C02 is pumped into the concrete prior to mixing, it is sequestered and kept out of the atmosphere. By minimizing manufacturing emissions while also trapping C02 that would otherwise be released into the air, carbonated concrete could greatly reduce the industry’s carbon footprint.
Beyond a significant reduction in the concrete industry’s greenhouse gas emissions, CCMC can benefit the environment by making roads more resistant to de-icing chemicals as well as the freeze/thaw cycle. According to a study published in Construction and Building Materials, freeze-thaw damage is reduced by CCSC’s unique pore structure. Moreover, CCSC does not react to de-icing chemicals and salts as does common Portland cement. CCSC could represent a significant time and cost savings for construction projects, as stronger concrete would require replacement less frequently. Less frequent replacement would also drive down the use of fossil fuels and other natural resources.
Before CCSC can be utilized on an international scale, it must be thoroughly tested against produce construction standards and codes. Expect early use of CCSC in pre-cast, factory-built concrete products. Down the line, look for other technological uses for CCSC, such as topical products to add de-icing resistance over existing roads.
Earth-Friendly Demolition Services
Until carbonated concrete is widespread, all of us can strive to use traditional concrete in eco-conscious ways. As leading Oregon building demolition contractors, we’re doing our part to make the end of the concrete lifecycle as earth-friendly as possible. With the right equipment, existing concrete can be demolished in environmentally friendly ways. Here at Elder Demolition, we invested in a concrete crusher because recycling concrete on site greatly reduces fuel use. Concrete is heavy, and a single demolition job site can contain thousands of tons of it. By breaking down concrete for onsite reuse—as filler, pipe bedding, and more—we’re eliminating the carbon footprint associated with transporting for recycling. Moreover, we’re managing demand for virgin concrete by reusing demolished materials. Finally, we’re conscious about dust and pollution control throughout building demolition, Portland to Burns and across our West Coast operations. And of course, Elder Demolition employees receive proper protection for cutting and working with concrete.