In recent old ages, self packing concrete has gained wise used for arrangement in congested reinforced concrete constructions with hard projecting conditions. For such application, fresh concrete must posses high fluidness and good coherence. The usage of all right stuffs such as category F flyash can guarantee the needed concrete belongingss. Self Compacting Concretes flows under its ain weight and fills into every corner of form work and base on ballss through even restricted spacing of extremely congested support. Self Compacting Concrete compacts by itself without the demand of quiver.
An experimental probe is undertaken for Self Compacting Concrete with mix M3 which are designed tantamount to classs of M30. The H2O cement ratio of 0.35 is The workability features of Self maintained changeless. The Self Compacting mixture had a cement replacing of 30 % . Fairflo 100 ( M ) , Carboxylic ether polymer based superplasticizer with a dose of 1.2 % of pulverization ( Cement + 30 % flyash + 10 % silica smoke ) .
Compacting Concrete such as make fulling ability, go throughing ability, and segregation opposition are exhaustively understood with Slump flow trial, L-box trial, and V-funnel trial.
2.0 General Introduction:
The development of development of Self Compacting Concrete ( SCC ) , a much-needed revolution in concrete industry. Self Compacting Concrete is extremely engineered concrete with much higher fluidness without segregation and is capable of make fulling every corner of formwork under its self-weight merely ( 1 ) . The SCC eliminates the demand of quiver either external or internal for the compression of concrete without compromising its technology belongingss ( 2 ) .
This concrete was foremost developed in Japan in late 1980 ‘s to battle the impairment of concrete quality due to miss of skilled labors along with concerns sing the homogeneousness and compression of dramatis personae in topographic point concrete within intricate constructions for betterment of lastingness quality of concrete ( 3 ) . After the development of SCC in Japan 1988 whole Europe started working on this alone noise free revolution in the field of building industry. The last half of decennary 1990-2000 has remained really active field of research in SCC concrete in Europe. That is why, Europe has become in front from USA in Publishing specification and guidelines for Self Compacting Concrete. Now, all over the universe a batch of research is traveling on, how to optimise the fluidness of concrete with its strength and lastingness belongingss without a drastically addition in the cost. The first North American conference on design and usage of SSC was organized in November 2002. However, at present many researches are being carried out in legion universities and authorities R & A ; D organisations due to benefits of the usage of this concrete.
2.1 Advantages of Using SSC:
Some of the of import advantages that are normally experienced by following SCC are as follows
SCC outputs homogenous concrete in state of affairss where the castings are hard due to engorged support, hard etc.
SCC shows a good filling ability particularly around support.
Reduces noise at sites, the precast mill, and vicinity ; hence, it is a soundless concrete.
Eliminates jobs with blood circulation taking to “ white fingers ” caused by packing equipment, therefore called healthy concrete.
Shortens the building clip by speed uping building procedure, particularly in precast industry.
Its easiness of arrangement improves the productiveness and the cost economy through reduced equipment and labour equipment.
Decrease in wear and tear of signifiers, hence, it extends the service life of signifiers.
Decrease in the figure of worker. Normally one semen requires 1.5 man-hours ; with SCC this is reduced to 0.35 man-hours.
Shows narrow fluctuation in belongingss on site.
It reduces the ingestion of resources and cost, even sing a higher monetary value per three-dimensional metre for the concrete
2.2 Disadvantages of SCC:
The production of SCC topographic points more rigorous demands on the choice of stuffs in comparing with conventional concrete.
An uncontrolled fluctuation of even 1 % wet content in the all right sum will hold a much bigger impact on the rhelogy of SCC at really low W/C ( 0.3 ) ratio. Proper stock pile of sum, uniformity of wet in the batching procedure and good sampling pattern are indispensable for SCC mixture.
A alteration in the features of a SCC mixture could be a warning mark for quality control and while a subjective judgement, may some times be more of import than the quantitative parametric quantities.
The development of a SCC requires a big figure of a test batches. In add-on to the research lab test batches, field size test batches should be used to imitate the typical production conditions. Once a promising mixture has been established, farther research lab test batches are required to quantity the features of the mixture.
SCC is costlier than conventional concrete ab initio based on concrete stuffs cost due to higher dose of chemical alloies, i.e. high scope H2O reducing agent and viscousness heightening alloy ( VEA ) . Increase in material cost can be easy offset with betterment in productiveness, decreases in quiver cost and care and proper utilizations of mineral alloies.
