DEPARTMENT OF CIVIL ENGINEERING

In many developing countries, the high rate of building collapses is a constant concern. It raises important questions about construction practices, enforcement of regulations, and the integrity of professionals. Lagos State, one of Nigeria’s fastest-growing urban centres, has seen a troubling trend of structural failures in residential, commercial, and institutional buildings. These collapses often lead to unnecessary deaths, property loss, and economic disruption, showing deeper problems within the built environment. Despite more awareness and media coverage, the issue remains unresolved. Commonly cited reasons for building collapses include poor structural design, low-quality materials, lack of supervision, failure to follow building codes, and corruption in regulatory bodies. Yet, while these factors are often discussed, there is little clarity on which ones have the greatest impact on collapse events. This lack of prioritization makes it hard for stakeholders to focus their efforts, implement changes, or take precise preventive measures. Understanding the importance of each contributing factor is key to effectively addressing the problem. Not all causes are equally significant, and treating them as such may weaken the effectiveness of proposed solutions. There is a need for a structured approach to assess and rank these factors, especially in high-risk areas like Lagos State, where construction is both dense and fast-paced. Without this analysis, the cycle of collapse and reactive responses will likely continue

The alarming rate of road traffic accident in the country (Nigeria) is among the most worrisome problems currently facing the nation. Sadly, Nigeria has earned the unenviable distinction of consistently leading all the nations of the world in high road traffic accident and high fatality rate. One of the best ways to understand the occurrence of road accident is to develop accident prediction models which are also standard practices in assessing and improving the safety of our roads. The aim of this study is to conduct a comprehensive evaluation of selected expert systems such as multiple linear regression and artificial neural
network for the modelling and prediction of road accident. The study area is Ugbowo-Lagos Road. A reconnaissance survey was done first to ascertain the geometric characteristic of the road which include; the chainage, the vertical and horizontal curve and the super elevation. Thereafter, secondary data which include road accident data was collected from Federal Road Safety Office at lucky way Benin City. To investigate the qualities of the secondary data, basic preliminary analysis techniques, namely;
outlier detection, homogeneity test, test of normality and autocorrelation test were done. While modelling and prediction of road accident was done with the aid of multiple linear regression and artificial neural networks. From the geometric characteristic of the road under study, it was observed that for a chainage of 11.5 to 13km, the vertical curve was 12.4% while the super elevation was 4.3%. Calculated Cronbach alpha value of 0.900 as observed in the reliability test revealed that the data are reliable and the computed goodness of fit statistics of reliability gave a maximum Guttman coefficient of 88.10% which further confirm the reliability of the data used. With a computed p-value greater than 0.05 for all the independent variables, the null hypothesis of the Dixon test was accepted and it was concluded that the accident data obtained from FRSC is devoid of outliers. In addition, with a centered VIF(Vehicle influence factor) < 10, it was concluded that there is the absence of multicollinearity between the dependent (NAC) and independent variables (NPIV, NPIJ, NPK, NVI). With a computed coefficient of determination (R 2) value of 0.9265, artificial neural network (ANN) was acclaimed better road accident prediction model compare to multiple linear regression model (MLRM) with a computed R2 value of 0.0617. The implication of this findings states that if the R2 value is
lesser than 0.0617 it is will not to work .

The project titled “The effect of admixtures on properties of concrete: case study of sugar cane shaft ash, cow bone ash, groundnut shell ash,” will be carried out with the aim of knowing the effect the of the various types of admixtures used on the properties of concrete, in term of the workability of concrete, durability of concrete and the concrete strength. The material used are cow bone ash, groundnut shell ash, sugar cane shaft ash. The cow bone will be sourced along new Benin market, Edo state and the groundnut shell will be sourced from uselu market. The cow bone will be sun dried after careful separation from flesh, tissues and fats, the ash will be carried out by incinerating the bone at a temperature of 900⁰C in a furnace. Also, the groundnut shell ash will be obtained by burning groundnut shell on an iron sheet in the open air under normal temperature while sugar cane shaft ash. The method adopted will be; batching of concrete materials, mixing of concrete materials, production of cubes, curing of cubes (for 7days, 14days and 28days) while the test carried out during and after the concrete cubes are produced or casted are; sieve analysis test, slump test and compressive strength test. From the sieve analysis test carried out on both fine and coarse aggregates, it will be discovered that the coefficient of uniformity (Cu) obtained are less than 4, hence they are both “well-graded” aggregates. The slump test shows that there is increase in the slump value from sugar cane shaft ash-concrete, GSA-concrete, CBA-concrete and LP-concrete, likewise the compressive strength test increases from sugar cane shaft ash-concrete, GSA-concrete, CBA-concrete and LP-concrete. From the findings, it is evident that the combination of the three admixtures resulted in the highest percentage increase in compressive strength. Additionally, the average maximum strength was achieved when the fine aggregate was replaced by 15% with the admixture. Despite variations in replacement percentages, all samples exhibited compressive strengths that align with the expected design characteristics of concrete, particularly around the target value of 20 KN/mm². The sieve analysis further revealed a well-graded particle size distribution in the fine aggregate samples, indicating suitability for achieving optimal concrete mix designs.

