Investigation of Suitable Foundation for Storey Building in Surcharged Swampy Soil (A Case Study of Lagos State)

In Lagos, Southwestern Nigeria, the land area has been developed such that there are insufficient land spaces for building construction. It therefore becomes imperative that construction of storey buildings is inevitable to accommodate buildings within the limited land spaces. The percentage of swampy – land is high, thus restricting people to build on the little available land with little or no convenience and to effectively utilize the available land, there is need to improve the large percentage of swampy–land for construction of storey building with suitable foundation. This study therefore focused on determination of soil properties for building foundations at 1.5km South of Lagos – Epe Expressway Oloja, Ibeju Lekki Local Government Area of Lagos State.Soil samples were collected from open pits in five different locations within the study area. The undisturbed samples were obtained at depths of  3m and  were carefully transported by putting each of the samples in polythene bag and then kept in sealed container before being transported.The particle size distribution analysis of selected soil samples from the study area was carried out in accordance with the provision of BS1377: Part 2, 1990. Compaction test, Unconfined compression Strength (UCS) test and bearing capacity test  were all carried out on the collected soil samples.The results of the tests carried out on the selected soil samples showed that the soil in the study area was largely made up of silty-clay material with OMC and MDD ranging from 9.60-12.5% and 1.82-1.91 g/cm3 respectively; UCS values between 22.24 – 56.67 kN/m2 and allowable soil bearing capacity ranging from 90.95 to 106.26 kN/m2. It is recommended that Raft foundation be used for bungalows while beam/slab raft should be used for structures that have 2-5 storeys and pile foundation for structures above 5 storeys in order to cater for silt-clay nature of the soil and to prevent differential settlement in future. Keywords: Swampy Soil, consolidation, foundation, storey building

EFFECTS OF RICE HUSK BIOCHAR ON THE GROWTH CHARACTERISTICS, RHIZOSPHERIC MICROFLORA AND YIELD OF TOMATO PLANTS

Human activities have degenerated nearly 40% of the universe soil through excessive chemical inputs, tilling and industrial activities. Biochar can increase soil fecundity, agricultural producti- vity and protects soil-borne diseases. This study aimed to assess the efficacy of rice husk biochar on the growth and yield of tomato plants. Biochar was produced through feedstock (rice-husk) pyrolysis and used as soil amendments at different concentrations (20 t/ha and 40 t/ha) and an unamend soil served as control. Physicochemical properties of the soil, rice husk, biochar and biochar soil before and after planting were determined using standard methods. Rhizospheric microflora of the plants were isolated and identified based on morphological and biochemical characterizations. Agronomic parameters such as plant height, stem girth, leaf area, number of leaves, flowers, fruits and weight of fruits were determined. Results revealed that rice husk biochar (40 t/ha) had the highest physical and chemical parameters while the unamend soil had the lowest constituents. Predominant bacterium and fungus are Bacillus subtilis and Aspergillus niger. Agronomic parameters: plant heights, stem girths, leaf areas, number of leaves, flowers, fruits and weight of fruits were higher in all the amended soil than the control at the various growth stages. The unamend soil yielded no fruit at 10th week while the amended soil yielded an average fruit weight of 34.95g ± 8.76 and 21.53g ± 5.16 at 20 t/ha and 40 t/ha respectively. This study revealed that biochar produced from rice husk could be used to improve growth and yield of tomato plants.   &nbsp

The Use of Fibre Waste as Complement in Concrete for a Sustainable Environment

One of the many challenges faced in developing world is the issue of waste management. Organic fibres forms major percentage of waste produced from agricultural products and should be of great concern. Fibres have been used to reinforce composites concrete to obtain lighter weight, reduce shrinkage effects which serve to reduce environmental waste. Natural fibre is 100% bio-degradable and recyclable, thereby eliminate pollution, promote biodiversity and conservation of natural resources and thus environmentally friendly.This paper focuses on utilization of some fibres as solid wastes for making economically-friendly and affordable green environment. Three fibres: Jute, Oil palm and Polypropylene fibres were used as complement in concrete and its suitability, durability and influence on the properties of concrete were assessed. The percentages of fibre used were 0.25 and 0.5 of cement content by weight. A total of 84 concrete cube specimens were prepared for standard tests which include compression test, slump test and compaction factor test. The compression test was carried out at concrete ages of 7, 14, 21 and 28 days. As the percentage of the fibre increases, the tendency for fibre to ball up becomes higher in water. The test results showed that for Jute and Oil palm fibres, the optimum fibre content was 0.25% and for Polypropylene fibre, the optimum fibre content was 0.5%. They all yielded increase in strength when compared to the control specimen and has proven to reduce reasonable environmental waste pollution. Keywords: Environmental Pollution, Fibre, Concrete strength, Jute, Waste reductio

