Civil Engineering

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Assessment of Fine Aggregates from Different Sources in Ibadan and Environs for Concrete Production
(2018) AGBEDE O.A.; AJAGBE W.O.
Assessment of natural sand being used as fine aggregate for concrete production in Ibadan and its environs was carried out. Ten sources (F1 – F10) were selected for the study; four (F5, F6, F7, F8) were river sand sources while six (F1, F2, F3, F4, F9, F10) were burrow pit sand sources. Samples from each source were subjected to sieve analysis, atterberg limit, bulk density, specific gravity, water absorption, sand equivalent, clay lumps and friable particles, amount of materials passing 75μm and organic impurities adopting ASTM standard procedures. Results revealed that sand from river sources met all the criteria for concrete production stated in ASTM standard while sand from burrow pits deviated from limits of the standard in some respects. F10 had water absorption of 2.6% which exceeded maximum 2% specified, F9 was not free from clay lumps and friable particles with a significant value of 6% as against 3% maximum specification. F1, F2, F3, F4, F9 and F10 have more amounts of materials passing the 75μm sieve ranging from 10.8% for F9 to 20.1% for F10 than maximum of 5% in standard specification while F1, F9 and F10 showed an indication of having organic impurities. It is recommended that performance test be conducted on concrete made from burrow pits sand before use for concrete production. The knowledge of this study can be used as a prospecting tool for selecting suitable sand for the production of quality concrete.
Comparative Study on the Design of Elevated Rectangular and Circular Concrete Water Tanks
(2012) AGBEDE O.A.; AJAGBE W.O.
Reinforced concrete overhead water tanks are used to store and supply safe drinking water. Design and cost estimation of overhead water tanks is a time consuming task, which requires a great deal of expertise. This study therefore examines the efficiency of Rectangular and Circular tanks. Tanks of 30m3, 90m3, 140m3 and 170m3 capacities were used in order to draw reasonable inferences on tank’s shape design effectiveness, relative cost implications of tank types and structural capacities. Limit state design criteria were used to generate Microsoft Excel Spreadsheet Design Program, named MESDePro for quick and reliable design. The basic tank’s construction materials- steel reinforcement, concrete and formwork were taken-off from the prepared structural drawings. Results of the material take-offs showed that, for each of the shapes, the amount of each structural materials increase as the tank capacity increases. Also Circular-shaped tank consumed lesser individual material as compared to Rectangular ones. Hence, this will give Circular-shaped tanks a more favoured selection over the rectangular shaped tanks.
Compressive Strength of Concrete Made from Aggregates of Different Sources
(2018) AGBEDE O.A.; AJAGBE W.O.
The use of substandard materials, particularly low quality concrete has been identified in literature as the leading cause of building collapse in Nigeria. The roadside artisans/bricklayers usually produce concrete for building construction without taking the aggregate source into consideration. This paper presents a comprehensive data on the compressive strength of concrete made from aggregates obtained from different sources in Ibadan, Nigeria. Experiments have been performed on 12 mixtures made up of fine aggregate from four sources and coarse aggregate from three different sources. The study utilize cement of the same strength (42.5R), coarse aggregate of the same size (10mm), the same water/cement ratio (0.6), and concrete mix (1:2:4) in order to determine the influence of aggregate source on concrete strength. Result revealed that only five mixtures had above the minimum cube compressive strength of 25N/mm2 recommended for the construction of the reinforced load-bearing building structural members. Three mixtures had above the cube compressive strength of 20N/mm2 recommended for use in plain concrete construction while the rest four mixtures had their cube strength between 19.3N/mm2 and 17.9N/mm2. Fine aggregate with higher compressive strength showed the lesser amount of deleterious materials. It was concluded that the compressive strength depend on aggregate source.
Construction and building materials
(2012) AGBEDE O.A.; AJAGBE W.O.
