Journal Articles

Permanent URI for this collection

http://hdl.handle.net/10204/11487

Browse

Now showing 1 - 20 of 32

African case studies: Developing pavement temperature maps for performance-graded asphalt bitumen selection
(2022-01) Mokoena, Refiloe; Mturi, George AJ; Maritz, Johan; Mateyisi, Mohau; Klein, Pieter
The reliable performance of roads is crucial for service delivery, and it is a catalyst for domestic and cross-border spatial development. Paved national roads are expected to carry higher traffic volumes over time as a result of urbanization and to support the economic development in the continent. Increased traffic levels combined with expected increases in air temperatures as a result of global warming highlight the need to appropriately select bituminous road materials for a reliable performance of asphalt roads. The objective of the paper is to present African case studies on the development of temperature maps necessary for performance-graded bitumen selection for road design and construction. A consistent approach, that caters for the variability of geographical, environmental and climatic conditions, does not currently exist within the continent. Therefore, this paper discusses a series of critical components in the development of temperature maps for performance-graded bitumen including (i) pavement temperature models and climatic zones in Africa; (ii) the effect of urban heat islands on pavement temperature; (iii) sources of weather data and (iv) the mapping procedure to produce temperature maps. Characterizing the thermal properties of the pavement was found to be an important factor for reliably calculating expected road temperatures as well as the consideration of the ambient climate for a given location. During this study, the urban heat island effect was found to have little influence on the maximum pavement temperatures but a significant effect on the minimum pavement temperatures. Some areas of the urban district assessed in this investigation were found to increase by two performance grades according to the minimum temperature criteria. The recent observed weather data from weather stations are the most accurate means of measurement of the ambient environmental conditions necessary for performance-based specifications, but they are not always easily accessible, and therefore other sources of data, such as satellite data, may need to be used instead. With the expected temperature increases expected as a result of climate change, the use of Global Climate Models also opens new avenues for performance-based material selection in the African continent for expected climates as an alternative to traditional approaches based on historically observed weather.
Climate change adaptation in the African roads sector: Constraints, opportunities and policy challenges [poster]
(2019-10) Maritz, Johan; Arnold, Kathryn A; Roux, Michael P; Le Roux, Alize; Verhaeghe, Benoit MJA
Roads play a vital role in strengthening the socio-economic development of regions in Sub-Saharan Africa by providing local communities with critical connections between essential market points, service towns and infrastructure. The United Nations Environmental Programme describes the African continent as a ‘vulnerability hotspot’ for climate change. During the past four decades, African countries have experienced more than 1,500 recorded weather-related disasters. These disasters impact on affected countries’ economies and, in particular, on rural communities and their livelihoods. Changes to the region’s climate are causing widespread damage to road infrastructure and its associated assets. Rural accessibility is being compromised by climate variability in a number of countries for significant periods of the year, adversely affecting livelihoods and associated socio-economic development, both directly and indirectly. Although climate commitments have been undertaken by many countries in the region, policy has not always been translated into action in all sectors and the transport sector (especially rural roads) has not featured strongly when countries consider climate change actions. To enhance the capacity of roads authorities to reduce the current and future impacts of climate change on rural roads, a project was initiated by the Africa Community Access Partnership (AfCAP), a research programme funded by UK Aid, to focus on climate adaptation in this sector. Through research and knowledge sharing, the objective was to compile pragmatic, cost beneficial engineering and non-engineering procedures and guidance that could be used to direct roads sector institutions to address climate threats. A methodology for carrying out climate adaptation assessments for rural roads was developed and packaged into a handbook and series of linked guideline documents. The project further looked at addressing capacity enhancement in the AfCAP partner countries to ensure a strong focus on embedment and uptake. The study focused predominantly on three AfCAP countries, namely Mozambique, Ethiopia and Ghana. In order to embed climate change adaptation into the respective national transport authorities, several constraints had to be addressed. Two prominent issues emerged, with the first being the lack of in-country collaboration between sectors when dealing with climate change science, and the second being gaps in policies that address climate change in the transport sector. These constraints have affected the capacity of the national transport authorities in the various countries to incorporate climate change risk and vulnerability into their planning systems. The project therefore provided an opportunity to address these challenges and to enable the practical implementation of climate change adaptation in the roads sector.