Effect of Epoxy-based Adhesives and Embedded Length in the Bond Strength of Post-installed Reinforcement in Concrete

In Nigerian building industry, there has been events in practice that required improving the structural integrity of existing structures: such as strengthening the interconnection between members. In cases where new structural members are to be added to the existing ones, instead of condemning the whole structure for demolition and rebuilding, post-installation process offers a remedial approach. However, the bond strength (BS) between the reinforcements and the concrete in the post-installed structural element goes a long way to determine the anchorage and effectiveness of the whole structural system. In this study, the BS characteristics of post-installed reinforcement in concrete using four different locally available epoxy-based adhesives in Nigeria were examined. Compressive strength test on concrete cubes and pull-out test on post-installed concrete were carried out for embedment lengths of multiples of 10 and 15 of bar diameters used. Average compressive strength at 28 days was 23.91N/mm2 while the highest BS for 10d and 15d are respectively 5.52 and 6.80 N/mm2 for 12mm bar diameter while corresponding values are respectively 5.38 and 6.35 N/mm2 for 16mm bar diameter. From the results, it was observed that the pull-out force which is a measure of bond Stress is more influenced by the embedded length while increasing the embedment depth from 10d to 15d for the same bar size has less influence compared to increasing bar diameter. The epoxy-based adhesives possess appreciable BS characteristics for post-installed reinforcement in concrete. However, of the three types of adhesives used, Hilti gave the highest BS capacity

Relationship Between Compressive Strength and Splitting Tensile Strength of Palm Kernel Shell Concrete

The use of palm kernel shell (PKS) has gained acceptance in the production of concrete. Compressive strength is the mostly used strength characteristics of concrete. The compressive strength CS of concrete should provide a good basis for predicting the splitting tensile strength STS. The aim of this study is to establish a mathematical relationship between the CS and STS of concrete produced with PKS. In this study, coarse aggregates was fully replaced with PKS at varying water-cement ratios (w/c) for concrete mix ratios 1:1½:3 and 1:2:4. Unit weigth of the PKS, slump, compressive and splitting tesnsile strength were determined. A relationship between CS and STS was developed for the different w/c ratios using exponential function aproximation. Physical property tests carried out on the PKS characterized it as lightweight aggregate with saturated surface dry unit weight of 1.27. The slump revealed that PKS concrete at 0.3 and 0.4 w/c is stiff and not workable. CS and STS at 28day for mix ratio of 1:1½:3 at w/c of 0.3, 0.4, 0.5 and 0.6 were respectively 3.2 and 1.2; 9.4 and 2.1; 10.8 and 2.6; 9.0 and 2.4 N/mm2. The corresponding values obtained for mix ratio 1:2:4 were 3.0 and 1.0, 1.7 and 1.3, 4.5 and 1.6, 7.7 and 1.9N/mm2, respectively. Equations relating CS and STS at 0.3, 0.4, 0.5 and 0.6 w/c were established. It was concluded that PKS concrete produced with mix ratios 1:1½:3 and 1:2:4 performed better in compression and splitting tensile strength at w/c of 0.5 and 0.6

Investigating the optimal combination for gravel and granite in blended palm oil fuel ash concrete

Global production of palm oil in 2022 was estimated at 73 million metric tonnes. The processing of palm oil generates a huge quantity of waste which is often left unprocessed leading to environmental pollution. Gravels are obtained from weathered rocks and are readily available and cheaper than granite as coarse aggregate in concrete. An innovative way of transforming waste into wealth is by incorporating these materials into concrete for construction purposes. Thus, this study was done to obtain an ideal combination of gravel and granite in palm oil fuel ash (POFA)-blended concrete. A water/cement (w/c) ratio of 0.5 in a nominal concrete mix ratio of 1:2:4 was adopted to achieve a strength of 20 N/mm2. The central composite method of optimization was utilized in designing the experiments. The best combination was determined to be 67% gravel, 33% granite and 32% POFA. This combination produced concrete with compressive strength of 23.80 N/mm2 which is 19% higher than the 20 N/mm2 target strength

