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TECHNICAL PAPER

table 6: comparison of experimental results and predictions of analytical models

ultImatE load ultImatE load - analYtIcal % dEvIatIon In ExpErImEntal and
spEcImEn - ExpErImEntal valuE (kn) analYtIcal valuEs
(kn) modEl 1 [KaushIK modEl 2 modEl 1 [KaushIK modEl 2
and sIngh] [ho et al.] and sIngh] [ho et al.]
S1 672.0 798.7 817.7 18.9 21.6
S2 483.0 556.0 591.0 15.1 22.4

5. cONcLUsIONs d - Depth of beam specimen
Based on test results and analysis of mathematical models, the σ c - Strength of confined concrete
following conclusions are obtained:
σ o - Strength of unconfined concrete
l Compressive strength as well as modulus of rupture K’ - Strength increase factor
of specimens tends to decrease with increase in % σ L - Lateral confining pressure
replacement of recycled aggregate.
A b - Area of transverse reinforcement
l Ultimate load carrying capacity of ferrocement confined f yh - Yield strength of transverse reinforcement
columns increased to 22.35% for type 1 columns and 18.96% s - Centre- to-centre spacing between successive
for type 2 columns respectively. transverse reinforcements

l Use of ferrocement as external strengthening material had P - Peak strength of circular RC column strengthened by
a significant effect on crack pattern of reinforced concrete Ferrocement
columns by delaying the crack appearance. P R - Peak strength of circular RC column
P F - Peak strength of circular plain concrete column
l Confined columns showed an increase in ductility by 33.98%
and 24.72% for type 1and type 2 columns respectively to strengthened by ferrocement
that of control columns. A st - Area of main reinforcement
- Yield strength of main reinforcement
f y
l A decrease of 6.62% and 7.4% is observed in load carrying
capacity of retrofitted type 1 and type 2 columns compared f’ co - Unconfined concrete strength
to control columns. A core - Area of confined concrete
- Diameter of transverse reinforcement between bar
d s
l Analytical models showed 18.85% and 21.60% increase in centre
ultimate load for type 1 column and an increase of 15.11%
R - Lateral confining pressure provided by transverse
and 22.36% for type 2 column compared to experimental f l
results. reinforcement
F
f l - Lateral confining pressure provided by ferrocement
l Ferrocement can be effectively utilised for the
strengthening of recycled aggregate concrete specimens T - Tensile strength of ferrocement
subjected to compression. d ext - Diameter of concrete core measured at the centrelines
of ferrocement
l It is observed that slightly larger values are obtained from
f w - Tensile strength of wire mesh
analytical models compared to experimental results. By
suitably modifying the coefficients in the analytical model, A w - Net area of wire mesh
they can be applied to the analysis of specimens with ρ s - Volumetric ratio of transverse reinforcement
recycled aggregates
d h - Diameter of transverse reinforcement
ɳ - Global efficiency factor of mesh reinforcement in the
LIst OF NOtAtIONs loading direction
F - Maximum applied load
V f - Volume fraction of mesh reinforcement
l - Span length
A c - Gross cross-section area of mortar section of
b - Breadth of beam specimen ferrocement

The IndIan ConCreTe Journal | JulY 2019 25