Microcrack detection in high performance cementitious materials
This presentation is the property of its rightful owner.
Sponsored Links
1 / 17

Microcrack Detection in High-Performance Cementitious Materials PowerPoint PPT Presentation


  • 96 Views
  • Uploaded on
  • Presentation posted in: General

Microcrack Detection in High-Performance Cementitious Materials. Pietro Lura, Ye Guang, Kyoji Tanaka, and Ole Mejlhede Jensen. Early-age cracking. Tokyo Institute of Technology, Yokohama, Japan. Microcracking. (Bisschop & van Mier 2002). Chemical shrinkage. Autogenous shrinkage.

Download Presentation

Microcrack Detection in High-Performance Cementitious Materials

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Microcrack detection in high performance cementitious materials

Microcrack Detectionin High-Performance Cementitious Materials

Pietro Lura,

Ye Guang, Kyoji Tanaka,

and Ole Mejlhede Jensen


Early age cracking

Early-age cracking

Tokyo Institute of Technology, Yokohama, Japan


Microcracking

Microcracking

(Bisschop & van Mier 2002)


Definitions

Chemical

shrinkage

Autogenous

shrinkage

Definitions

(Jensen & Hansen 2001)

solid

water

air


Autogenous shrinkage in hpc

Autogenous shrinkage in HPC

  • Less water

  • More cement

  • Silica fume


Microcrack detection in high performance cementitious materials

Internal microcracking

  • Does autogenous shrinkage lead to internal cracks?

  • How to detect them?


Superabsorbent polymers sap

Superabsorbent polymers (SAP)


Microcrack detection in high performance cementitious materials

Autogenous relative humidity

Paste C (w/c 0.30 + 20% SF +0.6% SAP)

Paste A (w/c 0.35)

Paste B (w/c 0.30 + 20% SF)


Microcrack detection in high performance cementitious materials

Autogenous strain

Paste C (w/c 0.30 + 20% SF +0.6% SAP)

Paste A (w/c 0.35)

Paste B (w/c 0.30 + 20% SF)


Microcrack detection in high performance cementitious materials

Samples for crack detection

- 3 cement pastes

  • 1.5, 3, and 6-mm rods

  • sealed at 32C


Microcrack detection in high performance cementitious materials

10

1.2 µm

]

1

m

µ

[

r

e

t

e

m

a

i

d

e

0.1

r

o

P

0.01

1.6 MPa

0.1

1

10

100

Intrusion pressure [MPa]

Properties of Gallium

- melting point 29.8 C

  • does not wet cement paste

  • nontoxic


Microcrack detection in high performance cementitious materials

Gallium intrusion


Microcrack detection in high performance cementitious materials

Sample preparation

  • epoxy resin

  • grinding

  • polishing

  • crack examination: - optical microscope

    - BSE

    - EPMA


Microcrack detection in high performance cementitious materials

Crack detection (1)


Microcrack detection in high performance cementitious materials

Crack detection (2)


Microcrack detection in high performance cementitious materials

Conclusions

  • Cracks before intrusion can be distinguished

  • High shrinkage, big rod  Cracks


Microcrack detection in high performance cementitious materials

Further research

  • EPMA

  • Acoustic Emission

  • FE calculations


  • Login