Masters Degree Dissertations

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12504/84

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Strength properties of concrete incorporating pine needle and sisal fibre composites
(Kyambogo University(Un Published work, 2025-11) Onyango, Julius
The constitution industry’s reliance on traditional materials has significant unprecedented material, economic, and environmental challenges. The urgent need for sustainable and environmentally friendly building materials has become increasingly important towards abating environmental degradation, Concrete, a widely used construction material, can benefit from the incorporation of natural fibres, which can improve on its mechanical properties whilst reducing its environmental-related footprint. The mine objective of this study was to develop an optimum cost-effective, environmental sustainable pine needle and sisal fibre reinforced concrete composite with enhanced strength properties. More specifically, this study evaluated the physical and mechanical properties, and examined the durability and economic viability including the environmental benefits of pine needle and sisal fibre content on concrete strength and determine the optimal fibre content for achieving desired mechanical properties, and examined the durability and economic viability including the environmental benefits pine needle and sisal fibres reinforced concrete composites. The methodological scope of this study involved an experimental approach, where the strength properties of concrete were evaluated under various fibre dosages(for single fibre type: 0.1%, 0.2%, 0.5%, 1%, 1.5% and 2% and for hybrid (0.1%+0. 1%, 0.2%+0.2%, 1%+0.5%, 0.5%+1% sisal and pine needle fibre respectively. Sigma plot and ANOVA were used in data analysis, presentation and determination of the statistical significance of the perceived variance. The optimal fibre content for compressive strength was found to be 0.1%, while 0.2% by weight was optimal for split tensile strength. The results showed that addition of pine needle and sisal fibres led to reduction in compressive strength by 19.1% and a reduction in flexural strength by 2.5% compared to plain concrete. However, a notable increment of 21.7% was recorded for the split tensile strength. Despite reductions in some strength properties, the design concrete strength class of 20 N/mm2 was still achieved. A cost-benefit analysis revealed that using fibres resulted in a cost savings of Ugandan shillings 55,000 in 0.36m3.The carbon dioxide emissions analysis showed that whereas using steel reinforcement would result in 34.4 kilogram s of C02 emission, the use of fibres would result in emissions of only 5.28 kilograms of C02 emission, this study demonstrated an innovative approach into sustainable material development.
Evaluating the impact of management practices on success of road construction projects in Uganda: a case study of Kabale district local government
(Kyambogo University(Un Published work, 2025-12) Rwehayo, Chrispus Kyarimpa
This study addresses the critical issue of road construction project success within Kabale District Local Government, Uganda, aiming to identify practices, evaluate their impact on project success, and propose a model for improvement. Despite the crucial role that road infrastructure plays in economic development, the region has been plagued by delays, budget overruns, and subpar quality all attributed to inadequate road construction management practices. However, limited empirical studies have examined the combined effect of these management practices within the Ugandan local government context, leaving a significant research gap that this study sought to fill. A descriptive research design was employed, combining qualitative and quantitative approaches through triangulation. Data were collected from 177 respondents and analysed using Relative Importance Index and regression analysis. The study revealed that project planning (RII = 0.80), stakeholder engagement (RII = 0.70), and risk management (RII = 0.60) are of moderate importance, while cost management (RII = 0.50) and project monitoring and evaluation (RII = 0.60) are perceived as less critical. Notably, quality management received the highest importance ranking (RII = 0.90). Regression analysis confirms the substantial influence of these management practices on project success. The model summary shows a strong positive relationship (R = 0.86) between road construction management practices and project success. Approximately 66% of the variance in project success can be explained by these practices. Conclusively, this study underscores the significance of project planning, risk management, stakeholder engagement, cost management, quality management, and project monitoring and evaluation for the success of road construction projects in Kabale District Local Government. The findings provide evidence-based insights that can guide policymakers in formulating targeted interventions, resource allocation strategies, and regulatory frameworks to improve road construction outcomes across Uganda. Therefore, implementing a comprehensive approach based on the identified recommendations is imperative for enhancing road construction project success in Kabale District Local Government, Uganda.
