EVOLVING (PORTLAND) CEMENT COMPOSITION

Pushing the boundaries in Concrete Technology

EVOLVING (PORTLAND)

CEMENT COMPOSITION

Warren SouthDirector – Research and Technical Services CCAA

Cement, Concrete and AggregatesAustralia is the peak bodyrepresenting the interests ofAustralia’s $7 billion a year heavyconstruction industry covering thecement, premixed concrete andextractive industries


OVERVIEW

Motivations

Progress in the cement industry

International perspective

Australian prototyping

Next steps


“IF IT AIN’T

BROKE, DON’T

FIX IT”

WHY THE

CHANGE?


“Tread softly lest you tread on my dreams”

SUSTAINABILITY

Aedh Wishes for the Cloths of

Heaven, William Butler Yeats,(1899)


A LESS EMISSIONS INTENSIVE PRODUCT

Cement production

• Thermal and electrical efficiency

• Alternative fuels

• Clinker substitution

• “Low carbon” cements

Concrete production

• Efficient use of natural resources

• Use of industrial co-products in binders and aggregates

• Use of recycled/reclaimed water

Concrete application

• Design for efficient use of delivered concrete

• Life Cycle Analysis

• Design for durability and resilience


Waste minimisation

Reduction in embodied emissions

Preservation of natural resources


Concrete can be made durable even in

aggressive environments.

Long-service life means not having to

replace buildings & infrastructure.

Long-service life means not having to

close down infrastructure as often for

repair or replacement.

Long-service life also lowers life cycle

costs and the intangible costs

associated with user inconvenience.

LIFE CYCLE CONSIDERATIONS


There is little point using “green” materials

for concrete construction unless the

concrete will perform at least as well and

be durable.

If a structure, pavement or building has a

shorter service life or needs more repairs,

then it is not sustainable.

Luckily, many of the materials used to

make concrete green also increase its

durability (provided attention is paid to

construction practices)

DURABILITY LEADS TO SUSTAINABILITY


CONCRETE SUSTAINABILITY STRATEGIES

Binders

SandAggregate

De-materialisation

StrategiesRecycled Concrete Aggregate

Reclaimed aggregate

Slag aggregate

Manufactured sand

Pre-stressed concrete

Fly Ash

Slag

Amorphous Silica

Mineral additions


An established downward

trend driven by process

efficiency improvements

Community (and market)

pressure to continue

reductions

Need to look at increased

clinker substitution while

maintaining concrete

performance

CEMENT PRODUCTION IMPROVEMENTS


DIRECTIONS IN

PORTLAND

CEMENT

COMPOSITION


EUROPEAN EXPERIENCE1965 Heidelberger produces 20% limestone cement in Germany

for specialty applications

1979 French Cement Standards allows limestone additions.

1990 15+/-5% limestone blended cements being used in Germany

1992 in UK, BS 7583 allows up to 20% in Limestone Cement

2000 EN 197-1 allows 5% MAC (Typ. Limestone) in all 27 common

cements, as was commonly practiced in various European cement

standards prior to that.

2000 EN 197-1 creates CEM II/A-L (6-20%) and CEM II/B-L (21-

35%)


2014

State Transport Authorities(State by State basis co-ordinated by PCA)

US INDUSTRY CASE STUDY

ASTM C150Specification for Portland Cements(no mineral additions)

1998ASTM C150Specification for Portland Cements(up to 5% mineral additions)

2007ASTM C150Specification for Portland Cements

ASTM C595Blended Hydraulic Cements(up to 15% as Type IL)

ASTM C1157Performance Specification for Hydraulic Cements (no restriction)


Limestone Cement Project - Objectives

• to evaluate the performance of cement with

higher limestone mineral addition levels in

both the plastic and hardened states of

concrete

• to be sufficient to allow the recommendation

of an increase in mineral addition substitution

from 7.5% to 10% or above for general

purpose cement (Type GP) described in the

Standard AS 3972-2010

• to evaluate a range of cement performance

properties in cement and concrete addressing

typical applications of concrete in construction


Limestone Cement Project – 4 stages

Stage 1 Influence of limestone content on mortar and concrete properties

Stage 2Comparative Concrete Properties

Stage 3Statistical analysis of results against Standard and other requirements.

Stage 4Compile a report to support recommendation to Australian Standards Committee


Scope 1. Control Cement: Currently produced GP cements (nominal 5% limestone for at least the next 6 months).2. Test Cement: Cements with 10% & 12% limestone level from the same cement plant as the corresponding Control Cement.3. Comparison of performance of the three cements (nominally 5% or 7.5%, 10%, and 12% limestone) in three groups of concrete with fixed mix design parameters.4. Composition of binder (GP+SCM): Practical & most common binders used by individual concrete manufacturer in different regions.5. Amorphous silica to be included where appropriate.

