Road operation phase sustainability indicator as a response to the climate change phenomena

Road infrastructure is a major contributor of greenhouse gas (GHG) around the world. Once constructed, a road becomes a part of a road network and is subjected to recurrent maintenance/rehabilitation activities. Studies to date are mostly aimed at the development of sustainability indicators that deal with the material and construction phases of a road when it is constructed. The operation phase is infrequently studied and there is a need for sustainability indicators to be developed relating to this phase to better understand the GHG emissions as a proper response to the climate change phenomena. During the operation phase, maintenance/rehabilitation activities are undertaken based on certain agreed intervention criteria that do not include environmental implications relating to the climate change aspect properly. Availability of appropriate indicators may, therefore, assist in sustainable road asset maintenance management. This paper presents the findings of a literature based study and has proposed a way forward to develop a key “road operation phase” environmental indicator, which can contribute to road operation phase carbon footprint management based on a comprehensive road life cycle system boundary model. The proposed indicator can address multiple aspects of high impact road operation life environmental components such as: pavement rolling resistance, albedo, material, traffic congestion and lighting, based on availability of relevant scientific knowledge. Development of the indicator to appropriate level would offset the impacts of these components significantly and contribute to sustainable road operation management

Comparison of outcome between suture and suture-less surgery following pterygium excision and conjunctival autograft

Background: A pterygium, known as surfer's eye, is a raised, wedge-shaped growth of the conjunctiva that extends onto the cornea, the outer layer of the eye. Aim was to compare the safety, efficacy and outcome of suture less technique with suture of conjunctival autograft in the management of pterygium. Methods: This study was carried out in the department of ophthalmology, Sir Salimullah medical college and Mitford hospital, Dhaka. Study period was July 2019 to June 2020. Subjects for this study were divided into two groups, forty patients were enrolled in each group of the study population. Group I (control) comprised the subjects in whom suture was used following pterygium excision and conjunctival autograft and group II (experimental) comprised the subjects in whom no suture was used following pterygium excision and conjunctival autograft. Results: In group I, 20% were 20-29 years old, 30% were 30-39, 27.5% were 40-49, and 22.5% were over 50, with 77.5% being male and 22.5% female. In group II, 22.5% were 20-29 years old, 27.5% were 30-39, 30% were 40-49, and 20% were over 50, with 72.5% being male and 27.5% female. The most common symptom was "foreign body sensation" in both groups. In group I, 5% experienced partial graft dehiscence, 2.5% a conjunctival cyst, 10% hyperemia, and 17.5% visual improvement. In group II, 2.5% had partial graft dehiscence, 2.5% hyperemia, and 22.5% visual improvement. Neither group had graft retraction or recurrence. Conclusions: Postoperative presentation like hyperemia was significantly less in experimental group. Incidence of post-operative complications like graft dehiscence and conjunctival cyst were comparatively less frequent in suture less technique. Thus, suture less technique following pterygium excision and conjunctival autograft is a safer and less complicated than sutured technique

Environmental indicators for sustainable road development and operation

Road construction, maintenance and operation are activities that impact the environment by way of energy use, resource consumption and emission. Components such as construction material, transportation, street lighting, rolling resistance, traffic congestion during works, albedo and end-of-life processing impact the environment at different phases of the life of a road. With a view to promote sustainable development, a few sustainability rating schemes, e.g. Infrastructure Sustainability and Invest (Australia), Envision and Greenroads (USA), and CEEQUAL (UK) have been developed, that can assess road projects. These schemes address environmental areas such as: energy and emission, land, water, materials, discharges into surroundings, waste and ecology as factors for sustainable development. This paper assesses different rating schemes based on a defined comprehensive life cycle assessment (LCA) system boundary for road projects to identify different environmental indicators that address sustainable road development and operation. The findings indicate that new indicators are required to address different environmental components during the operation phase of roads

Sustainability outcomes of infrastructure sustainability rating schemes for road projects

