Gideon Bamigboye

Structural Properties of Concrete Containing Ground Waste Clay Brick Powder as Partial Substitute for Cement

With the increasing concerns on the impact of cement production on the environment and the need to protect the environment, the use of mineral additives as cementitious material to partially substitute cement is being considered as an effective option. One of such material is fired clay brick which can be sourced as generated waste from clay brick industry. This has an added advantage of reducing industrial waste and preserving the natural resources. The experimental objective of this study is to examine the possibility of utilizing clay brick waste as partial replacement for Portland cement in concrete. The clay brick was finely ground into powder size, and after grinding, the morphological characterization of the powder materials was carried out using scanning electron microscopy (SEM). Moreover, the chemical composition of the brick material was determined using X-ray fluorescence (XRF). Laboratory tests were carried out to determine the workability, split tensile and compressive strength properties of the concrete with 0%, 10%, 20%, 30% and 40% partial replacement of cement with ground clay brick (CB). From the test results, the chemical composition of the brick powder meets the standard requirements for pozzolanic material, with the SEM revealing an amorphous solid mass. The workability of the concrete reduces with increase in brick powder content. A significant improvement of the split tensile and compressive strength of the concrete was achieved at 10% cement replacement, after which a decrease in strength with increasing ground clay brick content was recorded. The use of ground clay brick of not more than 15% was recommended for concrete production.

Economic Exploitation of Gravel in Place of Granite in Concrete Production

The paper investigated the application of gravel as partial economic replacement of granite in concrete production. Concrete was produced using granite/gravel combination in varying percentages of 90/10, 80/20, 70/30, 60/40, 50/50, 40/60, 30/70, 20/80 and 10/90. Concrete made from 100 % granite and 100 % gravel served controls while other constituents of concrete were kept constant. Two different mix ratios of 1:2:4 and 1:3:6 were employed. Sieve analysis was carried out on the aggregates, while slump and compaction factor tests were carried out on fresh concrete. Compressive strength tests were performed on hardened concrete. Specimens were produced using 150 mm cubes for compressive tests. The reliable percentage of granite/gravel combination from compressive strength view point 60/40 with a value of 21.15 N/mm2 for mix ratios 1:2:4 and 70/30 with 15.17 N/mm2 for 1:3:6 mix ratio at 28 days. Satisfying respectively the 20 N/mm2 and 15.17 N/mm2 minimum requirement of BS 8110: 1997.There were costs saving of 4 % per unit volume of concrete production for both 1:2:4 and 1:3:6 respectively. Empirical evidence from the regression analysis revealed that higher composition of gravel significantly improves the concrete consistency properties while greater proportions of granite do significantly enhance comprehensive strength.

Diameter Inconsistency, Strength and Corrosion Characteristics of Locally-Produced and Imported Steel Reinforcing Bars in Ilorin, Nigeria

There has been increasing incidents of collapse of reinforced concrete buildings in Nigeria. Many research works, suspecting the quality of concrete produced in Nigeria, have focused on concrete with few attention on steel, perhaps because its production is usually in a more controlled environment. Over the years, many clients of building construction projects or their representatives have shown preference for imported steel bars over the locally-produced steel bars. This research work sets out to investigate the quality of steel reinforcement produced locally and compare them with imported steel bars. The diameter of the two classes of bars available in the open market at Ilorin, Nigeria were measured and their deviations from their manufacturer’s designated diameter were determined. Also, their response to the application of load and deterioration in different environments, simulated by their immersion in water, hydrochloric acid (HCL) and sodium hydroxide (NaOH), were studied. Locally-produced bars deviated more from their designated diameter than the imported bars. The imported steel bars have higher strength and experienced lower strain compared to the locally produced steel. They also showed better corrosion resistance, when immersed in distilled water and HCL, than the locally-produced steel bars. The preference for imported steel by clients of building projects is justified.There is a need for regulatory bodies, such as the Standards Organization of Nigeria (SON), to strictly monitor and penalize local steel manufacturers that engage in corrupt practices leading to significant dimensional and strength deviations from specification. This has the potential of minimizing the incidence of building collapse in Nigeria.

