Speaker
Description
This study investigates the drying behavior and degree of hydration (DOH) of ternary cementitious systems composed of Portland cement (PC), calcium aluminate cement (CAC), and calcium sulfate (CS) sources using neutron radiography. CAC-based ternary binders can be preferred in interior flooring applications due to their self-leveling characteristics, rapid early strength development, and fast setting times. However, the early-age reaction mechanisms, drying behavior, and mechanical performance of these systems are significantly influenced by parameters such as the PC:CAC ratio, the Al₂O₃ content of the CAC, the nature and amount of CS, curing conditions, and ambient temperature. Due to their rapid setting characteristics, CAC-based systems are typically not subjected to conventional curing on-site. However, this can result in accelerated moisture evaporation, potentially limiting hydration, reducing mechanical strength, and promoting shrinkage and cracking. In this context, the present work examines the influence of CS type (gypsum, hemihydrate, anhydrite) and dosage (10%, 15%, and 20% by weight of CAC) on drying and hydration behavior. A total of nine ternary blends were prepared, along with reference samples containing only CAC or only Type III PC. To assess the impact of environmental exposure, specimens were either sealed immediately after casting or exposed to ambient drying conditions. Neutron radiography enabled non-destructive visualization of moisture distribution and hydration progress. The results indicate that both drying rate and DOH increase with higher CS content. Moreover, no significant difference was observed in drying behavior or hydration degree between sealed and unsealed ternary mixtures, suggesting minimal influence of early drying conditions. These findings demonstrate the stability of CAC-based ternary systems under practical drying scenarios, supporting their applicability in field conditions without the need for external curing.
Affiliations
aGazi University, Department of Civil Engineering, Ankara, Türkiye, 06500
damlanur.celik@gazi.edu.tr
bSchool of Civil and Construction Engineering, Oregon State University, 1491 SW Campus 5 Way, Corvallis, OR 97331, USA
| Title | Assessment of Drying Behavior of CAC-Based Pastes Using Neutron Imaging Method at Early Age |
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| Keywords | ternary-based systems, early-age drying, degree of hydration, porosity, neutron radiography |