Cement & Concrete Technology on Road Construction
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Cement & Concrete Technology on Road Construction
1. Introduction
Cement
Cement & Additions (Blended Cement)
Concrete
2. Cement & Concrete Applications on Road Construction
PFA Blended Cement for Stabilization
Concrete with Zero-slump
Special Design Concrete
3. Q&A
Table of Content
2
Introduction
3
Cement
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Most people think that ALL cement are the same…
…but there are 27cement products
(5 major types)
in the
cements
family
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The 27 cements products based on MS EN197-1: 2000
Cements Family
CEM I CEM II CEM III CEM IV CEM V
Portland slag
2#
Portland silica fume
1#
Portland pozzolana
4#
Portland fly-ash
4#
Portland burnt shale
2#
Portland limestone
4#
Portland composite
2#
Blast furnace 3# Pozzolanic 2# Composite 2#OPC 1#
1# 19# 3# 2# 2#
27#
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What is CEMENT?
Cement is a hydraulic binder, made of inorganic material which, when mix with water, it forms a paste which sets and hardens by means of hydration reactions and process; and after hardening, retains its strength and stability
Cement is manufactured at the cement
plant, through a closely controlled chemical
combination of calcium, silicon, aluminum,
iron and other ingredient.
Cement is made starting by heating
limestone to 1450oC in a kiln, in a process
called calcinations.
The raw material needed to produce cement
are generally extracted from a quarryLafarge Malaysia Kanthan plant
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Limestone
Shale
Pozolana/Clay
Grinding
Heat at
1450 oC
Clinker Gypsum
Other Mixing
Materials
PORTLAND
CEMENT
BLENDED
CEMENT
Grinding & Mixing
Grinding & Mixing
Process of Producing Cement
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Cement Manufacturing Process
Ordinary Portland Cement
Hydraulic binder
Clinker produced by intense burning (calcination) process of limestone & other raw minerals
Raw material for CEMENT(OPC or Blended Cement)
Contain approx. 80% limestone and remaining and alumino-silicate materials (eg. clay shale, sand, iron ore, etc..)
Raw Materials are homogenized and go through sintering and calcination process (burn in kiln at ~1450°C)
Clinker is ground to a fine powder and used as a binder in many cement products
Let’s us magnify
and observe clinker
particles!
What is CLINKER?
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Examination under Optical
Microscope
Alite (C3S)• Major component
(55% ~ 70%)
• Contributes to early and
late strength
Belite (C2S)• Second major component
(10% ~ 25%)
• Contributes in the late
strength
Clinker Under A Microscope
What is CLINKER?
11
12
Examination under Optical
Microscope
C3S
C2S
C4AF
C3A
Voids
Aluminate (C3A)• Consist at the range of 5%
~10%
• Contributes to high heat
generation and early stage
strength development
Ferrite (C4AF)• Contributes to the colour
effects that makes cement
grey
Clinker Under A Microscope
What is CLINKER?
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Main 4 cement crystallization components = C3S, C2S, C3A, C4AF
Once in contact with water, the cement hydration process occurs:
2Ca3SiO5 + 7H2O 3CaO 2SiO2 4H2O + 3Ca(OH)2
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Exothermic reaction
Cement Hydration
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X 5
C3A
C3S
C3S
____10mm_____
Cement Hydration
Cement & Additions
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• ACI 116 defines blended cements as hydraulic
cements “consisting essentially of an intimate and
uniform blend” of a number of different constituents
materials or supplementary cementitious materials
• The blended cement can be produced by inter-grinding
Portland cement clinker with the supplementary
cementitious materials or by a combination of inter-
grinding and blending
What is Blended Cement?
