Comparing the implementation of concrete recycling in the Australian and Japanese construction industries
Introduction
The promotion of environmental management and the mission of sustainable development have exerted pressure on the adoption of proper methods to protect the environment across all industries, including construction. Extensive extraction of natural resources for building construction jeopardizes the principle of sustainability and has received increasing objections from environmentalists. Construction by nature is not necessarily an environmental-friendly activity. The comprehensive building development and redevelopment plans in different countries have aggravated construction problems pertaining to building demolition. To optimize the use of natural resources and particularly concrete demolition waste, there is a need to develop long-term action plans on the use of materials and to coordinate various interests among stakeholders and companies in the construction industry [1]. The hierarchy of disposal options can be categorized into six environmental impact levels, from low to high; namely, reduce, reuse, recycle, compost, incinerate and landfill [2]. Three main waste minimization strategies of reuse, recycle and reduction are collectively called the “3Rs”. To reduce construction waste generated on site, coordination among all those involved in the design and construction processes is essential.
Sustainable construction is a set of processes by which a profitable and competitive industry delivers built assets [3], [4]: i) to enhance the quality of life and to provide customer satisfaction; ii) to offer flexibility and the potential to help to anticipate and respond to anticipated future, user demands; iii) to provide and support desirable natural and social environments; and iv) to maximize the efficient use of resources. A potential contributor for sustainable performance can include recycling of construction waste.
The best way to deal with material wastes is not to create them in the first place [34], [63]. Table 1 summarizes the problems of the current practices and highlights some of the recommended measures for reducing the generation of construction wastes by improved management and operational improvements. Four management measures are highlighted including: i) policy; ii) training; iii) audit; and iv) feedback and two operational measures on design and construction stages are also considered.
Recycling, being one of the strategies in waste minimization, offers three major benefits [5]: i) to reduce the demand upon new resources; ii) to cut down transport and production energy costs; and iii) to use waste which would otherwise be transferred to landfill sites. Construction and demolition waste including demolished concrete, bricks and masonry, wood, glass, insulation, roofing, wire, pipe, rock and soil [6] constitutes a significant component in the total waste.
Among various types of construction and demolition waste, concrete constitutes the major proportions of the total waste of about 81 percent in Australia [7]. The situation of surrounding concrete recycling is varied in different countries. Japan is a leading country in concrete recycling, in which about 98 percent of concrete waste is recycled [8]. Most demolished concrete structures are reused for road-base materials and backfill materials, some can even be used it for structural applications [9], [10]. Although concrete recycling is recommended in the Australian construction industry, it is still not clear on concrete recycling procedures and the lack of experience in conducting these [11]. This limits the concrete recycling rate in Australia to only about 40 percent which is mainly used for low-grade applications [12].
Section snippets
Research objectives
This paper aims to achieve the following objectives:
- •
to study waste generation in the Australian and Japanese construction industries;
- •
to examine their regulatory requirements on waste minimization and concrete recycling procedures;
- •
to investigate their current concrete recycling methods;
- •
to examine their existing standards on the use of recycled concrete;
- •
to examine and to compare benefits gained and difficulties encountered from concrete recycling in the Australian and Japanese construction
Construction waste problems
Waste is defined as by-product material of human and industrial activities that have no residual values [13]. From Table 2, about 32.4 million tons of solid waste are generated in Australia annually [7], of which about 42 percent is from the construction and demolition sectors. From that, about 7.8 million tons of material corresponding to about 57 percent of construction and demolition waste is recycled (see Table 3).
Among different types of construction and demolition wastes, concrete waste
Regulatory requirements on concrete recycling
One of the major factors to effectively handle waste recycling in the construction industry is the top management support [14]. However, the implementation of waste management requires a large amount of investment such as facilities and equipment, which is the main burden to the industry. To coordinate various construction stakeholders in implementing waste management, it is necessary that long-term policies and strategies should be developed and implement [15], [16].
Australia has three
Current concrete recycling methods
Basic equipment used to process virgin aggregate is similar to that used for crashing, sizing and stockpiling recycled aggregate. A recycling plant usually is comprised of crushers incorporating sieves, sorting devices and screens. The main recycling processes are crushing, sorting and screening to produce aggregate for use in civil engineering work, landscaping and as a substitute for gravel in concrete products [17].
Although the current concrete recycling method is used in many countries to
Existing standards on the use of recycled concrete
The construction industry and concrete manufacturers realize that they need to use available aggregate rather than search for the perfect aggregate to make an ideal concrete suitable for all concrete applications [24]. The importance of concrete recycling has been recognized by the industry, in which hundreds of tons of recycled aggregate concrete have been recycled and used for specific purposes such as road-base and pavement [11].
