Nature and Effects of Low-Volume Roads in Botswana

2003 ◽  
Vol 1819 (1) ◽  
pp. 88-95 ◽  
Author(s):  
Bizzar B. Madzikigwa
Keyword(s):  
Rural Areas ◽  
Road Network ◽  
Good Condition ◽  
Construction Materials ◽  
Road Construction ◽  
Rapid Improvement ◽  
The Road ◽  
Low Volume Roads ◽  
Low Volume ◽  
Sand And Gravel

The road sector in Botswana continues to develop its road network throughout the country at a tremendous rate. When Botswana gained independence in 1966, it had only 10 km (16 mi) of bitumen road. By 1992 the total length of bituminous surfaced road reached 3500 km (2,175 mi) out of a total road network of 18 000 km (11,285 mi). These statistics clearly show that the majority of roads are not yet surfaced; these are low-volume roads that provide access to the rural areas where most of the country’s population is found, though in low density. In spite of the rapid improvement in the quality of the national road network in recent years, much remains to be done. In the early 1970s and early 1980s the rural roads unit was introduced in the Ministry of Works Transport and Communications, which was charged with the responsibility of design and construction of low-volume roads around the country in a bid to integrate the country’s road network. This unit was later disbanded in the 1990s, and all roads are improved through the conventional procurement system using private contractors. For these roads the justification of a surfacing project based on conventional economic return methods does not apply, and worse still, the road improvements have to compete with other amenities for the same limited resources. Three ministries in Botswana are responsible for roads: Ministry of Works Transport and Communications, Ministry of Local Government, and Ministry of Trade, Industry, Wildlife and Tourism. These ministries have different responsibilities for different roads within the country, and earth, sand, and gravel roads are found under the jurisdiction of each of the ministries. The major drawbacks concerning low-volume roads in Botswana are inadequate maintenance, poor road construction materials, and the environmental impacts of the roads. Since the budget and resources are inadequate to keep these roads in good condition, it would be prudent to find technological means that would improve the locally available road construction materials so as to minimize their effects on the environment and vehicle operating costs.

scholarly journals Use of Road Stabilizers in Sensitive Environments

2020 ◽  
Vol 4 (10) ◽  
pp. 168-189
Keyword(s):  
Rural Areas ◽  
Construction Materials ◽  
Road Construction ◽  
Engineering Properties ◽  
The Road ◽  
Polymer Binders ◽  
Traffic Loads ◽  
Environmental Properties ◽  
Environmentally Sensitive ◽  
Maintenance Requirements

Road infrastructure is key for any developing country to enable its expansion such as those in Africa. Natural road construction materials can become depleted and increasing traffic loads produce higher maintenance requirements, leading to research to develop additives that can be used to enhance the engineering properties of available pavement soils. Providing all weather roads for large vehicles in rural areas, such as Northern Namibia, are often based only on the available soils, involving compaction and use of stabilizers, is required to both provide a suitable load bearing road surface and maintain the road network. The region is also environmentally sensitive to any potentially adverse impacts of chemicals that may be released into the environment during construction or as breakdown products. A number of road stabilizer products are available and the choice of stabilizer must take into account both its specific properties and the sensitivity of the environment where it is to be used to any environmental impacts. The main stabilizer types are cementitious, bituminous and chemical, with the latter broken down in a range of materials including synthetic polymer binders, organic and ionic compounds, salts, enzymatic products and combinations thereof. Twenty available stabilizer products were considered in terms of their environmental properties and assessed against the published literature and the general findings reported in terms of the overall ranking of the environmental impact of stabilizer types.

scholarly journals An investigation into the cause of road failure along Sagamu-Papalanto highway southwestern Nigeria

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ubido Oyem Emmanuel ◽  
Igwe Ogbonnaya ◽  
Ukah Bernadette Uche
Keyword(s):  
Construction Materials ◽  
Road Construction ◽  
Linear Shrinkage ◽  
Liquid Limit ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Southwestern Nigeria ◽  
Low Resistivity ◽  
The Road ◽  
Cause Of Failure