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Generally, there are 2 types of additions
Practically Inert Additions;
Limestone filler
Siliceous filler
Additions with Pozzolanic and / or latent hydraulic effect
– Pulverised Fuel Ash (PFA)
– Ground Granulated Blast furnace Slag (GGBS)
– Pozzolanas – volcanic ash
– Silica Fume
– Metakaolin
– Pulverised Fuel Ash (PFA)
– Ground Granulated Blast furnace Slag (GGBS)
– Pozzolanas – volcanic ash
– Silica Fume
– Metakaolin
Cement & Additions
Type W
Silica Fume
Metakaolin
Type V Fly Ash – Low CaO
Fly Ash – medium CaO
Type W Fly Ash – High CaO
Slag
Cement
Pozzolanic effect Hydraulic effect
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By-product of coal combustion at power plants
Cenosphere – improves rheology
Benefits
Improves rheology retention
Improves concrete durability
Reduces heat of hydration
Lower early strength but continues to gain strength after 28 days
Risks
Quality needs to be regulated since classified PFA is not available in Malaysia
Close monitoring of LOI – an indication of unburnt carbon which increases
water demand
These risks are overcome via production of pre-blended CEM II
Additions – Pulverised Fly Ash (PFA)
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By-product of the quenching process of steel smelting
Angular shaped
GGBS can increase paste viscosity at higher levels of
replacement
Benefits
Improves rheology retention
Improves concrete durability
Reduces heat of hydration
Lower early strength but continues to gain strength
after 28D
Early strength can be improved by grinding finer but
at the sacrifice of reducing its impact on lowering
heat of hydration
Additions – Ground Granulated Blast furnace Slag (GGBS)
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By-product of silicon and ferrosilicon alloy production
Spherical particles that are 100x finer than PFA
Benefits
Used in High Performance Concrete
Improves durability by reducing permeability
Risks
High variability in water demand between sources
High cost
Difficult to handle
Additions – Silica Fume
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Pulverized Fly ash
(PFA)
GGBFS
Silica Fume
Palm Oil Ash
• Reduce Permeability
• Longer Setting Time
• Lower Heat of Hydration
• Sulfate Resistance
• Increase Workability
• Increase Strength of Concrete
• Increase Setting of Concrete
• Increase durability
• Reduce permeability
• Produce high early strength
• Faster setting Concrete
• Increase tensile strength
• Increase Modulus
• Reduce Heat of Hydration
• Increase density
• Environmental friendly
• Cheaper
Examples on advantages of blended cement
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Concrete
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Concrete as per The Baker’s Analogy
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Concrete is produce when cement mixed and batched
with aggregate, sand and water producing building material
which can be spread or poured into mold and forms a mass
resembling stone on hardening
What is CONCRETE?
COARSEAGGREGATE
FINE AGGREGATE(SAND)
CEMENT
WATER
ADMIXTURE
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Regular concrete in Malaysia
Fine aggregates (0-5mm) – Silica sand
Coarse aggregates (5-20mm) – Granite
Selection for performance
Light weight (expanded clay) or heavy weight (magnetite)
High Modulus of Elasticity (basalt)
Performance Selection
Understanding Concrete – Aggregate
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Granular Skeleton is built on the ratio of fine to coarse aggregate fractions
– Target maximum compaction for slump concrete
– Target continuous gradation for flow concrete
flakiness and elongation = compaction
Granular Skeleton
0
Packing density
% CA
1
1
Optimum packing
Filling paste
Loosening paste
Understanding Concrete – Aggregate
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Water Cement Ratio
Understanding Concrete – Water
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Water Cement Ratio
0102030405060708090
100110
0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2
capillary pores
concrete strength
bleeding and
segregation
TOO MUCH WATER
LOW STRENGTH
POOR DURABILITY
Understanding Concrete – Water
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Plasticisers / Dispersing agents / Water Reducers
Admixtures – Water Reducers
With dispersing agent
Without dispersing agent
Water (kg/m3)
Fluidity
2
1
3 2
1
3
Dispersing agents are water
reducers that allow to:
• Increase the fluidity of the
concrete mix design without
changing the water content
• Decrease the water content
without changing the fluidity
of the concrete mix design
• Play on both: decrease water
and increase fluidity
Understanding Concrete – Admixtures
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Typical retarders: sugars, sucrose, glucose, sodium gluconate, citric acid
and tartaric acid
Admixtures – Retarders
Functions Risks
Delay cement hydration process Risk of bleeding and segregation with
too much retarders
Offsets accelerating effects of hot
weather on concrete setting time
Sensitive to cement properties
•Gypsum content
•Grinding fineness
•Time of addition to concrete mixing
Control delayed setting time for
special finishing techniques i.e.
