durability, concrete, environment and sustainability in ... anlegg og eiendom/2018... · eurocode -...

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Steinar LeivestadStandard Norge

2018-05-02

Durability, Concrete,Environment and Sustainability

in the Eurocodes

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Norwegian clients asks for

environmental-friendly concrete

in70 – 80% of all new contracts

voluntarily

Zero-emission building in Trondheim

Norwegian Concrete

- the past and- the future

We have great expectations to the general applicability of the Eurocodes

Development of the concrete-materialPrime drivers; Sutainability –Environmental- and CO2 - footprint

• New cements and new binder combinations

• Utilize gain in strength from 28- to 91-days

• Re-use of aggregates

• Other ???

• Consequences with respect to

• Durability

• Strength and strength development

• Mechanical properties in design

• There are two perspectives

• To save the world (+ 20C)

• To save the concrete (by maintaining its competitive position)

• Reduced concrete volume for same function

• Less CO2 per m3 used

• Account made up after end of life-cycle 4

Development on the material side will normally lead to changes in performance, the requirements must be able to accommodate this in an effective way

• With todays «Deemed to Satisfy» (DtS) will new materials have to be documented to show «equivalence» based on a material (CEM I) that is expected not to remain available in the future, and which show large variations in performance even within the same class

• With performance based design we have a discipline that is not yet mattured enough for daily use, where the selection of parameters gives much room for «optimistic» and «pessimistic» choices with large variations in results. The parameters should therefore be made on a neutral basis as part of the standardization.

• By use of «Exposure Resistance Classes» (ERC) we can have a performance based definition of classes, and the standards can give a calibrated set of requirements to;

Exposure Class / Exposure Resistance Class / cover to reinforcement dependant of Design Working Life.

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Eurocode - 1991

Actions on structures

TC250/SC1

Product and testing standards

TC104/SCs and WGs

EN 206-1

Concrete

TC104/SC1


ISO 6934 or ETA

Tendons & PT kits


EN 10080

reinforcement


EN 13369 - xx or ETA

Prefabricated elements

TC229

EN 13670

Execution of concrete structures

TC104/SC2

Eurocode - 1992

Design of concrete structures

TC250/SC2

Eurocode - 1990

Basis of structural design

TC250

Societal expectations

+

National legislation

Durability Design of concrete structures

Provisions coordinated between the various standards

Interface Society /

construction project

Basic requirement

Design provisions

Ececution requirements

Mate

rial re

sist

anc

eclass

es

The G

ane

ralpr

ovisions

app

lies

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Meetings of TC250/SC2 and TC104/SC1 dealing with Durability and the work of the JWG

TC250/SC2

TC104/SC1 or TC104

2/11-2005 Larnaca (20) Mentioned

06-11-2006 Brussels (23) Mentioned

17-18/9-2007 Helsinki (24) Discussed 13-14/6-2007 Stockholm (21) Pre mature, established TG17

9-10/6-2008 Brussels (25) Resolution 164

25-26/6-2008 Berlin (22) Discussed Resolution 360

11/11-2008 Torino (26) Discussed

7-8/5-2009 Budapest (27) Discussed 16-17/9-2009 Gent (23) Discussed Resolution 373

12-13/11-2009 London (28) Discussed

07-08/10-2010 Madrid (29) Discussed 15-16/2010 Delft (24) No discussion Presentation TC104

30/5-2011 Oslo (30) Presentation 06-2011 Helsinki (25)

No discussion

12-13/12-2011 Milan (31) Principles agreed

23-24/11-2011 Milan (26) Principle agreed

28-29/06-2012 Brussel (32) Discussed 11-2012 Berlin (27) No discussion

01/03-2013 Berlin (33) Discussed 20-21/02 2013 Paris (28) Discussed

19/03-2014 Ispra (34) Principles agreed

5-6/3-2014 Vienna (29) Discussed

22-23/10 2014 Workshop in Brussels convened by JWG

04/03-2015 Berlin (35) Discussed 5-6/5-2015 Brussels (30) Discussed Resolution 440 agreed

05/11-2015 Berlin (36) Reported

06-2016 Berlin (37) Reported 10-11/5-2016 London (31) SC1/WG1 Road map discussed

11-2016 Zürich (38) Reported

The work on durability and the development of the concept by the JWG has been thorougly presented and discussed in TC250/SC2 and TC104/SC1since 2010

Eurocode 2 Section 4 NDPs

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(5) The minimum cover values for reinforcement and prestressing tendons in normal weight concrete taking account of the exposure classes and the structural classes is given by cmin,dur.

