12-09-2014, 12:08 PM
BEHAVIOUR OF REINFORCED CONCRETE BEAMS WITH COCONUT SHELL AS COARSE AGGREGATES PROJECT REPORT
BEHAVIOUR OF REINFORCED.pdf (Size: 579.48 KB / Downloads: 19)
INTRODUCTION
The high demand for concrete in the construction using normal
weight aggregates such as gravel and granite drastically
reduces the natural stone deposits and this has damaged the
environment thereby causing ecological imbalance (Short and
Kinniburgh, 1978).Therefore, there is a need to explore and to
find out suitable replacement material to substitute the natural
stone. In developed countries, the construction industries have
identified many artificial and natural lightweight aggregates
(LWA) that have replaced conventional aggregates thereby
reducing the size of structural members. This has brought
immense change in the development of high rise structures
using LWC. However, in Asia the construction industry is yet
to utilize the advantage of LWC in the construction of high rise
structures. Coconut Shell (CS) are not commonly used in the
construction industry but are often dumped as agricultural
wastes. It was concluded that the CSs were more suitable as
low strength-giving lightweight aggregate when used to replace
common coarse aggregate in concrete production.
Gunasekaran studied the properties of concrete using coconut
shell as coarse aggregate were investigated in an experimental
study. Compressive, flexural, splitting tensile strengths, impact
EXPERIMENTAL INVESTIGATIONS
Test specimen details
All the ingredients of the mix were weighed and mixed
in the concrete mixture machine as per the concrete mix
design. The steel mould was used for casting the beam
specimens. Before mixing the concrete, the moulds were kept
ready by placing it on a horizontal surface. The sides and
bottom of all the moulds were properly greased for easy
demoulding. The concrete was placed in the mould in three
layers and compaction was done using needle vibrator. Proper
care was taken for uniform compaction and surface finish
throughout the beam.
Test setup
The experiments were conducted on a loading frame of
capacity 400 kN. The beams were tested as a simply supported
beam with a clear span of 2500mm and it is subjected to two
point loading. The loading set-up consists of a load cell,
hydraulic jack and a hand pump to apply the load. The
experimental set-up is shown below. Steel pellets for the
Demec gauge strain measurement was pasted on the
compression side and tension side
TEST RESULTS
Failure mode
In the control concrete beam initial crack is 35 kN. The
coconut shell 25% beam initial crack is 25 kN. The coconut
shell 50% beam initial crack is 30 kN. The coconut shell 75%
beam initial crack is 35 kN. The failure beams as shown in the
figure.
LOAD CARRYING CAPACITY
The strength beam without coconut shell is 90 kN with a
central deflection of 680 mm.The strength beam with coconut
shell 25% is 90 kN with a central deflection of 745 mm.The
strength beam with coconut shell 50% is 90 kN with a central
deflection of 1010 mm. The strength beam with coconut shell
75% is 70 kN with a central deflection of 1870 mm. The load
deflection behavior of the test specimens are shown in Figure3
CONCLUSION
The experimental results of four beams, two each in CS and the
NWC are presented in this paper.
The comparison of mechanical properties and structural
behavior of the NWC and CS beams is discussedThe crack width, deflection, ultimate strength, concrete and
steel strains are analyzed and compared for both beams.
Based on the results, the following conclusions may be
drawn:The overall flexural behavior of reinforced PKSC beams
used in this study closely resembles that of equivalent beam
made with NWC.