To address climate change mitigation goals, highway agencies are seeking alternative concrete paving mixtures that have a reduced embodied carbon content (ECC).

The research team first focused on developing a matrix of reduced ECC concrete mixtures to be tested at MnROAD. The 16 concrete mixtures selected for inclusion in the test matrix met minimum engineering requirements to ensure constructability and performance and were approved by MnDOT.

Between July 27 and August 9, 2023, 16 test cells were constructed at the MnROAD I-94 facility to evaluate reduced ECC concrete paving mixtures. The purpose of constructing these cells was to assess the in-service performance, environmental impact, and constructability of various alternative supplementary cementitious materials (ASCMs) that may reduce the embodied carbon content of concrete, while providing an opportunity to assess test results and in-service performance in coming years.

A preliminary environmental assessment showed that most mixtures were expected to have either a similar or lower ECC compared to the control mixture representative of typical MnDOT paving-grade concrete. Quality assurance testing conducted on field-cast specimens revealed generally acceptable results; most of the materials had similar performance compared to the control mixture, but the cells will continue to be monitored.