Recent initiatives promoting the "greening" of the concrete industry have provided an incentive for the development and evaluation of new cementing materials that may be used to either partially or fully replace the traditional portland cements used in concrete. Many alternative cementitious materials (ACMs) have been used in limited applications where their unique properties (including rapid strength gain, exceptional chemical resistance, and high temperature resistance) are of value. Of these ACMs, alkali-activated aluminosilicates (i.e., geopolymer concrete), calcium sulfoaluminate cements, calcium aluminate cements, phosphate-based cements, and novel portland cement formulations have been shown to be feasible in lab-scale studies for the partial or full replacement of the traditional portland cements used in concrete. There is, however, limited understanding of the scalability of these material systems (e.g., large-scale production, transport, and placement techniques), their long-term performance and durability in a range of environments, and their structural response when subjected to transportation-relevant loading conditions (e.g., large-scale compressive and flexural strength, rates of strength gain, shrinkage, fatigue).

The researchers propose a systematic and comprehensive investigation of novel ACMs for applications in sustainable transportation infrastructure, including evaluation of early-age material properties, long-term material properties, and a multiscale durability investigation. From this, they will provide guidelines for recommended test methods and, when relevant, test limits for acceptance of ACMs for transportation infrastructure, including highway structures and rigid pavements, along with preliminary specifications for use. The researchers take a multiscale, multidisciplinary approach that marries a fundamental science-based approach to materials chemistry and novel characterization with a well-informed and unbiased program of appropriate and informative accelerated testing. This will then be followed by large-scale assessment and marketing aimed at transportation applications to gain the fundamental knowledge about alternative cementitious materials chemistry, structure, and property development needed to take ACMs from the laboratory to practice.

Goals:

To provide a substantive product that truly provides a groundbreaking multiscale understanding of the behavior of ACMs in transportation infrastructure applications.

• Exploratory Advanced Research

• FY 2002-2022 / Infrastructure / Pavements and Materials