Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637133
Title: Micromechanical modelling of self-healing cementitious materials
Author: Davies, Robert Elfed
ISNI:       0000 0004 5359 9993
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2014
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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.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.637133  DOI: Not available
Keywords: TA Engineering (General). Civil engineering (General)
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