Papers by Olugbenga Ayeni
Multivariate regression approaches to predict the flexural performance of cellulose fibre reinforced extruded earth bricks for sustainable buildings
Cleaner Materials

LAUTECH Journal of Civil and Environmental Studies
The mitigation of indoor air pollution sources in printing facilities is crucial for ensuring hea... more The mitigation of indoor air pollution sources in printing facilities is crucial for ensuring healthy indoor environments and protecting the health and well-being of employees. This study assessed the severity of indoor air pollution sources and the different pollutant control strategies in use in 22 printing presses in Zaria metropolis, Kaduna State. The study adopted a quantitative method. A checklist was used to characterize the selected printing facilities and examine the severity of indoor air pollutant sources on a 5-point Likert severity scale. The instrument was also used to check the availability of Indoor Air Quality (IAQ) monitoring devices and Indoor Air Pollution (IAP) control technology/strategy currently in use in the printing facilities. Findings revealed 1 pollutant source (dust) with mean value of 3.55 to be severe, 9 others to be mild, and 11 to be non-severe. All the assessed printing presses have available compliant inks and coatings, while 100% unavailability o...

Buildings, 2022
Bone ash waste can be used to fabricate clay ceramic bricks, consequently managing their pollutio... more Bone ash waste can be used to fabricate clay ceramic bricks, consequently managing their pollution of the environment. This is because bone ash (BA) and clay predominantly consist of calcium and alumina-silicate, respectively, which are components of clay ceramic brick (CCB) materials. This study aims to investigate the effect of bone ash and temperature on the physio-chemical and mechanical properties of CCB. Different percentages of bone ash (5%, 10%, 15%, and 20%) were added to clay and heat treated at temperatures of 100 °C, 300 °C, 600 °C, and 900 °C, and their compressive strengths were measured. Prior to the determination of their mechanical properties, the CCB chemical and phase compositions were characterized using FTIR spectroscopy and X-ray diffraction (XRD). The CCB microstructure was evaluated with scanning electron microscopy (SEM) and the compressive strength was tested. The results suggest that the addition of bone ash (10% and 15%) improves the compressive strength ...

Journal of Contemporary Research in the Built Environment, 2022
Purpose: Indoor Air Quality (IAQ) is becoming an increasingly important building design considera... more Purpose: Indoor Air Quality (IAQ) is becoming an increasingly important building design consideration due to the growth in occupants' health and comfort problems attributed to indoor air pollution (IAP). This study evaluated the concentration of indoor air pollutants in the built spaces of printing presses within the Zaria metropolis with the view to improving the IAQ of this built environment. Design/methodology/approach: The study adopted the quantitative research method. Twentytwo (22) printing presses were studied during active periods of printing to identify air pollutants. Concentration levels were measured and compared against the National Environmental Standard and Regulatory Enforcement Agency (NESREA) standard for excellent IAQ. A handheld Air quality meter, Carbon monoxide meter, and Ozone concentration meter were used to measure the mean levels of nine (9) IAQ indicators; Temperature, Relative humidity, Carbon monoxide (CO), Carbon dioxide (CO2), Total volatile organic compound (TVOC), Formaldehyde (HCHO), Particulate matter (PM2.5 and PM10), and Ozone (O3). Data collected in this study were analysed using descriptive and inferential statistics. Findings: The levels of the air parameter in the printing presses were in the range: Temperature (25.67-33.67 o C), RH (56.33-85.00%), CO (0.00-31.00 ppm), CO2 (533.67-1425.33 ppm), TVOCs (0.113-9.999 mg/m 3), HCHO (0.015-0.078mg/m 3), PM2.5 (21.33-426 µg/m 3), PM10, (28.00-568 µg/m 3), and O3 (0.00-0.05 ppm). The mean levels of temperature, RH, TVOC, HCHO, PM2.5, and PM10 exceeded the acceptable threshold of the NESREA standard in about 60% of the assessed presses. Research limitations/Implications: Based on the air pollutant concentration levels recorded in this study, printing press operators and users in the Zaria metropolis are at risk of developing some health-related problems. Practical implications: Regular IAQ assessment by press owners, inspection by regulatory bodies, and installation of IAQ monitoring or capture systems are recommended to achieve good IAQ levels as well as improve occupants' well-being in the assessed printing presses. Originality/value-The result of the study revealed the need to control the concentration of air pollutants in the printing presses in the Zaria metropolis as the measured concentration of air pollutants poses a major health threat to users of the facilities.