Improving site quality management practices of local bulk construction materials at construction sites in Uganda
(Kyambogo University ( unpublished ), 2025-10) Mugagga, David
This study aimed at enhancing building quality by improving site quality management practices for local bulk construction materials at construction sites in Uganda. Uganda’s construction sites face significant challenges in ensuring the quality of local bulk construction materials, compromising the safety, durability and sustainability of construction projects. A mixed methods approach was used, incorporating surveys, interviews, and document review at sites across all cities. Questionnaires were distributed to 169 site professionals and managers, 56 key stakeholders were interviewed and 56 project files were reviewed. Quantitative data were analysed using SPSS version 20.0, while qualitative data were examined by content analysis. Findings revealed critical gaps in on site quality control practices, with only 30.1% of sites receiving regular inspections from regulatory bodies. Architects (84.3%) and engineers (96.4%) were actively involved in quality management, deficiencies persisted in documentation, issue resolution, and enforcement of standards. Key challenges included client preferences for cheaper materials, delays due to rejected materials and corruption. The study underscores systemic inefficiencies, inconsistent practice, and poor collaboration among stakeholders. It proposes a framework to strengthen site quality management, emphasizing stakeholder collaboration, enhanced regulatory oversight and comprehensive quality management practices. Recommendations include improving oversight, fostering profession collaboration and providing targeted training. Adoption of these measures can significantly improve construction quality, safety and durability in Uganda
Effect of scum on the dewaterability of Faecal sludge from septic tanks
(Kyambogo University(Unpublished work), 2025-06) Wonaira, Sheila
Understanding the properties of Faecal sludge (FS) is critical for over all faecal sludge management. This study investigated the impact of faecal sludge scum (FSS) on the dewaterability of faecal sludge (FS) from septic tanks. Samples of FS and FSS were collected from 35 septic tanks across Kampala. In-situ measurements and data on demographic, environmental, and technological variables were also recorded. Dewaterability rate (CST) was assessed using the capillary suction time method, while the extent of dewaterability (EXT) was determined through centrifugation. FSS depth ranged from none to 50 cm, with a median of 0.05 mm. Most scum was black (61%) and solid (77.4%), while 22.3% was foamy and watery. FSS showed high variability in characteristics with statistically significant differences between FSS and FS observed for Chemical Oxygen Demand (p=0.046), Total Solids (p<0.001), density (p=0.032), Oxygen Reduction Potential (p=0.008), Magnesium (p=0.010), Electrical Conductivity (p=0.025), Moisture Content (p<0.001), and Nitrogen (p=0.003). FSS had higher capillary suction time (CST) values with a mean of 163.5s compared to FS with a mean of 59.5 s, indicating lower dewaterability. Mean cake solids were 12.8% for FSS and 11.4% for FS. In FS samples, TS and OP positively correlated with CST, while MC showed a significant negative correlation (r = –0.532, p = 0.002). Findings showed that the percentage of FSS was positively associated with CST, while total FS volume had a significant negative correlation with CST (r = –0.3245, p = 0.0337). FSS percentage had a weak positive association with cake solids, whereas FS quantity was negatively correlated (r = –0.2142).). Scum dewaterability was found to be strongly influenced by FS characteristics. COD, ORP, fat, total solids (TS), and orthophosphates (OP) were positively associated with CST with increase in these parameters generally leading to longer dewatering times. In conclusion, the amount of FSS in FS has a greater impact on the time it takes for water to be drawn out from the sample i.e. dewaterability rate. Therefore, more scum in the sludge slows down the dewatering process but does not significantly affect the dryness of the resulting cake.
An assessment of the barriers to the adoption of design-build delivery method for road projects in Uganda
(Kyambogo University(Unpublished work), 2025-09) Tayebwa, Kamau Asaph
Timely delivery, budget devotion, construction quality, and stakeholder satisfaction remain the key indicators of successful road infrastructure worldwide. In Uganda, however, the road sector continues to experience recurring cost overruns and schedule slippages, most of which are attributed to the choice of project delivery approach. The Design-Build (DB) method offers an integrated alternative that could potentially mitigate these inefficiencies, yet its adoption in Uganda has remained minimal. This study assessed the level of DB adoption, identified barriers hindering its implementation, and formulated a practical toolkit to facilitate wider adoption in Uganda’s road construction industry to DB adoption in Ugandan road projects and developed a practical toolkit to address them. A mixed-methods design was applied, combining survey questionnaires, key informant interviews, and case study reviews of completed road projects. Data were obtained from 113 respondents, including contractors, consultants, design specialists, and Client Project Management Teams. SPSS version 25.0 was utilised to analyse quantitative data, whereas qualitative data were examined through content analysis. Findings revealed that DB adoption in Uganda’s road sector stands at only 10%. The main identified barriers include lengthy documentation processes, delayed payments to contractors, weak stakeholder communication, and limited participation of local firms. The developed toolkit emphasises enablers such as digitalised document management, transparent payment systems, and strengthened stakeholder engagement frameworks. Adoption of these measures has the potential to improve efficiency, can improve project efficiency, reduce financial and time overruns, and improve stakeholder confidence. Ultimately, the toolkit offers a pathway to increasing DB adoption in Uganda and provides lessons applicable to other developing economies.
