Sustainable Highway Infrastructure Research Articles

EVALUATION OF MARSHAL STABILITY AND FLOW OF HYBRID MODIFIED ASPHALT CONCRETE

Highway engineers and researchers are constantly trying to enhance the performance of asphalt concrete pavement, in order to keep up with the global adequate and sustainable highway infrastructure drive. Modification of asphalt concrete could improve certain properties of the mixture and reduce cost of road construction materials. In this research, evaluation of Marshal Stability and flow of hybrid asphalt modified concrete was studied, the wastes from various industries such steel industry, plastic industry and coal-fired power plant industries were combined together to form hybrid composite. Steel slag, fly ash, waste plastic, aggregate and bitumen were used to produce the asphalt concrete in a hybrid manner to evaluate effect of stability and flow properties of asphalt concrete mixture. The physical properties of steel slag, fly ash aggregate, bitumen and waste plastic based polypropylene were determined by carrying out tests such as sieve analysis, moisture content, flakiness and elongation, aggregate impact, aggregate crushing, specific gravity, hygrometer, penetration, softening point, flash and fire point, viscosity, ductility and water-in-bitumen test. Bitumen with penetration grade 60/70 was used and the content varied from 5.0 to 7.0 % at 0.5% interval. A cylindrical sample with the composite mixture of asphalt concrete was produced using varying proportions of hybrid composite which comprises of steel slag (SS) and fly ash (FA) at 2%, 4%, 6% and 8% by weight of the asphalt concrete to partially replace the conventional materials (aggregate and filler) and bitumen which was partially replaced with polypropylene (PP) at 5%, 10%, 15% and 20% respectively. The Marshal Stability test conducted on the hybrid composite asphaltic concrete gives optimum stability values of 10.50 kN, 12.50 kN, 12.30 kN and 13.50 kN and optimum flow values of 3.30 mm, 2.80 mm, 2.80 mm, and 2.70 mm at 2%, 4%, 6% and 8% respectively. Comparing with Asphalt Institute specification, the non-conventional material used as fillers, coarse and fine aggregate can be conveniently used in light, medium and heavy traffic. Based on the findings, the application of these wastes material which constitute higher stability and flow will improve the properties of asphalt concrete, reduce the cost of constituent material and decrease environmental problem that arise from various industries.

An Overview of Sustainable Highway Infrastructure Development in Yunnan, China

Highway infrastructure development in Yunnan Province remains a top priority for the Chinese Government, the aim is to improve access to neighbouring countries and support economic growth and social development in the province. While the social and economic benefits of highway infrastructure projects are indisputable, sustainable performance still leaves room for improvement in Yunnan. In an effort to promote a more sustainable approach to decisions relating to highway infrastructure projects, this paper explore the critical issues associated with sustainable highway infrastructure. Firstly, reviewed the economic, social and environmental background of Yunnan, and explain the functions of highways in its socio-economic development. After a brief overview of the conditions and future demands for highway infrastructure in Yunnan, analysed the challenges of building highways in a sustainable way.

Proposed Sustainability Composite Index of Highway Infrastructure Projects and Its Practical Implications

Highway infrastructure projects always have negative impacts on the sustainable development objectives. However, the construction of these projects will not be stopped due to their importance for the fulfillment of the nations’ economic, social and civilization development. Hence, it is necessary to find solutions for improving their performance toward the sustainability approach. One of these solutions is to quantify the highway projects’ sustainability before starting in their execution. This will guide the decision-makers to adopt the suitable alternative and policy for the development of sustainable highway infrastructure. Previous studies did not adequately integrate the sustainable development dimensions in the construction of highway infrastructure projects, which represents an obstacle to the effective evaluation of highway projects’ sustainability. Addressing this issue, this research proposes an integrated index capable of appraising the sustainability performance of highway projects. The research data were collected from a questionnaire survey conducted with Egyptian experts with lengthy experience in the construction of highway infrastructure projects. Fuzzy set theory and the analytic hierarchy process were utilized to develop the composite highway sustainability index (CHSI). A case study was conducted to elucidate application of CHSI. The study offers the decision-makers an effective methodology to assess the sustainability of their highway infrastructure projects in early planning phases.