2.3Applications in Precast Concrete Industry:
In the precast concrete industry SCC was welcomed as a considerable measure frontward. Many manufacturers now use SCC for a considerable portion of their production and some have even changed to 100 % to SCC. The advantages are converting.
SCC the quiver degree is reduced from the scope of 0.75 – 4.0 m/s2 to zero.
Dust: By the debut of SCC, the dust concentration can be reduced to a value every bit low as 0.2 mg/m3.
SCC is somewhat expensive than conventional concrete as per European Standards3. On the other manus there are considerable nest eggs.
Summarizing up all those advantages it is calculated that the cost of production lessenings by the debut of SCC and the labour conditions and the quality of the finished merchandises better.
2.4 Working Plan
A sum of 108 regular hexahedrons of 150mm side, 18 prism of 100mm ten 100mm ten 500mm and cylinder of 100mm Defense Intelligence Agency, 200mm tallness of Self Compacting Concrete and conventional concrete are cast. Test were carried out on all mixture to analyze the rheological belongingss.
Compressive strengths @ 1 yearss, 3 yearss, 7 yearss, 14 yearss, 21 yearss & A ; 28 yearss are recorded for Self Compacting Concrete & A ; Conventional Concrete, where as split tensile strength trial and Flexural Strengths trial are tested after 28-days hardening.
9 beams of size 2300mm ten 150mm ten 230mm, figure of beams each for ego compacting reinforced concrete for mix M3 & A ; figure of beam each for conventional reinforced for mix M30 are cast.
The consequence shows that an economical Self Compacting Concrete could be successfully developed by integrating 30 % category F fly ash & A ; 10 % Silica smoke
3.Workability Features of SCC
A concrete can be classified as self-compacting concrete merely when the demands such as make fulling ability, go throughing ability and segregation opposition are fulfilled ( 5 ) – table 1.
3.1 Filling ability ( first-class deformability )
3.2 Passing ability ( ability to go through support without barricading )
3.3 High opposition to segregation
3.1 Filling Ability:
Self packing concrete must be able to flux into all the infinites within the formwork under its ain weight. This is related to workability as measured by slack flow.
3.2 Passing Ability:
Self packing concrete must flux through tight gaps such as infinites between steel reenforcing bars under its ain weight. The mix must non ‘block ‘ during arrangement.
3.3 High Resistance to Segregation:
Self packing must run into the demands of 3.1 and 3.2 while its original composing remains unvarying. The cardinal belongingss must be maintained at equal degrees for the needed period of clip ( e.g. 20 min. ) after completion of blending. It is belongings 3.2 the passing ability and belongings 3.3 opposition to segregation that constitute the major progress from a simply ace elasticized fresh mix which may be more fluid than ego packing concrete mix.
3.4.5 Trials to be fulfilled to measure up as SCC:
Though there are many test methods to corroborate the making to SCC, as mentioned above, no individual method or combination of methods have obtained cosmopolitan credence.
So any mix aimed to be SCC must be tested for at least three workability trials. These can be a combination of any of the undermentioned, in add-on to slouch flow trial, V-funnel trial, L-box barricading ratio trial and U-box trial etc. ( 11 ) .
Unit of measurement
Typical scope of values
Slump flow by Abrams cone
T50cm slack flow
Time addition, V-funnel at T5minutes
( h2/h1 )
GTM screen stableness trial
Table No 1 Suggested value of credence for different trial
4. Experimental Program
The purpose of this experimental probe is to analyze the flexural behaviour of conventional concrete beams every bit good as ego packing concrete beams. In this probe, a series of Nine Numberss of under strengthened concrete Rectangular beams are tested to look into the ultimate burden transporting capacity and maximal warps.
4.2 Testing of Materials:
Ordinary Portland 53 class cement of Birla Super trade name corroborating to IS: 12269-1987 from a individual batch was used throughout the class of probe.
Flyash depends on the chemical belongingss and the choiceness of the Portland cement in the mix. Flyash obtained from Raichur Thermal Powder Plant, Karnataka with specific gravitation of 2.3.
4.2.3 Silica Fume:
Silica smoke is a byproduct of Si or Ferro-Silica industry and is 100 times finer than cement. The specific gravitation of silicon oxide exhausts is by and large 2.20 but it is really somewhat higher when the silicon oxide content is lower. This value can be compared with the specific gravitation of Portland cement, which is 3.15 the atoms of silicon oxide smoke are highly all right, most of them holding a diameter runing between 0.03 and 0.3m m ; the average diameter is typically below 0.1m m. The specific surface of such all right atoms can non be determined utilizing the Blaine method ; nitrogen surface assimilation indicates a specific surface of about 20000 m2/kg, which is 13 to 20 times higher than the specific surface of other pozzolanic stuffs, determined by the same method. Such all right stuff as silicon oxide smoke has a really low majority denseness: 200 to 300kg/m3.
