State Transportation Organization Tests Sustainable Concrete Mix for Road Projects

The Hawaii Department of Transportation (HDOT) (Honolulu, Hawaii, USA) is scheduled to perform tests to determine the viability of a concrete mix injected with waste carbon dioxide (C02) for use in sustainable transportation initiatives.

HDOT’s tests will compare a 150 m3 (114 m2) pour of carbon-injected concrete with an equal amount of standard concrete in order to determine specifications for the use of the carbon-injected concrete for future infrastructure projects. The side-by-side comparison of the two mixes is set to occur on an access road for the Kapolei Interchange Phase 2 complex in Hawaii.

According to the International Energy Agency, concrete is the second largest industrial source of CO2 in the world. According HDOT forecasts, carbon-injected concrete could reduce embodied carbon by 25 kg/m3. By comparison, a mile of concrete pavement uses approximately 21,000 m3 of concrete. According to HDOT estimates, approximately 1,500 lbs of CO2 will be saved as a result of the carbon-injected concrete, offsetting carbon emissions from 1,600 mi of highway driving.

Two local companies are responsible for the materials that will be used during testing: Island Ready-Mix Concrete (Kapolei, Hawaii, USA) produced the carbon-injected concrete, while Hawaii Gas (Honolulu, Hawaii, USA) provided the waste carbon dioxide. The latter product was then mixed into the concrete using technology from CarbonCure (Darthmouth, Nova Scotia, Canada). The project was also supported by Elemental Excelerator (Honolulu, Hawaii, USA), a “startup accelerator” for more than 50 projects.

Source: Hawaii Department of Transportation,