|
Test
on glass fibre reinforced gypsum panels partially
filled with RC
Jianwei
Yue and Peng Bao
With
a view to reduce usage of construction materials and
cost of construction, glass fibre reinforced gypsum
panels (GFRGP) partially filled with concrete was
designed for low-rise buildings in seismic zone. To
study the mechanical properties of GFRGP and provide
structural design method for GFRGP, six different
GFRGPs partially filled with concrete were designed
and low-cycle tests of specimens were carried out
under different axial loads. The method, parameters
and results of the low-cycle tests are presented.
As per the experimental results, the shear capacity,
ductility features, hysteretic characteristics, energy
dissipation and stiffness degradation of specimens
are quantified and discussed. GFRGP and concrete columns
are especially analysed to evaluate their performance
in resisting outside force. It is proven that the
GFRGP partially filled with concrete has better asesimic
behaviour and that fibre and concrete column play
a critical role in resisting horizontal force.
Effect
of concrete grades, cover thickness and surface coating
of RC on durability
J.
Prabakar, A. Chellappan and P. Srinivasan
Long
term durability is one of the most important factor
when structural concrete is used in severe environment.
Corrosion of rebars in the concrete has become one
of the serious problems affecting durability which
influence the service life of structures. The life
cycle cost of corrosion-prone buildings has increasingly
become difficult to manage. On account of technical
and economical concerns, efforts are being made to
enhance the service life of concrete structures by
various methods. Experimental studies were conducted
with different grades of concrete, concrete cover
thickness and concrete surface coating to assess the
corrosion protection efficiency under accelerated
test conditions. For comparison, uncoated concrete
specimens were also tested under similar accelerated
test conditions to determine the efficiency with respect
to concrete surface coating. In the accelerated test,
the current response was monitored with time during
the polarisation test, and weight loss of rebar and
chloride content were determined at the end of the
polarisation test. Adhesion test of coating material
was also conducted to evaluate the bond characteristics.
Concrete surface permeability and diffusion tests
were done to correlate the values with polarisation
test results. This paper discusses experimental studies
conducted in the laboratory on concrete surface coating
efficiency. The data obtained from the studies indicate
that the service life of reinforced concrete structures
can be enhanced by application of concrete surface
coating for the same grade of concrete for the given
thickness of concrete cover. The efficiency factor
for M70 grade concrete test specimen with 67 mm cover
and concrete surface coating was determined to be
4.57.
Chloride
penetration and drying shrinkage studies on blended
cement and OPC concrete with reference to marine environment
Raghuprasad.
P.S., A.V. Pradeep Kumar and R. Nagendra
The
paper presents laboratory investigations relating
to concrete produced from four different types of
cements namely fly ash (PPC), slag based (PSC), OPC
43 and 53 grade. An attempt has been made to compare
different parameters like workability of fresh concrete,
rapid chloride penetration, drying shrinkage of hardened
concrete, etc. for M30 grade of concrete mix made
with above mentioned four types of cement. From the
results of the investigation it is concluded that
the performance of blended cement concrete is superior
to that of OPC concrete.
|