The Exploratory Advanced Research Program

Novel Alternative Cementitious Materials for Development of the Next Generation of Sustainable Transportation Infrastructure

Summary

Usage Survey Results

The ACM usage survey results and the research team’s observations made during site visits, in addition to information provided by users or owners at these sites, demonstrate that there is growing interest in the use of ACMs for large-scale transportation infrastructure construction in the United States. At this time, the materials most commonly used for larger scale pavement construction include CAC, CSA, and AA products.

In general, the research team found ACM usage to be concentrated mainly in large urban areas, where the rapid setting and high early strength of these materials contributed to minimal road closure time. Such time-saving advantages provided value that superseded potential increases in costs for materials and construction, as well as challenges associated with the construction itself. For example, because of the rapid-setting characteristics of some of these materials, volumetric mixer trucks capable of combining materials at the job site were employed in some ACM construction projects. In some cases, more rapid-than-anticipated set times required pavement surface grinding because of difficulties achieving smooth finishes.

The research team found few examples of MPC and belite cement usage for larger scale transportation construction. The most common examples of MPC usage include small road repairs and joint construction. The research team found that MPC availability in the United States has been limited. Seasonal availability, variability in composition and quality, and challenges with short working time of the material have all prevented more widespread adoption of MPCs. Although usage for small-scale rapid repairs seems practical, larger scale construction using MPCs does not seem practical at this time. The research team also found that use of belite cements was less common. These cements have required longer cure times and relatively low strengths compared to other materials. New formulations may improve these current challenges.

Further Testing

Based on the results of the initial literature review, the ACM survey, conversations with material suppliers, and consultation with FHWA and the project’s technical working group, the research team identified a subset of materials for further testing. These materials include two CSA cements, two CA cements (in which one is a blend of CA and portland cement), one belite cement, and two AA cements. Because the research is aimed at the scalability of these materials, most cements examined by the research team are commercially available, with the exception of a geopolymer concrete that is being developed by using off-the-shelf constituent materials. Research is ongoing; the team is currently focused on screening of available ACM technologies by examining fresh and hardened concrete properties and assessing durability. The research team will use these assessments to identify viable candidate ACMs for further investigation and to construct larger test sections at the culmination of the project.