https://www.um.edu.mt/library/oar/handle/123456789/16067 Thu, 09 Apr 2026 01:20:52 GMT 2026-04-09T01:20:52Z https://www.um.edu.mt/library/oar/handle/123456789/145406 Title: Waste tire rubber recycling for developing a high viscosity-elasticity composite modified asphalt Authors: Zhang, Derun; Tang, Jinbiao; Luan, Dongxing; Xu, Xiong; Borg, Ruben Paul; Lewis, Odette Abstract: Non-biodegradable waste tire rubber poses serious environmental and public health risks. Thus, waste tires recycling has become a critical global issue. In this study, crumb rubber (CR) derived from waste tires was recycled to synthesize a new type of high viscosity-elasticity composite modified asphalt (RSTMA) with styrene-butadiene block copolymer (SBS), and terpene resin (T105). Three major indicators, dynamic viscosity, elastic recovery rate, and softening point difference after segregation were used to determine the optimal formula of RSTMA. Dynamic shear rheometer (DSR) tests were employed to systematically evaluate the rheological properties of RSTMA. The individual contributions of the three modifiers to RSTMA performance improvement were quantified via the Entropy Weight Method (EWM). Experimental results show that compared with base asphalt, the elastic recovery rate of RSTMA with the optimal formulation increases by 71%, while the non-recoverable creep compliance decreases by 98.56%. The segregation index (SI) of this optimal RSTMA reaches 0.87, and its fatigue life at a 35% damage degree exceeds 8000 loading cycles. It was also found that CR significantly increases the viscosity upper limit of RSTMA, CR and T105 jointly elevate its elasticity upper limit, while SBS improves both viscosity and elasticity. Overall, under the synergistic modification of CR-SBS-T105, the performance of RSTMA is significantly enhanced, with CR content reaching up to 15% (by asphalt mass). This study provides a pathway for the high-value, low-carbon recycling of crumb rubber, promoting sustainable development in the solid waste management. Thu, 01 Jan 2026 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/145406 2026-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/145252 Title: Hydration and marine durability of high-ferrite Portland cement-fly ash blends under varied curing temperature Authors: Yang, Huamei; Xu, Kaiqin; Zhang, Shuming; Liao, Yishun; Cui, Jinyang; Tang, Shengwen; Li, Wenwei; Wang, Lei; Barbara, Klemcazk; Bakhtiyarovich Atabaevh, Farrukh; Borg, Ruben Paul Abstract: To meet the demanding conditions of marine environment, cementitious materials of concrete must exhibit low hydration heat, high strength, and superior erosion resistance. This study investigates the hydration and marine durability of high-ferrite Portland cement (HFPC)-fly ash blends under varied curing temperature. Its mineral composition, rich in C4AF and C2S, results in significantly slower and lower early-age heat release – only 86.7% of ordinary Portland cement at 3 days (20°C). Fly ash slightly delays early hydration and reduces heat release of HFPC, but accelerates it after an initial inhibition period (~12 h at 20 °C, ~6 h at 60 °C) through providing hydration product nucleation sites and dilution effects. Incorporating fly ash (40% being optimal) markedly refines pore structure and enhances chloride penetration resistance. HFPC-fly ash blends demonstrate excellent early durability in NaCl and Na2SO4 solutions, offering promising marine applications. Thu, 01 Jan 2026 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/145252 2026-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/144728 Title: Mapping circularity strategies in building sustainability assessment methods Authors: Giarma, Christina; Askar, Rand; Trubina, Nika; Salles, Adriana; Lombardi, Patrizia; Karaca, Ferhat; Mateus, Ricardo; Feizollahbeigi, Bahar; Karanafti, Aikaterina; Moghadam, Sara Torabi; Pineda-Martos, Rocío; Santana Tovar, Daniela; Borg, Ruben Paul; Bragança, Luís Abstract: The widespread adoption of circularity principles in the building sector fuels the need for robust and comprehensive evaluation systems, which could benefit from the approaches and indicators employed in widely accepted building sustainability assessment (BSA) methods. Simultaneously, the effective consideration of circular economy (CE) principles into BSA methods becomes increasingly urgent. An important step towards achieving these targets is the investigation of whether, and to which degree, the existing BSA methods encompass and express circularity principles; this study focuses on this relatively underexplored theme. Specifically, this study investigates the degree of association between five widely used BSA methods and the circularity strategies included in the 10R Framework. The methods examined are BREEAM, DGNB, LEED, Level(s) and SBTool (versions and criteria for new buildings). The examination was conducted at the lowest self-contained and score-attributing level of each method and was undertaken by five expert groups—each assigned one method. A quantitative scale from 0 to 5 was used to assess the strength of the association. The results are analysed in terms of (i) the criteria/thematic areas within each method receiving high/low scores, and (ii) the circularity strategies deduced to be strongly/weakly represented in and across