needs: doing more with less in mozambique · gravel, otta seal surfacing provided • short-term...
TRANSCRIPT
SARF/IRF 2014 | 2-4 September, South Africa
ADDRESSING AFRICA’S MAINTENANCE NEEDS: DOING MORE WITH LESS IN
MOZAMBIQUE
By
Andrew Otto, BSc(Hons), MSc, CEng, MCIHT Senior Research Engineer, Transport Research Laboratory, UK
SARF/IRF 2014 | 2-4 September, South Africa
The Maintenance Burden
Maintenance Strategies
Mozambique Approach
Challenges Faced
Way Forward
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2
3
4
5
Discussion Topics
SARF/IRF 2014 | 2-4 September, South Africa
1. Introduction: – maintenance backlog
SARF/IRF 2014 | 2-4 September, South Africa
1. Introduction: - The maintenance burden (Main Network)
SARF/IRF 2014 | 2-4 September, South Africa
1. Introduction: - The maintenance burden (Rural Network)
SARF/IRF 2014 | 2-4 September, South Africa
1. Introduction: - the importance of all roads
Agricultural produce and Rural communities
Trunk Road
Link Road
Collector/ Rural Road
SARF/IRF 2014 | 2-4 September, South Africa
Enhancing the Value of each $ spent
for road maintenance
2. Maintenance Strategies
Improving bottlenecks on the network
Efficient utilisation of resources
Techniques that increase the life of the road
Research and development
SARF/IRF 2014 | 2-4 September, South Africa
3. Mozambique Approach • Mozambique launched Rural Roads Improvement Programme (RRIP) 2007 • Department for International Development (DFID) launched African
Community Access Programme (AFCAP) 2008
Mozambique RRIP • Critical sections of
road maintained to Satisfactory level
DFID: AFCAP • Promote use of
proven low-cost solutions that maximise use of local resources
• Share research and innovation that has been tried and tested in other countries
• Access to areas cut off during the wet season
• Access to rural communities to reach to basic services and social and economic opportunities
SARF/IRF 2014 | 2-4 September, South Africa
3. Mozambique Approach: - Projects
Research and innovative solutions tried out on bottlenecks so as to apply successes on wider scale
SARF/IRF 2014 | 2-4 September, South Africa
3. Mozambique Approach: - Projects
Marracuene - Macaneta
SARF/IRF 2014 | 2-4 September, South Africa
3. Mozambique Approach: - Projects
Marracuene – Macaneta • Challenge:
• Material available in abundance was only fine non-plastic sand
• Solutions • For unpaved road, blended with clay to meet certain
engineering parameters • For paved roads, used in Emulsion Stabilised Sand Base and
Slurry Seal
• Short-term Performance • Very good no defects; only slight abrasion of slurry 0.5m2
• Cost: US$342,000/km
SARF/IRF 2014 | 2-4 September, South Africa
3. Mozambique Approach: - Projects
Cumbana - Chacane
SARF/IRF 2014 | 2-4 September, South Africa
3. Mozambique Approach: - Projects
Cumbana – Chacane • Challenge:
• Loose sand in dry season, boggy in wet season and impassable; moderate plastic calcrete gravels
• Solutions • Plastic calcrete blended with loose sand to meet certain
engineering parameters and used as base course or gravel wearing course
• Plastic calcrete screened carefully and used as an Otta Seal surfacing
SARF/IRF 2014 | 2-4 September, South Africa
3. Mozambique Approach: - Projects
Cumbana – Chacane • Short-term Performance
• For sealed sections: Very good; minor stone loss and potholing. Roughness remained constant 4.3IRI
• For gravel wearing : low gravel loss < 20mm/year. Roughness increases rapidly from 7 to 21IRI in two years, but light grading and compaction restores it to 7IRI
• Cost: US$140,000/km
SARF/IRF 2014 | 2-4 September, South Africa
3. Mozambique Approach: - Projects
Inhacufera - Machaze
SARF/IRF 2014 | 2-4 September, South Africa
3. Mozambique Approach: - Projects
Inhacufera – Machaze • Challenge:
• Very large and coarse gravels, very low vehicle speeds and impassable to cyclists
• Solutions • Large stones removed by dozer, replaced by old river bed
gravel, Otta Seal surfacing provided
• Short-term Performance • Stone loss on Single Otta Seals, however the application of
fine river sand as a “grouting” layer on Otta Seal – 5years no defects
• Cost: US$135,000/km
SARF/IRF 2014 | 2-4 September, South Africa
3. Mozambique Approach: - Projects
Beira - Savanne
SARF/IRF 2014 | 2-4 September, South Africa
3. Mozambique Approach: - Projects
Beira – Savanne • Challenge:
• Only beach-type fine sands available nearby – loose and unstable, easily eroded
• Solutions • Cement Stabilisation and Emulsion Stabilisation for base course;
followed by Sand Seal. In-situ mixing to increase productivity rate
• Short-term Performance • “Granulation” unintended occurred as a construction defect but
became advantage. Unexpected heavy trucks abraded Sand Seal but bases remained intact
• Cost: US$124,000/km
SARF/IRF 2014 | 2-4 September, South Africa
3. Mozambique Approach: - Projects
Zero - Mopeia
SARF/IRF 2014 | 2-4 September, South Africa
3. Mozambique Approach: - Projects
Zero – Mopeia • Challenge:
• Flooding on low-lying sections; slippery sections
• Solutions • Raising road level by use of “free-draining” quartzitic gravels and
then surfacing with Otta Seal
• Short-term Performance • Road passable throughout the year, and very good riding
surface 2.4IRI. Minor potholing - corrected
• Cost: US$123,000/km
SARF/IRF 2014 | 2-4 September, South Africa
4. Challenges Faced
• Small and medium scale contractors not equipped and not trained or experienced in bituminous works • No bids received • Unacceptable quality of work
• Interventions perceived as small and not given priority by big contractors. • Overpricing (US$140K/km as compared to
US$100K/km) • Delayed construction
• Equipment such as mobile jaw crushers would have made significant difference but not available
SARF/IRF 2014 | 2-4 September, South Africa
5. Way Forward
• Training of small and medium scale contractors • Guaranteeing work to small and medium scale
contractors so that they build capacity • Government equipment pools should be considered
since small contractors do not have capacity to purchase
• Transfer of research results to wider scale maintenance of roads.
SARF/IRF 2014 | 2-4 September, South Africa
Questions and Discussions