Influence of Curing Age and Mix Composition on Compressive Strength of Volcanic Ash Blended Cement Laterized Concrete

This study investigates the influence of curing age and mix proportions on the compressive strength of volcanic ash (VA) blended cement laterized concrete. A total of 288 cubes of 100mm dimensions were cast and cured in water for 3, 7, 28, 56, 90 and 120 days of hydration with cement replacement by VA and sand replacement by laterite both ranging from 0 to 30% respectively while a control mix of 28-day target strength of 25N/mm2 (using British Method) was adopted. The results show that the compressive strength of the VA-blended cement laterized concrete increased with the increase in curing age but decreased as the VA and laterite (LAT) contents increased. The optimum replacement level was 20%LAT/20%VA. At this level the compressive strength increased with curing age at a decreasing rate beyond 28 days. The target compressive strength of 25N/mm2 was achieved for this mixture at 90 days of curing. VA content and curing age was noted to have significant effect (α 0.5) on the compressive strength of the VA-blended cement laterized concrete

Integrated geophysical methods and techniques for studying the perennial springs in Ikanje- Share, Kwara State, Nigeria

An integrated magnetic, self-potential (S.P.) and electrical resistivity survey involving magnetic profiling and 1D Vertical Electrical Sounding (VES) electrical imaging techniques were carried out in the transition environment between the Nupe Basin and Southwestern Nigeria Basement Complex at Ikanje-Share in Kwara State, Nigeria. The Ikanje-Share perennial springs started gaining a lot of attention after many travelers and tertiary institutions in Nigeria made it a good choice for their fieldwork exercise. The surveys were done in order to delineate the subsurface layers, determine the geoelectrical characteristics and identify geological structures (e.g., faults and fractures) that are responsible for the perennial spring formation. The magnetic profiling was used as reconnaissance technique to identify lineament features that are favourable to groundwater accumulation and transmission. Some magnetic lineaments were qualitatively inferred from some profiles in the study area. The fault locations coincide with inflection points in S.P. curves and occur as horizontal and consistent planes of discontinuities at depths of approximately 1.25, 4.25, 8.75, 13.15 and 21.25 m, respectively. The VES interpretation results indicated four to five major geologic units, which include: the topsoil/clay/lateritic layer, the lateritic layer, the weathered basement, the weathered/fractured basement and the fresh bedrock. The weathered and fractured basements constitute the main aquifer units and the overburden thickness varies from 5.0 to 16.8 m. The study has shown the usefulness of integrated geophysical methods and techniques in subsurface structural and groundwater development study over the perennial springs in the transition environment between the Nupe Basin and the Southwestern Nigeria Basement complex

Effect of Batching Methods on the fresh and hardened properties of Concrete

This paper investigated the effect of batching by mass and volume on concrete’s compressive strength and workability. Influence of mix proportion at five levels and various water-cement ratios were also studied. All samples were cured by complete immersion in water and tested up to 28 days. The results indicated higher workabilities for concrete batched by mass than concrete batched by volume at all w/c ratios and mix proportions investigated. The workability increased with increase in w/c ratios in both methods. The compressive strength results showed that for rich structural mixes (1:1:2 and 1:1.5:3), concrete batched by mass had 20 % and 6 % strength increases respectively over the concrete batched by volume. Ordinary structural mix (1:2:4) had 14 % increase while non-structural mixes (1:3:6 and 1:4:8) had 8 % and 6 % increases respectively. In all cases, concrete batched by mass had better fresh and hardened properties of concrete

An Investigation into the Pozzolanic properties of Dutsin Dushowa volcanic ash of Jos Plateau