Note: Structural classification and values of cmin,dur for use in a Country may be found in its National Annex. The recommended Structural Class (design working life of 50 years) is S4 for the indicative concrete strengths given in Annex E and the recommended modifications to the structural class is given in Table 4.3N. The recommended minimum Structural Class is S1.

The recommended values of cmin,dur are given in Table 4.4N (reinforcing steel) and Table 4.5N (prestressing steel).

Cover Table 4.3N - 4.5N out of 27;7 use recommended value5 use recommended value with conditions15 use ammended values

Systematic review 30 comments

Exposure resistance classes system and definitions

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Corrosion of reinforcement Deterioration of concrete

Carbonation Resistance Class

Chloride Resistance Class

Freeze/thaw Resistance Class

Chemical Aggressiveness Class

Low Medi- um

High Low Medi- um

High Medium High Medium High

Corrosion of reinforcement

Deterioration of concrete

Carbonation Resistance Class

Chloride Resistance Class

Freeze/thaw Resistance Class

Chemical Aggressiveness Class (for later)

RXC (Low)

RXC (Medi- um)

RXC (High)

RXSD (Low)

RXSD (Medi- um)

RXSD (High)

RXF (Medium)

RXF (High)

RXCA (Medium)

RXCA (High)

Definition of class is 50-

years of exposure to XC3 (Rh 65%) with 10%-probability of carbonation front exceeding (mm)


years of exposure to XS2, with 10%-probability of chloride concentration exceeding 0,5% at depth (mm)


years of exposure to XF4, with 10%-probability of scaling loss exceeding (kg/m

2)


years of exposure to XA3, ground water with SO

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6000mg/l and 10%- probability of loss

exceeding (g/m2)[??]

40 30 20 75 60 45 10 2 ? ?

System

Definitions

Void, not mature

Quoting fib State of the Art report on chloride ingress

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Would not going from left to right be nice

4.2 Exposure resistance classes, continued

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(2) Concrete can be documented for the various classes in Table 2 by testing in accordance with the listed testing standards and with the limiting values given in Table 3.

Table 3 Exposure resistance classes, limiting values and applicable test standards

Carbonation resistance class RXC

Chloride resistance class RXSD

Frost resistance class RXF

RXC20 RXC30 RXC40 RXSD45 RXSD60 RXSD75 RXF0,5 RXF1,0

Limiting value, estimated after 50 years (mm) or kg/m2

20 30 40 45 60 75 0,5 1,0

Classification standard

prEN12390-10/12 EN12390-11 CEN/TS 12390-9 CEN/TR 15177

(3) Concrete may also as an alternative to testing according to (2) be documented by applying the deemed to satisfy values in Annex F for the various cement/binders, water/binder ratios and minimum binder content.

Draft proposal for text in EN 206

PROPOSAL EN 206 Annex FTable F.1 Exposure resistance classes; deemed to satisfy values for various binder compositions (example, preliminary values)

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Tentative - Preliminary values




RXC20 RXC30 RXC40 RXSD45 RXSD60 RXSD75 RXF0,2 RXF0,5 RXF1,0

Cement type or equivalent binder combination

Maximum w/b-ratio b is the sum of cement and additions in the concrete, within the limits defining the cements according to EN 197-1

CEM I

0,55 0,60 0,65 NA NA 0,451 0,40 0,45 0,50

CEM II-A

0,45 0,55 0,65 0,40 0,50 0,60 ? ? ?

CEM II-B

0,40 0,50 0,60 0,40 0,50 0,60 ? ? ?

CEM III-A

NA 0,45 0,55 ? ? ? ? ? ?

CEM III-B

NA NA 0,45 0,38 0,45 0,55 ? ? ?

