Use of Innovative Sustainable and Durable Materials in Concrete Pavements

Location: Monticello, Minnesota

Award: Lower Carbon Concrete

Project Team

Owner and Engineer: Minnesota Department of Transportation

Contractors: C. S. McCrossan (Prime) and subsidiary PCi Roads, LLC (Paving Subcontractor) Concrete and Slag Cement: Holcim

To establish the durability and constructability of emerging sustainable concrete mixtures, the Minnesota Department of Transportation (MnDOT) selected four slag cement based cementitious systems for evaluation in test cells within the MnROAD Test Facility, a 2.5 mile (4 km) section of Interstate 94 (I-94) that is used to test pavement designs and materials. The cells included two mixtures using PLC-based blended cements, a mixture using an ASTM C1157/C1157M cement, and a mixture using an alkali-activated cement; and all four mixtures used slag cement as a major component, were produced using a conventional ready mixed batching process, and were placed using a conventional slip-form paving machine. Construction was completed in September 2024, and evaluation will continue through 2027.

The SCA cooperated in this study to demonstrate the performance of blended cements with significant slag cement contents and to demonstrate emerging applications where slag cement is the predominate component of the cementitious material. To accomplish the first goal, the SCA proposed a quinary blend comprising Type IL(8) blended cement along with 24% slag cement, 20% Class F fly ash, and 8% natural pozzolan. A second mixture, developed by Holcim, comprised Type IL(8) cement with 20% slag cement and 30% Class F fly ash. A third mixture, provided by Ozinga, comprised an ASTM C1157/C1157M slag cement blended with Type IL(8) cement. Lastly, C-Crete provided a product comprising slag cement blended with a dry alkali activator.

PROJECT OVERVIEW

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Application Type

Application Type
% Slag Cement Replacement
% Portland Cement
% Portland Limestone Cement
% Other SCM (if applicable)
Aggregate	Optimized meeting the requirements of MnDOT 2301.2C.3 of the 2020 Spec Book (see Table 1).
Water/cement ratio	SCA mixture – 0.38, Holcim mixture  –  0.40, Ozinga mixture – 0.41, C-Crete mixture – 0.32
7-day strengths	See plots
28-day strengths	See plots