The condition of the rural road network in South Africa is in a severe state of deterioration and remains a matter of concern for inhabitants of rural areas. Apart from heavy use, the main problem is that road development is often neglected and the main focus is placed on the geomorphic environment. The objective of this study is to identify the nature of the geomorphic constraints of vehicular access on unarmoured roads in the rural areas of KwaZulu Natal and the Limpopo Province of South Africa, and to gain a better understanding of how these function. It is hoped that some of the insights gained can then be used to inform policy decisions regarding the location and design of rural roads in the future. In this study, a number of unarmoured roads were studied in detail to identify the possible environmental constraints on vehicular access. A number of soil physical and chemical properties were used to examine the state of road degradation. These properties included particle size analysis, soil strength, Cation Exchangeable Capacity and Exchangeable Sodium Percentage. The results of the investigation of soil properties have shown that they play a significant role in road degradation. The major geomorphic factors involved in road deterioration include soil type, soil erosion and precipitation characteristics, mass movements, slope conditions and human activity. The physical characteristics, especially the soil and slope conditions, make the access roads in all study areas susceptible to soil loss. Factors such as geology, drainage and friable soils vulnerable to mass movements have been identified as seriously constraining vehicular access. Soil erosion problems in the study area are largely the result of physical and chemical properties of soils combined with steep gradients and have been identified as the primary cause of road degradation. It was further found that the socio-economic conditions, together with the anthropogenic influences such as the construction of rural access roads on vulnerable slopes, population density and the removal of vegetation cover in all the study areas have significantly enhanced road deterioration. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.

Thesis (Ph.D.)--George Mason University, 2007. / Title from PDF t.p. (viewed Oct. 29, 2007). Thesis director: Roger R. Stough. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Public Policy. Vita: p. 154. Includes bibliographical references (p. 149-153). Also issued in print.

Thesis (M. Tech.) - Central University of Technology, Free State, 2007

This research study intended to evaluate the impact of Local Government Performance Management System (PMS) on service delivery using Tshwane’s Roads and Stormwater division. / Graduate School of Business Leadership / (M.B.A.)

ENGLISH ABSTRACT: The importance of strategy execution in an organisation cannot be downplayed because without it the sustainability of the organisation is at stake. Merely having great strategies is not sufficient as the implementation is the key to direct the activities of the organisation. Middle management plays a central role in strategy execution and any disconnect between them and the top management is bound to lead to organisational failure of effective strategy execution. This research study was based on the role that middle management play in the execution of strategy at the Roads Authority (RA). Semi-structured interviews were used to interview ten middle managers of the organisation, who were randomly selected through purposive sampling. The findings reveal that middle management is failing to play the requisite role of interpreting and translating strategy into actions. The findings further indicate that there is a leadership disconnect between them and their supervisors. They are also facing challenges of questionable strategy alignment within the operations which is causing ineffective resource allocation. In addition, the results indicate that the enabling tools such as the performance management, business systems and allocation of resources are falling short of assisting middle managers in strategy implementation. Lastly, these findings can assist the case study organisation to understand the strategic transformation process at middle management level and to review it for improving and to take corrective actions. The research study was an explorative one and used a limited sample, hence it will be necessary to do further research to get more insights about the potential roles that middle management could play in strategy formulation and the contributions they currently make towards it. The findings of this study can also not be generalised as they are for use only by the case study organisation.

published_or_final_version / Public Administration / Master / Master of Public Administration

Highway alignment development is recognised as a non-linear constrained optimisation problem. It is affected by many economical, social, and environmental factors subject to many design constraints. The highway alignment development process is therefore considered complex but very important. Highway alignment development is about finding an optimum alignment solution between two termini points in a 3D space, subject to several constraints. The development process using the current method is considered complex because of the number of the design elements involved, their interactions, and the formulations required to relate them to a realistic highway alignment. Moreover, it is considered that an alignment, generated using the existing method, results in a sub-optimal solution. This is due to the fact that the two alignments (horizontal and vertical alignments) are found in two independent stages and from only a handful number of alternative evaluations. This research reports on a new approach for improving the process of highway alignment development by utilising modern technologies. It proposes a novel design approach, as an alternative to the existing method, for highway alignment development in a three-dimensional space (considering the horizontal and vertical alignments simultaneously). It describes a method for highway alignment development through station points. Station points, as points along the centre line of alignment which are defined by their X, Y, and Z coordinates, are used to define the alignment configuration. The research also considers the implications of access provision (in term of junctions) and their locations on highway alignment. The environmental factors (noise and air pollution in terms of proximity distance) and accessibility (user and link construction costs in terms of access costs) are embedded in the formulations required to represent junctions in the model. The proposed approach was tested through the development of a genetic algorithms based optimisation model. To achieve this, several algorithms were developed to perform the search. The evaluation of the solutions was handled by a fitness function that includes construction (length), location (land acquisition, environmentally sensitive areas, and soil condition), and earthwork (fill and cut material) dependent costs. Other forms of costs that are quantifiable can also be incorporated within the fitness function. The critical constraints, believed important for realistic alignments (horizontal curvature, vertical curvature, and maximum gradient) are also dealt with within the model formulation. The experimental results show that the problem of highway alignment can be better represented using the concept of station points, by which better alignment solutions (global or near global solutions) were achieved. It was also shown that the alignment development process could be simplified through the use of station points, resulting in the efficient evaluation of more alternatives. Furthermore, the results conclude that a highway alignment cannot be optimum unless it is simultaneously optimised with junctions. Further investigations and development are also recommended for future studies.

