https://www.um.edu.mt/library/oar/handle/123456789/89465 2026-04-23T09:43:21Z 2026-04-23T09:43:21Z https://www.um.edu.mt/library/oar/handle/123456789/89960 2022-02-28T15:50:42Z 2021-01-01T00:00:00Z

Title: Textile reinforced concrete exposed to aggressive environments Abstract: The most common reinforcement used in concrete is the conventional steel reinforcement. Although this composite can reach high strengths it can lead to concrete degradation as a result of steel corrosion in certain circumstances. Textile reinforcement is a new- innovative material which has different properties from steel and is currently being introduced to the construction industry. Yet, the longer term durability performance of this new material is not yet known. This study deals with the mechanical properties of textile reinforced concrete (TRC) and its durability performance. The program was focused to determine the difference between textile reinforced concrete samples left to cure under ideal conditions and textile reinforced concrete exposed to accelerated ageing in determining the effects of aggressive environments acting on TRC. Carbon-fibre textile reinforcement and high-performance concrete with a compressive strength of 100MPa were used. Samples were exposed to different temperatures and were cured alkaline solutions in water-tanks under controlled temperature. Tensile testing was carried out on samples having a cross-section of 15x50mm and a 300mm total length. The research further addressed the performance of pre and fresh impregnation of the textile in resin embedded in concrete. In addition, the test samples were also tested in ambient and high temperature conditions during the tensile test itself according to the exposure selected. Both variations in temperature and different alkalinity solution left affects on the resulting yield strengths. The difference between results according to different combinations increased as the Peak strengths was reached. The peak strength reached from the specimen cured initially in a high pH14 solution was 1.2 times higher than the peak strength obtained from the reference sample. As the temperature was increased from 20 to 60 degrees Celsius a resulting decrease of approximately 35% was obtained. The largest reduction in peak strength was detected from the specimen exposed to both elevated temperature and a high alkaline solution. The detected reduction in ultimate tensile strength amounted to approximately 40%, when compared to the reference sample. Description: M.Eng.(Melit.)

2021-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/89865 2022-02-25T12:53:28Z 2021-01-01T00:00:00Z

Title: Mitigating risk in the building and construction sector : developing risk management indicators for Malta Abstract: Construction projects operate in a challenging environment and proactively seek to counter problems as they arise due to the complex nature of processes and operational techniques. Recent updates to the local regulatory framework have recognised the need to upgrade the trade, impacting a wide range of stakeholders including (but not limited to) architects, contractors, site technical officers, civil engineers, geotechnical engineers and tradesmen. As the industry operates in a high-risk environment, it is considered critical to examine the level of risk that projects face. In this regard, risk mitigation would safeguard other project indicators such as quality, time and cost by triggering red flags when processes do not meet the required standards and commitments. This research seeks to explore indicators as triggers for risk mitigation within the local scene and a risk management route undertaken for a number of projects, if undertaken at all. The methodology used is a qualitative technique for extracting thematic elements followed by a thematic analysis, to serve as a baseline for the identification of indicators. The research presents a set of recommendations for strengthening and implementing risk management pathways to ensure that risk management processes are considered and properly followed. Description: M.Eng.(Melit.)

2021-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/89795 2022-02-23T15:39:50Z 2021-01-01T00:00:00Z

Title: Mechanical anchor strength in reconstituted stone Abstract: Sustainability is to be addressed as a fundamental pillar for a higher quality of life through the preservation of natural resources. Nowadays, growth and environmental protection are viewed as complementary rather than opposing factors. Rather than viewing the environment and sustainability as a barrier to economic progress, they are seen as the main drivers that may contribute to the development of the use of new materials such as that of the Reconstituted Stone. The study begins by examining several types of mechanical anchors, with a particular focus on undercut mechanical anchor fixing in stone specimens. The major goal of this study is to determine the tensile strength of an undercut fixing in an engineered stone, referred to as Reconstituted Stone when it is subjected to pull-out loading. Tensile strength is one of the most important mechanical qualities of construction materials in the built environment. The results of the pull-out loading tests are compared to those of soft stone such as Globigerina Limestone and those of hard stone such as Coralline Limestone. The correlation is based on additional results from the compression strength and flexural strength tests. This eventually obtains clearer knowledge of where Reconstituted Stone fits in the spectrum of materials. In addition to this, this research study compares the types of failure modes acquired from the same tests by the different types of stone. This investigation into the mechanical properties of the Reconstituted Stone provides a clearer picture to use it as a replacement for stone cladding panels on our façades. According to the findings of this study, the pull-out failure is proportional to the product of the material's compressive strength and the contact area of the undercut. Description: M.Eng.(Melit.)

2021-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/89794 2022-02-23T15:39:17Z 2021-01-01T00:00:00Z

Title: Application of downhole seismic refraction test to the rocks and sediments of the Maltese islands Abstract: This study focuses on conducting the downhole seismic refraction test on different stratigraphic sequences within the geology of the Maltese Islands, thus allowing for analysis and comparison of the ground’s geomechanical properties. Typically, two boreholes were drilled at each location to conduct the downhole seismic test, usually down to a vertical depth of 30 metres. Two perpendicular seismic wave energy sources were used to determine the compression (P-wave) and shear (S-wave) velocities, Vp and Vs respectively, of the different ground strata. On doing so, the density of the ground was determined from the P- wave velocities and the fundamental elastic moduli were determined from S-wave velocities. Through this, the different velocity profiles, and elastic moduli of the ground materials from different areas within Malta were derived, analysed, and compared. Velocity profiles were obtained for Quaternary deposits, weak Upper Coralline Limestone, intact Upper Coralline Limestone, Blue Clay, weak Lower Globigerina Limestone and intact Lower Globigerina Limestone, allowing these to be compared. These different stratigraphic layers, of widely varying rigidity, had their corresponding average shear modulus varying accordingly, having the lowest Gmax for quaternary deposits at 0.20GPa and the highest Gmax for Lower Globigerina Limestone at 3.30GPa. Determining the shear modulus, Gmax, at small strain is of fundamental importance to the prediction of the deformation behaviour of ground materials. The stiffness parameters of the ground are fundamental in estimating the effect of foundation loading and excavation. This study attempts to provide preliminary data related to the different stiffness moduli of the various categories of ground materials across the Maltese Islands, thus providing guidance to the engineer undertaking such analyses. Description: M.Eng.(Melit.)

2021-01-01T00:00:00Z