The project titled “Experimental Study on the Partial Replacement of Fine Aggregates with Plastic in the Production of Concretes,” was carried out with the aim of knowing the effect of partially replacing fine aggregates with plastic waste in concrete production. The aim is twofold: to mitigate environmental impact by repurposing plastic waste and to evaluate the performance of plastic-aggregate concrete. Methodologically, various types of plastic waste are selected and processed to suitable sizes for incorporation into concrete mixes. Comprehensive testing is conducted to assess both the fresh and hardened properties of the resulting concrete specimens. Tests include workability assessments using slump tests, as well as mechanical property evaluations such as compressive tests. The spent plastics were gathered, ground into smaller components, pulverized in order to get granules of plastic lower than 4.75mm size. Sieve studies were carried out for particle size distribution. 9 nos. of 10cm x10cm x10 cm cement concrete Cubes of 1:1.5:3 (C25) mix were cast for 0%, 5%, 10%, 15%, sand being substituted by Pulverized plastic material. Volumetric proportioning was utilized instead of design mix since the density of plastic material was too low. Workability test, weight and compressive strength of the cubes were determined. The results of the study shows that the slump of the fresh concrete decreased with increase in the replacement of the fine aggregate. This implies that the presence of plastic in the concrete decreased its workability. Also, the control sample, with no replacement, exhibited the highest compressive strength throughout the curing periods of 7, 14, and 28 days. As the percentage of sand replacement increased, there was a noticeable decrease in compressive strength. Notably, the replacement of 5% of sand with plastic material showed a gradual decrease, while beyond 10%, the decrease became more significant. This trend is attributed to the inability of plastic waste aggregate to effectively interact with the cement paste, unlike natural aggregate. Recycling of plastic trash with river sand decreases its negative environmental impact of river sand quarries, reduces the depletion of natural resources Based on the findings of this study, it can be concluded that the replacement of natural sand with plastic waste aggregate in concrete production leads to a reduction in compressive strength. However, the similarity in particle distribution between natural sand and plastic material suggests the potential for utilizing plastic waste as a partial replacement for sand without significant compromise in textural properties.

The rising cost of building materials, particularly concrete, has become a growing concern due to increased demand and limited availability of raw materials. To address this issue, there is a pressing need to find cost-effective and sustainable alternatives to conventional coarse aggregates. This project aims to investigate the potential of using coconut shells a readily available agricultural waste product from oil industries as a partial replacement for coarse aggregates in concrete. By utilizing coconut shells, the study seeks to reduce material costs, minimize environmental waste, and promote energy conservation while maintaining the required strength and durability of concrete used in roads and buildings.
In this experimental study, concrete mixes were prepared by partially replacing coarse aggregates with coconut shell particles in varying proportions ranging from 0% to 30%. The concrete mix used was designed for C30 grade concrete. Several tests were conducted to evaluate the properties of the modified concrete, including compressive strength and tensile strength after 7, 14, and 28 days of curing. Slump tests were also carried out to determine workability, which ranged between 60 and 75 mm, indicating that less water was required for the coconut shell concrete. Density, compressive strength, and durability (water absorption) tests were performed after 28 days of curing, and the results were compared with those of conventional concrete.
The experimental results showed that the compressive strength of concrete generally increased with curing time but decreased as the percentage of coconut shell replacement increased. The mix containing 5% coconut shell replacement achieved a compressive strength of 38.37 N/mm² after 28 days, demonstrating improved strength compared to the control mix. It was observed that up to 5% of the coarse aggregate could be replaced with coconut shells in high-performance concrete, particularly for construction applications, without compromising strength and durability. Therefore, the study concludes that incorporating coconut shells as a partial replacement for coarse aggregates is a viable, sustainable, and cost-effective solution for modern construction practices.

Road traffic noise is a harmful environmental pollutant that affects public health. Reducing the tire pavement noise by appropriate design of a durable pavement may reduce the road traffic, case study shows result shows that reducing the nominal aggregate size (NMAS) from 19.0mm to smaller value had a noticeable impact on the perceived noise from car traffic, the incorporation of seashell in OGAC (open graded asphalt concrete) can reduce the tire pavement noise by low frequencies. It has been observed also that rigid pavement makes more noise than flexible pavement.

Asphalt concrete roads are susceptible to deterioration over time due to factors such as wealthering, traffic loads, and environmental conditions. Premature cracking, rutting, and surface distress can lead to increased maintenance costs and reduced road service life. By conducting a thorough investigation into the key properties of asphalt concrete, this research aims to provide insights that will contribute to the development of optimized mix designs and construction practices, ultimately leading to more durable, safe and sustainable road infrastructure. A series of test was carried out including the marshal test to check asphalt mix design, proportion aggregate and asphalt materials for pavement construction.Penetration test was also carried out to to measure of consistency, hardness or softness of bitumen been used. From the test carried out, it is suggested that asphalts materials of high stability and stiffness should be used, as this reduces the shear deformation of roadswhich is a major failure of asphalt pavement. It was also noted that the asphalt concrete must be strong enough to withstand the stress transmitted to it.