LAUTECH Journal of Civil and Environmental Studies, 2023
Thermal discomfort in lecture theatres can create unsatisfactory conditions for effective learnin... more Thermal discomfort in lecture theatres can create unsatisfactory conditions for effective learning. Achieving a thermally comfortable indoor environment in any building is of great importance for all building users. However, this has become a complex task in educational buildings. This study assessed the thermal comfort parameters in 6 lecture theatres of the main campus of Ahmadu Bello University, Zaria. The study adopted both the objective and subjective approach of thermal comfort assessment. Checklist was used to characterize lecture theatres while measuring devices were used to collect data on air temperature, relative humidity, and air velocity. A total 510 questionnaire was used to collect data on users' perception on thermal sensation. Findings from the objective assessment for morning and afternoon sessions, showed that the indoor air temperature, relative humidity, and air velocity were in the range of 27.53 o C to 35.59 o C, 35.29% to 55.34%, and 0.01 m/s to 1.23 m/s respectively. Findings from the subjective assessment showed the thermal sensation vote to be 28.4% and 18.6% for morning and afternoon votes respectively. Results from the inferential statistical analysis showed significant differences (p≤0.05) in the mean value of the thermal comfort parameters measured across all the theatres. The study recommended that natural ventilation should be adequately augmented with sufficient mechanical ventilation systems in the lecture theatres to enhance the thermal condition of the indoor spaces. Also, future designs of lecture theatres should comply with accepted standard for achieving optimum thermal comfort.

Lift systems in high-rise buildings are often confronted with problems associated with optimum se... more Lift systems in high-rise buildings are often confronted with problems associated with optimum service delivery. The optimum performance of these systems in public high-rise buildings enhances the efficiency of vertical transportation systems. Time performance parameters like the Average Waiting Time (AWT), Transit Time (TRT), and Time to Destination (TTD) are amongst the key performance indicators for examining the performance of lift systems in high-rise buildings. This study assessed the performance times of lift systems of selected high-rise buildings in Abuja city with the view to enhancing the efficiency of vertical transport systems in buildings. Field measurements on the AWT, TRT, and TTD were performed and a well-structured checklist was used for the collection of relevant data on 14 selected high-rise buildings and 41 lift systems in the Central Business District (CBD) of Abuja city. A digital stopwatch was used to measure the AWT and TRT while TTD was derived from the simple computation of AWT and TRT. All the measured parameters were evaluated against the standard performance requirements for an ideal lift system. Findings from the study show that 100% of the lifts installed in these buildings are traction lift types with 90% having an average rated speed of 1.0m/s. Results from the analysis showed that 85.7% of the buildings have lift systems with AWT above the minimum standard requirement. Significant differences (p<0.05) in the mean values of AWT, TRT, TTD were observed. Based on the findings, the assessed lift systems were considered to perform below the expected standard as the majority of buildings experienced long waiting times. This study has provided performance data for optimizing the service delivery of lift systems in high-rise buildings in Nigeria.