Engineering properties of concrete made from gravels obtained in Southwestern Nigeria

Abstract This study investigates the engineering properties of concrete produced from gravels and also verify the suitability of local gravel aggregates obtained from Southwestern Nigeria in place of crushed granite. Preliminary investigations were carried out in five selected states (Ogun, Oyo, Osun, Ondo and Ekiti) in Southwestern Nigeria to determine the registered gravel mining pits. Fifteen gravel mining pits based on age and scale of mining operations were selected for this study. Appropriate gravel constituents in concrete mix were determined using Gs factor. Concrete cubes 150 mm, 150 × 300 mm2 cylinder modes and 150 × 150 × 750 mm3 beams were cast with collected gravel. 1:2:4 mix ratio was employed. Sieves analysis, density, water absorption were carried out on aggregates, while compressive, flexural and split-tensile strengths of the concrete were determined for 28 days using ASTM and BS methods. High concrete strengths resulted from high FM, low AAV and average Gs of gravels. Gravel location with highest compressive, flexural and split-tensile strengths of concretes had 24.8, 3.5 and 2.8 N/mm2 satisfying the minimum requirement of BS 811:1997 while that with lowest strengths had 9.6, 2.2 and 1.7 N/mm2, respectively. Sources of gravel highly influence compressive, flexural and split-tensile strengths of the cubes and beams.

Influence of Portland Cement Brands and Aggregates Sizes on the Compressive Strength of Normal Concrete

A good number of building failures have occurred in Nigeria which resulted in the loss of lives and a lot of these failures are attributed to the poor concrete practices used for the execution of these constructions. These have shown that the concrete technology adopted in Nigeria has some issues and requires urgent attention for development and improvement. This study explored methods of improving concrete practices so as to obtain better qualities structures. The research replicated some of the common concrete practices adopted by the construction industry in Nigeria to obtain the compressive strength of normal concrete. Two types of Portland cement brand, Type A and Type and three aggregate sizes (12.5mm, 19mm and 30mm) together with a mixed-size aggregate were utilized for the research. The concrete produced were tested for compressive strength and compared with test results from sites in Lagos Nigeria. The results showed how cement brands and aggregate sizes influence the compressive strength of normal concrete. The results also proved that the common poor quality concrete verified in Nigeria are not properly prepared.

Predicting Buildings Collapse due to Seismic Action in Lagos State

Buildings worldwide are one of the most essential assets of humans, and they serve as a major contributor to the sustainable development of any nation. The consequences of building collapse are colossal ranging from loss of lives, damage to properties and its attendant socio-economic implications, etc. This menace appears to be worst-off in developing countries like Nigeria where capacity to manage disaster is lacking. Recent incidence of seismic actions in hitherto geographically aseismic zone, has led to prediction of earthquake occurrence in the nearest future. This research attempts to compute the seismic hazard of buildings in Lagos State, a densely populated area of Southern Nigeria. Based on known seismic ground motion for South-Western Nigeria, a model is created that estimates the casualty and built area that would be affected by earthquakes with different seismic intensities. MATLAB software using Monte Carlo simulation to draw random data samples of built area, construction quality, probability of failure and occupancy level is used for the computational analysis. The result showed that existing construction quality is poor portending a high degree of damage during moderate intensity earthquake. A significant risk reduction is achievable for both the impending collapse and severe damage performance levels if the existing construction quality is improved.

ASSESSMENT OF STUDENTS’ CLASSROOM LEARNING OUTCOME: INFLUENCE OF ENVIRONMENTAL FACTORS

Classroom environment is not supposed to be attractive for teaching and learning alone but conducive for the test or assessment of the degree of learning taking place there. Classroom tests and examinations are means of establishing a students’ level of accomplishment in a given subject. The classroom is expected to protect the learner from the vagaries of weather, air pollution, noise and when tests are to be conducted, the time of the day, invigilation and seating arrangements has to be conducive and appropriate also. The aim of this work is to determine how these environmental factors influence the performance of students in test and examination. The research was conducted using the survey instrument of questionnaire to obtain the perception of the respondents to the effect of environmental factors on learning outcome assessment. The questionnaire was subjected to mean score analysis to obtain respondents satisfaction value of the ordinal data on Likert scale. It is reasonable to assert from the analysis of the data that a test/examination conducted in a poor physical environment, such as those with poor lighting, under poor weather, noisy environment and polluted air will not be conducive to both the student and teacher hence produce poor performance in results of test /examinations. The findings revealed that due to the poor infrastructural development of Nigeria educational system, it is obvious that there is agreement to the effect that the environment factors affect learning. It is therefore advocated that apart from good teachers being employed in our educational system, location of schools should be considered very critically using these environmental parameters before approval is given for its establishment in the country.

