Sustainability and Resilience of Transportation Infrastructure in African Countries

Lead Research Organisation: Durham University
Department Name: Engineering

Abstract

To address the global challenge of providing sustainable and resilient infrastructure for African countries, this proposal brings together leading researchers from Durham University with Kwame Nkrumah University of Science & Technology (Ghana), University of Pretoria (South Africa) and Nyaoro & Associates (Tanzania). The research outlined in this proposal will investigate (i) the use of sustainable (locally occurring) construction materials in road construction and (ii) the impacts of climate change on transportation infrastructure. A key common element will be the measurement of suction in laboratory and field testing, using high suction tensiometers developed at Durham University.

The use of locally available materials will be investigated for the design and construction of sustainable low volume roads (with traffic volumes of less than 300 vehicles per day). For low-volume sealed roads it is the road environment (controlled by climate, drainage and construction details) that is the most important factor influencing the road performance, rather than traffic loading. The novelty of the research proposed is to gain knowledge of the fundamental behaviour of road construction materials in tropical climate conditions through the principles of unsaturated soil mechanics. There is currently a disjoint between the requirements of specifications for road construction and observed performance. This can be explained by the lack of understanding of unsaturated conditions within the road base, due to a lack of field measurements of suction in these environments. Based on field measurements in different climatic conditions in Ghana and Tanzania, supported by water retention measurements in the laboratory, it will possible to address (i) adapting the specification and road design to suit local materials; or (ii) adapting or modifying the materials (by stabilisation) to suit a realistic specification.

Climate change in Africa has been manifest by extreme weather and changing rainfall patterns. To consider the impacts of climate change, suction and water content measurements will be obtained for a railway line in South Africa. These will be used to identify potential deterioration of transportation infrastructure due to wetting/drying cycles. This deterioration mechanism is likely to be exacerbated by climate change, when dry/wet cycles are expected to have greater amplitude, due to a reduction in precipitation (even drought) in dry seasons and more intense rainfall in wetter seasons. Another aspect related to the resilience of railway infrastructure in response to climatic and environmental influences is the performance of railway formation under heavy axle, cyclic loading. It is thought that the stiffness of the formation is linked to the unsaturated behaviour of the layerworks and that this relationship is key to understanding the long-term performance of the formation. These measurements will be interpreted in the light of existing historical data at this specific research site in South Africa, that spans a period of 12 years.

Planned Impact

The project will demonstrate the following contributions to society and the economy:

1. It will demonstrate major economic impact in providing technologies that can reduce the costs to the economy of African countries:

(a) Construction of Low Volume Rural Roads (LVRR) using sustainable local materials. Experience in Botswana led to cost savings in excess of £16m (on the main road network alone). More recently, AFCAP have reported cost savings to construct low volume sealed roads of the order of £490m in Kenya and £10m in Malawi. Seventy percent of the cost of constructing LVRR roads is the material costs, so use of local materials (rather that unsustainable crushed rock with long haul distances) will provide major cost savings.

(b) Identifying potential deterioration of transportation infrastructure due to wetting/drying cycles. This deterioration mechanism is likely to be exacerbated by climate change, when dry/wet cycles are expected to have greater amplitude. The project will enable strategies to be developed for improving the resilience of infrastructure in response to shrink/swell action that causes damage to roads and railway formations.

2. It will have social impact through assisting in developing the rural road network in African countries that can provide opportunities for trade and for mobility and access to services of education and health.

3. It will provide contributions to public services and policy, by setting out clear advice on use of local materials that can be adopted by government roads departments and civil engineering contractors.

4. It will provide economic opportunities for geotechnical design consultants and geotechnical contractors as a potentially novel approach to road design that will have an international market.
 
