Abstract
The properties of new Interfacial Transition Zone (ITZ) and old ITZ in Recycled Aggregate Concrete (RAC) were investigated by Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and nanoindentation. From the SEM images, obvious voids and high concentration of calcium hydroxide can be found in both old ITZ and new ITZ in RAC. Based on the nanoindentation study, it is indicated that the thicknesses of old and new ITZs are in the range 40-50 μm and in the range 55-65 μm, respectively. It is also found that the average indentation modulus of old ITZ is 70-80% of that of old paste matrix, while the average indentation modulus of new ITZ is 80-90% of that of new paste matrix. Additionally, the influences of mix proportion, aggregate types and hydration age on the properties of ITZs in RAC are discussed in this study.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 276-292 |
| Number of pages | 17 |
| Journal | Cement and Concrete Composites |
| Volume | 37 |
| Issue number | 1 |
| DOIs | |
| State | Published - Mar 2013 |
Funding
The authors would like to gratefully acknowledge the financial support from the National Natural Science Foundation of China (51178340), and the Kwang-Hua Foundation. The authors gratefully thank Dr. Gajendra Shekhawat and Dr. David J. Corr in Northwestern University for their supports. The second author would also like to thank China Scholarship Council (CSC) for its partial financial support during his study at Northwestern University, USA.
Keywords
- Atomic Force Microscope (AFM)
- Interfacial Transition Zone (ITZ)
- Microstructure
- Nanoindentation
- Nanomechanical properties
- Recycled Aggregate Concrete (RAC)
ASJC Scopus subject areas
- Building and Construction
- General Materials Science