This study investigates the pozzolanic properties of the volcanic ash (VA) sample obtained from Dutsin Dushowa, Kerang in Mangu Local Government Area of Plateau State. Chemical Analysis of the VA sample was carried out to determine the oxide contents, so also were some physical properties (specific gravity, fineness, soundness, consistency, and water requirement and setting times (initial and final)) tests carried out on the VA sample and VA-blended cement samples. The result reflects a Silicon Dioxide (SiO2) content of 41.13% and a total Silicon Dioxide, Iron Oxide, and Aluminium Oxide (SiO2+Fe2O3+Al2O3) content of 70.99%. The VA sample has a specific gravity value of 2.65 kg/m3 while the VA-blended cement was noted to be finer than the control (Dangote - Obajana) cement. The soundness of the VA-blended cement ranged between 1.5 and 4.5 for replacement levels of 0% to 30%. The consistency increased from 30.0% to 31.5% as VA substitution increased from 0% to 30%. The water required for a standard consistency was noted to increase as the VA content increased. The initial and final setting times increased from 50 to 105 minutes and 135 to 180 minutes respectively for this replacement levels. All the VA-blended cements thereby satisfy the various code requirements up to the 30% replacement levels

Effect of Market Reforms on Cotton Agriculture in Nigeria (1960-2010)

This study examined the effect of market reform on cotton agriculture in Nigeria using time series data on cotton production from a period of 1960 to 2010.The Autoregressive Distributed Lags (ARDL) modeling approach to co-integration analysis was employed to analyze the data. Results based on co-integration and error correction specification indicated that the exchange rate, import price, external reserve and SAP are the major determinants of cotton production in the long-run while exchange rate and SAP are the major determinant in the short-run. Findings indicated that market reform has a positive and significant effect on Nigeria’s cotton production both in short-run and long-run. KEYWORDS: Cotton, SAP, ARDL, Co-integration

Effect of Foreign Agricultural Aid and Corruption on Agricultural Growth in Nigeria (2002-2013).

This study examines the effect of Foreign Agricultural Aid and Governance on Agricultural Growth in Nigeria between 2002 and 2013. Agricultural growth (proxied as agricultural GDP) was specified as a function of factors such as Foreign Direct Investment, Foreign Agricultural Aid, Land, Real Exchange rate, Control of corruption, Rule of Law, Governance, Population, Government Expenditure, Human capital and Inflation. Augmented-Dickey Fuller (ADF) unit root test was used to check the unit root properties of the variables, while quantitative estimates were based on Ordinary Least Square (OLS) modeling. The study finds that, after controlling for other factors, foreign Agricultural aid and Government Expenditure significantly affect agricultural growth while Corruption has a negative and significant effect on Agricultural growth in Nigeria. These findings suggest that while foreign agricultural aid could be a driver of growth in the Nigerian agricultural sector if well managed, Corruption will continue to hinder the goal of sustainable agricultural growth if not addressed. Keywords: Agricultural Aid, Corruption, Agricultural Growth, Nigeri

Review of Agricultural Waste Utilization as Improvement Additives for Residual Tropical Soils

The development of a nation partially depends on sustainable materials obtained from agricultural products. Increased agricultural products could increase the amount of waste generated yearly. This paper presents a review on the use of agricultural waste with pozzolanic properties (rice husk ash, Locust bean waste ash, Palm oil fuel ash, Banana leaf ash, Bagasse ash, Coconut shell ash, Bamboo leaf ash, Corn cob ash, Cassava peel ash and Palm kernel shell ash) in various geotechnical engineering applications. Interestingly, these wastes were subjected to various laboratory tests such as (particle size distribution, Compaction, Atterberg, unconfined compressive strength (UCS) and California bearing ratio (CBR)) to assess their effectiveness in soil improvement. In all these, the percentages of the materials required for soil improvement were discussed. The reports from various researchers have shown that agricultural waste having pozzolanic properties improves the engineering properties of soil. For instance, palm oil fuel ash (POFA) is mostly used as an admixture in concrete as reported elsewhere. Few studies have been carried out on the use of banana leaf ash and palm oil fuel ash as soil improvement materials. It is recommended that further researches should focus on the possibility of using other agricultural waste from Cocoyam, Yam peel, maize trunk, Cashew and Guava that have limited reporting researches for use as soil improvement materials

