A research on the construction material export and energy consumptions using the gravity model

This paper applies a gravity model to estimate the relationships between energy consumptions and many kinds of construction material export over the period 1992-2009 in China. The empirical result shows that energy consumptions have a significant and positive influence on the construction material export of China.

Overcoming barriers to the reuse of construction waste material in Australia: a review of the literature

Although much has been written on how to improve the management of construction waste and increase the use of recycled materials, little progress has been made to address the reuse of construction waste. Yet there is a consensus in the literature that waste reuse practices have a decisive role to play in improving reduction of waste, and that institutional barriers are the most problematic obstacles to implementing identified reuse strategies. This paper examines the literature from the last 10 years on the issues facing different stakeholders around reuse of construction waste in Australia, and the causes and effects of the institutional barriers encountered. Key texts from before this period are also referenced. The findings reveal that institutional impediments are related to problems outside of the construction industry, such as social, economic and political barriers to change. A number of constraints are identified: lack of interest and demand from clients; attitudes towards reuse practices; and training all of which act as disincentives to a proactive and sustainable application of construction waste reuse strategies. Above all, it is argued that legislation should be better implemented to ensure that all states in Australia are required to implement strategies to reuse waste construction materials.

Low energy strategies for high-rise apartments in Hong Kong

High-rise apartments provide 90% of the living requirements in Hong Kong. (Lam 1995) The construction material of these buildings is primarily concrete for both external wall and interior partitions with little or no thermal insulation. Due to the hot and humid climatic conditions and expectations of an ever-increasing standard of living, occupants are installing air-conditioning systems into their apartments. This has generated a tremendous electrical demand as well as an environmental (greenhouse gas emission) concern. This paper explores some of the low energy strategies that can be applied to this building typology. The effect of seven energy-saving strategies ranging from thermal insulation to different window systems and shading devices was investigated. The results show that there is the potential to reduce the annual cooling energy consumption and peak cooling load by 40% and 33% respectively.

Strain rate effects for strength of geopolymer concrete

The effects of strain rate on compressive and tensile strength of fly ash based geopolymer concrete were investigated experimentally. Four mixes of geopolymer concrete using different alkaline solutions and under vary curing conditions were prepared. One mix of ordinary Portland cement (OPC) concrete was prepared for comparison. Both Quasi-Static tests using standard MTS and dynamic tests using Split-Hopkinson pressures bar (SHPB) were conducted, which were giving varying strain rate loadings from 10‾⁷ to 103 per second. The strain rate effect is presented as the ratio of dynamic compressive strength to static compressive strength (DIF). Results show that DIFs of geopolymer concrete are generally higher than those of OPC concrete at strain range of 187/s to 346/s (compression tests) and 7/s to 13/s (splitting tensile tests), respectively. This tendency is independent on loading regimes (compression or tension). This suggests that geopolymer concrete can be used as an alternative construction material to OPC concrete for the structures which has a high risk of being subjected to impact loadings.

The properties of fly ash based geopolymer mortars made with dune sand

This paper reports the properties of fly ash based geopolymer mortars made with dune sand. The geopolymer mortars of different cation type, namely sodium based (Na), potassium based (K) and a mixed Na/K, were prepared with dune sand (DS) and river sand (RS). The corresponding geopolymer pastes were also prepared. A series of tests including compressive strength, modulus of elasticity, splitting tensile strength, microanalysis (using scanning electron microscopy), porosity (using mercury intrusion porosimetry), sorptivity and air void (using section analysis method) were carried out. The results showed a strong correlation between strength and porosity of geopolymeric materials. The addition of DS had influences on the chemical compositions and physical properties of geopolymer mortars. These influences were dependent on the type of cation. Based on the results of mechanical properties, DS can be utilised as the fine aggregate for the production of geopolymer based construction material.