In Australia, the Commonwealth Scientific and Industrial
Research methodology
To examine the effectiveness of concrete recycling in the Australian and Japanese construction industries, a questionnaire survey was conducted. Four main sections are divided in the questionnaire. The first section seeks for awareness about concrete recycling, such as policy and participation of concrete recycling in their companies. The second section examines benefits gained from implementing concrete recycling. The third section investigates difficulties encountered in the implementation of
Awareness of concrete recycling
From the results shown in Table 11, it should be noted that awareness towards concrete recycling is quite high in both the Australian and Japanese construction industries, with more than half of the respondents being positive. In comparing the awareness between the two countries, it can be clearly shown that about 68 percent of the Japanese construction companies have used concrete recycling policies, objectives and procedures, which are higher than in Australia of about 48 percent. These
Recommendations to the Australian construction industry – lessons learned from japan
After collecting information from the questionnaire survey in the implementation of concrete recycling in the Australian and Japanese construction industries, it should be noted that the Australian concrete recycling practice is running behind Japan. Japan acts as a leading country in concrete recycling around the world. To improve concrete recycling in Australia, the following recommendations are suggested:
- a)
Although some states in Australia have been implementing concrete recycling very well,
Conclusions
The large generation of concrete waste causes a serious problem to the environment. Many countries are presently directing efforts towards measures to promote waste minimization and waste reuse. However, the situation surrounding concrete recycling in each country varies tremendously. This paper compared the cement waste recycling practices in Australia and Japan. From the questionnaire survey results, it is clear that awareness about concrete recycling is quite high in the Australian and
Acknowledgement
The author would like to thank Mr. Kazunobu Takagi for his help in conducting the survey.
References (82)
- et al.
Construction process improvement methodology for construction projects
International Journal of Project Management
(1998) - et al.
On-site sorting of construction and demolition waste in Hong Kong, resources
Conservation and Recycling
(2001) - et al.
Construction waste characterization for production of recycled aggregate – Salvador/Brazil, Waste materials in construction: WASCON 2000
- et al.
The use of reclaimed asphalt pavement aggregates in concrete, Waste Materials in Construction: WASCON 2000
- et al.
An application of bar-code system for reducing construction wastes
Automation in Construction
(2002) Waste minimization in practice
Resources, Conservation and Recycling
(2001)- et al.
Implementing of environmental management in the Hong Kong construction industry
International Journal of Project Management
(2002) Management of concrete demolition waste. Concrete technology for a sustainable development in the 21st century
(2000)- et al.
Strategies for successful construction and demolition waste recycling operations
Journal of Construction Management and Economics
(1997)
Constructing the best government client: achieving sustainability in construction procurement
Sustainable architecture: European directives and building design
The reclaimed and recycled construction materials handbook
Waste management: productivity commission draft report: productivity commission
Japan environment white paper
Recycled concrete and masonry
Experimental study on the possibility of using permanently recycled concrete for reinforced concrete structures
Annual survey of Victorian recycling industries 2002–2003
Sustainable raw materials: construction and demolition waste
Environmental performance evaluation for construction
Building Research and Information
A guide for managing and minimizing building and demolition waste
The second RILEM state of the art report on recycled aggregates and recycled aggregate concrete
Materials and Structures
Recycled aggregate applications as subgrade and pavement
Improvement of paste-aggregate interface by adding silica fume
Recycled aggregate from concrete waste for higher grades of concrete construction
Micro-structural analysis of recycled aggregate concrete produced from two-stage mixing approach
Cement and Concrete Research
The state of using by-products in concrete in Japan and outline of JIS/TR on recylced concrete using recycled aggregate
Concrete mix design: quality control and specification
Guidance on the preparation of non-structural concrete made from recycled concrete aggregate
Guide for specification of recycled concrete aggregate for concrete production (H155-2002)
New technology for the recycling of concrete – Japanese experience. Concrete technology for a sustainable development in the 21st century
Recycled concrete using recycled aggregate class H: JIS A 5021
Recycled concrete using recycled aggregate class L: JIS A 5023
Quest for continuous quality improvement for public housing construction in Hong Kong
Journal of Construction Management and Economics
Recycling spent sandblasting grit and similar wastes as aggregate in asphaltic concrete
Waste minimisation in construction: site guide
Recycling waste from the construction site
ISO 14031–environmental performance evaluation (EPE): practice tools and techniques for conducting an environmental performance evaluation
Conducting environmental performance evaluation using environmental performance indicators
Barriers for sustainable use of concrete materials. Concrete technology for a sustainable development in the 21st century
Cited by (228)
Transforming construction and demolition waste concrete as a precursor in sustainable cementitious materials: An innovative recycling approach
2024, Resources, Conservation and RecyclingNumerical simulation of backfilling behavior of boreholes
2024, Results in EngineeringMaterial requirements and impacts of the building sector in the Shared Socioeconomic Pathways
2023, Journal of Cleaner Production