Stabilisation of expansive soils using synthetic hair fibre
(Kyambogo University(Unpublished work), 2025-11) Okello, Milton
Expansive clay soils pose significant challenges to civil engineering infrastructure due to their high shrink swell behaviour, which often leads to structural instability, cracking, and costly repairs. Traditional stabilization methods such as cement and lime treatment, while effective in some contexts, are frequently expensive, degrade the environmental, or ineffective under unsuitable geochemical conditions. Other stabilisation methods have also been employed, such as natural and synthetic fiber reinforcements like coir, jute, and geotextiles are widely used. Other emerging methods include enzyme treatment, geopolymers, and electrokinetic stabilisation for improved performance. The improper disposal of synthetic hair fibre a waste product from salons possesses an increasing challenge to the environment, with 9,000 to 12,000 tonnes of waste generated in Uganda alone annually by the beauty industry. This study investigated the use of synthetic hair fibres as a sustainable and low-cost stabilising material for expansive clay soils. Physical and mechanical tests, alongside crack analysis using digital image processing and MATLAB R2025a software were conducted. Expansive clay samples were stabilised with synthetic hair fibres at a fixed amount of 0.5% by dry weight, with fibre lengths ranging from 2 cm to 16 cm. Key tests, including Unconfined Compressive Strength (UCS), California Bearing Ratio (CBR), and swelling potential, were conducted. The results showed a 56% increase in UCS, a 300% increase in CBR, and a notable reduction in swelling, particularly with fibre lengths between 6 and 8 cm. The research shows that synthetic hair fibre is a viable alternative for stabilizing expansive clay soils, offering both geotechnical benefits and a sustainable approach to managing synthetic hair waste.
Implementation of total quality management in road construction projects in Uganda – a client’s perspective
(Kyambogo University(Unpublished work), 2025-10) Obim, Benard Harold
There are many challenges faced by the construction industry today. Project managers and decision makers are faced with challenges comprising time overruns, cost overruns, and poor workmanship, among others. This has prompted important project implementers to think about total quality management (TQM) as an important tool for project management in order to attain high-quality results. This study sought to evaluate the implementation of Total Quality Management (TQM) in Ugandan construction projects, with a particular focus on the road sector from the standpoint of the client. This required a review of the literature on perception, current practices, and TQM implementation tools and techniques. A mixed method approach and a case study strategy was used and data were triangulated through various methods such as literature review, interviews, and questionnaire survey. Data were collected from two entities that are common clients in the road construction industry in Uganda (i.e., Uganda National Roads Authority-Moroto station and the District Local Government-Moroto). Descriptive statistical analysis coupled with content analysis methods were used as a means of data analysis. The study findings revealed that 92% perceived TQM as: involving everyone in the organization, teamwork, and participation for achievement of continuous improvement culture and customer satisfaction. 53.4% of the study further revealed that not all the steps for TQM implementation were being practiced. The findings of the study also indicated that there was moderate use of TQM tools and techniques at 58.4% and 51.5% respectively. Finally, the outcome of this research led to establishment of a tool that can be adopted to improve TQM implementation in the road construction industry in Uganda. There is need to adhere to aspects like continuous improvement, process approach, and measuring performance to better TQM implementation. The key elements of the tool developed were organizational commitment, employee involvement, training and development, and work environment and organizational culture. These findings are significant in the implementation of TQM and motivate other researchers to investigate more in this area of study.
The effect of mango fibres on structural properties of concrete
(Kyambogo University(Unpublished work), 2025-11) Nagemi, Peter
This study investigates the effect of mango fibres on the structural properties of concrete, focusing on mechanical performance, durability, and crack behaviour. Concrete’s inherent brittleness limits its resistance to crack initiation and propagation, yet natural fibres have been identified as effective reinforcements. The study evaluated mango fibre properties, the performance of plain and mango fibre-reinforced concrete (MFRC), and the mechanical behaviour of MFRC using both experimental testing and finite element modelling. A total of 351 C25 concrete samples were prepared, including 120 plain concrete specimens and 231 MFRC specimens with fibre contents of 0.1%, 0.25%, 1.0%, and 1.5% and fibre lengths of 30-, 40-, and 50-mm. Samples were tested at 7 and 28 days in accordance with ASTM, ACI, BS, and EN standards for fibre characterization, mixing, specimen preparation, curing, workability, mechanical testing, drying shrinkage, and water absorption. Experimental controls included use of calibrated equipment, standardized mixing and curing procedures, and consistent testing conditions to ensure reliability of results. Results showed that mango fibres possessed a tensile strength of 616.96 MPa. Incorporation of fibres increased compressive, flexural, and split tensile strengths by 13.6%, 49.8%, and 16.8%, respectively, with optimal performance observed at 1.0% fibre content and 40 mm length. Mango fibres reduced drying shrinkage by up to 100%, thereby limiting crack development, although water absorption increased by up to 22.4% at higher fibre contents. ABAQUS simulations of a representative volume element further demonstrated improved crack resistance and delayed failure in MFRC compared to plain concrete. This study addresses the limited research on the structural use of mango fibres in concrete, particularly regarding their influence on strength, shrinkage, and crack behaviour. The integrated experimental and numerical results provide mechanistic insight into fibre bridging and post-cracking stiffness. These findings demonstrate the practical potential of MFRC for improved crack control, enhanced structural resilience, and sustainable utilization of agricultural waste within Uganda’s construction sector.
