DOI QR코드

DOI QR Code

Influence of the Quality of Recycled Aggregates on Microstructures and Strength Development of Concrete

  • Published : 2004.12.01

Abstract

The quality of recycled aggregate is affected by original concrete strength and the manufacturing process of recycled aggregates. In this study, the porosity of old and new mortar, and the compressive strength of concrete were investigated to examine the influence of recycled aggregate on the concrete. Six kinds of recycled coarse aggregates were produced from concrete blocks of differing strength levels (A:60. 1MPa, B:41.7MPa, C:25.5MPa). Original concrete strength and the bond mortar of recycled aggregate influences the pore structures of both old and new mortar. The pore size distribution of old mortar was found to be greatly affected by age, and the reduction of the porosity of bond mortar on low strength recycled aggregate increased at a greater rate than that of bond mortar on high strength recycled aggregate. The pore size distribution of new mortar in recycled aggregate concrete changed in comparison with that of new mortar in virgin aggregate concrete. The total porosity of new mortar using B level recycled aggregates was smaller than that of new mortar with A, and C level recycled aggregates. Moreover, the compressive strength of recycled aggregate concrete was found to have been affected by original concrete strength. The compressive strength of concrete only changed slightly in the porosity of new mortar over $15\%$, but increased rapidly in the porosity of new mortar fewer than $15\%$.

Keywords

References

  1. Mosrafa T. and Parviz S., 'Strength of Recycled Aggregate Concrete Made Using Field-Demolished Concrete as Aggregate,' ACI Materials Journal, March-April 1996, pp.182~190.
  2. Anders H., 'Use of Recycled Aggregates in Europe,' International Workshop on Recycled Concrete, JSPS 76 Committee on Construction Materials, 2000, pp.1-8
  3. Sagoe-Crentil K.K., Brown T., and Taylor A.H., 'Performance of Concrete Made with Commercially Produced Coarse Recycled Concrete Aggregate,' Cement and Concrete Research, No.31, 2001, pp.707~712
  4. Nagataki S., Saeki T., and Iida K., 'Some Properties of Concrete Used Recycled Aggregate,' Cement Science and Concrete Technology, No.52, 1998, pp.462-467
  5. Neville A. M., 'Properties of Concrete, 4th Edition,' Longman Malaysia, 1996, pp.122-134
  6. Moon, D.J, Paeng, W.S., and Moon, H.Y, 'Evaluation on the Resistance to Freezing and Thawing of Concrete Using Recycled Aggregates,' Journal of the Korean Concrete Institute, Vol.14, No.3, 2002, pp.307-314 https://doi.org/10.4334/JKCI.2002.14.3.307
  7. Moon, D.J. and Moon, H.Y, 'Evaluation on Qualities of Recycled Aggregate and Strength Properties on Recycled Aggregate Concrete,' KSCE Journal of Civil Engineering, Vol.22, No.1-A, 2002, pp.141-150
  8. Shima, H. et al., 'New Technology for Recovering High Quality Aggregate from Demolished Concrete,' Proceedings of the International Seminar on Recycled Concrete held by Niigata University, Niigata, Japan, 2000, pp.33-44
  9. Otsuki, N. and Miyazato, S., 'The Influence of Recycled Aggregate on ITZ, Permeability and Strength of Concrete,' Proceedings of International Workshop on Recycled Concrete, Tokyo, Japan, 2000, pp.77-93
  10. Uchikawa, H., Hanehara, S., and Sawaki, D., 'Estimation of the Thickness of Transition Zone in Hardened Mortar and Concrete, and Investigation of the Relationship between their Thickness and Strength Development,' Concrete Research and Technology, Vol. 4, No. 2, July 1993, pp.1-7