Publication Date:
2017-04-06
Description:
This research investigates the long term shrinkage and Relative Mass Loss (RML) of mature Portland concretes (pure CEMI and blended CEMV/A), at temperatures of 20 and 80°C. When placed at 80°C and at relative humidities (RH) below 50-60%, concrete shrinkage increases with very slow stabilization kinetics by several hundreds of μm/m, while RML remains of about 0.2%. The origins of this continued shrinkage, simultaneously with limited RML, are investigated through the changes in (1) the pore structure of the concretes (by Mercury Intrusion Porosimetry and nitrogen adsorption) and in (2) their solid phases (by TGA/DTA, FTIR spectroscopy coupled to DVS, quantitative X-Ray Diffraction by Rietveld analysis, and 29 Si and 27 Al MAS NMR). While the pore structure coarsens during continued shrinkage, several phase transformations occur, namely ettringite decomposition and changes in the silicate chain length of the C-A-S-H. While these structural changes are documented, their relationship to shrinkage/RML and to the pore structure is novel. This article is protected by copyright. All rights reserved.
Print ISSN:
0002-7820
Electronic ISSN:
1551-2916
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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