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TECHNICAL PAPER

table 2: Details of column specimens

tYpE of no. of dEsIgnatIon sIzE of spEcImEns slEndErnEss tYpE of
column spEcImEns % ra ratIo rEhaBIlItatIon
hEIght dIamEtEr
(mm) (mm)
Type 1 C1 0 700 250 Nil
3 S1 100 700 250 2.8 Strengthening
R1 100 700 250 Repairing
Type 2 C2 0 1200 250 Nil
3 S2 100 1200 250 4.8 Strengthening
R2 100 1200 250 Repairing

The behaviour of circular columns subjected to axial loading is The compressive strength and modulus of rupture values of test
to be studied. The testing was carried out in the loading frame specimens are shown in Table 3. From this table, it is clear that
and the compressive load was applied with the hydraulic loading both compressive as well as modulus of rupture of specimens
jack of capacity 750 kN. Concentric compressive load was tend to decrease with increase in % of RCA.
applied on all the specimens. Lateral deflections were measured
at mid height using two LVDTs (Linear Variable Differential table 3: compressive strength and modulus of
Transducers) in two orthogonal directions.
rupture of concrete specimen with various RCA
percentages
pErcEntagE comprEssIvE modulus of
rEplacEmEnt strEngth of rupturE of
of rca spEcImEns In spEcImEns In
mpa (28 daYs) mpa (28 daYs)
0% 34.12 3.98
25% 33.48 3.86
50% 31.81 3.49
75% 31.19 3.09
100% 30.48 2.74

3.1 compression tests on control and
Confined Columns
For the control column C1, the first crack was observed at a
load of 382 kN near the one- fourth height from top and bottom
extending towards middle, from left to right of the observed
face. The brittle failure occurred at an ultimate load of 531 kN.
The compression mode of failure was observed. For confined
column S1, after application of the load, the column did not
show any sign of cracking up to a load of 310 kN. As the load
Figure 1: Reinforcement details of column specimens.
approached to 414 kN, first crack was observed in the mortar
layer with a cracking sound. The mortar layer was separated
3. resULts AND DIscUssION
from the wire mesh with compression failure of the column near
The details of various test results are now discussed to assess one fourth the total height from the top. The failure of the beam
the performance of the ferrocement confined recycled occurred at a load of 672 kN. The maximum lateral deflection
aggregate concrete column specimens. These test results cover was observed as 4.61mm.
compressive strength values of cube and modulus of rupture
of beam specimens with replacement percentages 0%, 25%, The control column C2 showed more deflection at lower load
50%, 75% and 100%. Results of compression tests on control, levels. As the load started to increase, the deflection also
confined and retrofitted column specimens are also discussed. increased. The first crack was observed at a load of 172 kN.

The IndIan ConCreTe Journal | JulY 2019 21