한국건설교통기술평가원 Korea Insitute of Construction & Transportation Technology Evaluation and Planning
등록번호
TRKO200700007951
과제고유번호
1500000437
사업명
건설핵심기술연구개발사업
DB 구축일자
2013-04-18
초록
본 연구에서는 기존의 재생골재 생산시스템으로부터 생산되는 저품질의 재생골재(1, 2차 파쇄 콘크리트)의 품질을 높임으로써 천연골재의 대체재료로서 사용가능한 재생굵은골재를 합리적인 비용하에서 생산하는 것을 최종적인 목표로 하고있다.
Abstract▼
Together with a lack of resources for the natural aggregates, the conditions to supply them are recently deteriorating. In these circumstances, the political support is required for stable supply of aggregate resources. In case the aggregate supply is getting unstable, the counterplan how to meet th
Together with a lack of resources for the natural aggregates, the conditions to supply them are recently deteriorating. In these circumstances, the political support is required for stable supply of aggregate resources. In case the aggregate supply is getting unstable, the counterplan how to meet this situation is urgently required since construction expense is increased due to increased price of aggregate as well as problem of all kinds of constructions, and troubled construction is expected due to low quality aggregate. In the meantime, the generation of construction waste are continuously increasing year t)y yew, and among them, waste concrete is mostly consisted of construction waste occupying about 70.9% (as of 2003) out of the total construction waste. Recycling ratio of waste concrete is relatively high as of 2003 reaching to 89.0%. Since the treated amount at site by mainly a simple crushing is included in it, however, an appropriate treatment and recycling method to collect. aggregate from the waste concrete is required. The most fundamental reason why these waste concretes have to be reused may be from the lack of aggregate supply owing to the resource exhaustion of natural aggregate in domestic. Crushed aggregate for coarse aggregate, and sea sand for fine aggregate are increasingly used. However, to use these crushed stones would considerably lower the concrete durability causing problem of alkali-aggregate reaction which causes expanded cracks in concrete. Even though enough washing process is passed for sea sand, salt containing in it makes corrosion the iron and makes problem lowering concrete durability. In 2000, sea sand and crushed aggregate are consisted about 70% out of total, whereas crushed stones are hardly expected to develop in future due to problem of environment destruction. Considering about 0.15 billion $m^3$ of the total consumption quantity of aggregate in 2000, it may only last for 25 years henceforth. It is calculated upon the reserved quantity of 4 billion $m^3$ which are securely buried ill Korea. The unbalanced supply by region due to limitation of transportation distance, etc. is expected to appear about within and after 5 years. For recycled aggregate which are reused from the waste concrete, it is competitive since it can be fully used in domestic road-base supply. However, starting from the point when the supply of recycled aggregate in future exceeds the demand of non-structural usage, the use of reused aggregate will become a social problem again. Accordingly, the technology development to satisfy the demand of natural aggregate whose utilizing fields of recycled aggregate is different from the current ones is required. Technology to produce the domestic recycled aggregate is collect waste concrete from the mixture of construction waste and separated mainly by crashing. Recycled aggregate produced from this process is considerably low in its quality like absorption rate, gravity of aggregate, etc. It was consequently acknowledged by many researches that the recycled concrete used by recycled aggregate is characteristic by low epidemiological characteristics and durability such as strength, modulus of elasticity and so on. It was a reason why recycled aggregate is restricted to be widely used in value-added purpose such as aggregate for concrete use from low value purpose such as road-base materials, etc. Also, it was turned out that the reason of lowering quality for recycled aggregate from various research results comes from the cement paste attached to the recycled aggregate. Thus, to increase the recycling application of aggregates, the study on specification standard, standardization of the recycled aggregate, etc. should be followed. However, it requires a study on the technology to fundamentally enhance the quality of recycled aggregate to minimize the paste quantity attached to the recycled aggregate. Although a study on recycled aggregate has been carried out for more than 10 years by the civil enterprises, the Ministry of Construction-Transportation, the Ministry of Environment, the Ministry of Commerce, Industry and Energy, etc., the fact that it is mostly used in road-base material, etc. so far can be understood to certify that the reliable technology development on high quality recycled aggregate comparable to the natural aggregate was not made. In this study, it alms to effectively remove the cement paste attached to the recycled aggregate, and to achieve to maintain resources of natural aggregate together with recycling of waste concrete through a study how to reuse the by-products.
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