New insights into early-stage time-dependent dielectric characteristics coupled with frequency dependency and hydration-driven reaction of hydraulic cement pastes: Experiments and statistical modelling

Abstract

In the field of cement and concrete materials engineering, a comprehensive understanding of dielectric properties is crucial for optimising hydraulic cement paste mix designs. This study examines the relationships among the dielectric constant (ε’), loss tangent (tan δ), frequency, hydration time, water content and admixture dosage in different compositions of hydraulic cement paste. A consistent pattern can be observed across the frequency spectrum, where dielectric constants decrease as frequency increases. This aligns with the expected behaviour of cementitious materials. The most notable finding is the inversely proportional relationship between the loss tangent and frequency. As the frequency increases, the loss tangent consistently decreases, indicating improved energy retention and reduced dissipation. This characteristic is of significant value for various applications, including sustainable infrastructure and smart materials. Furthermore, the interactions among hydration time, water content and admixture dosage present an opportunity for dynamic optimisation within the cement paste matrix. These factors collectively impact dielectric properties, providing insights into the potential for tailored material performance and durability, especially in applications where dielectric properties are critical, such as sensing applications and structural health monitoring of concrete structures. This study emphasises the importance of customising cementitious compositions for specific applications in cement and concrete materials engineering. It achieves this through a detailed comparative analysis of different compositions, each representing varying water content and admixture dosage levels. This approach has the potential to significantly transform the field by enabling engineers to create hydraulic cement pastes with customised dielectric properties that meet the specific requirements of construction, infrastructure and other related applications.