2. INTRODUCTION
โ By early 1990โs, Japan has developed and used SCC
โ Self Compaction Concrete is highly engineered concrete with much higher
fluidity without segregation and it is capable of filling every corner of formwork
under its own self-weight.
โ Thus SCC eliminates the vibration for the compaction of Concrete without
affecting its engineering properties
โ As of the year 2000, scc used for prefabricated products (precast members)
and ready-mixed Concrete (cast in situ) in JAPAN,USA and later on INDIA
etc.
3. DEVELOPMENT OF SCC
โ In 1983, the problem of the durability of the concrete structures was a major
problem topic of interest in Japan.
โ The creation of durable concrete structures required adequate compaction by
skilled workers.
โ Solution for the achievement of durable concrete structures independent of
the quality construction work is the use of SCC.
โ The necessity of this type of concrete was proposed by Okamura in 1986.
โ Studies to develop SCC have been carried out by Ozawa and Melawi at the
University of Tokyo.
โ Present day scc can be classified as an advanced construction material.
4. FATHER OF SCC TECHNOLOGY
Prof.Dr.Hajime Okamura
โ Developed Self compacting concrete in
1986 in JAPAN.
โ Currently President of Kochi University
of Technology
โ CANMET/ACI AWARD for Outstanding
contributions in the development of SELF
COMPACTABLE HIGH PERFORMANCE
CONCRETE (1995).
โ OKAMURA solved the issue of degrading quality of concrete construction due
to lack of compaction by the employment of SCC which is independent of the
quality of construction work.
5. CONSTITUTES OF SCC
With regard to its composition, SCC consists of the
same components as conventionally vibrated
concrete, which are
โ Cement
โ Aggregate
โ Water
โ Chemical Admixtures i.e. Super plasticizers and Viscosity Modifying Agents.
โ Mineral Admixtures i.e., Fly ash, Silica Fume, GGBFS etc.
7. PROPERTIES OF SCC
IN FRESH STATE, SCC HAVE FOLLOWING PROPERTIES-
โ Filling ability (excellent deformability) - flows easily at suitable speed
into formwork.
โ Passing ability (ability to pass reinforcement without blocking) -
passes through reinforcements without blocking.
โ High resistance to segregation- the distribution of aggregate particles
remains homogeneous in both vertical and horizontal directions.
โ Static segregation due to gravity, vertical direction
โ Dynamic segregation due to flow, horizontal direction
9. MEASUREMENT OF SCC FLOW
PROPERTIES
IN FRESH STATE
Slump Flow & T50 test :
โ Slump flow test is used to find the filling ability of the SCC.
โ The SCC sample is poured in to the slump cone then the slump
flow diameter is measured.
โ The flow time is measured & that is know as T50 slump time.
โ The higher the slump flow value, the greater its ability to fill
formwork under its own weight.
13. L-BOX TEST
โ The L-Box test is used to find the passing ability of SCC.
โ The SCC sample is poured in to the L-Box apparatus, now
the plate is removed to allow flow.
โ The L-box ratio is calculated as H2/ H1.
โ According to EFNARC , when the ratio of h2 to h1 is greater
than 0.8, self compacting concrete has good passing ability.
16. TESTS ON HARDENED
CONCRETE
โ Compressive Strength Test
โ Split Tensile Strength Test
โ Split cylinder test
โ Standard Beam test
โ Flexural Strength Test
Preparation of SCC specimens:
1.All the materials are placed in the mixer & mixed well.
2.The sample is taken out and poured in to the moulds.
3.The moulds are socked in water & allowed for curing .
17. ADVANTAGES OF SCC
โ Faster construction.
โ Elimination of problems associated with vibration.
โ Improves working conditions and productivity in construction industry.
โ Greater freedom in design.
โ Less noise from vibrators and reduced danger from hand-arm vibration
syndrome (HAVS).
โ Ease of placement results in cost savings through reduced equipment and
labour requirement.
โ Improves the quality, durability, and reliability of concrete structures due
to better compaction and homogeneity of concrete.
โ Reduced wear and tear on forms from vibration.
18. DISADVANTAGES OF SCC
โ More precise measurement and monitoring of the constituent materials.
โ Requires more trial batches at laboratory as well as at ready-mixed
concrete plants.
โ Costlier than conventional concrete based on concrete material cost
(exception to placement cost).
โ Lack of globally accepted test standards and mix designs.
โ More stringent requirements on the selection of materials.
19. CONCLUSION
โ Self Compacting Concrete (SCC) technology can save time, cost, enhance
quality, durability and Moreover it is a green concept.
โ Since the concrete is capable of self-consolidating and reaching the
difficult areas in moulds, manual variables in terms of placing and compacting
concrete is nil. This factor ultimately yields defect less, better-quality concrete
structures.
โ Cast-in-place concrete construction in tight space and congested
reinforcement, such as, drilled shafts, columns and earth retaining
systems, can be accelerated by using SCC.
20. REFERENCES
1. Okamura.H.โSelf-Compacting High Performance Concreteโ, Concrete
International, Vol. 19, No.7, pp. 50-54, July 1997
2. M.S. Shetty. โConcrete technology (theory and practice), S. Chand &
Company LTD. 2002.
3. IS 456-2000 Code of practice for plain and reinforced concrete (3rd revision).
4. IS 516-1959 Method of test for strength of concrete.
5. Nan Su, K.C. Hsu, H.W. Chai. A Simple mix design method for self-
compacting concrete, cement and concrete Research 2001.
6. Brain Paulson. EFNARC, Secretary General, โSpecifications and Guidelines
for
Self-Compacting Concreteโ, February 2002.