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1. Learning Transfer CCA 2008 17th Nov.2008
Key Learning's

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Holcim Group Support Course for Cement Applications 2008
Key Learning's 17.November.2008
1. Fundamental of Concrete – Role of Aggregate &
Water
2. Concrete Mix Design.
3. Optimization of Concrete Mixes.
4. Road Binders & Soil Stabilization.
5. Current situation in Concrete Technology
6. The role of Aggregates & RMC in Holcim Group

3. Fundamental of Concrete
The role of water and aggregates in Concrete

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Holcim Group Support Course for Cement Applications 2008
Fundamental of Concrete
 Definitions:
 Concrete: cement (MIC)+aggregates+water+admixtures
 Fresh Concrete: concentrated suspension of solids in water
- WORKABILITY: “It is not a property of concrete. Needs to be defined depending on
the type of application”
 Hardened Concrete: composite material in which aggregate are dispersed in the
cement paste matrix
 Effect of w/c on:
 concrete strength
 air-permeability of concrete
 Microstructure of hardened cement paste: Porosity

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Holcim Group Support Course for Cement Applications 2008
Type of Pores in Cement-based materials
Gel Pores and Capillary Pores (2.5nm-10nm)
Name Diameter of
Pores
Properties of the paste
affected
Gel Pores
<0.5 nm Shrinkage, creep at all RH
0.5nm-2.5nm Shrinkage, creep at all RH
Capillary
Pores
2.5nm-10nm
Shrinkage between 50%
and 80% RH
10nm-50nm
Strength, permeability,
shrinkage at high
RH,>80%
50nm-10µm Strength, permeability
Macropores 0.1 µm-1mm Strength
DRYING SHRINKAGE

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Holcim Group Support Course for Cement Applications 2008
Role of Water in Concrete
 Right dossing of water is the one of the most important parameters for durability
 Minimizing the water contents
- Increases strength
- Low permeability
- Freeze and thaw
 Excess of water impairs durability by
- Decreasing strength
- Loss of cohesion
- Segregation
- Bleeding
- Increasing permeability
- Favouring the ingress of aggressive ions
 Requirements for Mixing Water
 Avoid substances that may affect the hydration process (setting, hardening, strength):
ASTM C94 and EN 1008
 Concrete Recycled water (gray water)
- The increase of fines in the gray water lead to an increase of the water demand and
decrease of the compressive strength. Remaining admixtures could lead to deleterious
interactions
- Quality control of the gray water

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Holcim Group Support Course for Cement Applications 2008
Role of Aggregates in Concrete
 Aggregates occupy 3/4 volume in concrete.
- Reduce the heat of hydration
- Reduce costs: cheap filler
- Increases density, E-modulus and thermal conductivity of concrete
- Reduce volume changes due to filling effect and to restraining effect on paste
- Right grading of aggregates leads to a reduction of voids, making the concrete more
workable, cohesive
- Coarse aggregates improve bond with steel
- Improve durability since they are more stable than the paste
 Drawbacks:
 Aggregates are not an inert material
 Transition Zone:
- Porous and weaker areas: less C-S-H and more CH and ettringite is precipitating close to
the aggregates
- Deleterious expansive products preferentially deposit in this area
 Requirements for Concrete Aggregates
 Shape and grading of the aggregates :Sphericity and roundness
 The moisture content of our aggregates should be measure in order to correct our
mix design (w/c)

8. Concrete Mix design

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Holcim Group Support Course for Cement Applications 2008
Concrete mix design
 Concrete mix design
 Experimental procedure
 Appropriate selection and proportioning of constituents to
achieve pre-defined characteristics (workability, strength
or durability)
 Strength target: always adopt a margin of 4 to 7 MPa
(depending on production practices)
 New mix design has to be tested always with trial batches
 Optimisation of mix design
All possible
proportions
Compliant mixes Lowest cost
compliant mix