A flow model for optimization of highway toll stations

This paper is aimed at developing a highway toll stations route optimization model (HTSROM) for cost-effective and sustainable highway infrastructure planning and design. There are many factors for the locations of highway toll stations, including potential ridership, costs of land, construction and operation, and travel times. We developed HTSROM algorithm which used a genetic model to optimize and integrate a geographic information system for transfer of land-use, environmental, and topographic data during the optimal search process. The experimental results are discussed on the application, and more extensions of the HTSROM model remain to be studied in the future work.

Sustainable and Green Roadway Rating System

Road construction is a great investment, and annual industry. Yet there is no international rating system for highways and roads design and construction comparable to the LEED rating system for buildings, or the Energy Star system for appliances. Sustainable highway infrastructure design requires a good balance between environment, cost and social aspects. Green design for roads should have a voluntary sustainability rating system for roadway design, construction, and maintenance. It should be applicable to all roadway projects including new, reconstructed and rehabilitated roadways. It awards credits point for sustainable choices and practices and can be used to assess roadway project sustainability. The rating system can be used to rank, score and compare different road projects for their overall performance toward being more sustainable than an average road project. The philosophy of the suggested rating systems will be based on different categories, each of which explain one sustainability attribute and covers different topics in subcategories. The aim of this work is to study the feasibility of using sustainable rating system for roadway project after considering the local environmental conditions, economy, and materials processing actions available. A questionnaire was designed which includes all the design categories, and was distributed to 150 participant including site engineers, design engineers, pavement contractors, material supplier contractors and road users (drivers and pedestrian). The impacts of roadway design and construction and suggested credits were obtained, these categories and credits are as important as the roadway design itself.

High-Modulus Geocells for Sustainable Highway Infrastructure

Technological innovation in geosynthetics such as high modulus (stiff) geocells (cellular confinement systems) can help achieve a more sustainable highway infrastructure. Research, testing, field trails, and case studies demonstrate how geocells increase pavement performance on one hand, while achieving sustainable goals on the other. Recent published research and testing of high-modulus Novel Polymeric Alloy (NPA) geocell-reinforced bases are briefly reviewed in this paper. NPA geocells improved strength and rigidity of flexible pavements as indicated by: increased modulus of structural layers, reduced stresses to the lower layers and decreased surface degradation. Field trials validate that NPA geocells improve the modulus of road base layers, even while reducing the structural thickness and utilizing on-site or recycled materials for structural infill. Sustainable roads can be built with less virgin resources and a smaller environmental footprint, while extending the pavement service life and decreasing maintenance.

A Multiobjective Analysis of Impacted Area of Environmentally Preserved Land and Alignment Cost for Sustainable Highway Infrastructure Design

Sustainable highway infrastructure design requires a good balance between environment and cost. The available computer-based automated highway alignment optimization algorithms minimize the total highway alignment cost towards obtaining the optimized alignment. These are primarily single-objective optimization approaches with limited capability in considering various cost components and factors that may be dissimilar or conflicting in nature. In these approaches, the impacted area of environmentally preserved land is transformed to monetary value and included in the total highway alignment cost. Also, they have limited capability in yielding a set of alternatives with different levels of trade-off between the total highway alignment cost and impacted area of environmentally preserved land. This leads to the need for developing a model to estimate the impacted area of environmentally preserved land in terms of non-monetary values and use concurrently with total highway alignment cost providing a perspective comparison of highway alignment alternatives. A multiobjective analysis is presented in this paper to consider the impacted area of environmentally preserved land information expressed in non-monetary unit and total highway alignment cost expressed in monetary unit. In this analysis, a genetic algorithm (GA) based multiobjective optimization technique is adopted. The paper describes a special algorithm developed to estimate the impacted area of environmentally preserved land from a Geographic Information System (GIS) based study area map and simultaneous minimization of impacted area of environmentally preserved land and highway alignment cost. A Pareto-optimal front is used to graphically represent the trade-off values of highway alignment cost and impacted area of environmentally preserved land. Finally, the developed methodology is applied to a study area and results are compared with the available single objective highway alignment optimization model output.