Comparative Numerical Analysis of Elastic and Viscoelastic Properties in Warm Mix Asphalt
(2024-07) Kamdem, RFP; Abejide, Samuel O; Adedeji, J
The elastic and viscoelastic characteristics of Warm Mix Asphalt (WMA) and traditional Hot Mix Asphalt (HMA) are closely compared in this investigation. Motivated by the need to address environmental issues, WMA, which is characterized by lower manufacturing temperatures, efficiently lowers greenhouse gas emissions and energy consumption. Furthermore, by reducing reliance on natural aggregates, the use of Recycled Asphalt Pavement (RAP) in WMA improves sustainability. In this study, WMA15% RAP and WMA30% RAP samples were mixed with 50/70 grade bitumen modified with Sasobit additive, while the HMA samples were mixed with non-modified 50/70 grade bitumen. Through the use of Maxwell model in pony series technique, the study highlights the importance of viscoelastic characterization for precise finite element modelling, highlighting the behaviour of asphalt materials over time. Results of the study shows that elastic characterization in FEM overdesign when compared to viscoelastic while the elastic characterization in Layered Elastic Analysis model under design.
Comparing dynamic road wear of a performance-based standards and baseline vehicle
(2021-07) Steenkamp, Anton J; De Saxe, CC; Kienhöfer, F; Kemp, Lana
The paved road network is a critical asset to any country and its economy. South Africa's paved road network has an estimated value in excess of R2 trillion. This asset is threatened by a backlog in maintenance of more than R416.6 billion, estimated in 2018. Overloaded heavy vehicles can cause more than 60% of the road wear on a road network. Most road wear analysis methods use static axle loads that are assumed to be symmetrical on either side of the road. Generally, Performance-based standards (PBS) vehicles have been shown to cause less road wear per tonne of payload compared to baseline vehicles when an assessment based on static axle loads is conducted. In this study, the dynamic road wear effects and the effects of road crossfall are studied in a road wear comparison of a PBS side tipper with a baseline vehicle. The results show that the PBS side tipper vehicle produces less road wear per tonne of payload when considering the first and fourth order aggregate tyre damage criteria for 0% and 3% crossfall. The road wear saving for fourth order aggregate tyre damage criteria for the left and right side was 10% and 11.5% at 0% crossfall and 5.7% and 11.3% at 3% crossfall. The results from the aggregate fourth order tyre damage and that from the mechanistic-empirical methodology produced similar results and indicate that the aggregate tyre damage criteria could be used for assessing PBS and baseline vehicle dynamic road damage. The study supports previous research that crossfall has a substantial influence on road damage of the left and right side of a vehicle. The maximum difference in the left and right side dynamic fourth order aggregate tyre damage was 32% for the baseline vehicle and 38% for the PBS vehicle.
Contiguous aggregate packing as common principle for benchmarking asphalt density, stiffness and permeability control
(2022-03) Horak, E; Komba, Julius J; Maina, J; Sebaaly, H; Muller, J
Contiguous aggregates are aggregate sizes that consecutively follow a typical aggregate grading curve. Porosity calculation is possible for a binary or longer ranges of contiguous aggregates. Porosity is a fundamental density indicator and can indirectly be an indicator of permeability potential. The traditional Bailey method follows the principle of the ratio of void size to aggregate or simulated sphere diameter that ensures optimal aggregate packing of the aggregate skeleton. In this paper, the Bailey method description of the grading curve and defined control sieves were used as a reference, allowing the description of various Rational Bailey Ratios adhering to contiguous aggregate fractions in these ratios. Thus, porosity calculations can be done for the contiguous aggregate fractions in these defined Rational Bailey Ratios on the normal aggregate grading curve. Recent research work on asphalt mix design compaction, air void distribution, stiffness, rut resistance, correlation with permeability predictors, and density indicate Rational Bailey Ratios can be used for the optimization of HMA mix designs via benchmarking. This approach is described as the Contiguous Aggregate Packing benchmark methodology.