Minimum binder content (kg/m3)

280 280 280 280 280 280 280 280 280

Minimum air entrainment

4% 4% -

1 CEM I shall only be used with minimum 4% silica fume NA means that no deemed to satisfy values are given for that combination of binder and resistance class

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The large scatter among the curves show how different the various cements within one cement type can perform with the same w/c-ratio

Alternative more refined approach distinguishing between various binders in Annex F of EN206

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Preliminary values




RXC20 RXC30 RXC40 RXSD45 RXSD60 RXSD75

RXF 0,2

RXF 0,5

RXF 1,0



CEM I

0,55 0,60 0,65 NA NA 0,451 0,40 0,45 0,50

CEM II-A-

V 0,45 0,55 0,65 0,40 0,50 0,60 S

D L

LL M

CEM II-B- V 0,40 0,50 0,60 0,40 0,50 0,60 S

D L

LL M

CEM III-A S NA 0,45 0,55 ? ? ? CEM III-B S NA NA 0,45 0,38 0,45 0,55


280 280 280 280 280 280 280 280 280


Exposure classes rate of carbonation and risk of corrosion

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EN 1992Table 4.1: Exposure classes related to environ-mental conditions

Proposed changes;- X0 only for concrete without reinforcement- XC1 deleted permanently wet-XC2 added permanently wet

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Class

designation Description of the exposure Informative examples and comments

1 No risk of corrosion or attack

X0

For concrete without reinforcement or

embedded metal: all exposures except

where there is freeze/thaw, abrasion or

chemical attack

2 Corrosion induced by carbonation

Where concrete containing reinforcement or other embedded metal is exposed to air and moisture, the exposure shall be classified as follows:

XC1 Dry

Concrete inside buildings with low air humidity, where the risk of corrosion is insignificant

XC2 Wet or permanently high humidity, rarely

dry Concrete surfaces subject to long-term water contact or permanently submerged in water or permanently exposed to high humidity.

Many foundations, water containments (not external).

Note: Leaching could also cause corrosion (see (5), XA classes).

XC3 Moderate humidity

Concrete inside buildings with moderate humidity

External concrete sheltered from rain

XC4 Cyclic wet and dry Concrete surfaces subject to cyclic water contact, (e.g. external concrete not sheltered from rain as walls, fassades, concrete in the tidal zone).

3 Corrosion induced by chlorides

Where concrete containing reinforcement or other embedded metal is subject to contact with water containing chlorides, including de-icing salts, from sources

other than from sea water, the exposure shall be classified as follows:

XD1 Moderate humidity Concrete surfaces exposed to airborne chlorides

XD2 Wet, rarely dry Swimming pools

Concrete components exposed to industrial waters containing chlorides

Note: If the chloride content of the water is ≤0.5 g/l then XD1 applies.

XD3 Cyclic wet and dry Parts of bridges exposed to water containing chlorides

Concrete roads, pavements and car park slabs in areas where de-icing agents are frequently used

4 Corrosion induced by chlorides from sea water

Where concrete containing reinforcement or other embedded metal is subject to contact with chlorides from sea water or air carrying salt originating from sea

water, the exposure shall be classified as follows:

XS1 Exposed to airborne salt but not in direct

contact with sea water

Structures near to or on the coast,

XS2 Permanently submerged Parts of marine structures and structures in seawater

XS3 Tidal, splash and spray zones Parts of marine structures and structures directly over sea water

5. Freeze/Thaw Attack (XF classification is not necessary in cases where freeze/thaw cycles is rare)

XF1 Moderate water saturation, without de-icing agent

Vertical concrete surfaces exposed to rain and freezing

XF2 Moderate water saturation, with de-icing

agent

Vertical concrete surfaces of road structures exposed to freezing and airborne de-icing agents

XF3 High water saturation, without de-icing

agents

Horizontal concrete surfaces exposed to rain and freezing

XF4 High water saturation with de-icing agents

or sea water

Road and bridge decks exposed to de-icing agents

Concrete surfaces exposed to direct spray containing de-icing agents and freezing

Splash zone of marine structures exposed to freezing

6. Chemical attack

XA1 Slightly aggressive chemical environment

according to Table 4.2

Natural soils and ground water

XA2 Moderately aggressive chemical

environment according to Table 4. 2


XA3 Highly aggressive chemical environment

according to Table 4.2


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New

PROPOSAL in EN 1992-1-1Table 4.4: Minimum concrete cover cmin,dur dependant on design working life, exposure class and exposure resistance class

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Preliminary

values Minimum cover for 50 and 100 years design working life,

(preliminary values, values are rounded to nearest 5 mm)