Impact of pre-contract cost planning methods on the cost of building projects in Uganda
(Kyambogo University(Unpublished work), 2025-09) Mwesigye Chrispus
Uganda's construction industry continues to face persistent cost overruns primarily due to inadequate pre-contract cost planning, a challenge highlighted in both local and regional studies. This has slowed the industry’s growth and hindered achievement of housing development goals under Uganda’s Vision 2040. The main objective of this study was to investigate the impact of pre-contract cost planning methods on the cost of building projects in Uganda. Specifically, the study identified commonly applied cost planning methods, examined their effectiveness in minimizing overruns, and proposed a methodological framework for cost optimization. A cross-sectional research design was adopted, and data were collected from 180 practicing Architects and Quantity Surveyors in Kampala, Uganda’s capital city. Data were analyzed using the Statistical Package for Social Sciences (SPSS version 23) as the primary analysis tool, while Regression Analysis (RA) and the Relative Importance Index (RII) were employed as statistical methods. The findings revealed that unit cost planning, elemental cost planning and cost-benefit analysis are the most widely used methods. Others such as least cost planning, life cycle cost planning, comparative cost planning, and functional cost planning are moderately applied, while the superficial area cost planning method is rarely employed. Results further indicated that methods relying on historical data (unit, elemental, and comparative) provide more reliable cost estimates with overruns of 2–14%. In contrast, least cost, life cycle, cost-benefit and functional planning indicated overruns of 15–20%, while superficial area planning exhibited the highest overruns of 20–30%. The study developed a methodology integrating appropriate methods with practical measures to enhance cost control. It concluded that selecting suitable pre-contract cost planning methods is critical to budgetary success and recommends stronger professional standards, industry-wide guidelines, awareness programs, and continuous professional development.
Assessment of quality of government funded construction works in local governments in Uganda : a case study of Buvuma district local government
(Kyambogo University(Unpublished work), 2024-12) Mayega, Jasper
The study sought to assess the causes of the rampant non-compliance to quality standards of construction works in Local Governments (LGs) of Uganda. According to the Auditor General’s report of 2021, 80% of works in LGs under Uganda Intergovernmental Fiscal Transfers Program (UgIFT) constructions had defects such as honey combing, delayed completion and observed poor mixes. The study employed a cross-sectional research design that included the use of both quantitative and qualitative data collection approaches. Data were collected using stratified sampling and analyzed using Statistical Package for Social Sciences (SPSS) software version 16. Analysis of the findings based on both regression and Pearson correlation coefficient showed that, generally, the respondents agreed that funding had an impact on quality with an average mean value of 3.73 and a correlation coefficient of 0.520 indicating a strong positive relationship between funding factors and the quality of Government Funded Construction Projects (GFCPs) in Buvuma District Local Government (BDLG). The regression analysis indicated that the adjusted R-Square value of 0.30 was obtained implying that 30% of the variance in the quality of GFCPs is influenced by funding factors. The respondents were generally not sure whether personnel factors affected quality GFCPs with an average mean value of 2.887 and a correlation coefficient of 0.483 indicating a moderate positive relationship between personnel factors and quality of GFCPs in BDLG. However, the regression analysis indicated that the adjusted R-Square value of 0.93 was obtained implying that 93% of the variance in the quality of GFCPs is influenced by personnel factors. Procurement factors affecting quality of GFCPs had an average mean = 2.60 indicating that the respondents were generally not sure whether procurement factors affected quality of GFCPs with a correlation coefficient of 0.462 indicating a moderate relationship between procurement factors and quality of GFCPs. The regression analysis indicated that the adjusted R-Square value of 0.866 was obtained implying that 86.6% of the variance in the quality of GFCPs is influenced by the procurement factors. In conclusion, the impact of funding, personnel factors and procurement factors have a significant impact on quality of GFCPs in LGs. Therefore, the study recommended that BDLG and DLGs should address the issues on Funding, personnel and improving the procurement systems for better quality of GFCPs in LGs.
