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Bediako M.,Building and Road Research Institute | Adjaottor A.A.,Kwame Nkrumah University Of Science And Technology | Gawu S.K.Y.,Kwame Nkrumah University Of Science And Technology
ISEC 2011 - 6th International Structural Engineering and Construction Conference: Modern Methods and Advances in Structural Engineering and Construction | Year: 2011

Pozzolanic materials and their utilization in mortar for masonry are uncommon in Ghana. However in many developed countries and part of Asia, mortar formulation prepared from Portland cement and a pozzolan is common. In this work clay pozzolana was produced from local technology and used to replace up to 40% OPC for masonry mortar formulation. Physical, chemical and mineralogical characterizations were investigated on the powder clay pozzolana sample. Clay pozzolana content at 10%, 20%, 25%, 30%, 35% and 40% were used to replace Portland cement to prepare binary paste and mortar. Water demand and setting time test were determined on the binary paste and compared to the plain cement paste. Compressive strength testwas performed on a 1:3 binder to sand ratio andwater to cement ratio of 0.5whichwas cured under water for 28 days. Masonry mortar strength values were analyzed in accordance to the ASTM C270 standard specification. The test results indicated that the clay pozzolana specimen satisfied the ASTM C618 standard specification. Compressive strength analysis indicated that the optimum pozzolana content in Portland cement mortar that satisfied ASTM type M and S mortars were at 20% and 40%. The incorporation of clay pozzolana to replace part of Portland cement would provide alternative mortar formulation for builders and engineers in Ghana. Copyright © 2011 by Research Publishing Services.

Affam M.,University of Mines and Technology | Archibald J.,Queens University | Akayuli C.F.A.,Building and Road Research Institute
Research Journal of Applied Sciences, Engineering and Technology | Year: 2011

This study aims at evaluating the likely effect of high stress regime within the rocks of the Birimian Supergroup of Ghana, dated middle Precambrian and offer remediation strategies. The stress levels were therefore assessed between 26-level to 50-levels (i.e., 755 to 1500 m deep) within the deepest mine in the formation. Results indicated that pre-and-post mining stresses levels were 75 and 200 MPa, respectively. These levels are quite high and could induce stress related instabilities. Fundamental studies of failure behaviour of the rockmass show that elevated stress regime of this kind poses great potential for eminent rock bursting within the Birimian. Such situations demand concerted efforts of strategic mine design measures, including modified excavation geometry and destressing or preconditioning. These methods could be exploited to extend the normal zone of stress induced fractured rock to a greater depth ahead of the excavation face. Support could be improved further by adopting higher rockbolting density or tougher mesh together with shortcrete. If the excavation becomes prone to moderate rockbursting, provision of appropriate support structure can also be made either to limit the bulking process or reduce excessive rock deformation. © Maxwell Scientific Organization, 2011.

Awotwi A.,Med Mining Company Ltd | Yeboah F.,Building and Road Research Institute | Kumi M.,Water Research Institute
Water and Environment Journal | Year: 2015

Land use and land cover (LULC) have been and still changing, through human activities, creating variability in hydrological cycle. This paper investigates the hydrological impacts of LULC changes on water balance in the White Volta Basin located in the West of Africa using the Soil and Water Assessment Tool (SWAT). Two LULC data for 1990 and 2006 and two plausible scenarios of land use change were evaluated. Results show a link between land cover and the hydrologic response with a decrease in land cover corresponding to decrease in surface water and base flow and increase evapotranspiration (ET). The results indicated that different LULC contributed to various effects in annual water yield and ET. The results also indicate the capability of the SWAT model to be used in the West African subregion even though there are data limitations associated with the model in West Africa. Overall, the model results support the existing efforts of Volta Basin water resource managers to protect the area along the Volta river against farming and indicate that additional emphasis should be placed on improving land management practices. © 2014 CIWEM.

Ben-Awuah E.,Mining Consultant | Baah-Frempong E.,Geotechnical Engineer | Akayuli C.F.A.,Building and Road Research Institute
Dams and Reservoirs | Year: 2013

Ghana Bauxite Company Ltd operates an open cast bauxite mine at Awaso in the western region of Ghana. As part of its mining activities, a 36 000 m3 water storage facility has been constructed to store water for use in the processing plant. The facility consists of a 4 m high embankment built across a valley on a silty sandy gravel foundation. Seepage forces and pore pressures in the foundation and embankment have raised some stability concerns. The principal objective of this study is to carry out an assessment of the stability of the water storage facility embankment and foundation and propose measures to improve it. The stability assessment procedures include: (a) investigating the geological, geotechnical and engineering properties of the embankment and foundation material, (b) evaluating possible failure factors such as piping, erosion, sliding and seepage; and (c) reviewing operational parameters of the facility. From the qualitative and quantitative assessments, it was concluded that the embankment of the facility was susceptible to failure resulting from inadequate compaction, seepages and overgrown tree roots. The foundation, on the other hand, was found to be susceptible to failure resulting from seepages. Recommendations for improving the embankment integrity include the construction of a toe drain, implementation of a vegetation cover management scheme and documented periodic monitoring. © 2013, Dams and Reservoirs. All rights reserved.

Afukaar F.K.,Building and Road Research Institute | Damsere-Derry J.,Building and Road Research Institute | Ackaah W.,Building and Road Research Institute
Journal of Prevention and Intervention in the Community | Year: 2010

We conducted an observational survey of seat belt use to determine the use rate of drivers and front-right passengers of vehicles in Kumasi, Ghana. Unobtrusive observations of seat belt use were made at 41 locations composed of signalized intersections and roundabouts where vehicles come to a halt or slow down considerably. The overall driver seat belt use rate was 17.6% compared to 4.9% for front-right passengers. Driver belt use was 33.2% for private cars, 9.0% for taxis, 8.3% for minibus (trotro), 13.1% for large buses and 9.7% for trucks. Overall seat belt use was higher for female drivers than for male drivers (44.8% versus 16.4%, p. < 001), was lowest within the Central Business District (CBD) compared to the outskirts of the city (16.3% versus 21.0%, p. < 001) and seat belt use rate increased with age. Passengers belted more often if drivers were belted, but about three-quarters of male passengers and 70-80% of female passengers were unbelted even when drivers were belted. In conclusion, the seat belt use rate was generally low in Kumasi, Ghana, and it is a function of occupant seating position, gender, vehicle type and usage, age group, and location setting. The results provide important preliminary data about seat belt use, particularly among male drivers and commercial vehicle occupant population. The study also suggests the need to develop effective strategies and programs that address low seat belt use in Ghana. Copyright © Taylor & Francis Group, LLC.

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