Exposure

Class EC

RXC20 2

RXC30 2

RXC40 2

50-years 100-years 50-years 100-years 50-years 100-years

XC1 10 15 10 20 10 20

XC2 10 15 15 20 20 30

XC3 15 20 20 25 25 35

XC4 15 20 20 25 25 35

RXSD45 RXSD60 RXSD756

XD1 25 35 30 40 35 45

XS1 25 35 30 40 35 45

XD2 30 40 40 50 50 NA

XS23 30 40 40 50 50 NA

XD34 40 50 50 60 60 NA

XS33

40 50 50 60 60 NA

1 Concrete corresponding to RXC10, with kN,90 ≤ 1,4 mm/year0,5 may be designed with cmin = max {cmin,b; 10 mm}

2 The values are given for ‘slab type geometry’ in beams the cover shall be increased by 5mm in RC20 and by 10 mm in RC30 and

RC40 for exposure classes XC2, XC3, XC4,

3 In saline waters with chloride level below 2,0 % the minimum cover may be reduced by 10 mm, with a chloride level below 1,0 % the

cover may be reduced by 15 mm, the tabulated values are applicable for Mediterranean and North Sea conditions (3 %).

4 Structures in regions with only short periods of use of de-icing salts, or low quantities annually, the minimum cover may be reduced by

10 mm, in agreement with provisions valid in the place of use.

5 The tabulated values for minimum cover assume curing class 2 according to EN 13670 (curing to 35% of fck), where curing to curing

class 3 or more is specified the cover may be reduced by 5 mm in exposure classes XC3, XC4, XD1, XD2, XD3 and XS1.

6 Concrete RXSD75 is not considered applicable for structures with 100 years design working life in exposure classes XD2, XD3, XS2

an d XS3 due to excessive cover requirements.

DtS values compared to minimum cover

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Tentative - Preliminary values




RXC20 RXC30 RXC40 RXSD45 RXSD60 RXSD75 RXF0,2 RXF0,5 RXF1,0



CEM I

0,55 0,60 0,65 NA NA 0,451 0,40 0,45 0,50

CEM II-A

0,45 0,55 0,65 0,40 0,50 0,60 ? ? ?

CEM II-B

0,40 0,50 0,60 0,40 0,50 0,60 ? ? ?

CEM III-A

NA 0,45 0,55 ? ? ? ? ? ?

CEM III-B

NA NA 0,45 0,38 0,45 0,55 ? ? ?


280 280 280 280 280 280 280 280 280

Minimum air entrainment

4% 4% -


Preliminary

values Minimum cover for 50 and 100 years design working life,

(preliminary values, values are rounded to nearest 5 mm)

Exposure

Class EC

RXC20 2

RXC30 2

RXC40 2

50-years 100-years 50-years 100-years 50-years 100-years

XC1 10 15 10 20 10 20

XC2 10 15 15 20 20 30

XC3 15 20 20 25 25 35

XC4 15 20 20 25 25 35

RXSD45 RXSD60 RXSD756

XD1 25 35 30 40 35 45

XS1 25 35 30 40 35 45

XD2 30 40 40 50 50 NA

XS23 30 40 40 50 50 NA

XD34 40 50 50 60 60 NA

XS33

40 50 50 60 60 NA

1 Concrete corresponding to RXC10, with kN,90 ≤ 1,4 mm/year0,5 may be designed with cmin = max {cmin,b; 10 mm}

2 The values are given for ‘slab type geometry’ in beams the cover shall be increased by 5mm in RC20 and by 10 mm in RC30 and

RC40 for exposure classes XC2, XC3, XC4,

3 In saline waters with chloride level below 2,0 % the minimum cover may be reduced by 10 mm, with a chloride level below 1,0 % the

cover may be reduced by 15 mm, the tabulated values are applicable for Mediterranean and North Sea conditions (3 %).

4 Structures in regions with only short periods of use of de-icing salts, or low quantities annually, the minimum cover may be reduced by

10 mm, in agreement with provisions valid in the place of use.

5 The tabulated values for minimum cover assume curing class 2 according to EN 13670 (curing to 35% of fck), where curing to curing

class 3 or more is specified the cover may be reduced by 5 mm in exposure classes XC3, XC4, XD1, XD2, XD3 and XS1.