Compressive strength and cost-effectiveness of confined waste plastic bottle brick masonry walls
(Kyambogo University(Unpublished work), 2025-11) Masaba, Emmison Eric
Uganda faces persistent challenges of housing shortages, high construction costs, and environmental degradation resulting from unsustainable resource extraction and poor waste management. Large quantities of plastic bottles and saw dust waste remain underutilized, yet their potential as construction materials has not been sufficiently explored. This study investigated the compressive strength and cost-effectiveness of Plastic Bottle Brick (PBB) masonry walls as a sustainable alternative to conventional concrete block walls in Mbale City, Uganda. The research addressed the gap in empirical data on the structural performance of confined PBB walls with varying filler materials (uncompressed air, saw dust and pit sand). The pit sand PBB walls attained a compressive strength of 0.6 ± 0.02 MPa, which was comparable to that of the hollow concrete block walls (0.6 ± 0.06 MPa). The sawdust and air PBB walls, however, recorded lower mean strengths of 0.3 ± 0.05 MPa and 0.3 ± 0.03 MPa, respectively, which were well below the solid concrete block walls (0.8 ± 0.03 MPa). All PBB variants exhibited greater ductility, with failure strains of 1.8–2.0%, compared to 1.0–1.2% in concrete block walls. Although the PBB blocks did not meet the minimum compressive strength requirements of DS/EN 1996-1-1 DK NA:2019 for load-bearing masonry units, pit sand PBB blocks demonstrated adequate performance for small-scale or low-rise applications, while the air and sawdust filled variants were suitable for non-load-bearing infill walls. A cost-benefit analysis, based on materials, labour, time utilisation, and carbon emission costs, revealed that air PBB blocks were the most economical at UGX 11,694, followed by pit sand filled units, while solid concrete block walls were the least economical at UGX 28,759. The sawdust filled units were relatively more expensive (UGX 27,634) due to higher carbon emission costs. The study also developed a practical production method that enables PBB unit casting at a rate only 17% slower than that of conventional blocks, demonstrating commercial viability and compatibility with existing formwork systems.
An investigation into the barriers and drivers of sustainable construction in Uganda
(Kyambogo University(Unpublished work), 2025-07) Lugya, Duncan
This study investigated the barriers and drivers to Sustainable Construction (SC) in Uganda, with the aim of developing a framework to promote its wider adoption. The construction industry has immensely contributed to the development of the economy. However, the impact to the environment arising from construction activities is significant. Despite increasing awareness among construction professionals, limited empirical data exists on the specific barriers and enablers of SC adoption in Uganda necessitating this investigation. Questionnaires were administered to 173 construction professionals (civil engineers, architects, surveyors, and environmentalists) primarily based in Kampala and Wakiso. The research adopted both quantitative and qualitative research approaches. The data collected were analyzed quantitatively using SPSS and variables with Relative Importance Index (RII) greater than 0.8 were considered critical barriers and drivers. The findings revealed several barriers to SC, including limited market demand (RII: 0.90), limited public awareness about SC (RII: 0.86) among others. In terms of drivers, factors, such as reduction in natural resource use (RII: 0.84) and providing SC measurement (RII: 0.83) were found to motivate the adoption of SC. The study further assessed the level of awareness and interpretation of SC, highlighting the need for increased education on the benefits of SC. Based on the results, a framework was proposed, emphasizing the importance of government incentives and collaboration with stakeholders. The study provides valuable insights for promoting the wider adoption of SC in Uganda and lays the groundwork for future research and policy development.
Impact of professional contracts management practices on timely completion of building construction projects in Uganda
(Kyambogo University(Unpublished work), 2025-05) Latim, Genard
Building construction project completion delays are a serious problem in Uganda's construction sector and have long been significant on a worldwide scale. The price 91% of construction projects are finished late, according to Uganda. This study investigated how professional contract management techniques affect Ugandan building construction projects' timely completion. Simple random selection was used to get 82 responders from purposively chosen projects. A questionnaire was used as the data gathering instrument. Both descriptive and inferential statistics were used to assess quantitative data. The overall mean answer was 4.0 for contractor prequalification procedures and 4.6 for contractor monitoring procedures. The results of the study show that contractor prequalification procedures have a considerable impact on the timely completion of building construction projects, with a chi-square value of 101.246 and a p-value of 0.001. This also held true for contractor supervision procedures, with a p-value of 0.000 and a chi-square value of 151.046. To improve the timely completion of building construction projects, a model was created. The results of the study show that contractor pre-qualification and monitoring procedures have a favorable effect on building construction projects' timely completion. According to the report, pre-qualification procedures for contractors should be founded on their financial soundness, management team, and level of experience. Effective coordination, quality control, resolving environmental issues, and reducing site risks should be the main goals of contractor supervision procedures. This will minimize interruptions and ensure that the project is completed on schedule.
