SYMPOSIA PAPER Published: 01 January 1981
STP28303S

Compliance Measured Fracture Toughness of Mortar and Fiber Reinforced Mortar

Source

Contoured double cantilever beams 610 mm (24 in.) long were tested to measure the fracture parameters of plain and fiber reinforced mortar. The crack extension, the crack opening displacement (COD) and the crack opening of the cantilever's arms at the loading points were experimentally recorded in function of applied loads. The unloading-reloading technique was used to measure the compliance of the specimens. Slow crack growth was observed and the specimens experienced a permanent deformation at unloading. The permanent deformation was significant and increased linearly with crack extension for plain mortar and at a faster rate for fiber reinforced mortar. Specimens' compliances measured with and without the effect of the permanent deformation are compared and are shown to be substantially different. It is observed that the apparent critical stress intensity factor of plain mortar stabilizes at a crack extension of about 203 mm (8 in.) but no stabilization is observed for fiber reinforced specimens. One of the significant findings of this study is that cracks in mortar start propagating when their opening angle reaches a critical value called the critical crack opening angle (COA) regardless of their length.

Author Information

Visalvanich, K
University of Illinois at Chicago Circle, Chicago, Ill.
Naaman, AE
University of Illinois at Chicago Circle, Chicago, Ill.
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Details
Developed by Committee: E08
Pages: 141–156
DOI: 10.1520/STP28303S
ISBN-EB: 978-0-8031-4811-6
ISBN-13: 978-0-8031-0731-1