A MULTISCALE EXPERIMENTAL INVESTIGATION OF MICROSTRUCTURAL DEVELOPMENT, MASS TRANSPORT, AND CARBONATION PHENOMENA IN LOW CLINKER CEMENTITIOUS MATERIALS
Concrete is the most widely used construction material in the world. However, there is a need to develop sustainable concrete mixtures considering that cement production accounts for 5-8% of anthropogenic CO2 emissions. Low-clinker cementitious materials offer enormous CO2 reduction potential due to their lower embodied energy, lowered calcination temperatures, low clinker content, and the reduced content of limestone in the clinker feed. This study aims to implement a multiscale experimental approach to design low-clinker systems with different formulations to satisfy/surpass performance requirements for building/infrastructure applications in different geographic regions. Cementitious systems with low clinker content can offer a multitude of advantages, with different formulations that result in microstructures that display lower intrinsic permeability and varying phase assemblages. In this study, internal curing was implemented to improve the microstructure of low-clinker materials by extending the hydration/pozzolanic reactions. Internal curing typically consists of partially replacing the fine aggregates with an equivalent volume of pre-wetted fine lightweight aggregates (FLWA). The FLWA serves as the internal water reservoir for curing. This approach enhances the durability of concrete. Additionally, the application of internal curing reduces the duration of external curing. This may provide one option to address the construction schedule. Additionally, this study utilizes a suite of experimental methods to examine carbonation phenomena in low-clinker systems to discover the governing mechanisms and provide a novel method to limit the carbonation depth in low-clinker cementitious materials. The findings of this study can open opportunities to design highly sustainable cementitious systems with superior performance against carbonation. Carbonation-induced corrosion causes extensive damage to concrete infrastructure in the US every year.
Civil engineering, Engineering, Carbonation, Formation factor, Internal curing (IC), Limestone calcined clay cement, Neutron radiography, Supplementary cementitious materials (SCMs)
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