The project

MnROAD is a live pavement test facility on Interstate 94, owned and operated by the Minnesota Department of Transportation (MnDOT). It exists to find ways to make roads last longer, perform better, and cost less to build and maintain. In 2022, the National Road Research Alliance placed 19 new concrete test sections at MnROAD. One was made with OPUS SCM™.

The challenge

MnDOT provided a strict performance specification and a control mix design. Terra needed to identify the maximum possible OPUS SCM™ replacement level while meeting every target—compressive strength, flexural strength, air content, and workability—under real construction conditions, not just in a laboratory.

The result

All performance targets were met. The concrete set and finished comparably to the control mix.

A mix with 35% OPUS SCM™ replacement was identified as meeting the full specification—the highest replacement level of any participating product in the project. The mix used a Type IL (10) cement with a total cement content of 570 lb per cubic yard.

Performance data

Pre-construction lab mix

Field sample — construction site

One year later

Concrete cores were taken from the shoulder section after a full year of road use. OPUS SCM™ showed continued strength gain, low chloride permeability, and high electrical resistivity—consistent with fly ash at 30% replacement.

All concrete testing conducted by Braun Intertec, an accredited concrete laboratory in Minnesota.