Towards a holistic modelling framework for embodied carbon and waste in the building lifecycle

As the building industry proceeds in the direction of low impact buildings, research attention is being drawn towards the reduction of carbon dioxide emission and waste. Starting from design and construction to operation and demolition, various building materials are used throughout the whole building lifecycle involving significant energy consumption and waste generation. Building Information Modelling (BIM) is emerging as a tool that can support holistic design-decision making for reducing embodied carbon and waste production in the building lifecycle. This study aims to establish a framework for assessing embodied carbon and waste underpinned by BIM technology. On the basis of current research review, the framework is considered to include functional modules for embodied carbon computation. There are a module for waste estimation, a knowledge-base of construction and demolition methods, a repository of building components information, and an inventory of construction materials’ energy and carbon. Through both static 3D model visualisation and dynamic modelling supported by the framework, embodied energy (carbon), waste and associated costs can be analysed in the boundary of cradle-to-gate, construction, operation, and demolition. The proposed holistic modelling framework provides a possibility to analyse embodied carbon and waste from different building lifecycle perspectives including associated costs. It brings together existing segmented embodied carbon and waste estimation into a unified model, so that interactions between various parameters through the different building lifecycle phases can be better understood. Thus, it can improve design-decision support for optimal low impact building development. The applicability of this framework is anticipated being developed and tested on industrial projects in the near future.

Development of sustainable, innovative and energy-efficient concrete, based on the integration of all-waste materials: SUS-CON panels for building applications

The building sector requires the worldwide production of 4 billion tonnes of cement annually, consuming more than 40% of global energy and accounting for about 8% of the total CO2 emissions. The SUS-CON project aimed at integrating waste materials in the production cycle of concrete, for both ready-mixed and pre-cast applications, resulting in an innovative light-weight, ecocompatible and cost-effective construction material, made by all-waste materials and characterized by enhanced thermal insulation performance and low embodied energy and CO2. Alkali activated “cementless” binders, which have recently emerged as eco-friendly construction materials, were used in conjunction with lightweight recycled aggregates to produce sustainable concrete for a range of applications. This paper presents some results from the development of a concrete made with a geopolymeric binder (alkali activated fly ash) and aggregate from recycled mixed plastic. Mix optimisation was achieved through an extensive investigation on production parameters for binder and aggregate. The mix recipe was developed for achieving the required fresh and hardened properties. The optimised mix gave compressive strength of about 7 MPa, flexural strength of about 1.3 MPa and a thermal conductivity of 0.34 W/mK. Fresh and hardened properties were deemed suitable for the industrial production of precast products. Precast panels were designed and produced for the construction of demonstration buildings. Mock-ups of about 2.5 x 2.5 x 2.5 m were built at a demo park in Spain both with SUS-CON and Portland cement concrete, monitoring internal and external temperatures. Field results indicate that the SUS-CON mock-ups have better insulation. During the warmest period of the day, the measured temperature in the SUS-CON mock-ups was lower.

Final report : task 4 : waste minimisation in construction

The Regenerating Construction Project for the CRC for Construction Innovation aims to assist in the delivery of demonstrably superior ‘green’ buildings. Components of the project address eco-efficient redesign, achieving a smaller ecological footprint, enhancing indoor environment and minimising waste in design and construction. The refurbishment of Council House 1 for Melbourne City Council provides an opportunity to develop and demonstrate tools that will be of use for commercial building refurbishment generally. It is hoped that the refurbishment will act as an exemplar project to demonstrate environmentally friendly possibilities for office building refurbishment.