Study of aggregate dormancy and its effects on the properties of aggregates and concrete

Abstract In our society today most of the aggregates that were used for concrete work were usually abandoned on site for some times with minimum of 6 month or more due to different factors as it may apply. Some which might be due to lack of fund by the client and tussles. This abandonment led to a situation where construction materials are piled onsite over a range of periods of time. These materials are left dormant and exposed to harsh weathering conditions before utilization. This study accessed the effects of aggregates dormancy on its properties quality when use. The study was carried out in three calendar years (2015, 2016 and 2017) to check weathering activities on dormant aggregates. Experimental procedures such as Sieve analysis, silt content, specific gravity, water absorption and compressive strength test were carried out on these aggregates to determine its quality of performance on the product (building). Based on the duration of aggregate on site, it was observed that the strength of concrete produced from the aggregates increased and the aggregates were coarser when exposed to the weather. The study concluded that due to slight changes in compressive strength over the years, dormant aggregate has no negative effect on concrete strength and quality of structural components but it is advised that any procured aggregates meant for construction should be totally free from clay and silt contents. This will enhance the concrete strength and also accelerate its setting time.

Experimental Study on the Workability of Self-Compacting Granite and Unwashed Gravel Concrete

This study deals mainly with the mix proportions using granite and unwashed gravel as coarse aggregate for self-compacting concrete (SCC) and its workability, by considering the water absorption of unwashed gravel aggregate. Mix proportions for SCC were designed with constant cement and fine aggregate while coarse aggregates content of granite-unwashed gravel combination were varied in the proportion 100%, 90%/10%, 80%/20%, 70%/30%, 60%/40%, 50% /50%, represented by SCC1, SCC2, SCC3, SCC4, SCC5 and SCC6. 100% granite (SCC1) serves as the control. The workability of the samples was quantitatively evaluated by slump flow, T500, L-box, V- funnel and sieve segregation tests. Based on the experimental results, a detailed analysis was conducted. It was found that granite and unwashed gravel with SCC1, SCC2 and SCC3 according to EFNARC (2002) standard have good deformability, fluidity and filling ability, which all passed consistency test. SCC1, SCC2 and SCC3 have good passing ability while all mixes were in the limit prescribed by EFNARC (2002). It can be concluded that the mix design for varying granite-unwashed gravel combination for SCC presented in this study satisfy various requirements for workability hence, this can be adopted for practical concrete structures.

Assessment of Gravel Properties Sourced within Oyo North Senatorial District: Case Study of Ogbomoso

The study evaluated the properties of gravel aggregate sourced within Oyo north senatorial district for concrete production in place of crushed granite crushed at exorbitant cost since characteristic properties show significant reflections on the qualities of gravel aggregate used and also play major role in determining the properties of hardened concrete.Samples of gravel from four commonly used borrow pits: Aroje, Bolanta, Sunsun and Olomi sites were obtained and tested for Aggregate Crushing Value (ACV), Aggregate Impact Value (AIV), Specific Gravity, Water absorption Capacity, Bulk Density, Moisture Content and Particle Size Distribution.On the average the results of the observation for the selected four locations were 22.56 g, 28.17 g, 33.37 g and 40.19 g for Aggregate Crushing Value (ACV), 2.44 g/ml, 2.53 g/ml, 2.57 g/ml and 2.62 g/ml for Bulk density, 0.17 %, 1.43 %, 2.42 %, and 2.48 % for moisture content, 2.02 %, 2.92 %, 2.00 % and 3.15 for water absorption, 2.52, 2.63, 2.60 and 2.55 for specific gravity, 41. 55 %, 45.25 %, 45.59 % and 47.08 % for aggregate Impact respectively.The study revealed that, gravel aggregates from Aroje has superior properties over those of Sunsun, Bolanta and Olomi as compared with coarse aggregate properties in BS 812: 1995 and BS 882: 1992. It is hereby recommended for coarse aggregate in concrete production.