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Title: Microwave-based preconditioning for accelerated carbonation curing of cementitious materials
Author: Liu, Min
Awarding Body: UCL (University College London)
Current Institution: University College London (University of London)
Date of Award: 2019
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To increase the manufacturing efficiency of precast concrete, carbonation curing has been increasingly recognised as a potential technique to effectively address the sustainability issues facing construction industry. However, the water demand needed to ensure sufficient workability of vibrated concrete is relatively high compared to that for the compacted concrete, and is undesirable for carbonation curing. Various preconditioning methods have, therefore, been proposed and developed in the literature to remove excessive water in order to facilitate carbonation curing. However, all these preconditioning methods are inefficient and take a much longer time than the actual carbonation curing. To address this issue, a microwave-based method has been successfully developed in this project as an alternative preconditioning technique for accelerated carbonation curing. This has been achieved through a comprehensive study as reported in this thesis. Firstly, the effects of preconditioning time, carbonation time and carbonation pressure on the properties, reaction products and carbonation efficiency of cementitious materials were systematically studied. It was found that the microwave-based heating is an effective preconditioning method, which can reduce the threshold preconditioning time to around 70 min. A change in carbonation time results in different carbonation products and a higher degree of carbonation, while a change in carbonation pressure leads to little difference in carbonation products. Compared with other preconditioning methods, the microwave-based preconditioning removes water and enhance carbonation rapidly. The reaction products for the microwave-based preconditioning were found to be similar to those for other preconditioning methods. Furthermore, the application of the established microwave-based preconditioning and carbonation curing regime to samples was then extended to include different mineral additions. The mortars containing mineral additions had greater carbonation depths and CO2 uptake when compared to the pure cement mortar. In general, the microwave-based preconditioning in this project shows a good potential, as a novel and effective preconditioning method, for accelerated carbonation curing of cementitious materials.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available