Incorporating impact of covid-19 into routine road maintenance by local government : case study of the greater Nebbi
(Kyambogo University(Unpublished work), 2025-06) Kubi, James
In projects, a contingency cost is included to account for potential variation that may arise during the construction phase. These variations may result from factors such as unforeseen conditions, design errors, or changes in scope. Contingency costs are normally allocated 10% to 15% of the project cost. Despite the provision of contingency costs, there are eventualities termed as "force majeure" that can occur during construction that exceed the contingency cost. Such eventualities include earthquake, wars and epidemics. The emergence of the COVID-19 pandemic is an example of such unforeseen circumstances. Its impact on the construction industry, particularly with regard to the increase in material costs, had not been encountered before. The main objective of this study was to incorporate impact of COVID-19 into routine road maintenance framework for District Local Governments in Greater Nebbi. To achieve this main objective, the study focused on identifying road characteristics which affect maintenance cost per kilometre in the Greater Nebbi, established the impact in change of unit rate of road maintenance on cost per kilometre before, during and after COVID-19 pandemic, statistically tested the mean difference in the unit rate before and after the COVID-19 pandemic and developed framework for road maintenance that incorporates the impact of COVID-19. The study adopted a case study approach. A total of five (5) roads were selected from the greater Nebbi of which one was sampled from Jonam-Pakwach District, two from Padyere-Nebbi District, and two from Okoro-Zombo District. The field data collected were analysed using Microsoft Excel, because it had data analysis package for analysing research data. The analysed relied on both descriptive and inferential statistics. Field data were tested using t-Test: Paired Two Sample for Means to test statistical significant difference between mean. The research identified several factors that influence the maintenance cost per kilometre of roads in the Greater Nebbi, including terrain, climatic conditions during maintenance, road class and road condition, level of service, soil type, drainage condition and road surface type. The study concluded that road maintenance projects in the area underwent substantial changes in the unit rate of maintenance costs per kilometre before, during and after the COVID-19 pandemic. The research recommends that future investigations should develop a predictive model that account for the effects of global disruptions (such as pandemics) on supply chains and inflation could help road maintenance authorities anticipate cost changes. These models could use historical data from COVID-19 and previous economic shocks to forecast material and labour price trends and guide proactive budgeting strategies.
Investigation into the collapse potential of subbase material in the tropics region case study: the greater Kampala metropolitan area
(Kyambogo University (Unpublised work), 2025-10) Mbwali, Mary Christine
Road construction in tropical regions such as the Greater Kampala Metropolitan Area (GKMA) faces persistent challenges from hydro-consolidation, which can weaken subbase layers and compromise pavement durability. This study aimed to evaluate the collapse potential of subbase materials in the GKMA and recommend measures to enhance their performance for sustainable road infrastructure. Representative samples were subjected to physical-mechanical tests [Maximum Dry Density (MDD), California Bearing Ratio (CBR), Atterberg limits and Particle Size Distribution (PSD)], chemical analysis (chloride, sulphate, and pH content) and conventional oedometer testing under wetting conditions to determine hydro-consolidation behavior. The oedometer test results showed that subbase soils at Natural Moisture Content (NMC) exhibited medium to high collapse potential, exceeding 3% under higher applied stresses, indicating susceptibility to hydro-consolidation when saturated under load. However, samples compacted at Optimum Moisture Content (OMC) displayed collapse potentials below 2%, demonstrating that proper compaction significantly reduces collapse risk. These results confirm that collapse potential is stress-dependent and highlight the importance of achieving optimum moisture content during construction to enhance subbase stability. Based on the findings, the study recommends further evaluation of subbase materials under higher applied stresses to better simulate traffic conditions, expanding investigations beyond the GKMA to capture broader geological variability, and examining other road failure mechanisms such as drainage efficiency and construction practices. Overall, this research provides a practical evidence base on hydro-consolidation behavior of subbase materials, enabling engineers and policymakers in Uganda to design, construct, and maintain pavements that are durable, resilient, and cost-effective in tropical environments.