This study researches into solid waste management in South-West Nigeria in relation to pollution control using a an North as a case study. The generation pattern storage, collection and transportation, and the final disposal of solid waste ocean government are all discussed. Data used for this study were collected by the use of structured questionnaires and oral interviews. Analysis of the data revealed that all the functional elements of solid waste management system in the local government and the city of lbadan in general as practiced by existing institution - Ibadan Solid Waste Management Authority, are engulfed with fundamental problems which apparently have been the reason why institutions are unsuccessful in the efficient management of solid waste and control of environmental pollution. The various problems are identified, analyzed and discussed, pragmatic means of solving the problems, such as the encouragement of waste recycling; the active provision
Effect of aggregate type on properties of pervious concreteutajeet
(2019) AGBEDE O.A.; AJAGBE W.O.
Pervious concrete (PC) is a cheap and effective drainage system for reducing storm-water runoff in urban centers. This research aim to investigate the influence of different type of aggregate on PC properties. Three PC mixtures were prepared with different aggregate types [Granite, Gravel and Recycled Concrete Aggregate (RCA)]. Physical and strength characteristics of the aggregates were analyzed. Density, porosity, permeability as well as compressive strength of PC made with these aggregates were measured. Results showed that PC made from RCA has the highest porosity and permeability due to the porous nature of adhered mortar on RCA. However, highest density and compressive strength was obtained from granite PC followed by gravel and then RCA PC. The study concluded that aggregate type has significant influence on PC properties.
Effects of Crude Oil Imparted Sand on the Durability of Concrete
(2018) AGBEDE O.A.; AJAGBE W.O.
A large percentage of soils in crude oil producing areas in Nigeria were contaminated to a varying degree. Past research showed reduction in the compressive strength of concrete made with crude oil impacted sand (COIS). The current effort aimed at assessing the durability of COIS concrete. Soil samples were contaminated with crude oil concentrated levels of 0, 2.5%, 5%, 10% and 15% by weight of sand to produce COIS. Concrete design mix of 1:1.8:2.7 were made with COIS at the different concentrations from which concrete specimen – 100 mm cubes; 100 x 200 mm, and 75 x 150 mm cylinders, were made. COIS concrete were then tested for chloride and sulphate resistance using Electrical Resistivity(ER) test on 100mm x 200mm concrete cylinders and Water absorption (WA) test on 75 x 150 mm cylinders, respectively The COIS concrete was tested for Fire Resistance(FR) by testing the compressive strengths of heated 100 mm cubes. The results showed that COIS concrete exhibited an increased in durability properties as the contamination level increases. The control sample has the lowest value of ER of 119 kohm-cm which indicates low resistance to chloride ion penetration. It also has the highest value of WA of 3.9% indicating low resistance to sulphate attack. However, COIS concrete experienced reduction in strength when exposed to fire as the concentration of crude oil increases. The better durability property of the COIS concrete compliments the strength reduction.
Modeling the Effect of Crude Oil Impacted Sand on the Properties of Concrete Using Artificial Neural Networks
(2013) AGBEDE O.A.; AJAGBE W.O.
Modelling the effect of burning temperature and time on chemical composition of sorghum husk ash for optimum pozzolanic activity
(2018) AGBEDE O.A.; AJAGBE W.O.
Sorghum Husk Ash (SHA) can be used as partial replacement for cement in production of concrete due its pozzolanic behavior. This will reduce the cost and environmental pollution associated with the use and production of cement. The aim of this paper is to model the effect of burning temperature and time on chemical composition of SHA for optimum pozzolanic activity. The testing was done at 2-factors, 5-levels using Central composite design of Response Surface Methodology (RSM). Independent variables considered were: burning temperature (500, 600, 700, 800 and 900oC) and time (1, 2, 3, 4 and 5 hours). Dependent variables (chemical constituents) include: Silicon dioxide (SiO ), Aluminum oxide (Al O ), Iron 2 2 3 oxide (Fe O ), Calcium oxide (CaO), Sulphur oxide (SO ), Sodium oxide (Na O), Magnesium oxide (MgO) 2 3 3 2 and Potassium oxide (K O); all determined using atomic absorption spectrophotometer analysis. The 2 results revealed that the ash content decreases as the burning temperature and time increases. Optimum combined percent of SiO , Al O and Fe O (76.047%) which is the criteria for a good pozzolana was 2 2 3 2 3 achieved at temperature of 700oC and time 3 hours.
Professionals view on the causes and effects of construction projects abandonment in ibadan metropolis, Nigeria
(2016) AGBEDE O.A.; AJAGBE W.O.
