A Study on the Properties of Recycled Concrete Using Recycled Fine Aggregates with different Removal formulas of Powder In Aggregate

Title & Authors
A Study on the Properties of Recycled Concrete Using Recycled Fine Aggregates with different Removal formulas of Powder In Aggregate
Lee Mun-Hwan; Lee Sea-Hyun; Shim Jong-Woo;

Abstract
The research conducted to study the potential practicability of recycled aggregate concrete by analyzing the characteristics of concretes made of recycled quality aggregates produced by wet and dry process has found the following results. The air content of recycled aggregate concrete increased with increase of the substitut on rate due to mortar included while producing recycled aggregates. However, the concretes with aggregate produced by dry process had relatively low rate of increase in air content. The slump showed generally decreasing trend as the substitution rate of recycled aggregate increased regardless of the wet or dry process. It was assumed that the mortar particles remained in recycled aggregate absorbed the surplus hydration in concrete and decreased fluidity The compressive strength generally decreased as the substitution rate of recycled aggregate increased, however there was an increasing trend as well due to decreasing effect of water-cement ratio when the substitution rate of recycled aggregate reached 25, $\small{50\%}$ after mix. This phenomena also appeared in early age, which meant that recycled aggregate concrete should not be retarded in setting when applied in the field. The tensile strength also reached the maximum when wet or dry recycled aggregate replaced with $\small{25\%}$. To conclude, recycled aggregates for concrete produced by wet or dry process are expected to demonstrate essential characteristics of concrete without significant decline in physical or dynamic quality when the substitution rate is below $\small{25\%}$ although there are variations subject to water-cement ratio. However, slight differences are expected due to types of recycled aggregate and physical quality.
Keywords
recycled fine aggregate;recycled concrete;wet process;dry process;
Language
Korean
Cited by
References
1.
한국레미콘공업협회, '재생골재콘크리트의 제조기술 및 활용방안', 한국레미콘공업협회, 1998. 4, pp.18-32

2.
신동인, '폐콘크리트의 품질이 재생콘크리트의 특성에 미치는 영향', 명지대학교 박사학위논문, 1998, pp.57-62

3.
이세현, '재생골재콘크리트의 성능개선에 관한 연구', 건국대학교 박사학위논문, 2001, p.25

4.
연세대학교, '폐콘크리트를 이용한 재생골재의 표준화 및 품질평가시스템', 국립기술품질원, 1998, pp.7-17

5.
한국콘크리트학회, '재생(순환)골재 및 재생(순환)골재 콘크리트 정책 및 세미나', 한국콘크리트학회 재생콘크리트위원회 세미나, 2004, pp.III-24- III-45

6.

7.

8.

9.

10.
Frondistou Y.S., 'Waste concrete as aggregate for new concrete,' ACI Journal, 1977, pp.373-376