DEPARTMENT OF CIVIL ENGINEERING

This paper documents an investigation of the impact of climate change on global and regional water resources in Nigeria using Egor local government area as case study. The aim of this study is to comprehensively examine the impacts of climate change on water demand in Nigeria, and to understand specific challenges that climatic changes cause to our water as well as recommending adaptive strategies for sustainable water resource management. Primary climatic data (Rainfall and Temperature) for Nigeria were collected from the Nigeria Meteorological Station, Lagos between 1960 and 2002. Changes in Lake Chad waters were collected from the National Centre for Remote Sensing (NCRS), Jos. World temperature and water resources data were collected from different sources. The data were analysed using percentages and time series among others. The result shows that the atmospheric concentration of most greenhouse gases (GHGs) is increasing and this has resulted to changing global climate with increasing temperature. The rise in global average temperatures since 1860 now exceeds 0.6℃. The effect of the Green House Gas concentration on global warming as at 2100 is estimated by three scenarios to be 1.5℃ (Low), 2.5℃ (Middle) and 4.5℃ (High). In Nigeria, while rainfall has decreased by 92 mm, temperature increased by 0.8℃ since 1960. This has led to increasing evapotranspiration and water stress resulting in the drying up of rivers and lakes. For example, Lake Chad has reduced in size from 22902 km2 in 1963 to 16884 km2 in 1972 and 304 km2 in 2000. While climate change will make some countries to experience increase in water resources, majority will face serious water stress. Based on projection, by the 2080s, most countries in the Middle East, around the Mediterranean, part of Europe, North and South Africa will face acute water stress while Southern and Eastern Asia, U.S.A. and Alaska will experience reduction in water stress. Some recommendations were made to reverse this ugly situation.

This research investigates the geotechnical implications of water table fluctuations on the stability of near-surface soil strata by evaluating the relationship between fundamental soil index properties and measured shear strength parameters. Laboratory testing on soil samples recovered from 1.0 meter and 2.0 meter depths from warri, encompassing Specific Gravity (Gs),Compaction,AtterbergLimits,andTriaxialCompressiontests. The analysis revealed a critically poor soil profile characterized by low Specific Gravity (Gs < 2.54) and negligible cohesive strength (C as 0kPa}) across both strata, strongly indicating the presence of organic or highly compressible lightweight solids. The study's primary finding is the exceptionally low angle of internal friction (19.4 at 1.0 m and 16.7 at 2.0 m). This deficiency means that the soil's shear strength is entirely frictional and thus 100% dependentoneffectivestress. Theresultsdemonstratethatwatertableriseposesanacuteriskbycausingaseverereduction in�, leading to an immediate and significant loss of shear strength and bearing capacity, confirming the extreme moisture sensitivity of the subgrade. Consequently, the soil is classified as unsuitable for foundation support without extensive ground improvement. Mitigation recommendations include removal and replacement or deep foundations to bypass the weak, high-risk zone, providing essential data for informed foundation design and geotechnicalriskassessment.

Reinforced concrete (RC) structures form the backbone of modern infrastructure due to their strength, versatility, and cost-effectiveness. However, over time, these buildings are prone to various forms of deterioration caused by factors such as environmental exposure, poor construction practices, overloading, and lack of proper maintenance. These defects manifest in forms like cracks, spalling, corrosion of reinforcement, and structural deformation, which compromise the integrity and safety of the structure. Hence, this study aim to access the repair and rehabilitation of defective reinforced concrete buildings in Ekosodin Community of Ovia North East LGA, Benin City. The study Involves conducting a comprehensive review of literature, standards, and case studies to understand the mechanisms of deterioration and the corresponding repair techniques. A detailed site investigation was carried out on selected case study buildings to identify the extent of damage through visual inspection and non-destructive testing methods such as rebound hammer tests. Based on the diagnosis (that is watching out for crack defects only), a repair and rehabilitation plan was developed which incorporates suitable repair materials and structural strengthening method such as bitumen crack injection and stitching as a combined method of repair/rehabilitation. Visual inspection revealed multiple types of cracks on columns and walls, with widths ranging from 5 mm to 15 mm, attributed to various factors. Rebound hammer results showed that cracked areas had lower surface strength (11–13 N/mm²) than uncracked regions (24–27 N/mm²), confirming surface deterioration and validating the rebound hammer test as a reliable tool for assessing concrete integrity prior to selecting suitable rehabilitation method