exposed aggregates
Understanding Concrete – Admixtures
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Accelerators
• Accelerates hydration process - opposite effect of retarders
• Commonly used:
– Cold weather
– Shotcrete
Air Entrainers
Induces micro air bubbles for freeze-thaw environments
Admixtures – Others
Understanding Concrete – Admixtures
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Application On
Road Construction
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Conventional Road Pavement: Constructed With Asphalt & Aggregate (Stone) Materials
3333
Currently Cement Usages Are Mostly From Drainages, Road Kerbs & Concrete Safety Barriers In Roads
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Drainages Road KerbsConcrete Safety
Barriers
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Cement & Concrete Applications in Road Construction
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Application On
Road Construction
PFA Blended Cement
For Stabilization
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1m depth
Using Soil Stabilization with Blended PFA Cement will reduce the
demand of aggregate by 40 ~ 50% to build up the base course
Soil Stabilized
Stiffness of soil
(UCS)
Bearing Ratio
(CBR)
Stabilization help reduce imported material
PFA Blended Cement for Stabilization
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Replacing Soil
Stabilization with
Blended PFA
Cement or
commonly know as
Hydraulic Road
Binder (HRB)
Soil Stabilization Process
Cement
Stabilization help reduce imported material
PFA Blended Cement for Stabilization
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1 - Spreading of the hydraulic binder
3 - Levelling of the treated soil
4 - Compacting of the treated soil
H R B
2 - Mixing in place of the soil and the binder
Source: Global Infrastructure (Road)
PFA Blended Cement for Stabilization
Process of Stabilization
OPC
PFA Blended Cement
Initial Setting Time on
the treated soil
2hrs
4hrs
▪ Prevents “Demolishing”
Impact of the required
compaction process as
compared to using OPC
▪ Contractor has more time to
complete all the process
▪ Longer stretch
▪ Better productivity
Increase working Window for Compaction
PFA Blended Cement for Stabilization
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OPC
(Setting “Earlier”)
Layer to be
compacted
Layer to be
compacted
More effective compaction results
PFA Blended Cement
(Setting “Later”)
PFA Blended Cement for Stabilization
Increase working Window for Compaction
Whilst the layer is setting, loading (vibratory) introduces cracks
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Better
• Sulfate resistance
• Chloride resistance
• Acid resistance
SEM photomicrographs - PFA
Note:
Scanning Electron Microscope (SEM) photomicrographs
Increase Permeability of Sulfate that attacks Steel Reinforcement
PFA Blended Cement’s Advantages in Coastal Environment Roads
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Deep soil mixing is an in situ ground improvement technique that
enhances the characteristics of weak soils by mechanically mixing them
with a cementitious binder.
The action of mixing materials such as cement, fly ash, lime or bentonite
with soil causes the properties of the soil to become more like soft rock.
Example of DSM applications use for a railway track embankment
Deep Soil Mixing for Geotechnical Improvement
PFA Blended Cement’s for Deep Soil Ground Improvement of Road/ Rail Embankments & Foundations
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Summary of PFA Blended Cement’s Key Benefits
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Application On
Road Construction
Concrete with Zero-slump
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What is RCC?
“Dry” Portland Cement Concrete Mix with 0-slump, W/C 0.3 to 0.4 Dense-graded mix with maximum packing of aggregates Laid & Compacted with same equipment used in conventional asphalt
construction
Roller Compacted Concrete (RCC) with zero-slump
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MECHANICAL PROPERTY RCC Vs PCC
Compressive Strength
Flexural Strength
Splitting Tensile Strength
Fatigue Behavior
Modulus of Elasticity
Bond Strength in case of Multi-layer system
Shrinkage
Permeability
Differences between RCC and Normal Plain Concrete
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Hard Standing Facility
• Ports
• Airports
• Industrial Area
• Parking Area
• Toll Plaza
• Rest Area
Road Pavements
• Residential Street
• Urban Roads
• Rural Roads
Port terminal
Residential street
Arterial street
Commercial parking lot
Other Potential Usage of RCC
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Others
Road Shoulder
Road Widening
Sub Layer for heavy traffic pavement
Interstate highway shoulder
Road Widening
Road Widening
Sub Layer of Pavement
Other Potential Usage of RCC
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• Attractive initial cost
• Low Maintenance Cost
• Easy to be Constructed
• Early traffic Opening time
• Resistance to rutting, abrasion & chemical attack
Potential Advantage of RCC
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Application On
Road Construction
Special Design Concrete Fast Setting Concrete Self Compacting Concrete
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Benefits
• Solution to Site problem
• Increase Workability
• Pumping ability
• Self Compacting
Special Design Concrete
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535
3
Example: Lafarge Agilia® self levelling-self compacting concrete
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Significantly reduce manpower & casting time using Lafarge Agilia®
for horizontal casting of mass slab (+/- 3,000 m3 single pour)
Choices of Concrete
Normal Concrete
High Strength Concrete
Zero-slump Concrete (RCC)
Self Compacting Concrete
Self Leveling Concrete
Fast Setting Concrete
Cement Bound Material (CBM)
Colored Concrete
Porous Concrete
Light Weight Concrete
….ect
Concrete can be Design as per Specific Applications for Road Construction
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www.lafarge.com.my
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Thank you
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