4.2.4 All right Aggregate ( F.A. ) :
The sum which is go throughing through 4.75 millimeters sieve is known as all right sum. Locally available river sand which is free from organic drosss is used. Sand go throughing through 4.75mm screens and retained on 150 micrometer IS screen is used in this probe.
4.2.5 Coarse Sum:
The harsh sum used in this probe in 20mm down size crushed sum and angular in form.
4.2.6 Water: ( IS:456-2000 )
Water used for both commixture and hardening should be free from deleterious sum of hurtful stuffs. Drinkable H2O is by and large considered satisfactory for blending and bring arounding concrete. In the present work portable tap H2O was used.
4.2.7 Admixture: Fairflo:
Fairflo is a high public presentation superplasticizer intended for applications where increased early and ultimate compressive strengths are required, and it has been developed for usage in Self packing concrete and many more.
Fairflo is differentiated from conventional superplasticisers in that it is based on a alone carboxylic ether polymer with long sidelong ironss. This greatly improves cement scattering. At the start of the commixture procedure an electrostatic scattering occurs but the cement atom ‘s capacity to divide and scatter. This mechanism well reduces the H2O demand in flow able concret.
Fosroc provides a proficient consultative service for on-site aid and advice on mix design, alloy choice, rating tests and distributing equipment.
Appearance: Light yellow coloured liquid
Volumetric mass @ 20A°C: 1.06 kilogram / liter
Chloride content: Nothing to IS: 456
Alkali content: Typically less than 1.5 g Na2O tantamount / liter of alloy
4.3 Concrete Mix designed for CVC:
Indian criterion method of mix design ( as per IS 456 – 2000, IS 10262 – 1982 and SP – 23 ) the mix design of apparent concrete is
The mix proportion per three-dimensional metre of concrete so becomes.
Water Cement Fine sum Coarse sum
191.6 lts 491.30 kilograms 516 kilogram 1181 kilogram
0.39 1 1.198 2.40
4.4 Mix Proportion:
SCC is mostly affected by the feature of stuffs and mix proportions. Binu Sukumar et.al ( 12 ) have proposed a mix proportion for SCC from that mix proportion a ratio of harsh sum to ticket sum have been taken i.e. CA / FA = 0.86.
A mix have been design for CVC of class M30 grade so with above ratio and CVC mix proportion, a mix have been arrived for SCC.
Mix proportion of CVC
Mix proportion SSC
Mix M1 1: 1.52: 1.30
Mix M2 1: 1.198: 1.03
Mix M3 1: 1: 0.86
Table – 2: Mix, M3 equivalent to M30 class
4.5 Workability trial consequences:
Test carried out for repairing the dose of superplasticizer for different classs.
Unit of measurement
Slump flow by Abrams cone
T50 cmslump flow
Table – 3: Trial values
4.6 Cost Comparison:
A cost comparing of SCC is made with conventional concrete of the same strength. As respects of the cost of SCC, the addition in the cost of SCC on history of stuff is 10-12 % merely. If the nest eggs in the cost of SCC could be on par or even lower than that of the corresponding conventional concrete. Bonus is the improved lastingness and strength.
4.7 Specimens Detailss:
The specimen are classified into two groups.
1. Control specimen are as follows –
a. Cubes of 150mm ten 150mm ten 150mm size
b. Cylinder of 100mm Defense Intelligence Agency ten 200 millimeter length
c. Prism of 100mm ten 100mm ten 500mm size
2. Test specimen are as follows –
CVC set of beam tested for conventional concrete of grade M30 of span 2300mm, effectual span 2150mm, width 150mm, deepness 230mm.
SSC set of beam tested for Mix M3 ( Equivalent to M30 rate concrete ) of span 2300mm, effectual span 2150mm, width 150mm, deepness 230mm.
4.8 Casting and hardening of specimens:
4.8.1 Casting of control Specimens:
The molds of size 150x150x150mm, 10mm Defense Intelligence Agency ten 200mm tallness and 100x100x500mm are used for casting of regular hexahedrons, cylinders and prisms severally. The molds are cleaned and the corners are pasted with oil. One coat of cutting oil is applied on all the internal surfaces. The molds are filled in three beds and the tallness of each bed is about 1/3rd tallness of mold, each bed is compacted by giving 25 blows with a tamping rod over the full cross subdivision uniformly for CVC members and no compression is done for SCC members. After make fulling and packing the mold, the top surface are made smooth and kept for a period of 24 hours.