The persistent problem of unreliable electricity supply in Nigeria has made the use of electrical power generators a daily necessity for many homes and businesses. While these generators provide temporary relief from frequent blackouts, their emissions and noise significantly degrade air quality and create health concerns. This study aimed to assess air and noise pollution from electric power generators in selected commercial centers in Benin City, Edo State. The objectives were to measure key air pollutants like PM2.5, PM10, CO, O3, and TVOC at varying distances (0 m, 3 m, 5 m) from operating generators, evaluate their concentration trends, determine noise levels, and compare results with World Health Organization (WHO) standards. The study was carried out across sixteen commercial sites including Ring Road, Mission Road, Akpakpava, and Forestry Road. Air quality data were obtained using a portable multi-gas analyzer and ozone meter, while noise levels were measured with a digital sound level meter. Measurements were recorded for three minutes at one-minute intervals during active generator operation (1 p.m.–3 p.m.). The data collected at 0 m, 3 m, and 5 m were averaged to determine representative pollution values and compared against WHO limits to evaluate compliance. The results showed that air and noise pollution around generator sites were generally above recommended limits. The mean PM2.5 concentration ranged from 35–70 µg/�³, and PM10 from 40–85 µg/�³, both exceeding the WHO 24-hour limits of 15 µg/�³ and 45 µg/�³ respectively. Carbon monoxide (CO) levels were between 28–307 ppm, far higher than the WHO limit of 26 ppm (1-hour mean). Ozone (O3) concentrations varied from 0.04–7.18 ppm, and TVOC values ranged from 0.007–0.074 mg/�³, with higher values near generator exhausts. Noise levels ranged between 80.0 dB(A) and 96.8 dB(A), exceeding the WHO safe exposure limit of 70 dB(A). Pollutant levels decreased progressively with distance from the source, showing strong spatial attenuation within 5 m. These findings confirm that commercial generator clusters in Benin City contribute substantially to poor air quality and excessive noise exposure. The study concludes that generator emissions pose serious environmental and health hazards. It recommends strict enforcement of air quality standards, and the adoption of cleaner energy sources such as solar power to improve public health and urban livability.

Clay soils at many construction sites often exhibit low strength and high plasticity, making them unsuitable for supporting heavy structural loads without proper stabilization. This study aimed to investigate the potential of bamboo ash (BA) as an environmentally friendly and cost-effective soil stabilizer to improve the engineering performance of clay soils. The research specifically
examined how varying BA contents (5%, 10%, 15%, and 20% by dry weight) affect the geotechnical properties and California Bearing Ratio (CBR) characteristics of clay soils, with the goal of addressing the problem of weak subgrade performance in road and foundation construction.

The materials used were locally sourced clay soil and bamboo ash produced from the controlled burning of bamboo plants. Laboratory testing was carried out on both untreated and BA-treated soils. The experimental program included soil classification tests—specific gravity, particle size distribution, and Atterberg Limits—compaction tests to determine Maximum Dry Density (MDD) and Optimum Moisture Content (OMC), and CBR tests to evaluate load-bearing capacity. The natural clay was classified as A-4 and A-5 according to the AASHTO system, while BA was used as the stabilizing additive in different proportions. Results indicated that untreated clay soils exhibited low CBR values. The addition of BA improved both MDD and CBR, with the highest performance observed at 15% BA content.

Beyond this level (20%), both MDD and CBR values declined, and Atterberg Limit results showed an overall increase in plasticity with higher BA content. The findings demonstrate that BA has significant potential as a sustainable soil stabilizer, particularly at the 15% level, for improving clay soil strength and bearing capacity. However, the reduction in performance at higher contents and the rise in plasticity highlight the need for further microstructural analysis and field trials to develop practical guidelines for its use in construction projects.