Benchmarks for recycling practices in commercial office building refurbishment : data collection challenges

In recent years considerable effort has gone into quantifying the reuse and recycling potential of waste generated by residential construction. Unfortunately less information is available for the commercial refurbishment sector. It is hypothesised that significant economic and environmental benefit can be derived from closer monitoring of the commercial construction waste stream. With the aim of assessing these benefits, the authors are involved in ongoing case studies to record both current standard practice and the most effective means of improving the eco-efficiency of materials use in office building refurbishments. This paper focuses on the issues involved in developing methods for obtaining the necessary information on better waste management practices and establishing benchmark indicators. The need to create databases to establish benchmarks of waste minimisation best practice in commercial construction is stressed. Further research will monitor the delivery of case study projects and the levels of reuse and recycling achieved in directly quantifiable ways

Waste minimisation in office refurbishment projects : an Australian perspective

The refurbishment of commercial buildings is growing as a percentage of overall construction activity in Australia and this trend is likely to continue. Refurbishment generates a significant waste stream much of which is potentially reusable or recyclable. Despite this potential, several factors are known to unnecessarily inhibit the amount of recycling that actually occurs on renovation projects. In order to identify the reasons causing this reluctance, a process of project monitoring and expert consultation was carried out. Twenty three experts experienced in commercial refurbishment projects and three waste contractors with specific knowledge of construction waste were interviewed. Records of receipts for waste from a case study project reveal three principal factors inhibiting recycling rates: the presence of asbestos in the building; the continued occupation of the building during construction; and the breaking up of a large project into small separate contracts thereby reducing economies of scale. To ascertain the potential for improvement, current rates for reuse and recycling of materials were collected from the experts. The results revealed a considerable variation in practice between companies and indicated key areas which should be targeted to improve performance.

The efficacy of waste management plans in Australian commercial construction refurbishment projects

Renovation and refurbishment of the existing commercial building stock is a growing area of total construction activity and a significant generator of waste sent to landfill in Australia. A written waste management plan (WMP) is a widespread regulatory requirement for commercial office redevelopment projects. There is little evidence, however, that WMPs actually increase the quantity of waste that is ultimately diverted from landfill. Some reports indicate an absence of any formal verification or monitoring process by regulators to assess the efficacy of the plans. In order to gauge the extent of the problem a survey was conducted of twenty four consultants and practitioners involved in commercial office building refurbishment projects to determine the state of current practice with regard to WMPs and to elicit suggestions with regard to ways of making the process more effective. Considerable variation in commitment to recycling policies was encountered indicating a need to revisit waste minimisation practices if the environmental performance of refurbishment projects is to be improved.

Sustainability criteria for Industrialised Building System (IBS) in Malaysia

As the sustainability awareness rises globally, the construction industry is under increasing pressure to improve efficiency and project delivery. The implementation of Industrialised Building Systems (IBS), for which utility components are built offsite, has the potential of promoting sustainability deliverables. This can be achieved by better control of production environment, minimising construction waste, using efficient building material energy, and stabilising work conditions. As a unique building technology, IBS has not been effectively implemented in Malaysia. Possible reasons may include limited understanding among stakeholders on the IBS potential and its relevance to sustainability. This warrants studies on the sustainability issues of IBS design, construction, operation and maintenance, A framework is being developed through research to assess performance criteria related to sustainability, which should be considered during IBS design and application in the most consistent and systematic way. This paper discusses how these sustainability performance criteria are examined in a continuing research project and the processes conducive to implementing sustainable IBS in Malaysia. Existing tools, indicators and guidelines are reviewed, analysed and grouped according to characteristics and application. The research also hopes to produce guidelines for stakeholders to incorporate sustainability issues and concepts into IBS applications.

A theory of waste behaviour in the construction industry

Levels of waste within the construction industry need to be reduced for environmental and economic reasons. Changing people's wasteful behaviour can make a significant contribution. This paper describes a research project that used Ajzen's 'theory of planned behaviour' to investigate the attitudinal forces that shape behaviour at the operative level. It concludes that operatives see waste as an inevitable by-product of construction activity. Attitudes towards waste management are not negative, although they are pragmatic and impeded by perceptions of a lack of managerial commitment. Waste management is perceived as a low project priority, and there is an absence of appropriate resources and incentives to support it. A theory of waste behaviour is proposed for the construction industry, and recommendations are made to help managers improve operatives' attitudes towards waste.