Experimental study on strength and ductility of steel tubular stub columns filled with geopolymeric recycled concrete

Geopolymeric recycled concrete (GRC) is a new construction material which takes environmentalsustainability into account, by using alkali solution and fly ash to completely substitute Portland cementas well as by replacing natural coarse aggregate with recycled coarse aggregate. GRC could be used togetherwith steel hollow sections to form composite section. There is very limited study on such GRC filledtubular sections. This paper presents an experimental study on GRC filled tubular stub columns. A total of 12specimens were tested. The main parameters varied in the tests are: (1) two section sizes of square hollow sections(B × t) with 200mm×6mm and 150mm×5mm; (2) different concrete types: GRC and recycled aggregateconcrete (RAC); (3) different recycled aggregate (RA) replacement ratios of 0%, 50% and 100%. The relationshipof load versus axial strain was recorded and analysed to compare the ultimate strength and failuremechanism. Meanwhile, the ductility of the columns was investigated by a ductility index (DI). The resultsshow that the ultimate strength decreased with increasing RA contents for both GRC and RAC filled columns.The influence of RA content on the strength was greater in GRC than that in RAC. The effect of RA contenton the ductility of the columns was further investigated. Simulation method for predicting load versus strainrelationship is discussed for RAC and GRC filled steel tubular columns with different RA replacement ratios.

Performance and narrative, bodies and movement in the construction of places and objects, spaces and knowledges: The case of the Maltese megaliths

The article explores the ways knowledge and space are co-produced performatively through bodily movement in an examination of the Maltese megaliths the first complex stone structures in the world. It is argued that knowledge is best seen as spatialized narratives of human actions and objects as materialized forms of those spatial narratives. Rewriting our social and historical narratives so that the performativity of place, space and knowledge is restored opens new possibilities for rethinking the social and material order.

An analysis of factors influencing waste minimisation and use of recycled materials for the construction of residential buildings

Residential building construction activities, whether it is new build, repair or maintenance, consumes a large amount of natural resources. This has a negative impact on the environment in the form depleting natural resources, increasing waste production and pollution. Previous research has identified the benefits of preventing or reducing material waste, mainly in terms of the limited available space for waste disposal, and escalating costs associated with landfills, waste management and disposal and their impact on a  building company's profitability. There has however been little development internationally of innovative waste management strategies aimed at reducing the resource requirement of the construction process. The authors contend that embodied energy is a useful indicator of resource value. Using data provided by a regional high-volume residential builder in the State of Victoria, Australia, this paper identifies the various types of waste that are generated from the construction of a typical standard house. It was found that in this particular case, wasted amounts of materials were less than those found previously by others for cases in capital cities (5-10 per cent), suggesting that waste minimisation strategies are successfully being implemented. Cost and embodied energy savings from using materials with recycled content are potentially more beneficial in terms of embodied energy and resource depletion than waste minimisation strategies.

The social construction of child maltreatment: the role of medical practitioners

• Summary: This paper explores how medical knowledge in child protection practice operates, in conjunction with social work knowledge and legal knowledge, as a social process of constructing meaning as ‘maltreatment’ (or not) in which the physical body of the child and perceived abnormalities represent ‘evidence’. Through discourse analysis of two case studies, this paper makes explicit and problematizes the social processes by which meanings are given by medical practitioners, social workers, police and parents to material experiences, the preference given to some meanings over others, and the econsequences of particular meanings for children and families and social work practice.

• Findings: Medical, social and legal knowledge are not neutral but embedded in power relations. The case studies show, through a sociological analysis of professional practice in child protection, how preferred versions of knowledge and meaning may override or dismiss alternative meanings, with particular consequences for parents and children and for practice outcomes.

• Applications: The case studies offer opportunities by which critically to engage with child protection knowledge, policy and practice in keeping with contemporary approaches that advocate dialogue, critical reflection and reflexivity, so that professional knowledge and professional power may be deployed constructively rather than oppressively.

Development of a web-based information system for cascading utilisation of construction materials

This paper presents a Web-based information system for promoting the cascading utilisation of construction materials in order to mitigate the increasing environmental pressure by the construction industry. First, this paper points out me weaknesses of current waste material exchange systems. Then, a new approach is introduced to reuse demolished materials, by which the utilisation of demolished materials may be ascertained before the demolition is actually produced.. Information technologies, including web-based intelligent and distributed systems, are applied to actua1ise this approach. Finally, the development and implementation of the system is described in detail.