The need to reduce the increasing demand for crushed granite as coarse aggregate as well as the need to safeguard the environment from degradation has given rise to various researches on alternative materials that can serve the same purpose while minimizing environment hazard. The suitability of waste ceramic tiles as coarse aggregate in concrete and ascertain its strength against normal crushed granite were assessed. Crushed waste ceramic tiles was mixed with crushed granite stones as partial replacement for concrete. A mix ratio of 1: 2: 4, with attached mix design in appendix plate 1, for C20 concrete is produced with (0, 10, 20, 30, and 40) percent volume ceramic waste aggregate replacement for crushed granite at a constant water-cement ratio of 0.5. Concrete cubes of size 150mm x 150mm x 150mm were produced and tested for 7, 14 and 28 days for compressive strength, density and water absorption. The results obtained shows that the compressive strength of concrete reduced gradually for all ages with the increase in percentage replacement. Ceramic wastes from the construction sites and manufacturing industries could be recycled by breaking them into various coarse aggregate sizes and used in concrete mixes. However, a maximum content of 20% ceramic waste aggregate replacement in a mix is ideal to produce the required strength and durability of structural concrete. It was also observed that the percentage water absorption increased from 0% to 30%, it then dropped at 40% ceramic waste replacement of granite specimen. The increase in water absorption was probably due to relatively porous nature of the unpolished side of the ceramic waste as compared to the granite. It is therefore advised that coarse aggregate replacement must not exceed 20% since there was not much significant increase in water absorption up to this limit compared to the control. Meanwhile the density decreases with increase in percentage ceramic waste replacement, that is from 0% to 40%, for granite in the concrete produced. With no doubt, this mode of recycling ceramic waste could positively sustain the environment.

This study examines how curing reinforced concrete in a urea-salt solution, which simulates urine, affects its compressive strength and durability. This is compared to concrete cured in fresh water. The research addresses concerns about the decline of concrete structures in environments that are biologically or chemically harsh, such as areas often contaminated by urine. Understanding the impact of such exposure on concrete performance is important for improving the design and maintenance of durable structures under these conditions. The experimental work involved casting twenty concrete cubes, each measuring 100 × 100 × 100 mm, using a mix ratio of 1:2:4 and a water-cement ratio of 0.5. Ten cubes were cured in fresh water, while the other ten were cured in a urea-salt solution made with 10 g of urea and 2 g of sodium chloride (NaCl) per liter of water. The cubes were tested for compressive strength after 14 and 28 days of curing using a compression testing machine. The data gathered were analyzed and compared to evaluate the impact of the urea-salt solution on concrete performance. The average compressive strengths were 18.81 N/mm² and 23.17 N/mm² for the 14- and 28- day fresh-water samples, and 18.15 N/mm² and 17.81 N/mm² for the urea-salt-cured samples which indicates that concrete cured in fresh water showed normal strength growth with age. In contrast, the concrete cured in the urea-salt solution had a slight decrease in compressive strength over time. It was concluded that exposure to the urea-salt solution restricts full hydration and weakens concrete durability with extended contact. It is advised that structures in areas prone to urine contamination be shielded from direct exposure.

This study investigates the environmental impact of the Ekosodin dumpsite in Benin City, Edo State, on surrounding groundwater quality, specifically addressing the risks of leachate infiltration. The research aim was to evaluate twenty-two physicochemical and microbial parameters across eight sampling locations to determine the spatial extent of contamination and assess the suitability of local water resources for domestic use. By benchmarking these parameters against World Health Organization (WHO) and Nigerian Industrial Standards (NIS), the study provides a comprehensive overview of how inadequate waste management practices threaten the availability of safe potable water for the community. The methodology integrated systematic laboratory analysis with advanced geospatial modeling using ArcGIS 10.8. Groundwater samples were collected from eight borehole locations and analyzed for various physical, chemical, and biological properties, including heavy metals like Lead (Pb) and Cadmium (Cd). A Water Quality Index (WQI) was calculated for each site to classify water quality, while Inverse Distance Weighting (IDW) interpolation was applied to map the spatial distribution of pollutants. Furthermore, a Multiple Linear Regression (MLR) model was developed to quantify the relationship between five key parameters—including Electrical Conductivity (EC) and Iron (Fe)—and the calculated WQI, achieving a high predictive accuracy with an R 2 value of 0.9983. Results revealed a significant degradation gradient, with WQI values ranging from 27.20% to 130.05% (and up to 945.24% in specific computations), indicating that boreholes closest to the dumpsite possess very poor water quality unsuitable for drinking. Spatial analysis confirmed the dumpsite as the primary source of elevated heavy metals and organic contaminants, though quality generally improves as the distance from the waste source increases. The study concludes that leachate from the Ekosodin dumpsite severely impairs groundwater safety, leading to the recommendation that future boreholes be sited at least 400 meters away from disposal areas. These findings emphasize the urgent need for modernized waste management strategies and continuous groundwater monitoring to protect public health and ensure a sustainable water supply.

