Detecting crack on-set time in mortar prisms with a thermal image

Thermal images are used to visualise the crack forming processes in mortar prisms under the flexural strength test with a UTM (Universal Testing Machine). The surface temperature of the prisms increases as the stress on them increases. When the prisms are reinforced by carbon fibres, the aggregated...

Full description

Saved in:
Bibliographic Details
Published in:Nondestructive testing and evaluation 2023-03, Vol.38 (2), p.313-330
Main Authors: Park, Jong-Gun, Heo, Gwanghee, Kim, Jung, Venkel, Tetiana, Son, Jung-Young
Format: Article
Language:English
Subjects:
Carbon fibers
carbon fibre reinforced
Flexural strength
mortar prisms
Mortars (material)
Prisms
temperature gradient
Thermal image
Thermal imaging
visualising crack forming process
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Thermal images are used to visualise the crack forming processes in mortar prisms under the flexural strength test with a UTM (Universal Testing Machine). The surface temperature of the prisms increases as the stress on them increases. When the prisms are reinforced by carbon fibres, the aggregated fibres along the crack paths becomes distinctive due to their higher temperature compared with their surrounding mortar areas of the prisms. This enables to visualise the crack forming process. In this process, there is a moment of abrupt increase in the temperature gradient of the aggregated fibres. This moment matches closely to that of the crack on-set obtained from the video images of crack forming process taken with a panchromatic camera, with less than 2.2 % difference. The moment is also matched with that of sharp dropping in the force from the UTM after the peak. This sudden temperature gradient increase can be used to determine the crack on-set times of the prisms with a high accuracy.
ISSN:1058-9759
1477-2671
DOI:10.1080/10589759.2022.2121395