Understanding the complexity of the chemical and microstructural evolution of cement during hydration remains a controversial subject, and although numerous techniques have been used to assess this process, further insight is still needed. Alternating current impedance spectroscopy has been demonstrated to be a sensitive and powerful technique for cement characterisation in both fresh and hardened states; however, it has also shown certain experimental limitations (e.g. data interpretation, electrode, and parasitic effects) that prevent its wider acceptance. This study assesses electrochemical cell design and the impedance response during cement hydration. The results show that a significant decrease in the parasitic effects at high frequencies (caused mainly by leads and electrode effects) can be achieved through an optimal cell design and impedance measurements correction, enabling correlation of impedance measurements to particular aspects of the cement hydration process. However, due the limited solid phase microstructural development and the high conductivity of cement paste at low degrees of hydration, the parasitic effects could not be fully eliminated for fresh or early-age cement pastes.
This paper applies alternating current impedance spectroscopy to assess the effect of different sand, anhydrite, and water contents on the electrochemical response of Portland cement in the early stages of hydration. Potential factors that may affect impedance measurements and data interpretation are also discussed, such as the complexity of cement chemical composition, its physical properties and hydration kinetics, and technique limitations. The impedance data obtained are benchmarked against different supporting techniques and literature data, showing a strong relationship among hydration rates as determined by thermochemistry, setting time measurements by physical approaches, pore fluid chemistry, electrical conductivity, and the impedance behaviour observed. The results demonstrate that ACIS is a sensitive technique to assess cement hydration, enabling differentiation of changes in the water and cement content, hydration degree, and microstructural development during the first 24 hours after mixing.
Incorporation of graphene nano-particles in concrete can improve mechanical properties and as a result has received growing attention in the research community. Despite the promise revealed in laboratory trials, there remain significant obstacles to widespread adoption of graphene in concrete at a construction level scale. This briefing paper gives an overview of the key outcomes from a recent experimental campaign and accompanying field trials where pioneering use of graphene enhanced concrete (GEC) has been successfully deployed at scale.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.