Engineering and geological properties of rocks from eight different quarries in Ibadan were evaluated to determine their suitability for concrete production. Samples from each quarry sites were subjected to grading, relative density, water absorption, bulk density, amount of materials finer than 75μm, flakiness and elongation Index, Aggregate Impact Value (AIV), Aggregate Crushing Value (ACV), Aggregate Abrasion Value (AAV), 10% fines value and petrographical analysis adopting BS testing methods. The relationship between engineering properties with one another and the petrographical characteristics were described by Pearson correlation coefficient and bar charts. The results of engineering analysis revealed that rocks from all the quarries are generally sound and good because of their possession of necessary characteristics for use in concrete production when compared with British (BS), Indian (IS) and American Society for Testing and Materials (ASTM) standards. Petrographical analyses revealed that samples which have performed better in all the engineering tests possess higher content of quartz mineral and finer texture. Statistically significant correlations were found among the tests performed
Quality Assessment of Sandcrete Blocks in Ibadan – A review
(2013) AGBEDE O.A.; AJAGBE W.O.
Sandcrete blocks have been widely used for modern building construction in Nigeria; however cases of incessant building collapse are rampant. The usage of substandard sandcrete blocks is a contributing factor. This research was carried out to assess the engineering properties of sandcrete blocks produced in Ibadan and its environs. Two blocks each of size 450 x 225 x 225mm were purchased from selected block industries at eight sampled locations within the study area. Few units of blocks (450 x 225 x 225mm) conforming to the Nigerian Industrial Standard (NIS 87:2007) were also produced to serve as control samples. The 28th day dry compressive strength test result obtained for the sampled blocks ranges between 0.39-2.34N/mm2. For the control block samples, the average 28th day dry compressive strength of the three tested blocks was 3.02N/mm2. Conclusively, it was observed that the sandcrete blocks produced in major parts of Ibadan were of low quality and substandard; while the control samples were of adequate strength.
Reliability Assessment of Bridge Decks: A Case Study of Three Bridges Along Lagos – Ibadan Expressway.
(2012) AGBEDE O.A.; AJAGBE W.O
The ageing and gradual deterioration of bridges in Nigeria needs balancing of cost-effective plans for bridge maintenance, rehabilitation and replacement. This research aims at assessing the reliability of bridges using three existing highway bridges along Lagos-Ibadan expressway as a case study. Visual inspection, sounding, half-cell potential and chloride concentration tests were utilized to evaluate the conditions of the bridges. Deteriorations were observed on the decks’ surfaces. The level of corrosion on one deck was active and uncertain in the remaining two. The chloride concentrations on all the decks were within AASHTO standards and only one of the decks had delaminated. The results revealed that none of the decks needs total replacement but all require some form of rehabilitation.
Result Validation Analysis of Steel Testing Machines
(2018) AGBEDE O.A.; AJAGBE W.O.
Structural failures occur due to a number of reasons. These may include under design, poor workmanship, substandard materials, misleading laboratory tests and lots more. Reinforcing steel bar is an important construction material, hence its properties must be accurately known before being utilized in construction. Understanding this property involves carrying out mechanical tests prior to design and during construction to ascertain correlation using steel testing machine which is usually not readily available due to the location of project. This study was conducted to determine the reliability of reinforcing steel testing machines. Reconnaissance survey was conducted to identify laboratories where yield and ultimate tensile strengths tests can be carried out. Six laboratories were identified within Ibadan and environs. However, only four were nfunctional at the time of the study. Three steel samples were tested for yield and tensile strengths, using a steel testing machine, at each of the four laboratories (LM, LO, LP and LS). The yield and tensile strength results obtained from the laboratories were compared with the manufacturer’s specification using a reliability analysis programme. Structured questionnaire was administered to the noperators in each laboratory to consider their impact on the test results. The average value of manufacturers’ tensile strength and yield strength are 673.7 N/mm2 and 559.7 N/mm2 respectively. The tensile strength obtained from the four laboratories LM, LO, LP and LS are given as 579.4, 652.7, 646.0 and 649.9 N/mm2 respectively while their yield strengths respectively are 453.3, 597.0, 550.7 and 564.7 N/mm2. Minimum tensile to yield strength ratio is 1.08 for BS 4449: 2005 and 1.15 for ASTM A615. Tensile to yield strength ratio from the four laboratories are 1.28, 1.09, 1.17 and 1.15 for LM, LO, LP and LS respectively. The tensile to yield strength ratio shows that the result obtained from all the laboratories meet the code requirements used for the test. The result of the reliability test shows varying level of reliability between the manufacturers’ specification and the result obtained from the laboratories. Three of the laboratories; LO, LS and LP have high value of reliability with the manufacturer i.e. 0.798, 0.866 and 0.712 respectively. The fourth laboratory, LM has a reliability value of 0.100. Steel test should be carried out in a laboratory using the same code in which the structural design was carried out. More emphasis should be laid on the importance of code provisions.