The mitigation of indoor air pollution sources in printing facilities is crucial for ensuring hea... more The mitigation of indoor air pollution sources in printing facilities is crucial for ensuring healthy indoor environments and protecting the health and well-being of employees. This study assessed the severity of indoor air pollution sources and the different pollutant control strategies in use in 22 printing presses in Zaria metropolis, Kaduna State. The study adopted a quantitative method. A checklist was used to characterize the selected printing facilities and examine the severity of indoor air pollutant sources on a 5point Likert severity scale. The instrument was also used to check the availability of Indoor Air Quality (IAQ) monitoring devices and Indoor Air Pollution (IAP) control technology/strategy currently in use in the printing facilities. Findings revealed 1 pollutant source (dust) with mean value of 3.55 to be severe, 9 others to be mild, and 11 to be non-severe. All the assessed printing presses have available compliant inks and coatings, while 100% unavailability of IAQ monitoring devices/equipment or capture systems were observed. The study concluded that by implementing effective control measures and monitoring of indoor air quality, the risk of negative health effects associated with exposure to indoor air pollutants can be minimized in the printing facilities. The study also recommended that Facility managers and policymakers must prioritize the implementation of effective control measures in printing facilities to reduce exposure to indoor air pollutants and improve IAQ, which ultimately promotes the health and well-being of press employees.

Ride quality of lifts enhances the comfort of lift users in high rise buildings. This work invest... more Ride quality of lifts enhances the comfort of lift users in high rise buildings. This work investigated the ride quality of lifts in selected high-rise buildings within the Central Business District (CBD) of Abuja, Nigeria. The study adopted field survey method. Instruments like the WT85 Digital Sound Level Meter and Smart Sensor Vibration Meter alongside a checklist were used for data collection on lift cabin interior sound level and vibration during acceleration. Results show that 64.3% of the buildings have unsatisfactory interior lift sound levels and 71.4% with poor ride quality. Inferential statistical analysis showed significant differences (p<0.05) in the mean values of lift car interior sound levels and lift acceleration values. The assessed lift systems were considered to have unsatisfactory ride quality as majority of them produced sounds beyond established standards for optimum sound level and vibration in lift cars (£55dBA and 1m/s 2). For high-rise buildings considering modernization of lift systems or installation of new ones, ride quality is a factor to consider for optimum service delivery and users' ride comfort. However, the findings from the study could be of benefit to lift consultants and manufacturers when planning for lift design and installation in high rise buildings

Applied Sciences
This study explored the use of coir fibers extracted from coconut husks, an agro-waste material t... more This study explored the use of coir fibers extracted from coconut husks, an agro-waste material that constitutes sanitation and environmental pollution problems, as a reinforcing element in the production of metakaolin-based geopolymer composites with improved properties. A series of sample formulations were produced with varying coir fiber content (0.5, 1.0, 1.5, and 2.0 percent weight of metakaolin powder). The investigation was conducted using a 10 M NaOH alkaline solution with a 0.24 NaOH:Na2SiO3 mass ratio. Samples were cured for 28 days and tested for bulk density, ultrasonic pulse velocity (UPV), and compressive and flexural strength. Microstructural examinations such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM) were also performed on samples. Compressive strength values up to 21.25 N/mm2 at 0.5% fiber content and flexural strength values up to 10.39 N/mm2 at 1% fiber content were achieved in this study. Th...

Buildings, 2022
Bone ash waste can be used to fabricate clay ceramic bricks, consequently managing their pollutio... more Bone ash waste can be used to fabricate clay ceramic bricks, consequently managing their pollution of the environment. This is because bone ash (BA) and clay predominantly consist of calcium and alumina-silicate, respectively, which are components of clay ceramic brick (CCB) materials. This study aims to investigate the effect of bone ash and temperature on the physio-chemical and mechanical properties of CCB. Different percentages of bone ash (5%, 10%, 15%, and 20%) were added to clay and heat treated at temperatures of 100 °C, 300 °C, 600 °C, and 900 °C, and their compressive strengths were measured. Prior to the determination of their mechanical properties, the CCB chemical and phase compositions were characterized using FTIR spectroscopy and X-ray diffraction (XRD). The CCB microstructure was evaluated with scanning electron microscopy (SEM) and the compressive strength was tested. The results suggest that the addition of bone ash (10% and 15%) improves the compressive strength ...