AbstractInvestigation into the cause of road failure has been carried out along a 60 km long Sagamu –Papalanto highway southwestern Nigeria. Geochemical, mineralogical, geotechnical and geophysical analyses were conducted to evaluate the cause of failure along the study area. The results of the laboratory tests showed that the percentage amount of fines ranges from 12 to 61.3%, natural moisture content from 6.8 to 19.7%, liquid limit in the range of 25.1–52.2%, linear shrinkage between 3.96 to 12.71%, plastic limit ranges from 18.2–35%, plasticity index ranges from 5.2 to 24.6%, free swell in the range from 5.17–43.9%, maximum dry density ranges from 1.51–1.74 g /cm3, specific gravity ranges from 2.52–2.64 and CBR between 3 and 12%. The Cone Penetrometer Test (CPT) shows a resistance value of 20–138 kgf/cm2. The major clay mineral that is predominant in the studied soil is kaolinite. The major oxides present are SiO2, Al2O3, Fe2O3, K2O, Na2O, MgO and CaO. The result of the 2D Electrical Resistivity Imaging revealed a low resistivity values for profile 2 and 3 ranging from 100 Ωm – 300 Ωm, between a distance of 20 m – 240 m along the profile to a depth of 7.60 m and a low resistivity value ranging from 50 Ωm – 111Ωm, between a distance of 80 m − 120 m along the profile to a depth of 15 m. It was concluded that the low CBR, low MDD and the class of subsoils namely A-26, A-7, A-2-7 (clayey soils) which were identified are responsible for the cause of failure experienced in the study area. These makes the soils unsuitable as road construction materials and hence, there is need for stabilization during the reconstruction and rehabilitation of the road.

scholarly journals THE PENETRATION OF ENGINEERING BY ECONOMICS: McFADDEN AND THE TRANSFORMATION OF ROAD DEMAND ESTIMATION

2021 ◽  
Vol 43 (2) ◽  
pp. 262-278
Author(s):  
Ariane Dupont-Kieffer ◽  
Sylvie Rivot ◽  
Jean-Loup Madre
Keyword(s):  
Road Network ◽  
Road Construction ◽  
Demand Estimation ◽  
Demand Modeling ◽  
The Road ◽  
Collective Decisions ◽  
The Face ◽  
Decision Making Processes ◽  
On The Road ◽  
The 1960S

The golden age of road demand modeling began in the 1950s and flourished in the 1960s in the face of major road construction needs. These macro models, as well as the econometrics and the data to be processed, were provided mainly by engineers. A division of tasks can be observed between the engineers in charge of estimating the flows within the network and the transport economists in charge of managing these flows once they are on the road network. Yet the inability to explain their decision-making processes and individual drives gave some room to economists to introduce economic analysis, so as to better understand individual or collective decisions between transport alternatives. Economists, in particular Daniel McFadden, began to offer methods to improve the measure of utility linked to transport and to inform the engineering approach. This paper explores the challenges to the boundaries between economics and engineering in road demand analysis.

scholarly journals MODERN DEVELOPMENT OF RUSSIA'S ROAD SECTOR: PROBLEMS AND PROSPECTS

2018 ◽  
Vol 6 (1) ◽  
pp. 11-11
Author(s):  
Наталья Борисова ◽  
Natal'ya Borisova ◽  
Елена Егорова ◽  
Elena Egorova ◽  
Александр Борисов ◽  
...  
Keyword(s):  
Economic Development ◽  
Economic Activity ◽  
Road Network ◽  
Road Construction ◽  
Transport Infrastructure ◽  
The Road ◽  
Modern Development ◽  
Socio Economic Development ◽  
The Russian Federation ◽  
Advanced Development

The article considers the most important component of the transport infrastructure - the road infrastructure, which at the same time is one of the most important spheres of economic activity. The socio-economic development of the Russian Federation has been studied, requiring advanced development and modernization of the road network as part of the transport infrastructure of the country and world space, as well as improving the technical level of road construction.

