Cement & Concrete Technology on Road Construction 4 Cement and Concrete Technologies on Road... ·...

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

4

Most people think that ALL cement are the same…

…but there are 27cement products

(5 major types)

in the

cements

family

5

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#

6

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

7

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

8

9

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?

10

11

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?

12

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

13

Exothermic reaction

Cement Hydration

14

X 5

C3A

C3S

C3S

____10mm_____

Cement Hydration

Cement & Additions

15

16

• 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?

16

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

17

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)

18

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)

19

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

20

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

21

Concrete

22

Concrete as per The Baker’s Analogy

23

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

24

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

25

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

26

Water Cement Ratio

Understanding Concrete – Water

27

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

28

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

29

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


30

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


31

Application On

Road Construction

32

Conventional Road Pavement: Constructed With Asphalt & Aggregate (Stone) Materials

3333

Currently Cement Usages Are Mostly From Drainages, Road Kerbs & Concrete Safety Barriers In Roads

34

Drainages Road KerbsConcrete Safety

Barriers

34

35

Cement & Concrete Applications in Road Construction

35

Application On

Road Construction

PFA Blended Cement

For Stabilization

36

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


37

38

Replacing Soil

Stabilization with

Blended PFA

Cement or

commonly know as

Hydraulic Road

Binder (HRB)

Soil Stabilization Process

Cement

Stabilization help reduce imported material


38

39

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)


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


40

41

OPC

(Setting “Earlier”)

Layer to be

compacted

Layer to be

compacted

More effective compaction results

PFA Blended Cement

(Setting “Later”)


Increase working Window for Compaction

Whilst the layer is setting, loading (vibratory) introduces cracks

42

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

42

43

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

43

44

Summary of PFA Blended Cement’s Key Benefits

44

Application On

Road Construction

Concrete with Zero-slump

45

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

46

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

47

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

48

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

49

• Attractive initial cost

• Low Maintenance Cost

• Easy to be Constructed

• Early traffic Opening time

• Resistance to rutting, abrasion & chemical attack

Potential Advantage of RCC

50

Application On

Road Construction

Special Design Concrete Fast Setting Concrete Self Compacting Concrete

51

52

Benefits

• Solution to Site problem

• Increase Workability

• Pumping ability

• Self Compacting

Special Design Concrete

52

535

3

Example: Lafarge Agilia® self levelling-self compacting concrete

545

4

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

55

www.lafarge.com.my

56

Thank you

56

Cement & Concrete Technology on Road Construction 4 Cement and Concrete Technologies on Road... ·...

Documents

Transcript of Cement & Concrete Technology on Road Construction 4 Cement and Concrete Technologies on Road... ·...