Correlating the asphalt-binder high-temperature properties (DSR) to HMA permanent deformation (RLPD) and field rutting: A laboratory-field study
(2020-11) Walubita, LF; Mahmoud, E; Fuentes, L; Prakoso, A; Lee, SI; Souliman, M; Komba, Julius J
Asphalt-binders are part of the key material constituents affecting the performance of hot-mix asphalt (HMA), and ultimately, the field performance of flexible pavement structures. Quite often, it is desired/useful to predict the HMA permanent deformation (viscoelastic) properties and field rutting from the asphalt-binder properties. Using the Texas flexible pavements and overlays database, namely the Texas Data Storage System (DSS), as the data source, this laboratory-field study was conducted to correlate the asphalt-binder properties to HMA permanent deformation (viscoelastic) properties and field HMA-layer rutting performance of in-service highway sections. Data extracted from the Texas DSS included asphalt-binder high-temperature rheological properties measured using the dynamic shear Rheometer (DSR) test, HMA permanent deformation (PD) and viscoelastic properties from the repeated load permanent deformation (RLPD) test, and field rut depth (RD) data for the HMA layers of in-service highway test sections. Two Texas asphalt-binder types, four HMA mixes, and four in-service field highway sections were used in the study. For some parametric comparisons, the corresponding results indicated good statistical correlations among the asphalt-binders, HMA mixes, and field rutting performance, with a coefficient of determination (R2) over 60%. Overall, the study findings indicated that the HMA PD properties and field HMA-layer rutting can be predicted from the asphalt-binder high-temperature rheological properties, with a linear or logarithmic model, to an accuracy exceeding 60%.
Design and manufacturing of an aggregate abrasion test device for testing in high acceleration field
(2021-11) Xungu, Sipho; Mgangira, Martin B; Giani, John C
This paper describes the design and manufacturing of a mechanical system, the Aggregate Abrasion Test Device (AATD), which comprises of a rolling model drum, with the purpose of obtaining experimental data that is subsequently used to quantify the abrasion behaviour of aggregate particles. The study of the abrasion behaviour of geomaterials is complex due to among other factors, non-linear mechanical properties that depend on stress levels and stress history. In this case the aggregate assemblage is subjected to different stress levels by operating the system within the geotechnical centrifuge environment. The system was tested up to a maximum gravitational force of 25-G. The paper focuses on the design, manufacturing, construction, testing of the system and the experimental lessons or findings observed during the prototype testing. The system provides an alternative experimental way for determining the durability of the aggregate solely dominated by particle-to-particle interaction mechanism.
Developments in Sustainable Geomaterials and Environmental Geotechnics
(2021-07) Yao, K; Zhenyu, M; Komba, Julius
This book presents the advancements in the field of sustainable materials in pavement engineering and related geotechnical engineering issues and sheds light on recent developments and advancements in characterization, design, construction, and quality control of sustainable materials in transportation infrastructures. This volume is based on contributions to the 6th GeoChina International Conference on Civil & Transportation Infrastructures: From Engineering to Smart & Green Life Cycle Solutions -- Nanchang, China, 2021.
A framework of key growth factors for small enterprises operating at the base of the pyramid
(2020-11) Van der Merwe, MD; Grobbelaar, SS; Meyer, Isabella A; Schutte, CL; Von Leipzig, KH
Enterprises operating at the Base of the Pyramid (BoP) find it difficult to simultaneously achieve economic (profitable growth) and social (poverty alleviation) outcomes. This study builds on a previously published systematic literature review that identified the key growth-promoting factors of the Small, Medium, and Micro Enterprises (SMMEs) operating in this space. A Grounded Theory Approach was followed to identify six core focus areas, which form the basis of a practical framework to evaluate SMMEs at the BoP, namely: Business modelling; business strategy; innovation; marketing; strategic alliances; and sustainable development. Expert screening interviews were conducted to evaluate the framework for credibility and confirmability. Thereafter, 57 for-profit South African enterprises were surveyed to empirically explore how SMMEs view and implement these framework components. The outcome of the study is a validated high growth-promoting BoP portfolio framework against which SMME owners can evaluate their enterprises to identify areas of growth and development.