Effects of land use patterns on microplastic concentration and distribution in river Rwizi, Mbarara district
(Kyambogo University (Unpublished work), 2025-09) Kemigisha, Mariam
Microplastic pollution has become a pressing global environmental challenge, threatening aquatic ecosystems. In Mbarara District, growing industrial development, agricultural and urban activities, and poor waste management practices, contribute to the release of microplastics into River Rwizi. These plastic particles, typically less than 5 mm in size, largely originate from degradation of discarded plastics and can enter the food web through ingestion, biomagnification, and bioaccumulation. This research aimed to study the concentration, characteristics (colour, size, shape and polymer type), and distribution of microplastics in River Rwizi, with emphasis on the role of surrounding land use activities. Samples of water and sediments were obtained from nine purposively selected sites based on predominant land-use types, representing agricultural (upstream), urban/built up (midstream), and forested (downstream) land use types. Sample preparation involved sieving, drying, density separation, and filtration. Microplastics were then identified using stereomicroscopy and analyzed for polymer composition using FTIR spectroscopy. Land use mapping was conducted using Sentinel-2 satellite and supervised classification in ArcGIS, followed by ground truthing with a handheld GPS. Data analysis used IBM SPSS Version 29.0, while Pearson correlation and regression modeling were used to assess the influence of land use on microplastic concentrations. Results revealed that all samples collected contained microplastics. Concentrations in water samples ranged from 0.117 to 0.883 particles per liter, while sediments contained 0.012 to 0.132 particles/Kg. Built up and agricultural areas recorded higher concentrations of microplastics than forested areas. Fibers were the most common shape, most prevalent in built up land use, while blue particles were the most frequent colour. Most particles fell within 0.5–1.0 mm size range, suggesting they originated from larger plastic debris. Polyethylene and Polypropylene emerged as the dominant polymers identified across all land use categories. These findings demonstrate that land use patterns strongly influence microplastic pollution in River Rwizi. The study recommends improved waste management practices, promotion of alternatives to single-use plastic packaging materials, strengthening community awareness and policy interventions to reduce plastic pollution, and strengthening plastic recycling initiatives.
Investigating the effect of activating agents on removal of lead ions from water using activated rice husk carbon
(Kyambogo University (Unpublished work), 2025-11) Kamukama, Ivan
Activated carbon is very important in treating polluted water. Carbon can be produced from locally sourced agricultural waste. This helps in reducing the amount of agricultural waste in the environment. This study investigated the effect of activating agents on removal of Pb2+ ions from water using activated rice husk carbon. Chemical activation method was used where rice husk carbon (RHC) was impregnated with chemical activating agents before heating. Three distinct activating agents were used namely; potassium hydroxide (KOH), phosphoric acid (H3PO4) and zinc chloride (ZnCl2). RHC activated with a 7.5% concentration of KOH using 5g/L adsorbent showed 99.9% efficiency in removing lead ions, almost achieving complete elimination. RHC activated with 1% ZnCl2 while using 20g/L adsorbent demonstrated 98.5% removal efficiency, just 1.36% less than the RHC activated with 7.5% KOH. RHC activated with 2.5% H3PO4 while using 20g/L adsorbent showed 84.1% removal efficiency, making it least effective among the three agents tested at their optimal levels. Despite achieving removal efficiencies of 98.5% and 84.1%, RHC activated with ZnCl2 and H3PO4, respectively, required a higher adsorbent dosage (20 g/L), indicating lower effectiveness compared to KOH-activated carbon. KOH activation created a highly porous and rough surface with a well-developed network of interconnected pores. On the other hand, ZnCl2 and H3PO4 resulted in less aggressive pore formation and different surface morphologies, leading to less interconnected and less rough porous structures. It was observed that the uptake of Pb²⁺ ions by activated RHC aligns more accurately with the Langmuir isotherm model.
Performance of green silver Nano particles using Psidium guajava leaves for adsorption of lead from water
(Kyambogo University (Unpublished work), 2025-11) Kihumuro, Josephine
This research examined the effectiveness of green silver nanoparticles (AgNPs) produced from aqueous extracts of three varieties of Psidium guajava leaves (white, orange, and red fruit mesocarp) in adsorbing lead (Pb²⁺) ions from contaminated water. The study assessed antioxidant activity, characterized nanoparticles, and analysed adsorption performance across different dosages (0.1–1.0 g) and contact durations (5–25 minutes). White guava extract demonstrated the highest antioxidant activity, achieving 83.85% 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging. Additionally, AgNPs from all varieties displayed spherical morphology as observed through Scanning Electron Microscope (SEM), with white guava derived AgNPs exhibiting uniform distribution of the NPs in the matrix. Adsorption experiments demonstrated a maximum Pb²⁺ removal efficiency of 83.16% at a dosage of 0.6 g and a contact time of 20 minutes for white guava AgNPs, while orange and red had 81.53 and 78.35 % respectively. Clay filters infused with AgNPs demonstrated a Pb²⁺ removal efficiency of 99.59% (composite filter), surpassing the performance of unmodified clay, which achieved 91.62% removal. The research findings indicate that white guava derived from AgNPs possess significant antioxidant capacity and adsorption affinity, presenting a viable approach for heavy metal remediation, with prospective applications in point-ofuse water treatment technologies. It is recommended to optimise the ratios of hybrid nanoparticles and conduct field validation in real-world conditions.
