Davies, Robert Elfed ![]() Item availability restricted. |
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Abstract
A self-healing cementitious material could provide a step change in the design of concrete structures. There is a need to understand better the healing processes, to predict accurately experimental behaviour and to determine the impact on mechanical properties. Micromechanical modelling, with a two-phase Eshelby inclusion solution, is chosen as a suitable framework within which to explore self-healing. The impact of micro-cracking and other time-dependent phenomena are considered alongside self-healing experiments and the numerical mechanical strength response. A new approach describes simulating inelastic behaviour in the matrix component of a two-phase composite material. Quasi-isotropic distributed micro-cracking, accompanying volumetric matrix changes, is combined with anisotropic microcracking arising from directional loading. Non-dilute inclusions are homogenised and an exterior point Eshelby solution is used to obtain stress concentrations adjacent to inclusions. The accuracy of these solutions is assessed using a series of three dimensional finite element analyses and a set of stress/strain paths illustrate the model’s characteristics. The problem of autogenous shrinkage in a cementitious composite is applied using a volumetric solidification and hydration model, which quantifies the effects of micro-cracking. Experiments on early age concrete and mortar beams showed that autogenous healing is primarily due to continued hydration. A novel self-healing model focuses on mechanical strength recovery of micro-cracked material and considers healing whilst under strain as well as allowing for re-cracking the healed material. The constitutive model is combined with a layered beam model to allow successful comparisons with experimental results.
Item Type: | Thesis (PhD) |
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Status: | Unpublished |
Schools: | Engineering |
Subjects: | T Technology > TA Engineering (General). Civil engineering (General) |
Uncontrolled Keywords: | Micromechanical; Self-healing; Cementitious; Inelastic; Autogenous; micro-cracking. |
Funders: | Alun Griffiths Contractors, President's Scholarship |
Date of First Compliant Deposit: | 30 March 2016 |
Last Modified: | 27 Oct 2022 10:27 |
URI: | https://orca.cardiff.ac.uk/id/eprint/70424 |
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