Guidelines for the provision of bypass roads at and through-ways in cities and towns
(2023-07) Pienaar, PA; Mokonyama, Mathetha T; Das, DK; Pienaar, WJ; Stander, HJ; Van As, SC; Robinson, A
Roads provide linkages between cities and towns, neighbouring countries, and to other points of interest. Up until the mid-20th century, roads forming part of the national network in South Africa generally passed through cities and towns. As these areas grew and traffic volumes increased, it became clear that bypasses would be necessary. In 1960 the National Transport Commission adopted its freeway policy which included the concept of bypass roads. Despite the adoption of the concept of bypass roads, the provision of these roads remained a controversial issue. The perceived benefits to the city or town of through traffic are weighed up against the benefit of a bypass to long-distance traffic in terms of travel time and cost, and road safety considerations. The aim of the paper is to provide guidelines for the planning and management of bypass roads and through-ways, as well as for the economic impact analysis of these roads. The paper refers to Christaller’s Central Places Theory which explains the spatial distribution of a system of cities and towns, as well as the road network linking these centres with one another. The assessment of the need for a bypass road is then addressed. Guidelines are provided on aspects such as land use development, road network planning, and route determination principles. An economic analysis framework, addressing both social cost-benefit analysis and economic impact analysis methodologies, is presented. Finally certain conclusions are reached. The paper is based on a research project, Project P2.5 of 2018: “Provision of bypass roads and through-ways in settlements, towns and cities”, conducted as part of the SANRAL Research Programme.
High capacity vehicles road wear impact in South Africa
(2021-09) Kemp, Lana; Steenkamp, Anton J; De Saxe, CC
The substantial road maintenance backlog in South Africa, coupled with an inadequate budget allocation, requires high impact solutions in order to preserve the 158 000 km paved road network. Focussing efforts on the heavy vehicles operating on these routes, by ensuring they are more road friendly and payload-efficient, could potentially preserve and extend the pavement structure life. The Smart Truck demonstration project in South Africa permits high capacity vehicles to operate on approved routes outside the prescriptive South African combination mass and length limits, promoting innovation in productivity, safety and road-friendliness. Each vehicle combination participating in the project is subjected to an infrastructure assessment as a measurement of road-friendliness. The Smart Truck project has already shown an estimated $3.6 million savings in road wear over the past six years. This paper reviews the latest data on the road consumption characteristics of high capacity vehicles participating in the demonstration project and estimates the annual monetary savings of road consumption of these vehicles relative to conventional heavy vehicles.
The integration of smart mobility systems on the revised taxi recapitalisation program as a strategy to modernise the taxi industry
(2023-07) Ditshego, JK; Mokonyama, Mathetha T
This research was about establishing the extent to which digital technologies have impacted the institutional arrangements, efficiency of operational procedures, and coverage of the Revised Taxi Recapitalisation Program. However, the approach in executing this study consisted of two aspects, the first one entailed conducting field investigations to determine the geographical locations of taxi rank facilities within the study area and the categories of minibus taxis thereof, whilst establishing the type of technology systems used to manage the infrastructure and fleet within this sector. The second aspect was to assess the methods used to apply for the taxi scrapping subsidy and reviewing the government’s annual performance reports regarding the Revised Taxi Recapitalisation Program. Based on data obtained from these two approaches and using The Open Group Architecture Framework, a Taxi-Vehicle Monitoring System conceptual framework was developed. This system is anticipated to serve as a basis for incorporating and integrating smart mobility systems within the taxi industry to keep this sector competitive in the rapidly evolving digital transformation era. In addition, it is further envisaged that this system willenable the taxi industry to migrate from the current traditional methods to technology-based platforms that are integrated and efficient, thereby expediting the taxi scrapping program whilst expanding its scope to cater for all categories of taxis that transport commuters and to unlock additional government subsidies that can be introduced as a strategy to attract and enhance public-private partnerships.
