Maturity-Strength Trends Observed from Carbon Dioxide Test Sections at MnROAD

In 2022 the construction initiative that was undertaken at MnROAD was the largest to take place since the initial construction of MnROAD in 1993 on the Mainline of I-94 WB (a 3 mile stretch of interstate), a segment of I-94 WB that runs parallel and North of the original I-94 WB built during the early 1970s. The focus of the construction initiative towards rigid pavement materials was sustainability and resiliency, i.e., reducing the carbon footprint from material use, and mix design optimization while still performing well. As part of this construction in 2022, 18 new rigid pavement test sections were built, of which 6 test sections dealt with the use of carbon dioxide for sustainable and resilient concrete pavements. This work will discuss the flexural and compressive strength-maturity trends observed in each of these 6 mixes. The general form of the Nurse-Saul equation appeared valid for the carbon dioxide injected mixtures as well as their controls. The low level of injected carbon dioxide as well as the use of inter-ground limestone may have reduced the overall effect. However, the results indicated a clustering of the various factorials of the carbon dioxide mixtures and the controls on the basis of the model constants derived from the Nurse-Saul equation. Nevertheless, maturity method was proven to be a reliable and sustainable alternative to time-consuming production and elaborate testing of cylinders and beams for compressive and flexural strength.