This study assessed the dual-scale techno-economic feasibility of using Moringa oleifera as a natural coagulant–flocculant for greywater treatment. The study aimed to evaluate the dual-scale techno-economic feasibility of using locally sourced coagulants for coagulation-flocculation treatment of greywater, with a focus on treatment efficiency, costeffectiveness and possible reuse. The study involved the collection of greywater from a commercial kitchen and its treatment in a fabricated coagulation–flocculation water treatment prototype using locally sourced materials. Moringa oleifera seeds were processed into powder and applied at optimized dosages in operational use of the prototype for greywater treament. Physicochemical parameters including pH, electrical conductivity, turbidity, total dissolved solids (TDS), total suspended solids (TSS), chemical oxygen demand (COD) and biochemical oxygen demand (BOD) were analyzed before and after treatment. A techno-economic analysis compared the experimental moringa-based system with a conventional alumbased system in terms of capital expenditure (CAPEX), operating expenditure (OPEX), energy consumption, sludge management and payback period. The results of this study revealed substantial reductions in key pollutants: turbidity decreased from 8.4 NTU to 3.7 NTU, TSS from 22.4 mg/L to 8.7 mg/L, COD from 800.4 mg/L to 310.6 mg/L, and BOD from 101.3 mg/L to 79.4 mg/L, while colour reduced from 10.4 Pt.Co to 5.3 Pt.Co. However, TDS and EC values decresed from 2577 mg/L to 2554 mg/L and 5153 S/cm to 5107 S/cm respectively but remained above permissible limits, indicating a need for further treatment. The techno-economic analysis showed that the moringa-based system required lower CAPEX (₦ 2.2 million vs ₦ 3.0 million), reduced OPEX (₦ 540,000/yr vs ₦ 820,000/yr), and achieved a faster payback (3.8 years vs 6.5 years), yielding a return on investment of 28% compared to 15% for alum. The study concluded that Moringa oleifera is an effective, eco-friendly and cost-efficient coagulant suitable for decentralized greywater treatment. It is recommended that further optimization of dosage, integration with biological post-treatment and pilot-scale community deployment be pursued to enhance reuse potential and policy adoption.

This research was conducted to assess the structural integrity and performance of selected iconic buildings within the University of Benin, Benin City, Nigeria. The
primary aim of the study was to evaluate the current condition of these buildings in terms of their structural soundness, safety, and suitability for continued use. The study was driven by the growing need to ensure the long-term reliability and sustainability of public structures within tertiary institutions. The methodology adopted involved non-destructive testing (NDT) using the rebound hammer technique conducted on thirty-eight (38) structural elements, including beams and columns, across the selected buildings. For each element, rebound numbers were taken on both the top and bottom faces, yielding a total of seventy-six (76) test points. Statistical analysis was performed on the rebound data to compute the mean, standard deviation, and coefficient of variation (COV), from which estimated compressive strengths were derived. These results were then interpreted in accordance with ASTM C805 and BS EN 12504-2 standards to assess the quality and uniformity of the concrete across the sampled elements. The results revealed that the rebound numbers ranged between 40 and 52, corresponding to compressive strengths of approximately 52.6–61.4 N/mm². The mean rebound value was 48.21 with a standard deviation of 2.19, while the mean compressive strength was 57.86 N/mm² with a standard deviation of 2.38 N/mm², both yielding COVs below 5%. According to BS 1881 classification, these results indicate excellent concrete quality. The variation between readings across different members was minimal, confirming uniformity in construction and adequate material quality. Minor surface defects were observed but did not significantly affect the overall strength or stability of the structures. The study concluded that the assessed buildings remain structurally sound and safe for continued use, though regular monitoring and preventive maintenance are recommended to prevent progressive deterioration

Concrete remains the most widely used construction material globally; however, its production is heavily reliant on natural aggregates, the continuous extraction of which causes considerable environmental impact. With increasing concerns over resource depletion and waste management, the utilisation of recycled coarse aggregates (RCA) derived from demolished concrete presents a sustainable alternative. This study, entitled “Assessment of the Compressive Strength of Recycled Concrete Using the Rebound Hammer,” investigates the feasibility of partially replacing natural coarse aggregates (NCA) with RCA while maintaining acceptable mechanical performance for structural applications.
The research involves the preparation of concrete mixes of grades M20, M25, and M30, with RCA replacement levels of 0%, 25%, 50%, 75%, and 100%, at a constant water–cement ratio of 0.5. Fresh concrete is assessed through the slump test to evaluate workability, while hardened concrete specimens undergo compressive strength testing at 7, 14, and 28 days, in addition to non-destructive testing using the rebound hammer. The study aims to establish the relationship between the rebound number and compressive strength to develop calibration equations specific to Recycled Concrete. It is anticipated that compressive strength will decrease with increasing RCA content; however, a 25% replacement level is expected to provide performance comparable to conventional concrete while enhancing material sustainability. The study further predicts a strong correlation between rebound hammer readings and compressive strength, supporting the use of the rebound hammer as a reliable tool for non-destructive evaluation of Recycled Concrete in both research and practical field applications.