Investigating the use of isothermal calorimetry for predicting physical properties of cements
(2021-09) Mokoena, Refiloe; Motau, T; Mturi, George AJ
Isothermal calorimetry is a useful technique for studying the cement hydration process that measures the heat flow of cement paste during hydration. Standard cement properties, such as compressive strength, setting times and compatibility can be derived from calorimetry investigation. This becomes relevant in assisting with monitoring the strength development during construction activities and studying the thermal related behaviour of concrete structures. During this study, the heat generated from the cement hydration reactions was investigated of four different cement types, namely CEM II/B-V 32.5N, CEM II/B-V 42.5N, CEM II/A-M (S-V) 42.5R and CEM I 52.5N. Correlations between the calorimeter results and the (i) initial setting time and final setting time; (ii) 28 day compressive strength and; (iii) fineness, were established for the cement types investigated. With the exception of early-day strength, the results indicated strong correlations between the investigated parameters and the cement hydration curves. This was particularly the case for the setting time of the cements with an R2 value of 0.82 and 0.89 for the initial and final setting times respectively.
Laboratory performance and modelling behaviour of hot-mix asphalt with recycled crushed glass
(2020-09) George, Theresa B; Anochie-Boateng, Joseph; Jenkins, KJ
In South Africa research is currently under way to determine the suitability of using locally available recycled crushed glass as a partial fine aggregate substitute in the production of asphalt mixes. This paper characterises the laboratory performance of a dense-graded asphalt wearing course mix consisting of 15% recycled crushed glass. The influence of selected antistripping additives on moisture susceptibility was specifically assessed as a variable in the performance evaluation of the glass-asphalt mix as follows: (a) the effect of 1% hydrated lime, (b) the effect of 0.5% liquid antistripping additive, and (c) the effect without the addition of antistripping additive. The effect of these variables on the moisture susceptibility of the glass-asphalt mix was evaluated using the tensile strength ratio parameter supported with a microscopic imaging analysis. Additionally, the stiffness and permanent deformation properties of the glass-asphalt mix that demonstrated optimum resistance to moisture damage was compared to the same mix without crushed glass. The performance properties were evaluated using the Huet-Sayegh model and a polynomial model respectively, which were used particularly to develop performance characterisation models for the glass-asphalt mix. The findings of this study revealed that an anti-stripping additive is essential to meet moisture susceptibility criteria and alleviate moisture damage in dense-graded glass-asphalt mixes. In particular, moisture susceptibility was improved using hydrated lime rather than the liquid antistripping additive. Furthermore, the selected constitutive models were able to effectively characterise the laboratory performance of both mixes, with the glass-asphalt mix demonstrating improved resistance to permanent deformation when compared with the conventional asphalt mix.
One Health studies that adopt a formal modelling approach: A scoping review
(2023-07) Van Heerden, N; Grobbelaar, SS; Meyer, Isabella A
While the One Health perspective provides a useful approach by which to influence the complex interactions that pose a risk to the individual and collective health of humans, animals, and the environment, approaches to its operationalization can be enhanced. Aim This study examines models as contributors toward operationalization of One Health. It describes how modelling approaches have been applied to resolve the complexity of One Health problems. Methods A scoping literature review is based on the PRISMA-Scr approach. The literature is mapped from a One Health (area of application) as well as from a modelling (model type, modelling trends, unit of analysis, level of abstraction) perspective. Results 24 articles were identified that address a spectrum from strategic to tactical and operational considerations in One Health, with the bulk of the work slanted towards the former two aspects. Models focus on supporting high-level decision-makers on disease management strategies, investments, and resource allocation, and were developed with involvement of a broad set of stakeholders in One Health. Evidence could be found of the use of the major categories of simulation models, namely, systems dynamic models, agent-based models, and discrete-event models.
