Title:
Shear Strength of Concrete Block Masonry Using Direct Shear Test
Author(s):
Muhammad Masood Rafi and Sher Khan
Publication:
Structural Journal
Volume:
121
Issue:
2
Appears on pages(s):
99-109
Keywords:
block masonry triplets; fracture energy; mortar grade; precompression stress; shear modulus; shear strength
DOI:
10.14359/51740247
Date:
3/1/2024
Abstract:
This paper presents the details of experimental testing of block
masonry triplets using the direct shear test to investigate the shear
behaviors of block unit-mortar interfaces. Hollow blocks of 100
and 150 mm (4 and 6 in.) thickness and solid blocks of 100 mm
(4 in.) thickness were included in the testing program. These were
combined with mortars of three grades to cast a total of 84 triplets.
In addition to testing the triplets in an unconfined state, three
increasing levels of precompression stresses were used separately
to test the confined specimens. The shear behaviors of the tested
triplets were not influenced by block strength, while shear strength
increased (almost) linearly with mortar strength. The mean peak
shear stress for the unconfined triplets was 0.4 MPa (58 psi),
whereas the average shear modulus of the joint for these triplets
was 6.20 times the mortar compressive strength. The Mode II
fracture energy of the masonry joints increased at higher precompression levels. The methods of determining shear strength, shear modulus, and shear strength parameters for the mortar joint in block masonry are proposed using the observed data.