No description available.

No description available.

Eco-friendliness, energy efficiency and cost effectiveness are major drivers responsible for cold recycled asphalt mixtures being considered as alternatives to hot mixtures. Although such mixtures are still regarded in some quarters as second class asphalt, results from field trials on such materials under temperate climates have been reported to be highly impressive and encouraging. Some developed countries with temperate climates have since developed guidelines for the production and use of cold mixtures in road building. However, evidence from the literature shows that little or nothing has been done to ascertain the performance and suitability of such sustainable materials in developing countries located in hot tropical climates. Ascertaining the performances of such will, among other things enable the formulation of guidelines required for producing and using these alternative sustainable materials and methods in developing countries with hot tropical climates, where available funds for road building are increasingly inadequate to meet demand. The work reported in this thesis attempts to simulate what should be expected in terms of the performance of flexible pavements containing cold mixes of bitumen emulsion stabilized RAP as road base in hot climates. Cold recycling in-plant was deemed appropriate for the obvious reason that it enables control of the quality of mixtures produced. The challenge of sourcing severely aged RAPs required for this study afforded the opportunity of developing a laboratory ageing protocol for producing RAPs with controlled properties, typical of those found in hot tropical belts (with residual binders of very low penetration). The result of the physico-chemical and rheological studies showed that ageing hot mix asphalt at 125⁰C does not degrade the binder when compared to that aged at 85⁰C, which is the conventional protocol (for temperate climates). A target mix design based on Overseas Road Notes (ORN) 19 and 31 for 20mm DBM, which the literature suggests is suitable for road base layers of road pavements, yielded an aggregate gradation containing RAP (with residual bitumen of 20dmm penetration), 5mm granite dust and granite mineral filler in the proportion 65:30:5 respectively. Further investigations patterned after Marshall and Hveem mix design methods, indicated that a cationic bitumen emulsion content of 6.5% and pre-wetting water content of 1.5% were suitable. Unlike hot mixtures, cold mixtures due to their peculiarity i.e. intermediate nature (close to unbound granular materials in early life and close to fully bound materials when fully cured), require curing before being assessed for mechanical properties such as stiffness, strength etc. Performances of the five cold bituminous emulsions mixtures (CBEMs), one with 100% virgin aggregate, the others including RAP with binder penetrations 5, 10, 15 and 20dmm, manufactured at 20⁰C and 32⁰C (to reflect average minimum and maximum temperatures in hot tropical climates) showed that: • Properties of CBEM are dependent on the state of curing or maturation attained i.e. early life, intermediate life and fully cured or stable condition; • High air void content in CBEMs appears to be inevitable; • Mixing and compaction temperature is very important for achieving relatively low air void contents in CBEMs. For example, mixing and compacting CBEMs at 32⁰C gave better results than at 20⁰C; • Indirect Tensile Stiffness Modulus is useful for quickly ranking the CBEMs; • The RAP CBEMs performed better than the virgin aggregate CBEM in terms of water susceptibility; • An increase in stiffness modulus up the range from 10dmmCBEM to 15dmmCBEM and to 20dmmCBEM, with higher values than the virgin aggregate CBEM as observed in this work gives the impression that the residual binder in the studied RAPs is active as a result of possible softening or rejuvenation. Alternatively, the stiffness enhancements could possibly have been caused by the alteration of the volumetrics of such RAP CBEMs which consequently enhanced their compactability; • Overall, RAP CBEMs are better than virgin aggregate CBEM in mechanical performance and durability; • Fatigue lives of the CBEMs are generally lower than those for hot mix asphalt (HMA); • The CBEMs are stress-dependent as they all fitted the k-Θ model. The results of the analytical pavement design showed the importance of using tools such as KENLAYER which account for the non linearity of CBEMs. Although the structural design was a hypothetical case, the results confirmed that the virgin aggregate CBEM was inferior in terms of axle loads to failure compared to the RAP CBEMs, and the RAP CBEMs were inferior to HMA. The findings of this limited investigation suggest that the studied RAP CBEMs are suitable for low volume traffic roads, an indication of the great potential of these sustainable materials when properly harnessed. In the light of this, a short and concise set of guidelines for mix design of RAP CBEMs and structural design of pavements containing such non linear materials was proposed in the thesis.