Abstract/Details

Characterization of shrinkage behavior in concrete materials using cure reference method


2009 2009

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Abstract (summary)

A novel experimental technique was developed to investigate the shrinkage behavior in cementitious materials. The Cure Reference Method (CRM), previously developed for residual strain measurements in composites, was used to determine the shrinkage that develops in concrete materials during the curing or drying process. This technique involves the replication of diffraction grating on the concrete specimen during the curing process and the use of high sensitivity moiré interferometry. A specially-designed stage was created to help obtain a set of the consecutive phase shifted fringe patterns. Instead of the intensity-based methods, an automated fringe analysis program was used to analyze fringe patterns to obtain full-field displacement and strain information. Shrinkage as a function of time, location, humidity, temperature, water/cement (w/c) ratio and size was measured for unsealed cement paste specimens. Also, a method of combining CRM and removing drying effect was used to explore the relative contribution of non-drying shrinkage (autogenous shrinkage) to the total shrinkage in cement pastes. Furthermore, CRM technique was applied to explore the effect of fine aggregates (sand) on the shrinkage behavior. The effect of sand quantities was investigated to observe how shrinkage responded to this influential factor. The method of removing drying effect was modified to explore the relative contribution of autogenous shrinkage to the total shrinkage in the specimen with the fine aggregates (mortar specimen). The effect of coarse aggregates (gravel) on shrinkage was also displayed.

An inverse method based on finite element moisture diffusion model and optimization was developed in order to obtain the material properties of cement paste from the complex geometry used in the tests. Once the material parameters were determined, they can be the inputs in finite element analysis for the predictions. The tests in different drying conditions, with different geometry of the specimens, and for the reinforced specimens were performed and their results were compared with FEA to validate the constructed model and the obtained materials properties.

Ring tests were performed under both normal and extreme low humidity conditions for crack investigation. Also, the FEA of the ring test under normal humidity has shown that the numerical result had good agreement with that from the experiment.

Finally, stresses were predicted in FEA model for both free shrinkage and restrained (ring test) shrinkage cases.

Indexing (details)


Subject
Civil engineering;
Mechanical engineering
Classification
0543: Civil engineering
0548: Mechanical engineering
Identifier / keyword
Applied sciences; Concrete; Cure reference method; Shrinkage
Title
Characterization of shrinkage behavior in concrete materials using cure reference method
Author
Chen, Tzu-Chau
Number of pages
126
Publication year
2009
Degree date
2009
School code
0070
Source
DAI-B 71/03, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9781109671278
Advisor
Ifju, Peter G.
University/institution
University of Florida
University location
United States -- Florida
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3400236
ProQuest document ID
304887418
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/304887418
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