http://bura.brunel.ac.uk/handle/2438/25435 2026-04-18T12:22:34Z 2026-04-18T12:22:34Z Breen, Morgan James http://bura.brunel.ac.uk/handle/2438/33131 2026-04-11T02:00:31Z 2026-01-01T00:00:00Z

Title: An assessment of the unintended consequences of structural coastal flood protection Authors: Breen, Morgan James Abstract: This thesis investigates the unintended socio-hydrological consequences of structural coastal flood protections (SCFPs) and assesses the implications for coastal flood risk management strategy in the UK. Climate change, and the continued urban development of flood exposed areas can exacerbate coastal flood risk, and thus flood risk management authorities often tend towards structural coastal flood protection measures to minimise losses. However, these structurally proactive measures can lead to infrastructural lock-ins, whereby the decrease in flood probability from the defence can lead to increased urban development and population, ultimately leading to higher losses due to an inundation event. This process has been referred to as the Safe Development Paradox (SDP), a cross-cutting science-practice-policy challenge that requires a systematic understanding in the context of increased uncertainty associated with climate change and the United Nations Sustainable Development Goals. However, literature of the phenomena is limited, compounded by a lack of consistent terminology, limited geographic distribution, and a skewed emphasis on fluvial flooding. Moreover, despite being an island nation, the UK, to date, has had very little research conducted into these unintended consequences of structural flood protection. This thesis developed and applied a methodology that captures these coupled human-flood processes, by integrating well-established methods from other spheres of flood risk assessment in a novel way to explore the currently poorly understood phenomena in coastal settings. The study contributes to addressing this knowledge gap based on insights from three contrasting UK case studies: Portsmouth, Weston-super-Mare, and Southport. Differential analysis of historic LiDAR Digital Surface Models (DSMs) was used to identify temporal changes in the urban landscape to create a DSM of Difference (DoD), representing elevation change between two locations over time. Geostatistical testing, specifically t-tests, were then used to infer statistical significance of changes in urban development. The results reveal a consistent pattern: following completion or improvement of large-scale SCFPs, there is subsequent, and statistically significant, increases in coastal population and urban development within/near flood-exposed areas in all case studies, contrary to the limited flood-exposed development in neighbouring settlements, with no comparable defences constructed, or upgraded, during the same period. On average, new urban development occurs approximately 2 years after the completion of coastal flood defence projects. These data were then inputted into a newly developed agent-based model (ABM) that simulates futures changes under different climate scenarios. The results demonstrate that each SCFP project led to an initial decrease in Affected Population (AfP) following implementation, confirming the intended immediate benefits of flood risk reduction. However, long-term projections revealed significant unintended consequences under the scenarios where SCFPs were exceeded by Extreme Coastal Water Levels (ECWLs). For Southport and Weston-super-Mare, the ABM output shows a dramatic increase in AfP once ECWL surpassed the SCFP crest height, affecting a larger population than those initially protected, primarily due to the increased population growth behind the defences and the larger flood extent. Portsmouth, however, exhibited a more limited increase in AfP, attributed to its high urban density and limited room for further development behind the defences. This highlights how pre-existing land-use and population density can act as brakes on the unintended consequences of SCFPs. The thesis concludes with a recommendation for future flood risk managers and policymakers to be aware of these unintended socio-hydrological consequences. SCFPs are crucial assets, and their construction and maintenance will continue to play an integral role in coastal adaptation to climate change, particularly in highly developed urban settlements. This thesis does not attempt to provide a comprehensive predictive modelling tool for planning, nor a detailed analysis of real estate markets, but instead focuses on socio-hydrological interactions of population change and SCFP. However, new SCFP design and implementation need to account for their long-term unintended consequences on communities and climate adaptation planning. In the short-term, flood risk communication provides a means of tackling these risks, improving flood memory, awareness, and preparedness. Furthermore, in the longer term a more holistic cost-benefit analysis and spatial planning strategy, internalising these factors should be utilised in order to create more sustainable and resilient coastal communities in the UK. Description: This thesis was submitted for the award of Master of Philosophy and was awarded by Brunel University London

2026-01-01T00:00:00Z Liu, Mingqing http://bura.brunel.ac.uk/handle/2438/32798 2026-02-10T03:00:32Z 2025-01-01T00:00:00Z