4.8.2 Cast of Test Specimens:
Wooden molds of internal dimensions 2300mm x 150mm ten 230mm are used for projecting the beams. The internal surfaces are cleaned and mould oil paste is applied at all corners, so a coat of cutting oil is applied on all internal surfaces. Steel reinforcement coop prepared earlier is kept in the mold. To obtain the needed effectual deepness howitzer blocks of 25mm thickness are kept one at each terminal. The mold is filled with the concrete in three beds, tallness of each bed being 1/3rd tallness of mold and compacted uniformly over the full cross sectional country with packing rods for CVC members and no compression for SCC members.
4.8.3 Test for Compressive Strength ( IS 516-1959 ) :
The compressive strength of concrete is one of the most of import belongingss of concrete in most structural application concrete is implied chiefly to defy compressive emphasis.
Graph No 01 Comparison and Effect of Bring arounding on Compressive Strengths of SCC
( Mix M3 equivalent to M30 Grade ) and CVC of M30 Grade
4.8.3Test for split Tensile Strength:
. These trials were carried out as per the specifications of IS: 58166 – 1970 ( 14 ) on three Numberss of cylindrical specimens. The tensile strength of concrete was calculated by utilizing the expression ;
Number of cylinders tested for different proportion with cvc and scc are shown below
No. of Cylinders
Bring arounding period
Comp Load ( Tons )
Split tensile strength
Average split tensile stre ( N/mm2 )
Table- 04 Split tensile strength of SCC-mix M3 ( tantamount to M30 )
4.8.4Test for Flexural Strength ( IS516-1959 ) :
. The trial is performed in conformity with IS 516-1959.
The maximal tensile emphasis readed is called modulus of rupture and is computed from the standard expression.
F = M / Z
M = Bending minute at the subdivision where rupture occurs
Z = subdivision modulus
Z = I/Y
I = minute of inactiveness of the subdivision
Y = distance from impersonal axis = d/2
Number of prisms trial for different proportions with CVC and SCC are shown in table figure 11 ( A ) – 11 ( F ) .
No. of Cylinders
Bring arounding period
Oppressing Load ( Tons )
Flexural Strength ( N/mm2 )
Average Flexural strength ( N/mm2 )
Table No 5 Flexural strength of SCC For Mix M3
5. Testing and Results of SCC Beams
5.1 Testing Procedure:
After 28 yearss of hardening, the beams were surface dried, they were cleaned with a wire coppice to take all grit and soil. Then all the specimens were white washed from all the sides to ease easy sensings of cleft extension. The beams are tested for pure flection on a loading frame of 500 KN capacity, the beam is kept on two girders, so as to obtain the clear span of 2000 millimeter. On the beam, two rods are kept at a distance of 360mm from centre of the beam on either side so that it acts as a two point burden, over which an I-section is placed. By sing a plummet, the centre line of the beam and the hydraulic doodly-squat were made to co-occur with each other in order to forestall bizarre lading on the beam.
The trial consequences of the beams tested are given in table figure 12-15, graph figure 4-7, demoing load warp curve.
5.2 Test Results of CVC & A ; SCC beams:
Graph No 02 Load Vs Deflection Curves for SCC ( Mix M3 equivalent to M30 Grade Beams )
Graph No 03 Load Vs Deflection Curves for SCC ( Mix M3 equivalent to M30 Grade Beams )
During the experimental work, close observations have been done to analyze the followers.
It is noted that the burden transporting capacity of SCC member is more compared to CVC member.
The cleft breadth have besides decreased for SCC members compared to CVC members.
the first cleft appeared for CVC member at early phase, where as for SCC member the first cleft has appeared subsequently.
The present probe has shown that it is possible to plan a ego packing concrete integrating category F fly ash & A ; silica celebrity. The fly ash ego packing have a slack flow in the scope of 600 to 800mm, a flow clip ( funnel ) runing from 8-10 seconds.
Strength development at the early ages is found to be similar to that of conventionally vibrated concrete.
In instance of Mix M3 one twenty-four hours strength is found to be 13 MPa. This is about 25 % of 28 twenty-four hours strength.
SCC is found to be a really good option for conventionally vibrated concrete.