Methodology of Inventory the Real Estate Components for the Purpose of Their Valuation Due to Road Construction – Case Study in Krakow

2017 ◽  
Author(s):  
Monika Siejka ◽  
Monika Mika
Keyword(s):  
Real Estate ◽  
Communication Systems ◽  
Road Network ◽  
Measurement Techniques ◽  
Road Construction ◽  
The Real ◽  
The Real Estate ◽  
The Road ◽  
Investment Process

The development of the communication systems determines the economic level of the country. In Poland, despite the successive investments in this area, it is still not enough beneficial solutions to the road network and international calls. The problem of the acquisition of property for public roads on both the valuation principles and the way of obtaining land for these purposes is constantly modified. These changes are intended to simplify the procedures, which have a significant impact on shortening of the investment process. The current provisions of law give the possibility of the start of road investment before a property owner receives compensation for land taken for this purpose. This situation requires an inventory of component parts of the property for the purposes of their valuation. The paper presents the methodology of inventory the real estate components for the needs of their valuation using modern measurement techniques GNSS and GIS.

Evaluation of the Long-Term Performance of Woven Geotextile Used between Base Course and Subgrade of a Paved Road

2019 ◽  
Vol 2673 (8) ◽  
pp. 310-321 ◽  
Author(s):  
Saad Ullah ◽  
Burak F. Tanyu ◽  
Erol F. Guler ◽  
Edward J. Hoppe ◽  
Emre Akmaz
Keyword(s):  
Transportation Network ◽  
Experimental Program ◽  
The Road ◽  
Low Volume Roads ◽  
Road Profile ◽  
Low Volume ◽  
Base Course ◽  
Virginia Department ◽  
Paved Road ◽  
Term Performance

The purpose of this research was to investigate the properties of the exhumed geotextile from a low-volume road on the Virginia Department of Transportation network. The exhumed geotextiles have been in service for 23 years, which provided an opportunity to evaluate the longevity of the materials as well as to make assessments of how it relates to the changes in material properties. During this investigation, subgrade and base course materials were also obtained from the same site and an experimental program was developed to evaluate the effectiveness of the exhumed geotextiles for separation, stabilization, and filtration for the base course thicknesses of 4, 6, and 8 in. The results from this study combined with the results from the previous studies conducted at the same site showed that when the geotextile is placed between the subgrade and base course, the thinner the pavement section, the more evident the effectiveness of the geotextile improvements. One important finding of this research was that the placement of a geotextile reduced the particle breakage caused by abrasion under the applied transient loads. This was observed as a stabilization effect of the geotextile inclusion. As a general conclusion, for low-volume roads with relatively thin pavement sections, properly selected geotextiles provide benefits for separating the subgrade and base course (minimizing pumping), filtering infiltrated or ground water, and stabilizing the road profile. These benefits become more apparent when the thickness of the base course is less than 8 in.

Long-Lasting Gravel Roads: Case Study from the United States

2003 ◽  
Vol 1819 (1) ◽  
pp. 161-165 ◽  
Author(s):  
Ali A. Selim ◽  
Kenneth O. Skorseth ◽  
Ratnasamy Muniandy
Keyword(s):  
United States ◽  
Rural Areas ◽  
Road Construction ◽  
The United States ◽  
Fine Aggregate ◽  
The Road ◽  
Dynamic Cone Penetrometer ◽  
Subgrade Soil ◽  
Long Time ◽  
Aggregate Base

Gravel surfacing is commonly used on low-volume roads in rural areas of the United States to form farm-to-market networks that contain more than a million miles of unpaved roads. Some of these roads carry appreciable amounts of trucks and farm machinery. Some of these roads, if properly designed and constructed, can last a long time. One such road is in Hand County, South Dakota. This road was constructed in 1963 and has never been rehabilitated or reconstructed since its construction, and it has shown excellent performance for more than 37 years. This road normally carries less than 200 vehicles per day, but significant numbers of heavy trucks use the road. This exceptional performance led to an investigation of the reasons why that road lasted as long as it did without major maintenance or rehabilitation. Although this type of road construction is common in other nations, under different names, the practice of constructing this type of road in the United States was done without documented specifications. The main objectives of the study were to determine all factors that contributed to the longevity and the remarkable performance of this road through field and laboratory investigations. Field investigations with a dynamic cone penetrometer (DCP) revealed that both the quality and the quantity of aggregate base were more than adequate. Although the subgrade soil was classified as A6 according to AASHTO soil specifications, it provided good support according to DCP data. Tests of the flatness and elongation of the coarse aggregate and the angularity of the fine aggregate also revealed satisfactory results. Gradation tests also revealed compliance with specifications.