Solid waste management in south western Nigeria
(2004) AGBEDE O.A.; AJAGBE W.O.
This study researches into solid waste management in South-West Nigeria in relation to pollution control using a an North as a case study. The generation pattern storage, collection and transportation, and the final disposal of solid waste ocean government are all discussed. Data used for this study were collected by the use of structured questionnaires and oral interviews. Analysis of the data revealed that all the functional elements of solid waste management system in the local government and the city of lbadan in general as practiced by existing institution - Ibadan Solid Waste Management Authority, are engulfed with fundamental problems which apparently have been the reason why institutions are unsuccessful in the efficient management of solid waste and control of environmental pollution. The various problems are identified, analyzed and discussed, pragmatic means of solving the problems, such as the encouragement of waste recycling; the active provision
Structural Investigation into the Causes of Cracks in Building and Solutions: A Case Study
(2018) AGBEDE O.A.; AJAGBE W.O.
Cracks are commonly found on and in structures and are usually undesirable features naturally occurring due to age, workmanship and other natural and environmental causes. This study is set to characterize cracks with the principal aim of recommending proper maintenance and efficient repair actions. Crack occurrence in an office building (storey with basement) was investigated as a case study. Reconnaissance survey was carried out to locate and note the tools that would be required for the investigation of the cracks. Visual examination and measurement of cracks to know the cause and type of each crack were performed. Strength test of all the structural members was done using Schmidt hammer to determine the residual strength of the members on which they appear and the results were analyzed. The results of the reconnaissance survey revealed that most of the cracks are located at the left side than at right side elevation of the building. The nature of the cracks showed that 91% are dormant cracks, while 9% are active cracks. Some of the cracks extended to the plastered surface, while the rest extended to the structural elements region. Therefore, the cracks in this building were found to be caused by the drying shrinkage at the wall section, the compressive force from the beams exceeding the ultimate strength of the affected blocks, foundation settlement at the courtyard was also discovered through topographical survey, due to underground erosion of the foundation wall footing. The results of the non-destructive test (NDT) indicated that, the average strength of the structural elements is within acceptable limit.
Use of the Beam Analogy Approach to Predict the Ultimate Shear Strength of Prestressed Flat Slab
(2012) AGBEDE O.A.; AJAGBE W.O.
The aim of the study was to predict the ultimate shear strength of a prestressed flat slab at the slab-column junction using the beam analogy approach. The beam analogy method, with other shear strength prediction methods such as the methods proposed by Hawkins, ACI 318-02, CSA A23.3-2004 were studied. The results were compared with the BS Code results to determine the variation in shear strength values. The approach employed a hypothetical flat slab layout, which was analyzed and designed for shear using all the various approaches while considering centre, edge and corner conditions. Values of the shear capacity were obtained using spreadsheet by varying the depth of the slab, and the area of the column. The values of the shear capacity of all the four methods were compared with the BS 8110. The results showed that there was a close relationship between the beam analogy approach and the BS 8110 method of shear strength prediction. As the depth of the slab increased, the beam analogy method was found to be more conservative, and as expected, the concrete shear stress at the slabcolumn junction reduced with increase in slab depth, which is the same depth for the idealized beam. Also, as the column area increased, while other parameters held constant, the shear strength at the junction was fortified. Also increasing the column area gave a closer relationship between the beam analogy approach and the BS Code than increasing the slab depth.