Use of renewable building materials in residential construction : a review

The development of mass-produced environmentally-benign housing is one of the critical factors in the transition to global sustainability. Such housing will need to be constructed from renewable and/or recycled materials, be conditioned using minimal or no non—renewable energy, and be affordable. The universal need for such built environment resource stewardship is urgent. In developing countries, the requirement is to shelter growing populations, and in industrialised countries, there is a need for an alternative to the current resource and nergy-intensive material usage in housing. While there are some good surveys of building materials made from renewable resources, such as the BEDP Environment Design Guide Pro 11 by Gelder (2002), there does not appear to be a comprehensive database of these materials linked to abundant and reliable supply. This paper reviews the current availability and potential usage of renewable materials applicable to Australian mainstream residential construction. It concludes that the current state of publicly available information is dispersed and embedded in multiple sources with variance in detail, incomplete access and uncertain comparison across the sources.

A comprehensive framework for assessing the life cycle energy of building construction assemblies

Environmental decision making during the building design process has typically focused on improvements to operational efficiencies. Improvements to thermal performance and efficiency of appliances and systems within buildings both aim to reduce resource consumption and environmental impacts associated with the operation of buildings. Significant reductions in building energy and water consumption are possible; however often the impacts occurring across the other stages of a building‘s life are not considered or are seen as insignificant in comparison.

Previous research shows that embodied impacts (raw material extraction, processing, manufacture, transportation and construction) can be as significant as those related to building operation. There is, however, limited consistent and comprehensive information available for building designers to make informed decisions in this area. Often the information that is available is from disparate sources, which makes comparison of alternative solutions unreliable and risky. lt is also important that decisions are made from a life cycle perspective, ensuring that strategies to reduce environmental impacts from one life cycle stage do not come at the expense of an increase in overall life cycle impacts

A consistent and comprehensive framework for assessing and specifying building assemblies for enhanced environmental outcomes does not currently exist. This paper presents the initial findings of a project that aims to establish a database of the life cycle energy requirements of a broad range of construction assemblies, based on a comprehensive assessment framework. Life cycle energy requirements have been calculated for eight standard residential construction assemblies integrating an innovative embodied energy assessment technique with thermal performance simulation modelling and ranked according to their performance.

Energy analysis of the construction of office buildings /by Graham J. Treloar

Buildings have a significant impact on the environment due to the energy required for the manufacture of construction materials. The method of assessing the energy embodied in a product is known as energy analysis. Detailed office building embodied energy case studies are very rare. However, there is evidence to suggest that the energy requirements for the construction phase of commercial buildings, including the energy embodied in materials, is a significant component of the life cycle energy requirements. This thesis sets out to examine the current state of energy analysis, determine the national average energy intensities < i.e. embodied energy rates < for building materials and assess the significance of using national average energy intensities for the energy analysis of a case study office building. Likely ranges of variation in the building material embodied energy rates from the national averages are estimated and the resulting distribution for total embodied energy in the case study building simulated. Strategies for improving the energy analysis methods and data are suggested. Detailed energy analysis is shown to be a useful indicative method of quantifying the energy required for the construction of buildings.

Electrospinning of nanofibres for construction of vital organ replacements

This paper described the production of a novel biosynthetic material using the manufacturing technique of electro spinning for the construction of scaffold for organ replacement. This electrostatic technique uses an electric field to control the deposition of polymer fibres onto a specific substrate to fabricate fibrous polymer constructs composed of fibre diameters ranging from several microns down to 100 nm or less. Two areas of research, in particular, heart valve leaflets and blood vessel will be discussed. Here, a sandwich structure nanofibre mesh was used to construct materials for leaflets of heart valve and blood vessel. In the case of heart valve leaflet, the randomly oriented polyurethane nanofibres were prepared as the first layer, followed by gelatin-chitosan complex layer. Complex nanofibres were initially used to spin on the PU layer with cross orientation to mimic the fibrosa layer. A gelatin and chitosan complex was then spun onto the other side of PU nanofibre mesh to mimic the ventricularis layer. This particular sandwich structure using the PU layer was designed to simulate the mechanical properties of natural tissue. In addition, this design was aimed to provide good biocompatibility and improved cellular environment to assist in adhesion and proliferation. Smooth muscle cells adhered and flattened out onto the surface of the gelatin-chitosan complex as early as 1 day post seeding. There is great potential for this biosynthetic biocompatible nanofibrous material to be developed for various clinical applications.

Linear-motor based five-axis parallel machine for effective material processing

The aim of the work was to reduce the cost and improve the performance of five-axis machines. The main performance criteria were motion cycle-time and positioning accuracy/precision. A novel machine that utilizes the concept of parallel-kinematics and linear motor technology is proposed, designed, built and controlled for this sake.