Abstract: The purpose of this study is to investigate a sustainable management for construction waste and the use of recycled concrete and mixed aggregates in concrete, the percentage of the recycled material being as high as possible. The investigations are done not only from the viewpoint of technical development, but also an environmental impact and a practicable-ness with case study. Since construction waste comes from various sources to different types of commercially active mobile crusher and crusher plants, the properties and characteristics of crushed aggregates can be very variable. In order to facilitate the practical use of the recycled materials in concrete, these varieties have to be classified to establish a reliable market. As a part of this research, characteristics of recycled aggregates and the applicability of ordinary standard test methods for these materials will be investigated.
Full description:
This research contains the following items;
- Design for disassembly -
Cost and Eco-costs assessment
- Process for improving quality of recycled aggregate
- Minimum requirements for an aggregate
- Requirements for a concrete aggregate
- Requirements for a tolerant concrete.
Design for disassembly
If the building is dismantled in a way for recycling of materials instead of the ordinal demolishing process, constructions and materials could be reused/recycled. From this point of view, the investigation is done including cost calculation. With this study the results can also reflect to the design for recycling (DFR). The way of building inspection, treatment of hazardous waste and sampling of materials is discussed as well.
Cost and Eco-costs assessments
To reduce the environmental impact of materials (emissions and depletion) for a sustainable management of the building materials, the Eco-costs, the hidden costs required to manufacture and use a product in a sustainable manner, or `in line with earth's carrying capacity' are calculated in the assessment for sustainability. Cost effectiveness is also calculated as a case study, since this is the one of the most important factor for the market.
Minimum requirements of the properties of recycled mix aggregate for new concrete 'No organic components in aggregate' is a minimum obligation to use them into new concrete. Using the washing process of recycled mix aggregate by current instruments does not only cost raise, but there is also the problems on the remaining of contaminated water and sludge that come after from washing process.
Process for quality improving of aggregate. Basically, additional cost for the processing is required, and it may also cause another problems will respect to the secondary unanticipated product such as sludge and residue. As treatment methods in the processing of demolishing construction waste, the following ways are considered. Thus, the materials from these resources are used in this project.
1. Try to make tolerant recycled concrete without a washing process from the materials both of crusher plants and mobile crusher.
2. Using separation technique at the crusher plant is also a possibility to make highly qualified concrete aggregate.
3. Try to obtain a high quality recycled concrete aggregate with mobile crusher on site, by cooperating with a company that disassemble buildings. (As a case study, this investigation focus not only the quality of the materials, but also the location of site, the methodology for disassembling, cost effectiveness and noise/dust/vibration problems are seriously considered.) |