Optimization of Road Networks Using Evolutionary Strategies

1997 ◽  
Vol 5 (4) ◽  
pp. 419-438 ◽  
Author(s):  
Frank Schweitzer ◽  
Werner Ebeling ◽  
Helge Rosé ◽  
Olaf Weiss
Keyword(s):  
Road Network ◽  
Optimization Problems ◽  
Optimal Solution ◽  
Road Construction ◽  
Stationary Regime ◽  
Analytical Approximation ◽  
Evolutionary Strategies ◽  
The Road ◽  
Total Length ◽  
Fitness Value

A road network usually has to fulfill two requirements: (i) it should as far as possible provide direct connections between nodes to avoid large detours; and (ii) the costs for road construction and maintenance, which are assumed proportional to the total length of the roads, should be low. The optimal solution is a compromise between these contradictory demands, which in our model can be weighted by a parameter. The road optimization problem belongs to the class of frustrated optimization problems. In this paper, a special class of evolutionary strategies, such as the Boltzmann and Darwin and mixed strategies, are applied to find differently optimized solutions (graphs of varying density) for the road network, depending on the degree of frustration. We show that the optimization process occurs on two different time scales. In the asymptotic limit, a fixed relation between the mean connection distance (detour) and the total length (costs) of the network exists that defines a range of possible compromises. Furthermore, we investigate the density of states, which describes the number of solutions with a certain fitness value in the stationary regime. We find that the network problem belongs to a class of optimization problems in which more effort in optimization certainly yields better solutions. An analytical approximation for the relation between effort and improvement is derived.

scholarly journals An Investigation into the Cause of Road Failure Along Sagamu-Papalanto Highway Southwestern Nigeria

2021 ◽  
Author(s):  
OYEM EMMANUEL UBIDO ◽  
Igwe Ogbonnaya ◽  
Bernadette Uche Ukah
Keyword(s):  
Construction Materials ◽  
Road Construction ◽  
Linear Shrinkage ◽  
Liquid Limit ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Southwestern Nigeria ◽  
Low Resistivity ◽  
The Road ◽  
Cause Of Failure

Abstract Investigation into the cause of road failure has been carried out along a 60km long Sagamu –Papalanto highway southwestern Nigeria. Geochemical, mineralogical, geotechnical and geophysical analyses were conducted to evaluate the cause of failure along the study area. The results of the laboratory tests showed that the percentage amount of fines ranges from 12-61.3%, natural moisture content from 6.8 to 19.7%, liquid limit in the range of 25.1-52.2%, linear shrinkage between 3.96 to 12.71%, plastic limit ranges from 18.2-35%, plasticity index ranges from 5.2 to 24.6%, free swell in the range from 5.17 – 43.9%, maximum dry density ranges from 1.51 -1.74g /cm3, specific gravity ranges from 2.52-2.64 and CBR between 3-12%. The Cone Penetrometer Test (CPT) shows a resistance value of 20-138 kgf/cm2. The major clay mineral that is predominant in the studied soil is kaolinite. The major oxides present are SiO2, Al2O3, Fe2O3, K2O, Na2O, MgO and CaO. The result of the 2D Electrical Resistivity Imaging revealed a low resistivity values for profile 2 and 3 ranging from 100 Ωm – 300 Ωm, between a distance of 20m – 240 m along the profile to a depth of 7.60m and a low resistivity value ranging from 50 Ωm – 111Ωm, between a distance of 80 m –120 m along the profile to a depth of 15m. It was concluded that the low CBR, low MDD and the class of subsoils namely A-26, A-7, A-2-7 (clayey soils) which were identified are responsible for the cause of failure experienced in the study area. These makes the soils unsuitable as road construction materials and hence, there is need for stabilization during the reconstruction and rehabilitation of the road.

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