Description Ministry of Roads and Highways, Ghana 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Workshop with stakeholders involved in roads and transportation was held on 2nd March 2018 in Accra, Ghana. A total of 34 Engineers participated in the presentation with the following breakdown: 10 from the Ministry of Roads and Highways, 4 from the Department of Urban Roads, 10 from the Ghana Highway Authority, 8 from the Department of Feeder Roads and 2 from KNUST. Prof. S.I.K. Ampadu made a presentation on "Sustainability
and resilience of transportation infrastructure in African Countries".
Year(s) Of Engagement Activity 2018
 
Description Sustainability and Resilience of Transportation Infrastructure in African Countries 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The Engineer's Centre in Accra, Ghana hosted a Stakeholder meeting and workshop on Tuesday 14th May 2019 for the UK funded "Transport Africa" research project. The workshop was organized to present the outcome of the project at the time and discuss the influence of climate change on the sustainability and resilience of transportation infrastructure (roads and railways) in Ghana, Tanzania and South Africa. Participants were 50 and from Ministry of Roads and Highways, Ghana Consulting Engineers Association, Ghana Institution of Engineers, Building and Road Research Institute, Association of Road Contractors, Association of Progressive Contractors (APC). According to the question and discussion afterwards, the audiences showed interests in the presented subject and outcome of the project and were motivated to consider the influence of climate change on the road construction protocols at the design stage.
The breakdown of the workshop was as below:
Welcome - Prof. Samuel Ampadu; Background to the Transport Africa project - Prof. David Toll; Sites, Materials and Field Monitoring; Previous work in Ghana - Prof. Samuel Ampadu; Suction measurement system - Arash Azizi; Ghana sites - Felix Ayeh; Tanzania Sites - Mwajuma Lingwanda; South Africa Sites - Sydney Larea; Suction measurements and water retention behaviour - Arash Azizi; Triaxial and Direct Shear Test Results - Ashutosh Kumar & Arash Azizi; Questions and Discussion.
Year(s) Of Engagement Activity 2019
 
Description Transport Africa Group Stakeholders Meeting and Workshop on Sustainability and Resiliencce of Transportation Infrastructure 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Stakeholders meeting and workshop was organized in University of Cape Town, South Africa on Friday 11 October 2019. The outcome of the project at the time was presented and influence of climate change on the sustainability and resilience of transportation infrastructure was dicussed. Participants were 12 and showed interests in the presented subject and outcome of the project. The breakdown of the workshop was as below:

Hosts welcome; Hannes Gräbe (University of Pretoria); Denis Kalumba (University of Cape Town)); General introduction David Toll (Durham University); Railway Research at the University of Pretoria; Field Measurement of unsaturated soil properties Arash Azizi; Railways Field testing 1 (South Africa) Sydney Laryea; Railways Field testing 2 (SA) Rick Vandoorne; Roads Field Testing (Tanzania) Mwajuma Lingwanda; Roads Field and Soil testing (Ghana) Felix Ayeh; Laboratory Testing & Numerical Analysis Ashutosh Kumar; Laboratory Testing & Numerical Analysis Arash Azizi; Discussion and Closing Remarks
Year(s) Of Engagement Activity 2019
 
Description Unsaturated Soils Course at the African Regional Conference SMGE 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact TC106 (with support for TC107 on Lateritic Soils) ran a Course on Unsaturated Soil Mechanics during the 17th African Regional Conference on Soil Mechanics and Geotechnical Engineering in Cape Town, South Africa on Monday 7th October, 2019. More than 100 people participated in the presentations including practitioner, engineers, academics and postgraduate students. Discussions made afterwards showed audiences have realised the importance of unsaturated soil mechanics for future climate risk managements.
Presentations were given by:
Professor David Toll, Durham University, UK
Introduction to basic principles of unsaturated soils: suction measurement, soil water retention behaviour, shear strength of unsaturated soils
Professor Samuel Ampadu, Kwame Nkrumah University of Science and Technology, Ghana
Behaviour of tropical/lateritic soils and their uses as road construction materials.
Professor António Gens, Universitat Politècnica de Catalunya, Barcelona, Spain
Introduction to numerical modelling of unsaturated soils with applications
Professor Charles Ng, Hong Kong University of Science and Technology
Fundamental properties and behaviour of lateritic soils from Nigeria and Ghana including wetting and drying, heating and cooling.
Year(s) Of Engagement Activity 2019