Calcifying epithelial odontogenic tumour-case series from five Nigerian Teaching Hospital

Background: Calcifying epithelial odontogenic tumour (CEOT) also known as Pindborg’s tumour is a relatively rare odontogenic neoplasm of epithelial derivationthat constitutes about 0.4-3% of all intraosseous odontogenic tumours.Objectives: To document all cases of CEOT encountered in five tertiary centres in Nigeria and their clinical, radiologic and histologic characteristics.Design: A retrospective study.Setting: Tertiary Dental Facilities in Lagos, Ibadan, Ife, Port Harcourt and Zaria (all in Nigeria) were involved in the study.Subjects: All odontogenic tumours (OTs) in the period from 1970 -2014. Case file records and biopsy reports were retrieved from the records of the five Teaching Hospitals, to obtain age, gender, location, size, clinical symptoms, pathological reports and radiographic description.Results: Out of a total of 1369 OTs, 20 (1.5%) cases of CEOT were reported. CEOT had a male to female ratio of 1.9:1, with mandible: maxilla ratio of 1.5:1 and the most common location being the premolar /molar region in the mandible. Nine (45%) cases appeared radiolucent while 11(55%) cases had mixed radio density. The mean diameter for mixed radio-dense lesions (4.83±2.99) was higher than that for radiolucent lesions (2.75±1.17) and the difference was statistically significant (p=0.049).Conclusion: CEOT is a rare tumour representing 1.5% of OTs. CEOT presents with some subtle geographic differences in its demography, however, further studies are required to investigate if these differences are coincidental or genetically  determined

A Response Surface Approach for Determining Optimal Mix Parameters for Normal Strength Concrete

The study evaluates the influence of water/ cement ratios and aggregates contents on the engineering properties of normal weight concrete. Response Surface Methodology (RSM) using historical design was adopted to design and develop predictive models and perform the optimization of concrete prepared with cement, fine aggregate (FA), coarse aggregate (CA) contents at different water/ cement ratio f0Q /C) by volume. Concrete mixes were prepared using fixed content of ordinary Portland cement and the different mixtures. The density and compressive strength of hardened concrete specimens were determined at the curing 28 days. The response surface analysis showed that W / C and aggregate contents have significant effects on density and compressive strength of concrete. The regression model yielded good correlations with the experimental data. The optimized density and 28-day compressive strength values of 2522.973 kg/m3 and 29.977 N/mm2 were achieved for the concrete mix containing 1.5-part ofF A, 3-part of CA and 0.60 W /C, respectively. The optimal concrete mix parameters determined using RSM provides the basis for selecting appropriate safe concrete component ratios

Geo-Electrical Exploration for Groundwater within the Premises of University of Ilorin Teaching Hospital, Ilorin, Kwara State, Nigeria

Schlumberger Vertical Electrical Soundings for groundwater search within the premises of University of Ilorin Teaching Hospital (UITH) situated along Ilorin- Jebba road in Kwara State, were carried out with a view to establishing the different subsurface geoelectric layers, the aquifer units and their hydrogeologic properties. Data were collected from 12 VES stations over an area of about 500 m x 650 m. From the quantitative interpretation of the data collected, using the usual method of curve matching with the Orellana-Mooney Master curves and 1-D forward modeling with WinResist 1.0 version software, four Hthologic units were identified. These include: the topsoil, the lateritic layer, the weathered layer/fractured layer and the fresh basement. The weathered and fractured basement constitutes the main aquifer units. The 2-D resistivity structure has elicited 2 lobes of low resistivity which constitutes the prospective zone for water in the area. The first lobe exists below stations 3 and 4 at about 5-15 m depth, with resistivity between 80- 147 ohm-m and over 300m wide, while the other lobe of low resistivity which also signifies a possible borehole location exists below stations 7,8 and 9 at a depth of about 2-14 m, with resistivity between 141-200 ohm-m and over 550 m wide. The study concluded that the area investigated contains two lobes of low resistivity which could be explored for water supply