Evolution of sustainability in global green building rating tools

Green building rating tools (GBRTs) are well-known and important instruments for assessing building sustainability. GBRTs constantly upgrade to meet rapid development, one of which is achieving a reasonable balance among the “three pillars” of sustainability, namely, environmental, social and economic sustainability. This study analyzes the changes and trends in the three sustainability pillars of GBRT and reinforces the previous GBRT longitudinal studies in terms of research sample, time span, equal terms, and research depth. Ten global GBRTs are selected by specific screening principles, and a unified criterion framework is presented to compare these selected GBRTs on equal terms. The changes of GBRTs are then analyzed on three levels, namely, categories, subcategories, and criteria. The results show that in the past three decades, there is a continuous decrease in the weight of the environmental category, an obvious increase in the weight of the social category and a little rise in the wight of the “economic” category. “Pollution,” “physical comfort,” and “flexibility” are identified as “sensitive criteria” of environmental, social, and economic categories, respectively, given their significant changes; they are also critical factors for the evolution of GBRT for the past three decades. © 2020 Elsevier Lt

Utilisation of Recycled Concrete Aggregates for Sustainable Porous Asphalt Pavements

The use of recycled concrete aggregates (RCA) for porous asphalts is a viable attempt towards waste management and sustainable conservation of natural resources. Installation of a porous asphalt wearing course is justified in highway pavements because it offers higher skid resistance, glare reduction, lesser traffic noise, reduction of hydroplaning, and mitigation of urban heat island phenomenon. The performance of porous asphalt mixtures containing 0%, 20%, 40%, 60%, 80% and 100% of coarse RCA as replacement for granite was studied and reported in this paper. The mixture containing 0% RCA was used as the control. The skid properties, permeability, water susceptibility and mechanical behaviour of the mixtures under various loading conditions were investigated. Blending granite and RCA in the porous asphalt mixture gave better Indirect Tensile Strength (ITS), rutting resistance, and impact strength indicators. The mixture with 60% RCA achieved desirable results in all tests. It exhibited the best performance based on its ITS and impact strength of 431 kPa and 380 J, respectively. These values were higher than the control by 3% and 30%, respectively. Utilisation of RCA in porous asphalt pavements is recommended based on the results of this study

Strength, Carbon Footprint and Cost Considerations of Mortar Blends with High Volume Ground Granulated Blast Furnace Slag

Ground granulated blast furnace slag (GGBFS) is a by-product obtained from the iron making process and has suitable properties to be utilized as high volume cement replacement to produce sustainable concrete. This study focuses on investigating the influence of GGBFS replacement level (0%–70%) and water/binder ratio (0.45 and 0.65) on the performance of cement mortar blends. In order to characterize the engineering performance, the compressive strength of the mortar blends was evaluated. Whereas to ascertain the carbon footprint, environmental life cycle assessment was conducted. Besides the compressive strength and carbon footprint, the materials cost for each mortar blends was computed. Based on the compressive strength/carbon footprint ratio analysis, it was found that increased replacement level of GGBFS gave better performance while the cost efficiency analysis shows that suggested GGBFS replacement level of up to 50%. Overall, in considering the strength performance, carbon footprint and materials cost, the recommended GGBFS replacement level for cement blends is 50%. In addition, when the binder content is kept constant, mortar blends with lower water/binder ratio is preferable when considering the same parameters

Bee Inspired Novel Optimization Algorithm and Mathematical Model for Effective and Efficient Route Planning in Railway System

<div><p>Railway and metro transport systems (RS) are becoming one of the popular choices of transportation among people, especially those who live in urban cities. Urbanization and increasing population due to rapid development of economy in many cities are leading to a bigger demand for urban rail transit. Despite being a popular variant of Traveling Salesman Problem (TSP), it appears that the universal formula or techniques to solve the problem are yet to be found. This paper aims to develop an optimization algorithm for optimum route selection to multiple destinations in RS before returning to the starting point. Bee foraging behaviour is examined to generate a reliable algorithm in railway TSP. The algorithm is then verified by comparing the results with the exact solutions in 10 test cases, and a numerical case study is designed to demonstrate the application with large size sample. It is tested to be efficient and effective in railway route planning as the tour can be completed within a certain period of time by using minimal resources. The findings further support the reliability of the algorithm and capability to solve the problems with different complexity. This algorithm can be used as a method to assist business practitioners making better decision in route planning.</p></div

Operational parameters effects on photocatalytic reactors of wastewater pollutant: a review

This study presents the operational parameters effects on photocatalytic degradation of liquid pollutants using titanium dioxide. Organic pollutants photodegradation is the most widely studied method, where photocatalysis is observed in many forms. Due to the cost efficiency of titanium dioxide as a photocatalyst, it has a greater role in this process as compared to other semiconductors. The operating parameters effects on photocatalytic degradation in wastewater pollutant using titanium dioxide based photocatalyst are presented in this paper. The findings are used to identify and explain the individual influence of different parameters, such as the photocatalyst composition, catalyst loading, initial pH, pollutant concentration, light intensity and temperature, on wastewater pollutants photocatalytic degradation. The successful application of laboratory scale techniques and the choice of treatment are generally dependent on the wastewater composition, however, much research is needed from the aspects of modelling and engineering design for a large scale operation. Besides that, a general overview of a prevailing trend in the use of titanium dioxide photocatalyst is presented with the emphasis placed on its achievements and problems

Comparison of solutions between the proposed algorithm and exact method.

<p>Comparison of solutions between the proposed algorithm and exact method.</p

Test cases created to verify the algorithm.

<p>Test cases created to verify the algorithm.</p