Periodic Reporting for period 1 - NMRCement (Zero-CO2 cement concept evaluated with novel Nuclear Magnetic Resonance (NMR))
Période du rapport: 2021-09-01 au 2023-08-31
The production of cement is predicted to account for 25% of anthropogenic CO2 emissions by 2025. There is a need to produce novel reduced CO2 cement materials to reduce global carbon emissions. This project investigated gepolymers, an emerging construction material that can be used as a cement alternative with lower CO2 emissions. It is well known that geopolymers have favorable mechanical properties such as strength in compression, however detailed knowledge of the curing process and the pore structure are still needed. To meet address these questions, the tuneability of the pore network, curing time and mechanism of geopolymers was characterized with varying compositions.
It was shown that the curing time and pore structure of geopolymers are only moderately affected by the amount of water used in the initial reaction. However, the curing time and reaction mechanism during curing are highly sensitive to the ratio of aluminum and silica used in the initial reaction. One important finding of these studies was that the pore network formed inside geopolymers is a continuous, interconnected pore network accessible to both gases and water. These findings together give key information regarding usable source materials, manufacturing conditions, and long term stability of geopolymer based cement products.
Additional outcome of this work includes training activities of the fellow. This work was done as part of a collaboration between the NMR Research Unit and the Fibre and Particle Engineering Group at the University of Oulu. This gave the Fellow unique access to training in a wide range of methods from microscopy, nitrogen desorption measurements, NMR, and synthesis of the materials. Additionally, the Fellow attending training in University Pedagogy. The Fellow attending several conferences to present this work including EUROMAR, The Finnish NMR Symposium, and Diffusion Fundamentals. The work was published in high impact publications in a field specific journal, Cement and Concrete Research.
Additional outcome of this work includes training activities of the fellow. This work was done as part of a collaboration between the NMR Research Unit and the Fibre and Particle Engineering Group at the University of Oulu. This gave the Fellow unique access to training in a wide range of methods from microscopy, nitrogen desorption measurements, NMR, and synthesis of the materials. Additionally, the Fellow attending training in University Pedagogy. The Fellow attending several conferences to present this work including EUROMAR, The Finnish NMR Symposium, and Diffusion Fundamentals. The work was published in high impact publications in a field specific journal, Cement and Concrete Research.
The work expanded on the state of the art and thus resulted in high impact publications. Before this work, studies of the pore structure and curing times of geopolymers were limited to destructive and invasive methods such as nitrogen desorption and microscopy. This work utilized Nuclear Magnetic Resonance (NMR) studies of the hydrogen found inside the geopolymer framework as well as of water and Xenon gas trapped inside the pores of the geopolymer. This allowed for longitudinal studies of the curing of samples as a function of water content and alumina to silica ratio as well as non-invasive studies of the pore accessibility to water and gas. The most important findings were that the curing mechanism, pore structure, and pore accessibility are a function of water content as well as silica to alumina ratio. The effect on wider society is that the evaluation of a low CO2 cement product was evaluated for feasibility and further characterization for use as cement.