Abstract:
This study presents the results of investigations into the
compressive behaviour of brick masonry constructed with cement
mortar and mud mortar. For cement mortar, a particular cementsand
ratio (1:4) has been used and for mud mortar different
percentages of randomly distributed jute fibre and jute mat
conforming uniform distribution have been used. Stack bonded
prisms of different heights, prisms with vertical joints and
wallettes(walls) have been used in the investigation. All the
specimens have been tested under vertical compression in the
laboratory. The deformation, strength characteristics and failure
modes have been analysed and explained in the study. Besides ,two
dimensional linear elastic finite element method of analysis has
been used to investigate the platen effect imposed on the
specimens used in the study.
The study reveals that in case of five brick high prism, the
effect of platen restraint is substantially minimized. It has
been found that the deformation characteristics of masonry can be
represented by a parabolic equation of best fit. However, with a
minor modification, Saenz's stress-strain relation originally
proposed for axially loaded concrete can also be used to
represent the deformation characteristics of masonry with good
approximation. The study also suggests that the wall(wallette)
strength is 0.87 times the strength of five brick high stack
bonded prism and 0.75 times the strength of five brick high pr~sm
with vertical joint. A theoretical formula has also been proposed
from finite element analysis to predict the compressive strength
of stack bonded prism. The formula predicts the compressive
strength of stack bonded prisms more closely than any other
existing formula. Investigation into the mud mortar reveals that jute fibre
prevents the formation of crack in mortar bed joints. A limiting
maximum inclusion of 1.9% jute fibre results in a maximum
increase of unconfined compressive strength of mud mortar by
35.3%. For resistance to lateral deformation the limiting
inclusion lies between 1.5% to 2.0%. Above these limiting values
the increase of both strength and resistance to lateral
deformation are inhibited. The use of jute fibres in the mud
mortar has no appriciable effect on the strength of the masonry.