Investigation of the impact of ancillary roadworks on road safety in Uganda : a case of Kampala – Jinja road
(Kyambogo University (Unpublished work), 2025-08) Ssebuliba, Isaac
The 1949 Geneva Convention on road traffic put in place a unified approach to promote road safety and development of international road traffic. This coupled with the Global Sustainable Development Goals (SDGs), the United Nations Agenda 2030, African Union Agenda 2063, have had a great impact on ensuring safety on the world’s roads. However, road safety for Low Developed Countries like Uganda is still a challenge, despite the adoption of the country’s Vision 2040 and the launching of the National Road Safety Action Plan (2021-2026). A study to investigate the impact of ancillary roadworks on road safety in Uganda, a case of Kampala – Jinja road was conducted, with an aim of establishing a relationship between Road Signs, Road Marking, Guard Rails, Humped and Rumble Strips, Road Lights, Walkways and Service lanes with Road Safety. This study therefore used correlation research design supported by cross sectional survey design with qualitative and quantitative approaches for interviews and questionnaires respectively. Primary data were collected from 30 field traffic officers, 19 drivers, 03 Officers in Charge (OC) traffic police stations, 36 road engineers, 01 Inspectorate of Vehicles (IOV), 01 Regional Traffic Officer (RTO) and 12 market leaders, all within the study area, whereas secondary data were extracted from accident data from Uganda Police. Questionnaire data were analysed with SPSS version 24.0. The interview data was analysed using content analysis. Results indicated that 61% of installed informatory signs, 53% of the installed regulatory signs and 40% of installed warning signs still existed on the road and others were missing which exposes road users to risk of accidents. Guardrails were still existing but some had rusted and others covered with grown grass, making them not visible to road users. Majority of road accidents were serious, accounting for 159 (47.8%) cases, followed by 130 fatalities (39.2%) and 43 (13.0%) minor accidents for the period from 2017 to 2022. A relationship between the independent variables and dependent variable, (βeta) of the study was made. Results of correlation analysis indicated that all ancillary road works were significant except road signs, yet regression results indicated that road marking (βeta = 0.207, p-value = 0.029), guardrails (βeta = 0.186, p-value = 0.045) and humps and rumbles strips (βeta = 0.260, p-value = 0.028) have a positive significant effect on the road safety unlike road lights, road signs, walkways and service lanes which were insignificant. Field inspections together with traffic police officers within the study area, identified 14 blackspots with high annual frequency of accident occurrence in the section between Lugazi and Kitigoma village. It is concluded that road marking, guardrails and humps and rumbles strips significantly affect road safety. The study recommended that construction of humps and rumble strips of moderate size, visible road marking with higher retro reflectivity and strong guardrails, can help in ensuring road safety with support of enforcementof traffic laws of Uganda.
Investigating the effect of occupational safety and health measures on the cost of construction works in Uganda : a case Nakawa division, Uganda
(Kyambogo University (Unpublished work), 2025-10) Eluru, John
The Occupational Safety and Health Act of 2006 was enacted by the Government of Uganda as one of the strategies taken to enhance the welfare and health of workers on construction sites. It was important to investigate if the occupational safety and health (OSH) measures had a good effect. Design, progressive and incident reports were reviewed before considering over 500 respondents from 24 bungalow construction sites across Nakawa Division. Questionnaires and interview guides were distributed to site workers. Among those considered, only 216 valid questionnaires and interview guides from 10 construction sites were returned from respondents that were randomly considered from class category A-3, A-4 and A-5 of indigenous construction companies. Frequency and percentage tables were used to analyse the data. The findings show that the cost associated with OSH measures recorded the Safety Investment Ratio (SIR) of 0.71%. The cost incurred due to construction accidents recorded the Accident Loss Ratio (ALR) of 0.47%. The overall effect of OSH measures was 1.18%, which was considerably low. This result indicates that, despite the fact that 77% of construction workers experience accidents, indigenous construction companies do not make significant investments in occupational safety and health. Adherence to OSH was difficult with negligence, manual lifting and shortage of personal protective equipment (PPE) as the major causes. There is need to invest more on OSH measures in order to minimize the costs implications of sickness and death associated with accidents. It was recommended that the effect of OSH measures needs to be investigated on sites with fatal injuries. Fire protection and chemical storage too need to be investigated in Uganda. The study was limited to only Nakawa Division. Research on the effect of occupational safety and health measures on cost needs to also be conducted in other Divisions in Kampala and cities within Uganda. More studies should be conducted on innovative technology on safety and health measures at construction sites in Uganda. These findings are significant in the formulation of safety and health regulations and in the application of occupational safety and health measures.

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