10. Road Binders/ Soil Stabilizators

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Holcim Group Support Course for Cement Applications 2008
Road Binders/Soil Stabilizators
 Low Water/Cement Ratio, as well as low cement content
 Compared to Cements this is a system with much more variables
and in need of technical approach
 Tailor made solutions no standardized approach
 Utilization of Just in Time logistics
 Used for:
 Soil Improvement (Increae bearing capacity, trafficability,
and reduce water content)
 Soil Stabilization (Increase bearing capacity, frost and
water resistance)
 Substitutes: CEM, QL, MIC, AGG – depending on application
 Possible Cannibalization

12. Current situation of concrete technology

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Holcim Group Support Course for Cement Applications 2008
CURRENT SITUATION OF CONCRETE
TECHNOLOGY
(a) Cost Efficient
• Concrete : Mostly widely used construction material of World today :-
(b) Durability factor
(c) Choice & Variety for the Construction
(d) Aesthetic Look
• Reasons for wide Concrete Usage :
(a) Plasticity & More Workability
(b) Strong in Compression
(c) Easily Transportable
(d) Environment Friendly
• Failure of Concrete – Non performance
(a) Concrete technology not well mastered due to Ignorance & not well
educated.
(b) Educated people tends to stay away from actual work place.
(c) Not taking intrinsic properties of cement
(d) Too much fragmented – Design, Manufacturing, Aggregate prod., Admixture
Manufacturing, Concrete manufacturing etc. – Specialized approach
• Reasons for wide Usage & Standing of Concrete Technology :
(a) Not taught & educated properly – Level too Low. Big Variance between
state of art tech.
(b) Importance of putting all technologies in practice – not only on theory.
(c) Importance of new generation concrete structures.
(d) Usage of Self – Compacting Concrete - Commonly used in America
(e) Reactive Powder Concrete – Usefulness – First used in Sherbrooke Pedestrian
Bridge Canada
(f) Advantages & usage of Ductal Concrete – e.g. Footbridge in Seol, S. Korea, Monaco
Rail station, Clinker Dome in Joppa. Illinois etc.

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Holcim Group Support Course for Cement Applications 2008
CURRENT SITUATION OF CONCRETE
TECHNOLOGY
• Importance of Mineral Components (MIC) & Super Plastisizers:
(a) MICs are mainly contributing to the factor of reducing ‘Portlandite’ in
concrete – thus more durable concrete
(b) Superplastisizer Technology – Role of Admixture in of utmost importance
to enhance the performance & quality of concrete in modern days.
• Relevance of Concrete in Holcim Business :
(a) History & Applications of Super Sulphated Cement (Rheolith) – renamed as
brand ‘CEMROC’
(b) Role & effictiveness of Sulphate Resistance cement – CEMROC - mainly
used in Belgium & Netherlands Area – new building under construction in
Belgium
(c) Gypsum storage built with SR Cement – can withstand more than normal
OPC Cement – Also Acid Resistance – Improves appearance – compared as
much superior cement than Austrian brand Slagstar
Effectiveness of concrete depends not only on the
cement quality but also practice & real knowledge

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Holcim Group Support Course for Cement Applications 2008
Reasons for wide Usage &
Standing of Concrete
Technology :
(a) Not taught &
educated properly – Level
too Low. Big Variance
between state of art tech.
(b) Importance of
putting all technologies in
practice – not only on theory.
(c) Importance of new
generation concrete
structures.
(d) Usage of Self –
Compacting Concrete -

16. Aggregates and Ready-mix

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Holcim Group Support Course for Cement Applications 2008
Aggregates and Ready-mix
 Learning Point
1. Market potential has both Aggregates and Ready – mix
2. Importunacy of aggregate quality
3. Aggregate production process
• Quarry to market
• Quarry rehabilitation
4. Ready mix preparation process
• Order of the material placing
• Weighing of the material
• Mixing process
• Transportation

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Holcim Group Support Course for Cement Applications 2008
Aggregates and Ready-mix
1. Sales volume of ready mix in 2007
• 45.1 million of cubic meter for 38 countries
2. Challengers Of Holcim
• Price Cost
• RONOA
• EBITDA
• Cash flow
• Become a price leader