Title: Effects and mechanisms of reactive nanoparticles and triethanolamine on the properties of limestone calcined clay cement Authors: Liu, Mingqing Abstract: The large-scale production of cement worldwide contributes to 6-8% of global anthropogenic CO2 emissions. Among supplementary cementitious materials (SCMs), limestone and calcined clay are abundant and widely available yet remain underutilised. Limestone Calcined Clay Cement (LC3) enables up to 60% clinker replacement, achieving approximately 40% lower CO2 emissions compared with ordinary Portland cement (OPC). LC3 containing 40% calcined kaolinite develops higher strength than OPC from 7 days onwards. However, LC3 shows lower early-age strength and a slower rate of strength gain compared with OPC. To address this limitation, this thesis focuses on enhancing the early strength of LC3 through the incorporation of nanomaterials and triethanolamine (TEA). In addition, the effects of nano-SiO2 (NS) and calcined clay content on the durability and rheological properties of LC3 are also investigated. Chapter 4 mainly investigates the effects of nano-Al2O3 (NA) and nano-SiO2 (NS) on the hydration and mechanical properties of LC3. Gypsum optimisation is carried out first with a moderate dosage of 2% by weight, yielding the highest cumulative heat release. Results suggest that NA exhibits both pozzolanic and nucleation effects, whereas nano-TiO2 (NT) functions only as a nucleation site. However, the beneficial contribution of NA is largely restricted to the very early stages of hydration (within the first day) and even leads to reduced strength in LC3 at later ages. When NS is incorporated into LC3, it is observed to accelerate hydration, reduce workability, and enhance strength at all ages, with particularly significant gains at early ages. Furthermore, this chapter examines the influence of calcined clay (Cc) content on LC3 hydration. A higher Cc content enhances the pozzolanic reaction and improves compressive strength across all curing ages. While increasing Cc raises the total porosity of LC3, it simultaneously refines the pore structure by increasing the proportion of fine pores, despite a concurrent rise in large pores. Chapter 5 evaluates how NS and Cc influence the sulfate resistance of the LC3 system. The incorporation of NS improves dimensional stability during sulfate exposure, as evidenced by reduced relative mass and length changes. While NS has minimal influence on ettringite formation under standard curing, it significantly inhibits ettringite generation when the system is subjected to sulfate attack. Increasing the Cc content also enhances sulfate resistance, reflected in lower mass and length variations. Under standard curing, LC3 mixes with Cc achieve higher long-term strength than those without Cc. However, in Na2SO4 solution, only the blend containing 30% Cc shows a clear early age strength improvement, and the long-term strength benefit remains limited. Sulfate exposure promotes the formation of mono-carboaluminate (Mc), but its overall content decreases as Cc levels rise. Although adding Cc increases ettringite formation across all blends, its influence differs between curing conditions: under standard curing, higher Cc has little effect on ettringite content, whereas under sulfate attack, it distinctly suppresses ettringite formation. Chapter 6 studies the effects of nano-SiO2 (NS) on the rheological behaviour of the LC3 system. Results reveal that increasing NS dosage leads to higher plastic viscosity as well as greater static and dynamic yield stress. Similarly, extending the resting time increases viscosity and both yield stresses (static and dynamic). All mixes exhibit a gradual decrease in phase angle over time, indicating a transition from viscous (fluid-like) to elastic (solid-like) behaviour. Chapter 7 explores the individual and synergistic effects of NS and TEA on the hydration and hardened properties of the LC3 system. The findings show that NS primarily enhances the hydration of the silicate phase, whereas TEA regulates the timing of the silicate peak. For the aluminate peak, both NS and TEA advance its occurrence, with NS exerting a stronger influence. Either additive alone increases the intensity of the aluminate peak, while their combination produces an even stronger synergistic effect. TEA enhances LC3 strength at all ages, whereas NS contributes mainly to early age strength. The synergy of NS and TEA produces more pronounced improvements than either additive alone. Furthermore, TEA primarily alters pore size distribution rather than total porosity, driving a shift from larger to finer pores. The synergistic blend of NS and TEA achieves the most favourable pore size distribution. Description: This thesis was submitted for the award of Master of Philosophy and was awarded by Brunel University London

2025-01-01T00:00:00Z Huang, Xiangjun http://bura.brunel.ac.uk/handle/2438/32415 2025-12-13T16:27:43Z 2025-01-01T00:00:00Z