Improvement of the statutory framework for construction and demolition waste management exemplified in Germany and Australia

Construction and demolition (C&D) waste occupies the largest share of overall waste generation in many countries. However, waste management practices and outcomes may differ between countries. For instance, in Australia, C&D waste recovery is continuously improving during the last years but the amount of C&D waste increases every year, as there has been little improvement in waste avoidance and minimization. In contrast, in Germany, waste generation remains constant over many years despite the continuous economic growth. The waste recycling rate in Germany is one of the highest in the world. However, most waste recycled is from demolition work rather than from waste generated during new construction. In addition, specific laws need to be developed to further reduce landfill of non-recycled waste. Despite of the differences, C&D waste generation and recovery in both countries depend on the effectiveness of the statutory framework, which regulates their waste management practices. This is an issue in other parts of the world as well. Therefore countries can learn from each other to improve their current statutory framework for C&D waste management. By taking Germany and Australia as an example, possible measures to improve current practices of C&D waste management through better statutory tools are identified in this paper. After providing an overview of the statutory framework of both countries and their status in waste generation and recovery, a SWOT analysis is conducted to identify strengths, weaknesses, opportunities and threats of the statutory tools. Recommendations to improve the current statutory frameworks, in order to achieve less waste generation and more waste recovery in the construction industry are provided for the German and Australian government and they can also be transferred to other countries.

An integrated approach to enhance sustainability in industrialised building systems

Building prefabrication is known as Industrialised Building Systems (IBS) in Malaysia. This construction method possesses unique characteristics that are central to sustainable construction. For example, offsite construction enables efficient management of construction wastage by identifying major causes of waste arising during both the design and construction stages. These causes may then be eliminated by the improvement process in IBS component's manufacturing. However, current decisions on using IBS are typically financial driven and hinder the wider ranged adoption. In addition, current IBS misconceptions and the failure of rating schemes in evaluating the sustainability of IBS affect its implementation. A new approach is required to provide better understanding on the sustainability potential of IBS among stakeholders. Such approach should also help project the outcomes of each levels of decision-making to respond to social, economy and environmental challenges. This paper presents interim findings of research aimed at developing a framework for sustainable IBS development and suggests a more holistic approach to achieve sustainability. A framework of embedding sustainability factors is considered in three main phases of IBS construction; 1) Pre-construction, 2) Construction and 3) Post-construction phase. SWOT analysis was used to evaluate the strengths, weaknesses, opportunities and threats involved in the IBS implementations. The action plans are formulated from the analysis of sustainable objectives. This approach will show where and how sustainability should be integrated to improve IBS construction. A mix of quantitative and qualitative methodology was used in this research to explore the potential of IBS in integrating sustainability. The tools used in the study are questionnaires and semi-structured interviews. Outcomes from these tools lead to the identification of viable approaches involving 18 critical factors to improve sustainability in IBS constructions. Finally, guidelines for decision-making are being developed to provide a useful source of information and support to mutual benefit of the stakeholders in integrating sustainability issues and concepts into IBS applications.

Waste and resource management practices, legislation and policy encouraging and influencing ‘regeneration reuse’ of property assets

Carbon taxation governance is becoming increasingly popular, further evolving the polluter pays concept already well established in the built environment as a mechanism to controlling and licensing waste generation. This paper presents an explanation of property asset ‘regeneration reuse’ principles following deconstruction, which reduce waste generation associated with the process of demolition, construction and operation. An analysis is made of strategies in Australia and the United Kingdom, comparing jurisdiction targets pertaining to construction and demolition waste that encourage ‘regeneration reuse’. From examination of applicable Australian and United Kingdom legislation, strategic, fiscal and policy that influence on the 'regeneration reuse' of property assets, an evaluation to the variety of issues relevant to waste and resource management practices is reached. The paper concludes that a systematic evaluation framework to selecting building components and structures suitable for reuse after deconstruction must be considered in legislation.