Engineered cementations composite (ECC) is a class of high-performance cementations
composites with strain-hardening behaviour and excellent crack control. Substitution of concrete
with ECC can avoid the cracking and durability problems associated with brittleness of concrete.
Extensive inelastic deformation is achieved in ECC through Recron 3’s fibre. ECC can be used in
high rise buildings due to their appearance, high bearing capacity, ductility, Fast construction and
cost effective. The aim of the paper is to study the flexural behaviour of ECC and concrete
composite reinforced beams. Size of the beam is 1200mm x100mmx150mm. The percentage of
Recron 3’s fibre replaced is 0.5 %, 1.5%, 2.5% by weight of cement. Finally conventional beam is
compared with ECC beam and also compare ECC at top and bottom of composite beams
2. M.Velmurugan, S.Kesavraman and A.Radhakrishnan
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vibration due to its self-consolidating characteristics. The moderately low fiber content has also made
shotcreting ECC viable.
Engineered Cementations Composites (ECC) is a unique representative of the new generation of high
performance fiber reinforced cementations composites, featuring high ductility and medium fiber content.
The microstructure to composite performance linkage can be further extended to the structural performance
level and integrate the material design into performance based design concept for structures.
Figure 1 ECC slab under two point loads
2. PROPERTIES OF MATERIALS
2.1. GENERAL
Materials used in this study are Cement, Fine aggregate, Coarse aggregate, Flyash, Recron3’s fibre, Super
Plasticizer, steel and their characteristics were obtained by testing of materials.
2.2. MATERIALS USED
Water: Water fit for drinking is generally considered fit for Making concrete
Cement : The cement used in all mixture was commercially available Ordinary Portland Cement ( OPC )
of 53 grade confirmed to IS: 8112-1989. The initial and final setting times were found as 80 minutes and
453 minutes respectively.
Fine Aggregate: Fine aggregate / natural sand is an accumulation of grains of mineral matter derived from
the disintegration of rocks. Usually commercial sand is obtained from riverbeds or from sand dunes
originally formed by the action of winds. The fine aggregate was passing through 4.75 mm sieve and had
a specific gravity of 2.68. The grading zone of fine aggregate was zone III as per Indian Standard
specification.
Coarse Aggregate : Coarse aggregate used in this study consist of crushed stone of size 20mm and below.
Laboratory tests were conducted on coarse aggregate to determine the different physical properties as per
IS: 383-1970.
Fly ash: Fly ash is finely divided residue resulting from the combustion of powedered coal and transported
by the flue gases and collected by electrostatic precipitator. It can be manufactured by using the low calcium
(class-F) fly ash obtained from Tuticorin Thermal Power Plant.
Recron3’s fibre: Recron3’s fibre is mainly used for to improving the quality of plaster and concrete.
Recron 3s fibres can be used in concrete elements such as RC and PC lintel, beam, column, flooring and
wall plastering.
3. Experimental Study On Flexural Behaviours of ECC and Concrete Composite Reinforced Beams
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Cut length 6 mm or 12 mm
Shape of fiber special for improved holding of cement aggregates
Tensile strength 4000-6000 kg/cm²
Melting point > 250OC
Dosage rate Concrete Use CT 2024 (12mm) at 909 g/m3g/cement bag 1:4
Cement/sand ratio Optimize as per application
Figure 2 Recron 3’s fiber
Super Plasticizer: (CONPLAST SP430)
High strength concrete production is greatly facilitated by the incorporation of a water reducing agent as
admixture. This enables easy handling of concretes with low water-cement ratios without loss of adequate
workability. The quantities of super plasticizer used were as per the specifications given by manufacturer.
The properties of Conplast SP 430 (complies with IS: 9103-1999) as reported by the suppliers are given in
Table.
Sl. No Description Property
1 Specific Gravity 1.220 to 1.225 at 30ºC
2 Setting times At higher dosage levels without water reduction
retards setting times 1-2 hours approximately.
3 Air entrainment Approximately1% additional air is entrain.
4 Compatibility Can be used with all types of Portland and Slag
cements except High alumina cement.
5 Workability Can be used to produce flowing concrete that
requires no compaction. Some minor
adjustments may be required to produce high
workable mix without segregation.
6 Durability Reduction in W/C ratio enables increase in
density and impermeability thus enhancing
durability of concrete.
7 Compressive strength Early strength is increased upto 20% if water
reduction is taken advantage of. Generally, there
is improvement in strength upto 20% depending
upon W/C ratio and other mix parameters.
3. EXPERIMENTAL METHODS:
3.1. General
The experimental program consisted of casting, curing and testing the cube of size 150x150x150 mm.
4. M.Velmurugan, S.Kesavraman and A.Radhakrishnan
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3.2. Mix Proportions
For ECC: (M45)
Cement sand Fly ash Water
1 0.8 1.2 0.51
For Conventional Concrete: (M45)
Cement Fine Aggregate Coarse
Aggregate
Water
1 1.64 1.85 0.37
3.3. Casting and Curing
Steel mould was used for casting the cubes. Before casting, machine oil was applied on the inner surface
of the mould. Concrete was mixed using a tilting type laboratory mixer and was poured into the moulds in
layers. Compaction of concrete was done using a needle vibrator. After 24 hours from casting, all the cubes
were curing into the water for 7 & 28 days compressive test.
3.4. Testing
All the cubes were tested in Compression Testing Machine (CTM).For loading the Cubes 2000 KN capacity
hydraulic compression testing machine was used.
Figure 3 Specimen placed in CTM
4. SUMMARY OF SPECIMEN INFORMATION
S.no Concrete type Grade Curing days
1 ECC M45 7 28
Conventional M45 7 28
2 ECC at top M45 7 28
ECC at Bottom M45 7 28
5. Experimental Study On Flexural Behaviours of ECC and Concrete Composite Reinforced Beams
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5. EXPERIMENTAL RESULTS AND DISCUSSIONS
X axis = days; Y axis = Comp. strength (N/mm²)
Graph 1. Comp. strength result at 7days. (Cube)
X axis = days; Y axis = Comp. strength (N/mm²)
Graph 2. Comp. strength result at 28days. (Cube)
From Graph 1. ECC is compared with conventional concrete of 7 days compressive strength results. It
is the composite concrete is (3 to 5%) better than conventional and Ecc concrete. From Graph 2.compared
ECC and Conventional concrete of 28 days compressive strength results. ECC and Conventional concrete
results values arrived through best mix proportions. But doesn’t get expected results.
6. BEAM DETAILS
Figure 4 Comparison between Conventional and ECC concrete
0
5
10
15
20
25
30
35
0 7
ECC
Conventiona
l
ECC at Top
ECC at
Bottom
0
10
20
30
40
50
60
0 7 28
ECC
Conventiona
l
ECC at Top
ECC at
Bottom
6. M.Velmurugan, S.Kesavraman and A.Radhakrishnan
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Figure 5 Comparison between ECC at Bottom and Top
6.1. TEST SETUP
Figure 6 Two point loading in beam
7. CONCLUSION
ECC with conventional concrete is compared with ECC concrete of 7& 28 days compressive strength
results. It is the composite concrete is (3 to 5%) better than conventional and Ecc concrete. According to
the cube compressive test results, if use of ECC with conventional composite concrete may the beam is
withstanding high load and a large deformation without succumbing to the brittle fracture typical of normal
concrete, even without the use of steel reinforcement.