the BSA methods. Common trends and milder differences across these axes are observed. Generally, the associations appear stronger in thematic areas relevant to, among others, resources and lifecycle performance, and weaker regarding parameters linked to user comfort. The R-strategies Reduce, Reuse, Recycle and Rethink emerge as more intensely represented in the examined methods. The study’s results indicate areas for further research and potential methodological enhancement. Thu, 01 Jan 2026 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/144728 2026-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/144596 Title: Understanding the impact of value management in public services : setting up a value management framework academic year 2025 Abstract: The purpose of this research endeavour is to demonstrate how improving organisational performance and decision-making while taking quality and efficiency into account, aside cost, can still result in benefit for the public good. Presently, industry and commerce are experiencing substantial market upheavals owing to fierce competition, volatile markets, uncertain economies, and rapidly evolving technologies. The demands on public sector management in this context are significant, necessitating individuals with technical expertise and the capacity to adapt, innovate, and cooperate successfully as team members. Shifting from models that prioritise only cost-cutting and financial gains, this study advocates for public procurement through a formal, structured, value-based management methodology that involves stakeholders in a value mapping system to guarantee that strategy implementation encompasses projects genuinely required by the country, rather than merely serving as a public relations exercise. This research focused on investigating the use of Value Management (VM) approaches, including Value Engineering (VE), within the local context and, if absent, the potential advantages of creating a Value Management Framework in the local public service sector. Value Management has been greatly used and advocated in the public sector in countries such as the United States and the United Kingdom in various industries and scenarios. However, in small states, especially in Malta, studies regarding Value Management and its potential are few if any, hence it should be understood whether public organizations, including government departments, utilise value management techniques to address challenges such as cost overruns, while taking into account the requirements of customers and consumers of the respective products or services, along with the environmental and social benefits stipulated by public procurement regulations. In order to discover this a mixed-method design using both quantitative and qualitative techniques for data collection in the context of Ambjent Malta was employed - quasiexperimental research design utilising the Value Management Approach and Value Management Workshops methodology. The research utilised a holistic case study design framework, namely Ambjent Malta, to form the intervention of the quasi-experiment method. This methodology employed three stages. During the first phase, baseline data was gathered to assess existing attitudes and use of Value Management techniques, with the objective of outlining the prerequisites for establishing the groundwork for a standardisation model. This was accomplished by a pre-test exploration. The second component of the study design was the intervention stage which included an information session using the same cohort of participants and a final stage post-test exercise to recalibrate the knowledge-sharing activity. The pre-test and post-test data were analysed using both qualitative and quantitative methods. Three cases (multiple units of analysis) were used throughout the whole framework. The analysis of post-test research outcomes encompassed five key pillars: the influence of job designation; the implementation of a systematic tool or framework to guarantee a cost- ii benefit analysis in public contract allocation; holistic value-based adjudication, moving beyond lowest cost criteria; the alignment of the project's original intent and technical solutions with client requests and long-term sustainability goals; and the improvement of communication levels within project teams and stakeholders. Conclusions indicate that by tackling identified problems and using strengths, organisations may improve project results and attain sustainable value via proficient Value Management strategies. The study concludes that Value Management techniques can markedly improve project efficiency, quality, and stakeholder satisfaction. By adopting a systematic Value Management framework, public organisations can attain improved alignment with client specifications and original objectives, decrease expenses, and establish effective communication channels among stakeholders. The research promotes the incorporation of a Value Management framework within the Maltese public service sector across several contributing domains, emphasising its capacity to provide sustainable and efficient project outputs amid fluctuating resource needs. Description: Ph.D.(Melit.) Thu, 01 Jan 2026 00:00:00 GMT https://www.um.edu.mt/library/oar/handle/123456789/144596 2026-01-01T00:00:00Z