The Joy of Disruptive Things

Fall 2015

Carbon curing is making an impact on the Concrete Paver Industry

David R. Smith


The Joy of Disruptive Things

Disruptive technology: One that displaces an established technology and shakes up the industry, or a groundbreaking product that creates a completely new industry. Examples: cellphones, personal computers and flat screens. From

Disruptive innovation: One that helps create a new market and value network, and eventually disrupts an existing market and value network (over a few years or decades), displacing an earlier technology. Examples: Uber, Wal-Mart and iTunes. From

Does the concrete paver industry have a disruptive technology? Maybe so, and it might be carbon curing. In very simple terms, carbon curing is using carbon dioxide to cure concrete instead of air. CO2 is captured into the concrete, holding some generated by cement production. This sounds good given the rising CO2 levels in the atmosphere and the broader implications for global warming, climate change, rising sea levels, etc. Fortunately, the segmental concrete pavement industry takes a smidgeon of comfort in knowing that 95 percent of CO2 emissions comes from burning fossil fuels to heat/cool buildings and from operating ships, trains, planes and automobiles.

A requirement fixed in concrete manufacturing is curing time. While concrete never stops curing, 28 days was established decades ago for curing time prior to testing for strength, absorption/density, and freeze-thaw deicer resistance. Concrete pavers often take less than 28 days to achieve the minimum 8,000 psi (55 MPa) unit compressive strength required in ASTM C936 or the minimum 7,200 psi (50 MPa) cube compressive strength in CSA A231.2. Nonetheless, significant sums of venture capital are being invested into carbon curing of concrete pavers because it presents a disruptive 24 hours for curing instead of 672.

What does a 24-hour cure time mean regarding substantive efficiency increases? Most of our readers haven’t experienced a concrete paver plant. It consists of millions of dollars of equipment and computers that mix concrete and quickly form it into a layer of 30 to 40 pavers within a steel mold. Paver production machines can’t go much faster to reduce cycle times for vibration and compaction of wet concrete within the mold. Perhaps this could be reduced to just a few seconds if the vibration of the concrete mix happens before it enters the production mold. Another option is placing more production machines in a plant (next to another or in line) such that daily throughput is quadrupled or taken higher. This implies a corresponding expansion of curing areas within a plant, meaning larger plants.

But let’s assume that the part of the plant that makes concrete units increases output that corresponds to the curing rate output now at one day instead of 7 to 28 days. That suggests factories won’t need much time or space next to them in “the yard” to store pavers. While a larger indoor space might be needed for higher production output, plants can make and ship paving units pretty much on order, even very large orders. Inventory management becomes just in time. The need for the yard next to the plant decreases, making inventory less important, and financing costs to create it diminish.

An innovative rearrangement of old commodities like cement and CO2 present a disruptive framework. The disruption from carbon curing extends to rearranging the plant and reprogramming computers that control mixing, batching and cycle times so equipment paces with faster curing and packaging times, and on multiple machines. This seems like the difference between using radar for airport air traffic control (linear sequencing) and more efficient GPS. The latter requires operational simultaneity in a four-dimensional space with new rules for aircraft spacing on approach, landing, take-off and hand-off.

The coming disruption within the paver industry could be CO2 curing with shorter curing times. This means rethinking the configuration of existing manufacturing equipment: its extent, layout and software programming. The joy of disruption doesn’t only come from the environmental benefits of CO2 curing. It potentially comes from disruptive pricing. All of this eventually could mean that segmental concrete pavement might have a future with a lower initial cost than asphalt. That disruption is pure joy.

For more information on companies that help reduce carbon emissions from concrete products, watch the following videos:

SEK | PolySweep Superior Strength Polymeric Sand
Kobra | Having the right team makes a difference