6 Concrete RXSD75 is not considered applicable for structures with 100 years design working life in exposure classes XD2, XD3, XS2

an d XS3 due to excessive cover requirements.

Sammenligning overdekning i mm

Eksponeringsklasse RXC30 M60

XC1 10 15

XC2 15 25

XC3 20 25

XC4 20 25

RXSD60 M40 (M45)

XD1 30 40 (M45)

XS1 30 40 (M45)

XD2 40 40

XS2 40 40

XD3 50 40

XS3 50 50

The durability concept is easy to apply for all parties involved;

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Exposure classes

Exposure resistance classes

Design working life

Minimum concrete cover

The designer will in the execution specification specify;Strength class, Exposure resistance class, chloride class, Dupper/Dlower and nominal cover as well as the Execution Classe.g C30/37 – RXC30 – Cl 0,20 – Dupper 32 – Dlower 16 – cnom 30 mm (20+10) – EXC3

The contractor will in the concrete specification specify;Strength class, Exposure resistance class, chloride class, consistence class, segregation resistance class etc.e.g C30/37 – RXC30 – Cl 0,20 – Dupper 32 – Dlower 16 – S4 – SR1 etc.

The concrete producer produce and deliver a conforming concreteC30/37 – RXC30 – Cl 0,20 – Dupper 32 – Dlower 16 – S4 – SR1

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91-days strengthNew cements and new binder-combinattions that reduces CO2-footprintSeems to give a slower strength development, a major part of the final strength comes after 28-days.

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Present draft EC2

5.1.3 Strength

(1) The compressive strength of concrete

shall be denoted by concrete strength

classes which relate to the characteristic

(5%) cylinder strength fck of the concrete

in accordance with EN 206, determined at

an age tref .

(2) The value for tref should be taken as:

(i) 28 days in general

(ii) or may be taken between 28 and 91 days when specified for a project.

Should be default, to become usedand have effect on CO2

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(7) For concrete of strength Class C30 and lower, recycled aggregates may be used in

accordance with the parameters in Table 3.2. For higher strength classes or for higher

replacement values of the coarse fraction, including replacement up to 10% of the fines

fraction, the design provisions of this standard may be applied provided it is demonstrated by

tests that all values derived as a function of fck are in accordance with the values given in Table

3.1. The procedure for testing and approval shall be given in the execution specification.

Table 3.2: Maximum fraction of recycled coarse aggregates (4/32) in strength class C30

and lower, for exposure resistance classes documented by deemed to satisfy values in

EN 2061

Recycled aggregates (4/32)

Type according to EN 12620

RX0 RC40 RC30 RC20 RSD

Type A 30% 30% 30% 20% 0

Type B 30% 30% 20% 0%

1 Where the resistance class is documented by tests with the actual recycled aggregates the

maximum value may be taken as 30%.

New clause and table regarding recycled aggregates.

Systematic review DK07

EN 206 deals with re-cycled aggregates, but not from a design perspective, designers concern is within what limits of - Aggregate type (EN 12620)- Aggregate quantity (% – replacement coarse and fine)- Intended concrete strength (upper limit)are design parameters used in EC2 unaffected ? Within this range use of RA should be open for the Ready-mix producer

Annex N (normative): Recycled aggregates concrete structures

(1) Concrete with recycled aggregates may be used where the use of recycled aggregates will

not impair durability, service performance like appearance or wear, or represent a risk of

polluting water or air. Recycled aggregates may be used in normal concrete production without

any particular consent if done in accordance with the provisions of EN 206.

Note: The National Annex or the project specification can give further provisions and restrictions for the

use of recycled aggregates for concrete.

(2) If the properties listed in 5.1.2(3) for concrete with recycled aggregates are relevant for

the design in accordance with this standard, they should be determined by testing in

accordance with the tests specified in EN 206. The exposure resistance class should be

determined based on durability performance testing.

(3) All other clauses of this standard are generally applicable, unless they are substituted by

special provisions given in Table N.1.

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The report express concern for creep, shrinkage and E-modulus, but also for normal density concrete there is a variation of +/- 30%There is also concern for shear, since failure mode can differ, but capacities are not lower than the reference.

The Goal is there……………

Thank you for your attention

durability, concrete, environment and sustainability in ... anlegg og eiendom/2018... · eurocode -...

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