33 Mechanism of deterioration due to frost damage and ...

（（33））Mechanism of deterioration Mechanism of deterioration due to frost damage due to frost damage

and performance predictionand performance predictionand performance predictionand performance prediction

Prof. Yukio HAMAProf. Yukio HAMAProf. Yukio HAMAProf. Yukio HAMA（（（（MuroranMuroranMuroranMuroran Institute of Technology)Institute of Technology)Institute of Technology)Institute of Technology)

Deterioration assessment of existing structures

Simulation model for durability design

Permeability

Performance prediction system

Mechanism of frost deterioration

Mixture Materials

Neutralization

Evaluation of environmental condition

Weathering condition

Pore structure

PermeabilityMixture Materials

Diagnosis

technique

Equivalent cycles to ASTM C666 A

Temperature Humidity

Frost damage


Moisture in concrete


CyASTM-sp = C×F×s×p×Ra90

Cy ASTM-sp： Equivalent cycles to ASTM （cycles／year）C： Coefficient of curing conditionsF： Coefficient of freezing and thawing conditions

Evaluation index of environmental conditions :

[ Equivalent cycles to ASTM ]

F Coefficient of freezing and thawing conditionss： Condition factor of sunshinep： Factor of degradation process

Ra90＝∑（-ts/18)β

ts：Minimum freezing temperature β： Constant

Ra90： Equivalent cycles to ASTM by air temperature

Relative dynamic modulus of elasticity(%

)

ＲａＲａＲａＲａ90-ＡＡＡＡ ⇒⇒⇒⇒ ＲａＲａＲａＲａ90-ＥＥＥＥB sluice:Ra90-A

A sluice:Ra90-A=Ra90-E

A sluice B sluice


Yearly number of equivalent cycles to ASTM Ra90

Relative dynamic modulus of elasticity

Ra90-A： Number of equivalent cycles to ASTM by concrete temperature

Ra90-E：Effective number of freeze/thaw cycles

【 Number of equivalent cycles to ASTM over 90％RH】

B sluice:Ra90-E

B :slab

A :slab

B :upper wall

B :lower wall

A :upper wall

Clarification of various deterioration mechanism


Permeability



Mixture Materials

Neutralization



Pore structure


Diagnosis

technique



Frost damage



Pore structure change by aging and frost resistance

Aging under real environment

Coarsening of pore

structure

Degradation of Frost

resistance

Nano structure of C-S-H before drying

Nano structure of C-S-H after drying


drying

Capillary pore

Drying and Wetting

drying

60

Outline of Experiment

50DWMuroranMuroran TokyoTokyo

<Specimen>

Mortar

Cement : OPC(N), FB, BB

W/B : 0.35, 0.55

Curing : 4 weeks in water, 6 months in water

Drying and wetting : 50DH, 50DL, 50DW, 50W

Exposure : Muroran, Tokyo, Okinawa for 1 year


-10

0

10

20

30

40

50

0 20 40 60 80 100Relative Humidity(％)

Tem

per

atu

re (℃

)

Environmental conditions

50DH50DL50W

４WK

50DW

20W

20D ・6MK

Muroran(M)Tokyo(T)

Okinawa(O)

OkinawaOkinawa

Outdoor exposure test

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Pore volume of 40～～～～2000nm diameter

Drying and wetting curing

Exposure

Ref.

Ref.

～2000nm

(cc/

g)

NW/B＝0.35

NW/B＝0.55

Exposure



0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0

Ref.

Ref.Pore

volu

me

of

40～

Specimens

FBW/B＝0.35

FBW/B＝0.55

Exposure

Exposure



0.04

0.05

Relationship between pore volume of 40～～～～2000nm

diameter and ink bottle pore volume

BB

Ink

bot

tle

por

e (c

c/g)

N FB

4WK/6MK 室内環境変化養生屋外暴露Outdoor exposureDrying and wetting


0

0.01

0.02

0.03

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07

Pore volume of 40～2000nm diameter（cc/g）

Ink

bot

tle

por

e (c

c/g)

