Characterization and Performance of Eco and Crack-Free High-Performance Concrete for Sustainable Infrastructur

The main objective of this study is to develop, characterize, and validate the performance of a new class of environmentally friendly, economical, and crack-free high-performance concrete referred to as Eco and crack-free HPC that is proportioned with high content of recycle materials. Two classes of Eco-HPC are designed for: (I) pavement (Eco-Pave-Crete); and (II) bridge infrastructure (Eco-Bridge-Crete). Eco-HPC mixtures were designed to have relatively low binder content up to 350 kg/m3 and develop high resistance to shrinkage and superior durability. A stepwise mixture design methodology was proposed to: (i) optimize binder system and aggregate skeleton to optimize packing density and flow characteristics; (ii) evaluate synergy between shrinkage mitigating materials, fibers, and moist curing duration to reduce shrinkage and enhance cracking resistance; and (iii) validate performance of Eco HPCs. The composition-reaction-property correlations were developed to link the hydration kinetics of various binder systems to material performance in fresh state (rheological properties) and hardened state (strength gain and shrinkage cracking tendency). Results indicate that it is possible to design Eco-HPC with drying shrinkage lower than 300 mustrain after 250 days and no restrained shrinkage cracking even after 55 days. Reinforced concrete beams made with Eco-Bridge-Crete containing up to 60% replacement of cement with supplementary cementitious materials and recycled steel fibers developed significantly higher flexural toughness compared to the reference concrete used for bridge applications. In parallel, autogenous crack healing capability of concrete equivalent mortar mixtures was monitored using microwave reflectometry nondestructive testing technique. Research is in progress towards analyzing life cycle assessment of Eco-HPCs under field condition.