Title: Data-driven modelling of nitrous oxide production in wastewater treatment processes using neural ordinary differential equations Authors: Huang, Xiangjun Abstract: Nitrous oxide (N₂O) emissions from wastewater treatment facilities pose a significant environmental challenge. This study proposes a novel data-driven modelling approach using emerging neural ordinary differential equations (NODE) to capture the complex dynamics of N₂O production in typical activated sludge processes. The author established an experimental simulation platform, based on the BSM1 (benchmark simulation model no.1) plant, with the ASMG1 (activated sludge model for greenhouse gases no.1) mathematical model. This platform generates simulated monitoring data and validates the model. The author then proposes NODE-based models, analogous to traditional biokinetic models, capable of capturing the complex dynamics of N₂O generation through learning from process monitoring data. However, two primary challenges need to be overcome. First, to address inherent stiffness in the underlying dynamics, the author proposes a 𝗽𝗮𝗶𝗿𝗲𝗱 𝗻𝝾𝗿𝗺𝗮𝗹𝗶𝘀𝗮𝘁𝗶𝝾𝗻 𝗺𝗲𝘁𝗵𝝾𝗱 for training stability. Additionally, an 𝗶𝗻𝗰𝗿𝗲𝗺𝗲𝗻𝘁𝗮𝗹 𝘁𝗿𝗮𝗶𝗻𝗶𝗻𝗴 𝘀𝘁𝗿𝗮𝘁𝗲𝗴𝘆 was introduced, starting from a 𝗰𝝾𝗹𝗹𝝾𝗰𝗮𝘁𝗶𝝾𝗻 𝗺𝗲𝘁𝗵𝝾𝗱 to establish a robust foundation, followed by refinement using the 𝗱𝗶𝗿𝗲𝗰𝘁 𝝢𝝤𝗗𝗘 𝗺𝗲𝘁𝗵𝝾𝗱 for enhanced accuracy and efficiency. Second, as monitoring data in wastewater plants typically contain confounding factors from continuous influent variations and operational adjustments, representing 𝗲𝘅𝝾𝗴𝗲𝗻𝝾𝘂𝘀 𝗲𝘅𝗰𝗶𝘁𝗮𝘁𝗶𝝾𝗻𝘀 to the dynamics to be captured, therefore the training procedures was extended to account for these external influences. The approaches were validated on the established platform. The results demonstrate the effectiveness of the NODE-based model in capturing the intricate dynamics of N₂O production in wastewater treatment. This research presents a promising new avenue for data-driven modelling of N₂O in wastewater treatment, with the potential to improve process optimisation and emission control strategies. Description: This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London

2025-01-01T00:00:00Z Osei-Bonsu, Hilary http://bura.brunel.ac.uk/handle/2438/32386 2025-12-13T18:47:11Z 2024-01-01T00:00:00Z

Title: Developing a quality assessment tool for the Ghanaian construction industry Authors: Osei-Bonsu, Hilary Abstract: Globally, there has been an increasing interest and demand in the adoption and implementation of quality management systems in the construction industry, as they provide heightened effectiveness and efficacy for client satisfaction. However, in Ghana, collapses of newly built and on-going building projects have become common place, much of which have been attributed to poor quality works. This situation is engendered by numerous challenges facing the Ghanaian construction industry (GCI), notable of which are lack of appropriate quality standards, resource constraints, and a dynamic regulatory landscape. These underscore the importance of developing a tailored quality management model for the Ghanaian construction setting, which currently has nothing of this sort, as evidenced by the literature. Instigated by this gap, a research study was undertaken to develop a quality management assessment tool (in the form of a maturity model) for improving quality management practices among construction organisations in the GCI. This research employed a mixed research method by triangulating data obtained through various techniques, namely literature review, questionnaire survey and semi-structured interviews. A pilot study was carried out to evaluate the validity of the questionnaires, which contributed to enhancing the research design and its overall quality. Following the development of a conceptual framework that established the key quality management criteria and standard requirements, relevant primary data was gathered from construction organisations of the GCI and analysed using descriptive and inferential statistical analysis, including Independent sample T-Test, Binary logistic regression, Spearman’s correlation and factor analysis. The factor analysis was used to extract components required for the development of the Quality Management Maturity Model (QMMM). Moreso, based on the results and the conceptual model, the structure of the proposed QMMM was designed, which was then validated using feedback acquired from industry experts from the GCI to ascertain the model’s usefulness and suitability. Research findings indicated that the three most significant factors contributing to the successful implementation of QMS are top management commitment, client satisfaction, and the application of legislative instruments. In contrast, the two main challenges affecting the implementation process were found to be inadequate training and education from top management, as well as the belief that engaging in QMS practices is both time-intensive and costly. The model consists of various structural components, maturity levels and scores, a maturity flowchart and an evaluation sheet. QMMM enables identifying areas of improvement for quality management practices in the GCI. A key contribution to knowledge of this research includes the new QMMM developed for the GCI, which is innovative and has the potential of improving quality management practice and standards. Additionally, QMMM can be used by industrial professionals and the wider international community through the adoption of the steps developed for its applicability as indicated in Chapter 6.4.3. Using the QMMM will help organisations to be quality conscious to help engender or bring about a change in the culture, as far as quality management is concerned in order to avoid project collapse. Another contribution lies in the fact that the study findings can foster a more robust academic discourse and encourage a collaborative effort among scholars to investigate the use of maturity models in diverse organisations. Description: This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University London

2024-01-01T00:00:00Z