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

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

Progress From Selection of Some Maize Cultivars' Response to Drought in the Derived Savanna of Nigeria

Field experiments were conducted to investigate the variations in sixteen maize genotypes in relation to drought tolerance. The experimental set up was subjected to drought stress after five weeks of planting for three weeks before data on morphological and yield characters of maize genotypes were [DBO1] obtained for three cropping years. Plant height and grain yield of Bodija yellow maize were the highest overall. There was a significant difference among genotypes for drought stress resistance and Bodija yellow maize showed the most tolerance, while TZBR Comp 1 – C1 S2 510 genotype was the least. First principal component axis (Prin 1) had the highest contribution to the variation of the morphological, yield and drought tolerance traits. Prin 1 was highly related to the morphological and yield characters more than to the drought resistance. [U2] Plant height was negatively and strongly correlated (p<0.01) with stem height, number of leaves, stem girth, leaf length, leaf width and week after planting, but negatively correlated with the drought resistance. Therefore, Bodija yellow maize should be considered as parent material in breeding for the development of drought tolerant traits in maize

Surveillance of anti-HCV antibody amongst in-school youth in a Nigeria university

Infection with Hepatitis C Virus (HCV) is a public health problem. Worldwide, there are about 170 million people infected with HCV. HCV is transmitted through sex and use of contaminated sharp objects during tattooing or intravenous drug abuse. These routes make youth to be more vulnerable. Transfusion and mother to child transmissions are also documented modes. This study was carried out to determine sero-prevalence of hepatitis C virus infection among in school youth at Achievers University, Owo in southwest Nigeria. Samples of blood were collected from 70 undergraduate students and sera harvested were tested for the presence of antibodies against hepatitis C virus by Enzyme Immunoassay Technique. Most participants fall within age range 21-25 (91.4%). The study showed that none of the subjects was positive for anti- HCV antibodies. Education and awareness level might have impacted positively on this outcome. Thus routine screening for HCV and sustained awareness creation activities to eradicate HCV and its attendant consequences from our society is of paramount importance.Key words: HCV, prevalence, in-school youth, education

EFFECT OF COMPACTION DELAY ON THE STRENGTH OF CEMENT STABILISED LATERITIC SOIL

Soil stabilisation is a major technique in enhancing the engineering properties of Lateritic soil. There is need to investigate the effect of scenarios when there is elapsed time between when the soil-cement is mixed and when it is spread and compacted. Therefore, this study focussed on the influence of this compaction delay on the engineering properties of cement-stabilised lateritic soil. The lateritic soil was stabilised with 1.5, 3.0, 4.5 and 6.0% cement by weight of soil. The mixture of the soil-cement was left for elapsed time of 1, 3, and 5 h. The natural, stabilised and the stabilised soils with compaction delay were subjected to Sieve analysis, LL, PL. BSL, WAS and AASHTO compaction, UCS and CBR tests. The natural soil was suitable for highway construction except for base course. The MDD of the stabilised soil decrease while the MDD, UCS and CBR increase with increase in cement content. The optimal cement content for the A-2-4(0) soil is 4.5% and the effect of the compaction delay was more prominent after 2 h elapsed time

A Genetic Algorithm Approach to Optimal Sizing and Placement of Distributed Generation on Nigerian Radial Feeders

Mitigating power loss and voltage profile problems on radial distribution networks has been a major challenge to distribution system operators. While deployment of distributed generation, as compensators, has made a suitable solution option, optimum placement and sizing of the compensators has been a concern and it has thus been receiving great attention. Meta-heuristic algorithms have been found efficacious in this respect, yet the use of the algorithms in addressing problems of radial feeders is still comparatively low in Nigeria where analytical and numerical programming methods are common. Hence; the use of genetic algorithm to site and size distributed generator for real-time power loss reduction and voltage profile improvement on the Nigerian secondary distribution networks is presented. Backward-forward sweep load flow analysis, together with loss sensitivity factor, is deployed to identify the buses suitable for the installation of the distributed generation, while the algorithm is employed in estimating the optimum size. This approach is tested on the standard IEEE 15-bus system and validated using a Nigerian 11 kV feeder. The result obtained on the IEEE test system shows 183 kW loss using the compensator, as compared to 436 kW loss without the compensator; while on the Nigerian network the loss with the compensator was 4.99 kW, in comparison with no-compensation loss of 10.47kW. By the approach of this study, real power loss on the Nigerian feeder decreased by 52.3% together with energy cost reduction from N658,789.12 to N314,227.38. Likewise the minimum bus voltage magnitude and the voltage stability index of the network are improved to acceptable limits. This approach is therefore recommended as capable of strengthening the performance of the Nigerian radial distribution system

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