Search

Carbon-conditioning or chemical permeation methods can provide excellent microstructural improvements to recycled concrete and brick aggregate; however, the applications have their limitations. Further, recycled brick aggregate cannot be effectively carbon-conditioned with conventional methods as it contains only trace amounts of reactive materials. It is therefore a necessity to use hybrid methods involving dual technologies combining carbon-conditioning and chemical permeation for its improvement. This paper is focused on developing a novel hybrid method for improving the microstructural properties of recycled concrete aggregate and recycled brick aggregate for concrete usage. This study conducts particle density, water absorption and crushing value tests to measure the physical improvements achieved with the novel hybrid method, and utilises a variety of chemicals and a reaction chamber for carbon-conditioning for aggregate treatment. The study evinces that both the recycled concrete aggregate and recycled brick aggregate experienced significant improvements, with 10 mm and 20 mm recycled concrete aggregate and 10 mm recycled brick aggregate exceeding the density of virgin aggregate. Magnesium hydroxide plus carbon dioxide (Mg(OH)2 (s) + CO2 (g)) treatment for recycled concrete aggregate and calcium hydroxide plus magnesium hydroxide plus carbon dioxide (Ca(OH)2 (s) + Mg(OH)2 (s) + 2CO2 (g)) treatment for recycled brick aggregate can be considered as potential candidates for optimal hybrid treatment methods. [ABSTRACT FROM AUTHOR]

Occupant behaviour (OB) is impacted by several interdisciplinary factors: environmental, psychosocial, cultural and economic. One of these impacting factors is the climate. In this study, the patterns of OB interactions with heating, cooling, lighting, equipment, windows and shading collected in questionnaire surveys were used as input data in the simulation models of two university buildings. The buildings, a green-rated and a non-rated one, are in Western Sydney University in Sydney, Australia. Then, the models were simulated in eight different climate zones in Australia. Therefore, this research aimed to understand how different climate zones may impact the energy related to OB and compare this impact between a green-rated building and a building without any rating. The results showed that there is no correlation between climate and OB and the levels of discomfort are related to the cooling season. The green building is less subjected to external changes, indicating that in buildings with automatic and properly controlled centralised management systems, the impacts related to the misuse of energy due to OB would be almost irrelevant. The results of this study should not be extended to other occupant behavioural patterns or situations. The results should be confined within the present research and context. [ABSTRACT FROM AUTHOR]

Pond ash is one of the main residual wastes from coal combustion. In coal power plants, the pond ash is usually mixed with seawater and stored as stockpiles, commonly known as ash dams. Once the ash dam 'dries out', the particles scatter with the wind, giving rise to various health issues. This research study aims to identify effective strategies for remediating the ash dam sites of coal power plants. Initially, the researchers conducted a literature review and expert interviews to identify strategies for remediation. The four alternatives are using (a) a sprinkler system, (b) Nu-Rock technology, (c) silicone extraction technology and (d) tree-planting technology. To validate the expert interview findings, this research quantified all the costs and benefits of the Port Augusta power plant in Australia as a case study. Silicone extraction technology and Nu-Rock technology create up to AU$20 million worth (AU$1 = US$0.718) of jobs within the area. Based on the analysis, it is identified that the Nu-Rock technology, silicone extraction process and plant regeneration alternatives are effective in ash dam remediation. The sprinkler system is a quick and temporary fix to ash dams until a permanent solution is introduced. [ABSTRACT FROM AUTHOR]

Thermal insulation is a significant factor in building construction. As a result, Green Star in Australia requires building envelopes to be insulated properly. Further, green buildings require at least 15% above the required R-values (which are measured in m2 K/W) for achieving Green Star credit points. Thermal insulation of the roof depends on various factors such as insulation material, sarking material, air films and roof covering. Therefore, there are many options with different combinations available to obtain the required total R-values. This research aims to identify optimum solutions for roofing solutions considering the life-cycle cost. There are ten commonly used roof types in Australia. Therefore, this research calculated the life-cycle costs using the net present value technique for more than 2000 options of roofing solutions and selected optimum solutions for each climate zone in Australia. The outcome shows that the initial cost and the replacement cost significantly influence the life-cycle cost. Further, the maintenance, replacement and disposal costs vary from 47 to 69% of the life-cycle cost. Sensitivity analysis concludes that the discounting rate has a significant influence on the life-cycle cost of the roofing solution. However, the changes in labour rate have only a slight impact on the life-cycle cost of roofing solutions. [ABSTRACT FROM AUTHOR]

With the continuous advancement of urbanisation, a large amount of construction and demolition waste (CDW) is generated in large-scale construction activities, which has aggravated the problems of environmental pollution, resource waste and ecological damage. The recycling of CDW can effectively solve such problems, and research on this topic has important practical significance. This paper selects 1090 articles on CDW recycling included in the core database of Web of Science from 2000 to 2021 as samples and uses two sorts of bibliometric analysis software, VOSviewer and CiteSpace, to obtain the annual publication volume, country, journal, author, institution, keywords and co-citation visualisation atlas, analysing the hotspots and development trends of CDW recycling research from the two dimensions of time and space. The analysis results show that in China, compared with developed countries, the research on CDW recycling and utilisation started late, and the phenomenon of focusing on construction and ignoring environmental protection is obvious. At present, the relevant research mainly focuses on three aspects: the performance of recycled aggregates, the management of CDW recycling and the strategy for improving CDW recycling. The bibliometric analysis results help scholars in this field to clarify quickly the development trend of CDW recycling, provide research directions for China's CDW recycling and point out research hotspots, aiming to improve China's CDW recycling rate and promote sustainable social development. [ABSTRACT FROM AUTHOR]