1,720,969 research outputs found
THE ENVIRONMENTAL RELEVANCE OF THE CONST RUCTION AND END-OFLIFE PHASES OF A BUILDING: A TEMPORARY STRUCTURE LCA CASE STUDY
Get PDFLCA can prevent shifting the environmental burden of a building to peculiar life cycle phases. Components production and demolition stages became much more relevant in new low-energy buildings. The same applies also to temporary structures, whose useful service life is generally limited to the duration of the related event. More attention must therefore be paid to the choice of the construction materials and the way they are assembled in order to reduce resource depletion, embodied energy and waste production. To achieve this goal, it is essential to act in the design phase of the building in order to include environmental problems in the early stages of the decision making process. The objective of our study is to assess the environmental impacts of the different life stages of a temporary structure to support the design phase of future ones. The reference case study is the Brazilian pavilion constructed in Milan (Italy) for EXPO 2015. The aim of the research is to evaluate how much the design phase of the building, the choice of the materials and the end-of-life scenarios can influence the environmental performances of the structure. Primary data for the whole lifecycle are considered and a sensitivity analysis on the materials sustainability is performed. LCA results confirm the importance of the design phase for temporary structures. The predilection of natural and recycled materials in the construction phase and the prevision of a second life significantly reduce the impacts of the building. Among the end-of-life scenarios the best environmental solution proves to be the refunctionalization on site. The priority must be therefore to foresee a second life of the components at an early stage of the decisionmaking process. Similar conclusions could be expected for low-energy buildings too
Relevance of retrofitting in a historical household in northern Italy: LCA of the intervention and comparison of different operational phase scenarios
No full text
Life cycle analysis of environmental impact vs. durability of stabilised rammed earth
Get PDFRammed earth (RE) has enjoyed a revival in recent decades due to the increasing awareness of environmental issues surrounding the building industry. Although RE in its traditional form is deemed a highly environmentally-friendly material, the same cannot be said for its modern stabilised counterpart. Comprehensive experimental procedures exist to estimate mechanical strength properties of stabilised RE (SRE). However, tests for material durability are far less common. Engineers and practitioners therefore assume that strength and durability are interchangeable properties, i.e. the stronger the material, the more durable. Inflated strengths are recommended to ensure adequate durability, leading to high environmental costs through excessive use of stabilisers. This paper rates the relevance of two acknowledged durability tests (accelerated erosion due to sprayed water and mass loss due to wire brushing) and relates outcomes to the strength and the environmental impact of several SRE mixes. The environmental impact of each mix was estimated using attributional and consequential life cycle assessment (LCA) approaches as well as an assessment of cumulative energy demand. Results demonstrated that it is possible to have durable SRE mixes without paying the cost of using environmentally-expensive stabilisers
Reduction of rammed earth's hygroscopic performance under stabilisation:an experimental investigation
Get PDFOne of the acknowledged qualities of rammed earth (RE) is its moisture buffering capacity. Recently, stabilisation of RE has become a common practice to improve the mechanical resistance but very little is known about the effect that stabilisation has on hygroscopic properties. The present study aims to fill this gap by understanding the role that stabilisation plays in the buffering and sorption capacity of RE. The use of alternative stabilisers such as fly ash and calcium carbide residue and a comparison with traditional unstabilised RE (URE) have also been investigated. Moreover, the effect of weathering, simulated by cyclic wetting-drying, on hygroscopic performance has been analysed. Moisture Buffer Value (MBV) testing, moisture and nitrogen adsorption-desorption isotherms and mercury intrusion porosimetry were performed on stabilised samples to examine microstructural phenomena responsible for behavioural changes. URE was confirmed to be a good-to-excellent passive air conditioner according to the MBV scale but its performance seemed to be highly influenced by the soil particle size distribution and mineralogy. Based on the experimental outcomes of the mixtures investigated, stabilisation had a detrimental effect on the moisture buffer capacity of rammed earth, likely due to the inhibition of the physico-chemical interactivity between moisture and clays. Weathering had a variable effect on the buffering capacity, depending on the availability of unreacted particles in the matrix. (C) 2017 Elsevier Ltd. All rights reserved.</p
Weathering’s beneficial effect on waste-stabilised rammed earth:a chemical and microstructural investigation
Get PDFThe most common method to improve the mechanical properties of a rammed earth mix is to add chemical stabilisers like cement and/or lime. Varying the stabiliser type will affect strength gain but also the environmental impact. In this paper, the effect of wetting-drying cycles on the long-term unconfined compressive strength of stabilised rammed earth (SRE) mixes was investigated through the chemical characterisation of the soil components and microstructural analyses. The mixes were stabilised using different agents characterised by distinct environmental impacts, such as cement, calcium carbide residue and fly ash. These last two are considered waste materials, significantly affecting their use’s associated environmental implications. The results of this experimental campaign support others in this series of work and showed an improvement of the mechanical properties after cyclic wetting-drying due to the formation of new hydration products which bound particles together. The use of waste materials proved to be an effective solution to stabilise RE
- …
