Browsing by Author "Chandrathilake, SRMSR"

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item: Conference-Abstract
Effect of Albedo on surface temperature of concrete interlocking paving blocks in mitigating urban heat islands
Asmone, AS; Chandrathilake, SRMSR; Halwatura, RU
Out of the environmental impacts of anthropogenic activities and urbanization, urban heat island effect (UHEE) is considered most prominent and is identified to have many socio-economic implications, such as; deterioration of living environment, increased energy demand, elevation of ground level ozone and smog - events, adverse health conditions and even increase in mortality rates. The progressive replacement 6{f f natural environment is identified as a major cause of UHIE. Pavements are identified as a countermeasure to reduce urban heat, whereas this paper evaluates how existing pavements can be modified tiding surface treatments and how much a reduction of urban heat can be expected from that using surface energy balance model. Experimental measurements were taken of different coloured (albedo) pavers, and how it affects the ® surface temperature of the installations. It was identified that lighter coloured surfaces are cooler than conventional dark pavements; hence albedo can be used in countering the effects of UHL However, considerations have to be made about the decrease in surface albedo with traffic and weathering of pavers., This study was limited to surface thermal properties of concrete interlocking pavement blocks in tropical +1 climate conditions, which can be used in green building design and construction projects in Sri Lanka.
item: Conference-Full-text
Market feasibility and practicability assessment of rubberised bitumen for Sri Lankan road pavements
(Ceylon Institute of Builders, 2014-06) Thiwanka, RAY; Chandrathilake, SRMSR; Asmone, AS; Sandanayake, YG; Karunasena, GI; Fernando, NG
Conventional Bitumen (CB) has limitations in Sri Lankan context due to its tropical climate, as CB’s low stiffness modulus, low softening point, low viscosity, high temperature susceptibility and poor cohesion properties are aggravated in this environment. This leads to cracks on the road surfaces, which subsequently leads to surface failure because of frequent heavy rains in the region. Therefore, to avoid the adverse properties of CB, the technical feasibility of modifying bitumen with natural rubber and crumb rubber has been studied recently. However, the question remains whether these options are economically feasible in the Sri Lankan context. This paper presents a study which was carried out focusing the above issue. The study was carried out based on a preliminary literature review on the use of Natural Rubber Modified Bitumen (NRMB) and Crumb Rubber Modified Bitumen (CRMB) to identify technical feasibility and impacts, and an expert opinion survey with academic and industrial experts in the Highway field to identify the impacts. These impacts were identified in three categories, i.e. Economic, Social and Environmental. Comparing the economic impacts and lifecycle cost aspects it was concluded that NRMB and CRMB are more economically feasible over CB. Moreover, during the study NRMB and CRMB were found to be more environmentally and socially feasible as well. CRMB further provides additional benefits as it uses recycled rubber, which in turn reduces environmental and social issues created by waste tyres. Furthermore, CRMB has a lower cost of modification compared to the NRMB. Owing to these aspects and the prevailing market situation, it was concluded that CRMB is more appropriate to Sri Lanka.
item: Thesis-Full-text
Multi-criteria assessments for environmental sustainability of buildings
Chandrathilake, SRMSR; Dias, P
In the last couple of decades there has arisen a crowded toolbox of quantitative methods used to assess construction sustainability. The evolution of the assessment systems shows the interest in quantifying sustainability with a range of very specific indicators. The majority of the existing sustainability assessment methods for buildings evaluate performance of buildings for a selected set of domains, with a lot of commonality. This study focuses on the building sector and as the first step relevant domains were identified though comprehensive analysis of available assessment systems. Site, energy efficiency, water efficiency, material, indoor environmental quality and waste and pollution are the identified domain for the study. Secondly, aspects of (criteria for) the selected domains were identified and the relative importance of the domains and aspects was established by an expert survey. Thirdly the overall domain weights were compared with those assigned by other rating systems, originating from different countries to find the correlation which can demonstrate the influence of national contexts for relative weights in rating systems. The fourth step is to analyse the applicability of continuous functions to assess the sustainability in contrast to step functions to facilitate ‘assessment’ rather ‘rating’ of buildings. Fourth aspect of this research is to establish the dependencies and influences between indicator scores within domains. The matrix representation was used to handle these direct and indirect influences. Finally the research focused on optimisation techniques that can be used to handle tradeoffs between indicator scores and to arrive at acceptable indicator combinations with optimised environmental sustainable scores for a given building. It was found that in the building hierarchy the “system” level is the most important, having over fifty percent of overall weight. In the building lifecycle, the “operation” stage is the most important phase. There is also strong coupling between the operation stage and system level. Good correlation was found between national statistics and the weights, demonstrating that national contexts influence the relative weights in rating systems. The outcome of the dependency evaluation shows that there are considerable dependencies between indicator scores. It was found that the proposed optimisation technique is truly useful to arrive at planning strategies that yield high environmental sustainability scores for buildings while accounting for negative dependencies.