The construction and operation of infrastructure assets can have significant impact on society and the region. Using a sustainability assessment framework can be an effective means to build sustainability aspects into the design, construction and operation of infrastructure assets. The conventional evaluation processes and procedures for infrastructure projects do not necessarily measure the qualitative/quantitative effectiveness of all aspects of sustainability: environment, social wellbeing and economy. As a result, a few infrastructure sustainability rating schemes have been developed with a view to assess the level of sustainability attained in the infrastructure projects. These include: Infrastructure Sustainability (Australia); CEEQUAL (UK); and Envision (USA). In addition, road sector specific sustainability rating schemes such as Greenroads (USA) and Invest (Australia) have also been developed. These schemes address several aspects of sustainability with varying emphasis (weightings) on areas such as: use of resources; emission, pollution and waste; ecology; people and place; management and governance; and innovation. The attainment of sustainability of an infrastructure project depends largely on addressing the whole-of-life environmental issues. This study has analysed the rating schemes’ coverage of different environmental components for the road infrastructure under the five phases of a project: material, construction, use, maintenance and end-of-life. This is based on a comprehensive life cycle assessment (LCA) system boundary. The findings indicate that there is a need for the schemes to consider key (high impact) life cycle environmental components such as traffic congestion during construction, rolling resistance due to surface roughness and structural stiffness of the pavement, albedo, lighting, and end-of-life management (recycling) to deliver sustainable road projects

Life cycle analysis for sustainability assessment of road projects

Road infrastructure has been considered as one of the most expensive and extensive infrastructure assets of the built environment globally. This asset also impacts the natural environment significantly during different phases of life e.g. construction, use, maintenance and end-of-life. The growing emphasis for sustainable development to meet the needs of future generations requires mitigation of the environmental impacts of road infrastructure during all phases of life e.g. construction, operation and end-of-life disposal (as required). Life-cycle analysis (LCA), a method of quantification of all stages of life, has recently been studied to explore all the environmental components of road projects due to limitations of generic environmental assessments. The LCA ensures collection and assessment of the inputs and outputs relating to any potential environmental factor of any system throughout its life. However, absence of a defined system boundary covering all potential environmental components restricts the findings of the current LCA studies. A review of the relevant published LCA studies has identified that environmental components such as rolling resistance of pavement, effect of solar radiation on pavement(albedo), traffic congestion during construction, and roadway lighting & signals are not considered by most of the studies. These components have potentially higher weightings for environment damage than several commonly considered components such as materials, transportation and equipment. This paper presents the findings of literature review, and suggests a system boundary model for LCA study of road infrastructure projects covering potential environmental components

'Road use phase' environmental indicator for sustainable pavement management system

Once a road is constructed, it enters into use or operation phase as part of a road network. The road use phase involves management of road maintenance and rehabilitation activities to keep the road functional based on certain approved intervention triggers, maintenance work standards and budget. Road agencies usually have a Pavement Management System (PMS) in place that prioritizes road sections for maintenance and rehabilitation works. This is primarily based on economic indicators. With the emergence of sustainable development concept to address the climate change phenomena as a principal concern for human sustenance on the earth, consideration to environmental issue like carbon emissions is becoming an internationally agreed requirement. This needs a holistic indicator that can address key road environmental components during the use phase for comparing different maintenance strategies based on Global Warming Potential (GWP). This paper presents an environmental indicator concept termed as ‘Road Use GHG Factor (RUGF)’, which could be used to calculate life cycle carbon footprint of alternative road maintenance strategies. RUGF provides combined GWP of key use phase environmental components like rolling resistance, albedo and construction materials. The application of RUGF leads to the development of a comprehensive sustainability parameter ‘Road Sustainability Factor (RSF)’ that can accommodate different indicators of sustainability in road project development and management. Incorporation of RSF may help upgrade the PMSs to Sustainable Pavement Management Systems (SPMS)