High workability concrete, also known as self-compacting concrete, has properties that allow it to flow and fill congested areas without vibration. It contains a higher amount of cementitious material, less coarse aggregate, more fine aggregate, and admixtures like superplasticizers and viscosity modifying agents. Tests like the slump flow and J-ring tests evaluate its flowability and passing ability. Benefits include faster construction, easier placement, and smoother surfaces, while drawbacks include potentially higher cost and drying/thermal shrinkage.

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3. HIGH WORKABILITY CONCRETE

4. High Workability Concrete
 Also known as self compacting concrete, self-
placing concrete, self levelling concrete, self-
consolidating concrete (SCC).
 The constructability of highly congested
reinforced concrete elements requires the fresh
concrete mixtures to be very fluid.
 Developed in Japan in the mid 1980’s
 SCC has high fluidity and high cohesiveness.

5. SELF COMPACTING CONCRETE
can be defined as
“a flowing concrete that can be cast into place
without the use of vibrators to form a product
free of honeycombs (i.e. no unfilled space
within the formwork) and bug holes (i.e. no
entrapped air voids).”

6.  SCC owns over three key properties that is:
a) Filling Ability
Ability of to fill a formwork completely
under its own weight
b) Passing Ability
Ability to overcome obstacles under its own
weight without hindrance. Obstacles are
e.g. reinforcement and small openings etc.
c) Segregation Resistance
Homogeneous composition of concrete
during and after the process of transport and
placing.

7. The Important Properties
 Self compactibility
 Avoidance of bleeding and segregation
 Low shrinkage
 Low permeability
 Strength as needed
 Aesthetically pleasing appearance
 Thorough coating of reinforcement and
optimal filling of formwork

8. The Making of SCC
 Ordinary SCC designed for 0.45 to 0.50 w/cm
 Higher cementitious material
 Lower coarse aggregate content (19 or 25mm
max. size)
 Increased fine aggregate
 Viscosity modifying admixture
 Mineral admixture of fine particle size
 Superplasticizer

9.  it is generally necessary to use superplasticizer
in order to obtain high mobility
 Adding a large volume of powdered material
or viscosity modifying admixture can
eliminate segregation.
 The powdered materials that can be added are
fly ash, silica fume, lime stone powder, glass
filler and quartzite filler.

10.  Incorporation of viscosity – modifying
admixtures (VMA) in concrete mix enables the
mixture to be cohesive even without the use of
high content of fine particles of cement and
mineral admixtures.
 VMA are generally composed of 2 basic
chemicals that is hydrolyzed starches and bio
polymers such as welum gum.

11.  Normally acquire 28-day strength at 40 MPa
 The SCC mixture can be categorized to 2 types:
a) those which contain a high powder content
(more than 400 kg/m3 cement + fly ash +
pulverized slag or limestone)
b)those which contain a viscosity – modifying
chemical admixture such as welum gum,
hydrolyzed starch, silica fume and ultrafine
amporphous colloidal silica known as
nanosilica.

12. What’s Different From
Normal Concrete???
 Segregation resistance from mortar viscosity,
not aggregate grading
- How the mortar viscosity is obtained???
i) High cement content
ii) High content of fly ash, slag
iii) High Viscosity Modifying Admixture
 Workability through admixtures, not water
content

13. How To Check Suitability??
 There are many new tests: V-funnel, L-box, U-
box, Fill-box, Orimet, GTM Screen + Slump
Flow and J-ring
 While, several of these may be used in mix
development, only the latter will find site use

14. Testing For SCC
 Slump Flow Test is a test method for
evaluating the flowability of SCC, where the
slump flow of SCC with coarse aggregates
having the maximum size of less than 40 mm
is measured.
 J-Ring Test is conducted to determine the
passing ability of concrete

15. Slump Test

16. J-Ring Test

17. Advantages
 Faster construction
 Reduced noise and increased safety because
vibrators are not used
 Less labor required or less dependent on skills
at site
 Smoother surface finish or better appearance
 Readily available
 Easy to deliver
 Ease of placement

18.  Will not settle
 Increased rate of production and safety
 Easily flow into complex shapes
 Reduced equipment needs
 Requires no on-site storage
 Makes use of waste by-product
 Reduced field inspection
 Product versatility
 Strong and durable
 Improved working comfort & safety at worksites

19. Ease of handling, placement and no vibration

20. Smooth surface finish

21. Disadvantage
 The shortcomings of SCC is
a)drying shrinkage is high
b)thermal shrinkage is high when the concrete
contains a relatively large proportion of
Portland cement and other reactive powders
(e.g., finely ggbfs or ASTM Class F fly ash)
c)higher cost – especially if higher strength is
not needed

22. Application
 Underwater concreting
 Construction of heavily reinforced structures
 Backfills and Structural fills
 Pavement bases
 Conduit bedding
 Erosion control
 Void filling
 Filling of complex formwork

23. High Workability Concrete

24. High Workability Concrete