Impact of Erosion on Street Roads: A Case Study Of Sijuwade Area Akure Ondo State Nigeria

This research evaluates the impact of erosion and runoff on street roads. Reconnaissance survey   was carried out to assist in the identification and accurate delimitation of the study area, out of which thirteen streets were selected. Factors responsible for erosion in the study area were observed to ranges from natural cause including topography, rainfall and soil nature. Human factor responsible for erosion in the area studied include land use pattern and waste disposal method, poor construction and maintenance activity. Effect of erosion on the studied area includes Rendering of road way non motorable through creation of gullies, Carving in (slope instability) on drains ditches that were not lined, Flooding of road ways during rain due to blockage of drains, Pollution of water bodies in the environment as a result of sediment deposition, Destruction of Pavement infrastructure i.e. pavement, culverts and drainages. It is therefore concludes that Erosion also have various effects on street roads not all factors assumed to be responsible for erosion form agricultural perspective is responsible for erosion on street roads. However, with good management practices, and paving of roads, the problems of erosion in built up area can be controlled. Keywords: Reconnaissance Survey, Erosion, Runoff, Street Roads, and Road infrastructur

Performance appraisal of the traffic intersection complex at Mokola, Ibadan, Nigeria

Throughput time reduction is an integral part of transportation benefit analysis and traffic engineering optimization objectives. It is for this reason, that a large majority of transportation projects view throughput time reduction as one of their principal objectives. An appraisal of the performance of a traffic intersection complex at Mokola, Ibadan, Nigeria using a conflict intensity approach is presented. This work was carried out in order to quantify the effects of the flyover on the reduction of throughput times of vehicular traffic at the intersection. Conflict intensities were measured through traffic volume counts at various conflict points (through, merging and diverging locations). A floating vehicle equipped with a GPS was adopted to capture throughput times through several trial runs at the intersection. Statistical relationships were established between conflict intensities and throughput times using regression analysis. These relationships served as a framework for simulation for generating travel times (augmented), assuming the absence of a flyover. The results show a statistically significant reduction in throughput times due to the presence of the flyover with p-value of < 0.0001 at alpha level of 0.05 using Wilcoxon-Signed rank test. Specifically, reductions of 40.2seconds (33%) for northbound traffic and 27.6 seconds (28.8%) for southbound traffic were observed. This work has shown that the flyover reduced throughput times. The construction of the flyover is therefore justified and its residual potentials are enormous to handle traffic growth in the area in the near future.Keywords: Intersection Performance, Conflict Intensities, Flyover, Throughput time

Performance and Microstructural Evaluation of Asphalt Concrete Produced with Hydrated Lime, Glass Powder and Cement Modifiers

The increasing axle load arising from the growth in vehicular volume reduces the durability of road pavement, hence the need to further strengthen the road pavement. This research focuses on the determination of the performance of asphalt concrete in relation to the microstructural characteristics of the asphaltic concrete produced with hydrated lime, glass powder and ordinary Portland cement as modifiers. Asphalt Concrete (AC) mixes were prepared with Dangote 3X cement (D3C), Lafarge Superset cement (LSC), hydrated lime (HL) and glass powder (GP) in varying proportions of 20, 40, 60, 80 and 100%. The stability and morphology of the asphalt concrete produced were determined using Marshall stability test and scanning electron microscopy respectively. AC containing GP and HL showed maximum stability of 3.61 kN and 4.01 kN respectively. The maximum stability values obtained for the samples containing D3C and LSC as fillers are 4.21 kN and 5.10 kN respectively; these stability values meet the minimum Marshall Design criteria of the Asphalt Institute. The microstructural analysis of the asphalt concrete samples showed that GP has the lowest maximum pore value of 4.39 µm2 in which the inter-particulate spaces in the AC produced with GP are small and the agglomeration of the particles indicated that they are densely packed and are characterized with good strength

Evaluation of the Strength Properties of Asphalt Concrete using Natural Fibres as Reinforcing Additives

The period of maintenance and rehabilitation of asphalt concrete pavement can be increased by using fibres as reinforcement in a bituminous mix. Shredded Sisal fibre (Agave sisalana) and Sponge gourd (Luffa cylindrical) were used as reinforcements in bituminous mix. The fibres were added to hot mix asphalt in varying proportion of 0.1%, 0.2%, 0.3%, 0.4% and 0.5% by weight. The strength of fibre reinforced asphalt concrete was determined by conducting Marshall stability test. The tensile strength on 40 strands of fibre gave 167.43 N/mm2 and 24.58 N/mm2 for Sisal fibre and sponge gourd fibre respectively. Marshall Stability test results indicated that Sisal fibre gave minimum and maximum values of 4.46 kN and 5.54 kN, respectively, which exceeded the 3.5 kN minimum stability value for wearing course in the Nigerian General Specification for Roads and Bridges. The flow values obtained showed that the flow values are more than the 4 mm minimum value except for 0.1 sisal fibre dosage which has a value of 3.99 mm. The high flow values obtained was an indication of the reinforcing effects of the fibres which made the asphalt concrete stronger and hence have great resistance to plastic deformation