Performance evaluation of bio-based fractions derived from Bacillus spp. for potential in situ soil stabilisation
(2022-02) Ramdas, Veshara; Lalloo, Rajesh; Mandree, Prisha; Mgangira, Martin B; Mukaratirwa, Samson; Ramchuran, Santosh O
Current and future research focuses on the use of renewable technologies and materials to stabilise weak soils, of varying degrees, for road construction applications. Soil stabilisation is a method of strengthening a natural soil to meet this purpose. Our interest is in the use of bio-based components, derived from microbial growth processes, that contribute to the needed desirable strength characteristics for in situ soil stabilisation. This investigation focuses on novel Bacillus-based stabilisers obtained from the vegetative and spore growth stage. In this study, eighteen bio-based components were derived from a Bacillus licheniformisfermentation and extracted into various aqueous and non-aqueous fractions for strength property assessment. The strength properties of the treated soils (i.e., dolerite and weathered granite soil) were assessed via previously developed lab-scale equipment to rapidly pre-select the best performing fractions, (i.e., compression stress, erosion, abrasion, and water absorption tests). The effect of one superior performing prototype (a) was validated at large-scale, using standard erosion and abrasion tests (i.e., whole broth at 1.8% stabiliser concentrations), and showed resistance to abrasion (3.37 ± 0.03%) (p value = 0.0001) and resistance to erosion (33.20 ± 0.15%) (p value = 0.001). The elemental composition and microstructure of the bio-stabilised soil was determined using energy dispersive X-ray spectroscopy and scanning electron microscopy, respectively. This evaluation formed part of the selection of the best performing Bacillus derived fractions and achieved a proof of concept for the next phase of product prototype development. This study demonstrated a novel bio-mediated approach to the overall criteria for evaluation and selection of candidate product prototype/s, for stabilisation of two varying soils, and for potential application in road construction works.
A QoS-based evaluation of SDN controllers: ONOS and OpenDayLight
(2021-05) Mamushiane, Lusani; Shozi, Themba C
SDN marks a paradigm shift towards an externalized and logically centralized controller, unlike the legacy networks where control and data planes are tightly coupled. The controller has a comprehensive view of the network, offering flexibility to enforce new traffic engineering policies and easing automation. In SDN, a high performance controller is required for efficient traffic management. In this paper, we conduct a performance evaluation of two distributed SDN controllers, namely ONOS and OpenDayLight. Specifically, we use the Mininet emulation environment to emulate different topologies and the D-ITG traffic generator to evaluate aforementioned controllers based on metrics such as delay, jitter and packet loss. The experimental results show that ONOS provides a significantly higher latency, jitter and low packet loss than OpenDayLight in all topologies. We attribute the poor performance of OpenDayLight to its excessive CPU utilization and propose the use of Hyper-threading to improve its performance. This work provides practitioners in the telecoms industry with guidelines towards making informed controller selection decisions.