Manual pavement inspection methods are slow, subjective, and often inconsistent, leading to delayed maintenance and increased road deterioration. This study was carried out to develop an automated, image-based system capable of detecting and classifying visible defects in flexible pavements using machine learning. The objectives of the study were to review existing pavement inspection techniques, collect and preprocess pavement image data, and design and train a model capable of identifying pavement failures accurately. The study was with the aim of improving the speed, objectivity, and reliability of pavement condition assessments. A dataset of pavement images was obtained from the Edo State Ministry of Works, field surveys, and public sources. The images were annotated in YOLO format and augmented by flipping, rotation, cropping, and brightness adjustment. The YOLOv8 object detection model, implemented in Python using TensorFlow, PyTorch, and OpenCV, was trained on Google Colab with an NVIDIA T4 GPU. Training was performed at varying epochs (50, 100, and 200) and hyperparameters to optimize detection performance. The model’s accuracy was evaluated using mean Average Precision (mAP) and recall metrics to assess its ability to detect cracks, potholes, and rutting in flexible pavements. Results showed that the model achieved a mean Average Precision (mAP₅₀) of 0.68 and recall above 0.80 for visible defects such as potholes and alligator cracking, at a confidence level of 0.5. The model was less effective in detecting faint, low-contrast linear cracks. This study concluded that YOLOv8-based models can effectively automate pavement distress detection, providing a faster and more reliable alternative to manual inspection. It is recommended that future work expand the dataset and explore enhanced training strategies to improve the detection of subtle linear cracks.

This project examined the environmental and health hazards from the disposal of liquid waste generated by industries, particularly those involved in beverage production in Nigeria. Increased urbanization and rapid industrialization have occasioned increased volumes of effluent being discharged, usually without proper treatment, into River Niger and other water bodies. This results in various forms of pollution, contaminating the organic and inorganic content, ultimately causing about 25% of all preventable diseases, including waterborne diseases. This research work aimed to study and upgrade the liquid waste disposal methods at the International Breweries Limited Onitsha, Anambra State. Specific objectives included establishing the physical, chemical, and biological characteristics of the effluent and also appraising the sustainability and efficiency of the existing effluent treatment and disposal processes with respect to compliance with WHO standards.The methodology used in this research involves a case study approach at the brewery plant. Effluent samples were collected from pre-treatment and post-treatment points during the month of August, at morning periods to capture peak production waste. Each sample size was 2 liters, preserved at 4°C, and conveyed to the laboratory within 4 hours. Physical parameters such as pH, temperature, turbidity, total suspended solids, and color were analyzed using calibrated instruments like pH meters and spectrophotometers. Chemical parameters for biochemical oxygen demand, chemical oxygen demand, heavy metals, and nutrients were analyzed by digestion followed by atomic absorption spectrophotometry. Biological parameters-total heterotrophic bacteria, coliform counts, and E. coli-were determined by membrane filtration and incubation on selective media. Data analysis involved the use of descriptive statistics and comparison with WHO benchmarks. These results portrayed partial efficacy of the treatment. Physical parameters were improved, with turbidity falling from 1.0 NTU to 0.5 NTU; however, pH and total dissolved solids were still above WHO limits at 5.0 and 2829 mg/L, respectively. The chemical parameters were reduced-for instance, COD was reduced from 80.1 mg/L to 56.3 mg/L-but remained high, as were heavy metals (e.g., lead, 0.74 mg/L> 0.01 mg/L) and nutrients (ammonia, 8.74 mg/L> 0.5 mg/L); thus, offering a high risk for eutrophication and toxicity. Biological parameters were fully met, as coliform and E. coli counts were nil after treatment. -The study concluded that the brewery's treatment system was inefficient to achieve full compliance, with the need to invest in effective treatment technologies such as reverse osmosis and nutrient removal. Individuals should advocate for clean water practices, corporate organizations should invest in advanced treatment technologies, and government agencies should establish stricter monitoring and incentives for sustainable waste management.