SUSTAINABLE MANAGEMENT OF COW DUNG FROM SLAUGHTER HOUSES

Large amount of cattle dung are generated daily from slaughter houses which are not only of environmental concern due to methane emission but also present a significant health risk if not adequately managed.  In this study, cow dung obtained from slaughter house was anaerobically digested and its composition evaluated.8 kg of the collected cow dung was mixed with water using a mechanical stirrer set at a speed of 150 rpm to form slurry before pouring it into a laboratory scale digester affixed with stirrer, inlet and outlet ports and temperature detector. The set up was left for 3days for microbial activation to take place, before daily stirring.  Average weekly temperature of the slurry inside the digester tank was observed. Biogas produced was collected in a rubber tube and trapped with activated charcoal dissolved in 500 ml of carbon disulphide (CS2) for 120 minutes in an open air. The liquid filtrate was then analysed using a Gas Chromatography. The optimum temperature was observed at 36.5 OC. The digestion temperature variation was between 0.5 to 2 OC. Methane bacteria worked best in the temperature ranges between 34 and 37 OC. After the liquefaction process, 30 cm3 of biogas was generated. Out of which, methane occupied 25.002 cm3 (83.34 %), carbon dioxide 4.467 cm3 (14.89 %), nitrogen 0.468cm3 (1.56 %) while carbon monoxide generated was 0.063 cm3 (0.21 %). The result clearly show that methane has the highest yield, the energy contained in methane can be used as domestic gas.Cow dung is an excellent substrate for biogas production in anaerobic digesters instead of indiscriminate disposal. Bio-digestion of cow dung is a viable and sustainable solution to the problem of waste pollution, disposal, control and management

Preventing the transboundary spread of pests and pathogens through germplasm phytosanitary management

Many introduced pests (=pathogens, pests, and weeds) are responsible for major crop disease epidemics. The estimated economic impact of introduced pests on Africa's agricultural sector was up to US$3.6 trillion per year. Seed transmission of pests, along with the international distribution of plant propagation materials, is a major risk for germplasm distribution activities of IITA. As a pest risk mitigation measure, IITA established Germplasm Health Unit (GHU) to facilitate germplasm production free of harmful quarantine pests for conservation and international distribution and comply with national and international quarantine procedures. GHU uses a multidisciplinary and multistage process for ensuring phytosanitary safety: seed health testing using a range of diagnostics. Between 2017-21, GHU tested about 700,00 samples of 15 species and eliminated 8$10 per sample (US$ 5.6 million over five years). GHU distributed safe germplasm to 69 countries and prevented the transboundary spread of quarantine pests with IITA activities, making the most important contribution to national biosecurity

Strength Evaluation of Aluminium Fibre Reinforced Particle Board made from Sawdust and Waste Glass

This research investigated the effects of aluminium shavings on particleboards produced from sawdust and waste glass using Urea formaldehyde as binder. Twelve (12) boards were produced and each had different variations of sawdust, waste glass and aluminium shavings with a constant volume of adhesive used. The boards were tested for physical properties such as density, Thickness swelling (TS) and Water absorption (WA) and mechanical properties such as modulus of rupture (MOR) and modulus of elasticity (MOE). The effects of the aluminium shavings on the boards were observed in the MOR and MOE values such that these values for board A1 were 3.30 N/mm2 and 10.45 N/mm2 for 20% aluminium shavings content but reduced to 3.16 N/mm2 and 8.97 N/mm2 respectively for board A2 with 10% aluminium shavings content. This trait was observed in other boards with the same content except in boards B1 and B2 where the MOR and MOE values increased with the values for B1 being 2.06 N/mm2 and 6.98 N/mm2 and 2.91 N/mm2 and 10.17 N/mm2 respectively. The values for density of the boards increased as the sawdust decreased and also as the glass content increased. The boards with the highest values for thickness swelling and water absorption were the first three as they possess the highest quantity of sawdust. From the results, none of the boards produced met up to the requirements for use for structural purposes, board B3 possesses the highest MOR value while board D3 possesses the highest MOE value. Therefore, the boards can serve non-structural purposes such as partitions and indoor uses