Review of current and future bio-based stabilisation products (enzymatic and polymeric) for road construction materials
(2020-10) Malapermal Ramdas, Veshara; Mandree, Prisha; Mgangira, Martin B; Mukaratirwa, S; Lalloo, Rajesh; Ramchuran, Santosh O
In situ soil modification is required in order to improve the primary engineering properties of the material to meet a road construction standard. Bio-stabilised soil is an environmentally friendly, cost-effective alternative to imported granular fills, concrete, costly hauling of materials or export to a landfill. In-service soil performance and required maintenance is highly dependent on methods of stabilisation, ranging from expensive mechanical stabilisation to chemical processes. As such, many alternative materials originating from bio-based sources are being explored as potential stabilising additives to improve weak subgrade soils (i.e., dispersive, erodible and collapsible soil, and soft or expansive clays). Some key solutions include the use of bio-derived enzymes, microbes, and polymeric additives to avert road failure caused by water penetration and/or erosion. The role of microbial substrate specialisation has been largely unexplored, since the level of research done on alternative stabilisers consists mostly of small ad hoc studies. In addition, research has focused on a reduction in permeability and an increase in compressive strength using enzymes and polymers, however, the complexity of these products and their implementation for a wide range of soil types and structural applications remain limited. Currently there is a need for more supporting research methodologies and systematic approaches on the implementation of bio-based materials for infrastructure development. This also includes the simplification of bio-based products for potential construction applications. This review provides (a) an overview of soil stabilisation techniques, (b) the primary challenges that lay ahead for future research in bio-based stabilisation products application in the road sector and (c) innovations to address the challenges of using modernised techniques in the road construction industry (i.e., weak subgrade and the required maintenance thereof, as well as the development of potential bio-based additives for unpaved road construction application).
Review of current and future bio-based stabilisation products (enzymatic and polymeric) for road construction materials (article)
(2021-03) Ramdas, Veshara M; Mandree, Prisha; Mgangira, Martin B; Mukaratirwa, S; Lalloo, Rajesh; Ramchuran, Santosh O
In situ soil modification is required in order to improve the primary engineering properties of the material to meet a road construction standard. Bio-stabilised soil is an environmentally friendly, cost-effective alternative to imported granular fills, concrete, costly hauling of materials or export to a landfill. In-service soil performance and required maintenance is highly dependent on methods of stabilisation, ranging from expensive mechanical stabilisation to chemical processes. As such, many alternative materials originating from bio-based sources are being explored as potential stabilising additives to improve weak subgrade soils (i.e., dispersive, erodible and collapsible soil, and soft or expansive clays). Some key solutions include the use of bio-derived enzymes, microbes, and polymeric additives to avert road failure caused by water penetration and/or erosion. The role of microbial substrate specialisation has been largely unexplored, since the level of research done on alternative stabilisers consists mostly of small ad hoc studies. In addition, research has focused on a reduction in permeability and an increase in compressive strength using enzymes and polymers, however, the complexity of these products and their implementation for a wide range of soil types and structural applications remain limited. Currently there is a need for more supporting research methodologies and systematic approaches on the implementation of bio-based materials for infrastructure development. This also includes the simplification of bio-based products for potential construction applications. This review provides (a) an overview of soil stabilisation techniques, (b) the primary challenges that lay ahead for future research in bio-based stabilisation products application in the road sector and (c) innovations to address the challenges of using modernised techniques in the road construction industry (i.e., weak subgrade and the required maintenance thereof, as well as the development of potential bio-based additives for unpaved road construction application).
A scoping review for proposing an eParticipation framework for South African local municipalities
(2023-06) Mahwai, Nare J; Phiri, Charles; Dlamini, Sifiso B; Herselman, Martha E; Meyer, Isabella A
Governments globally are making notable efforts to facilitate conversations with citizens to improve their participation in government decisionmaking by using various digital technologies in what could be coined as electronic participation approaches (e-Participation). It is even more critical for local governments as they want to apply feedback from citizens through e-participation to improve service delivery and inform policies. Both e-participation and local government have unique issues, challenges and important aspects to consider. This paper aims to identify these concepts through a scoping review to build a conceptual framework for local South African municipalities to implement e-participation for improved service delivery. The scoping review analysed 19 papers after applying the exclusion criteria used to conceptualise the framework. Both e-participation and local government need to consider value, content for access, skills, transparency, trust and funding to make e-participation a reality. The concepts that emanated from the scoping review under e-participation and local government considerations allowed for a list of requirements to consider when implementing e-participation. Key findings are that a conducive environment that allows for both online and offline participation platforms is needed to be of value to citizens and where they feel safe to participate otherwise, they will not engage in e-participation.

Browse

Browsing Journal Articles by browse.metadata.cluster "Smart Mobility"

Results Per Page

Sort Options