Buildings, 2021
This paper explores the effects of cement stabilization (5, 10, 15 and 20 wt%) on the structural ... more This paper explores the effects of cement stabilization (5, 10, 15 and 20 wt%) on the structural and mechanical properties (compressive/flexural strengths and fracture toughness) of abandoned termite mound soil. The crystal structures and crystallinity of the constituents were determined using X-ray diffraction (XRD), while the microstructure was characterized via scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The functional groups were also identified using Fourier transform infra-red spectroscopy (FTIR). The compressive/flexural strengths of the stabilized and un-stabilized termite mound soil were also studied after curing for 7, 14 and 28 days. The fracture toughness mechanism was analyzed with the aid of the R-curve method. Additionally, the underlying deformation and cracking mechanisms are elucidated via in-situ/ex-situ optical and scanning electron microscopy. The stabilized termite mound soil displayed the highest mechanical properties of ...

Heliyon, 2021
This investigation prospects the feasibility of optimizing the mechanical behavior and dimensiona... more This investigation prospects the feasibility of optimizing the mechanical behavior and dimensional stability of termite's mound soil through alkaline activation. The raw aluminosilicate (termites' soil) was used without any pre-thermal treatment and natural occurring potash was used as the alkaline activator. Different activation level and different initial curing temperature were adopted to examine the effect of the initial temperature and the activator concentration on the Alkali Activated Termite Soil (AATS). Similarly, Scanning Electron Microscopy (SEM)/Energy Dispersive X-ray Spectroscopy (EDS), X-ray Diffraction (XRD) and Fourier Transform Infra-Red Spectroscopy (FTIR) were conducted to characterize the microstructure, to determine the crystallinity of the constituents and to identify the functional groups present within the specimens. These characterizations were carried out on the specimens at 15 days after their moulding. The compressive strength was determined for 7, 15 and 90 days to illuminate the fundamental of the optimization process. Results showed that the optimal initial curing temperature was 60 C for the oven-dry regime at 3wt% activator with compressive strength of 2.56, 4.38 and 7.79 MPa at 7, 15 and 90 days respectively. From the mechanical performances results, the alkali stabilized termite's soil can be used as masonry elements predominantly submitted to compression. The repercussions of the results are analyzed for potential applications of the Alkaline Activation techniques as an environmental-friendly approach to obtain renewable and sustainable building materials at low cost with low energy consumption henceforth replicable in most of the regions.

Characterization and mechanical performance of metakaolin-based geopolymer for sustainable building applications
Construction and Building Materials, 2021
Abstract Previous research has revealed geopolymer technology to be a promising alternate constru... more Abstract Previous research has revealed geopolymer technology to be a promising alternate construction material to Portland cement. Existing data show that Portland cement material production contributes ~8% to the global CO2 emissions. This is detrimental to the environment and contribute to global warming. It is therefore pertinent to develop alternative cost-effective and environmentally friendly cement material. This study examined the performance of a Nigerian metakaolin-based geopolymer as a sustainable material alternative to Portland cement. Kaolin clay from Katsina State, Nigeria, was calcined at 700°C for 2 h prior to geopolymer processing. Different sample formulations of geopolymers were prepared in a 50 × 50 × 50 mm mold and tested in compression after curing at ambient temperature, 40 and 60 °C for 7 and 28 days. The geopolymerized specimens were characterized using XRD, FTIR and SEM techniques. Parametric study on the effects of the fractions of sodium hydroxide, sodium silicate, calcium hydroxide, fine aggregate and curing temperature on the geopolymer strength were examined. The results of the study revealed that Kankara metakaolin-based geopolymers can serve as a potential sustainable construction material for the Nigerian construction industry due to its availability, affordability, compressive strength values, and eco-friendliness.
Assessment of hygrothermal and mechanical performance of alkali activated Borassus fiber reinforced earth-based bio-composite
Journal of Building Engineering
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Papers by Olugbenga Ayeni