Type of Concrete Durable Concrete High Strength Concrete Normal Class Concrete

Field or Lab Batching Lab batching Lab batching Lab & Field batchingMix Design Parameters Typically:

450 kg/m3 cement 0.4 w/c max

20mm max aggregate120mm slump

80 MPa14mm max aggregate

(180mm slump),500mm spread

N20, N3220mm max aggregate

Binders See Table 3 Up to each concrete manufacturer Up to each concrete manufacturer

Plastic Concrete Properties

Slump Yes Slump & Spread YesSetting times Yes Yes YesAir content Yes - YesBleeding rate & Volume Yes - YesHardened Concrete Properties

Compressive Strength 1*, 3, 7, 28, 56, 90 days 1, 3, 7, 28, 56 days 1, 3, 7, 28, 56, 180** days

Drying Shrinkage 56 days 56 days 56 daysModulus of Elasticity - 28, 56 days -Creep - Up to 1 yr -AAR No requirement† No requirement† No requirement†Concrete Durability Indicators

RCP (ASTM C1012) 7-day water cured, 21-day in standard lab, tested at 28-day No requirement No requirementVPV (AS 1012)

Dnssm (NT Build 492)

Limestone Cement Project – Detail


Limestone Cement Project – Strength

Laboratory Testing Field Testing


Mix

Designation Control 10% limestone 12% limestone

1

Hig

h T

yp

e G

P c

on

ten

t

70GP/30FA

Low Low Not tested

2 72GP/20FA/8AS

Moderate Moderate Not tested

3 75GP/25FA

Moderate Moderate Moderate

4 72GP/25FA/3AS

Low Low Moderate

5 75GP/25FA

Moderate Moderate Moderate

6 72GP/20FA/8AS

Very Low Very Low Very Low

7

Lo

w T

yp

e G

P

co

nte

nt

55GP/20S/25FA

Low Low Low

8 50GP/30S/20FA

Low Very Low Very Low

9 35GP/65S

Very Low Very Low Very Low

Mix

Designation Control 10% limestone 12% limestone

1

Hig

h T

yp

e G

P c

on

ten

t

70GP/30FA

Excellent Excellent Not tested

2 72GP/20FA/8AS

Good Excellent Not tested

3 75GP/25FA

Normal Normal Normal

4 72GP/25FA/3AS

Marginal Marginal Marginal

5 75GP/25FA

Good Good Good

6 72GP/20FA/8AS

Excellent Excellent Excellent

7

Lo

w T

yp

e G

P c

on

ten

t 55GP/20S/25FA

Normal Marginal Marginal

8 50GP/30S/20FA

Excellent Excellent Good

9 35GP/65S

Excellent Excellent Excellent

Limestone Cement Project – Durability

RCPT Testing VPV Testing


Limestone Cement Project – Summary

� Report details experimental data for

existing and proposed cements.

� Provides extensive literature review of

the effect of increased limestone mineral

addition on evaluated properties.

� Evaluates cements against existing

performance requirements of Australian

Standard.

� Evaluates results against internationally

adopted acceptance criteria.

� Reports on these cements used in pre-

mixed and precast concrete applications.

� Statistical analysis of experimental data


SETTING THE

RIGHT

ENVIRONMENT


AN INDUSTRY APPROACHSustainability is integral to the vision and

values of major supply chain participants

Consider performance vs prescriptive

specification


A NEW THINKING FOR SPECIFICATIONSPERFORMANCE

• Wide range of design solutions• Risk of non-compliance lies with the supplier• Defining performance may be difficult• Specifier must determine what can be specified• Project benefits by the provision of• services requested by innovative methods to

achieve performance objectives.

PRESCRIPTIVE

• Specifier has full control• Straightforward quantification• No proprietary solutions• Limits the ingenuity and innovativeness of the

contractor.• Design responsibility with specifier• Certainty of product• Prescriptive specifications are often not precise;

they may be ambiguous• Requirements are often not sufficiently defined

In general, a performance specification should provide the best value and ensure that the owner receives the most benefits and the contractor selects the most cost effective materials and methods of construction.

It tells the contractor what functionality is expected rather than what equipment and procedures to use.


RESOURCES

www.ccaa.com.au


Documents

EVOLVING (PORTLAND) CEMENT COMPOSITION