R＝0.833 R＝0.894 R＝0.826

80

100

120

40

60

80

100

120

Du

rab

ilit

y F

act

or BB

NW/B＝0.35

Relationship between pore volume of 40～～～～2000nm

diameter and durability factor （（（（N，，，，FB，，，，BB））））

Du

rab

ilit

y F

act

or FBW/B＝0.35

Dry/Wet

Dry/Wet

Exposure


0

20

40

60

0 0.02 0.04 0.06 0.08

0

20

Du

rab

ilit

y F

act

or

Pore volume of 40～2000nm（cc/g）

W/B＝0.35Air：3.7％

0

20

40

60

80

100

120

0 0.02 0.04 0.06 0.08 0 0.02 0.04 0.06 0.08

Du

rab

ilit

y F

act

orNW/B＝0.55Air：1.4％

W/B＝0.35Air：2.8％

FBW/B＝0.55Air：1.0％

Pore volume of 40～2000nm（cc/g）

Dry/WetDry/Wet

Exposure

Exposure

Exposure

0.02

0.03

0.04

0.05

0.06

0.07

Relationship between temperature

and pore volume of 40～～～～2000nm diameter

NW/B＝0.35

2000n

m(c

c/g)

R＝0.984

R＝0.733

NW/B＝0.55

20D-4W 50DH-4W M T O


0

0.01

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0 10 20 30 40 50 60 0 10 20 30 40 50 60

Temperature（℃）

Por

e vo

lum

e of

40～

2000n

m

NR＝0.984

R＝0.925

R＝0.971

FBW/B＝0.35

FBW/B＝0.55

0.02

0.03

0.04

0.05

0.06

0.07

Relationship between relative humidity

and pore volume of 40～～～～2000nm diameter

NW/B＝0.35

2000n

m(c

c/g)

R＝0.673

R＝0.781

NW/B＝0.55

50DL-4W 50DH-4W M T O


0

0.01

0.02

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0 20 40 60 80 100 0 20 40 60 80 100

Relative Humidity（％RH）

Por

e vo

lum

e of

40～

2000n

m

R＝0.673

R＝0.821

R＝0.580

W/B＝0.55

FBW/B＝0.35

FBW/B＝0.55

Factors effecting on pore structure change by aging

Y = 0.088 Temp.– 0.120 W/B + 1.582 FB – 1.522 BB + 5.749

Here, Y : Pore40-2000 after aging / Pore40-2000 at 4 weeks in water

W/B(%)

FB : cement type ( N=0, FB=1, BB=0)

BB : cement type ( N=0, FB=0, BB=1)

12


-2

0

2

4

6

8

10

12

-2 0 2 4 6 8 10 12

Y :

Calc

ula

ted

valu

e

Y : Experimental value

R=0.85


Permeability



Mixture Materials

Neutralization




Pore structure


Diagnosis

technique



Frost damage



Relationship between relative dynamic modulus of elasticity

and ratio of carbonation speed

Cr=-0.0145RDM+2.5034 ｂｙ Matsumura et al.(2003)

(R2=0.61)2.0

2.5 Ratio of carbonation speed

y = -0.0163x + 2.6433R² = 0.8968

0.0

0.5

1.0

1.5

0 20 40 60 80 100

Ratio of carbonation speed

Relative dynamic modulus of elasticity (%)

Assume frost damage

（W/C=0.65、0.75）

Damaged depth

試験体作製 Deterioration assessment of existing structures

Outline of Experiment

base

W/C=0.55

Model specimenDamaged concrete

Carbonation speed

Permeability

Dynamic modulus of elasticity

Silicon plug50mm

10mm

Air permeability test : Figg’s intrusive method

Vinyl tube

Vacuum pump


Needle

T>10s: T=Time from P1(25.3kPa) to P2(21.3kPa) (s)

T<10s: T=Time from P1(33.3kPa) to P2(13.3kPa) (s)

R² = 0.9653

60%

80%

100%

RD

M

R² = 0.9977

2.2

2.4

2.6

2.8

3.0

Ca

rbon

ati

on s

pee

dN

e(m

m/√

wee

k)


Experimental results

0%

20%

40%

1.0 1.2 1.4 1.6 1.8 2.0

RD

MCarbonation speed ratio Ne/Ni

1.6

1.8

2.0

2.2

0.10 0.15 0.20 0.25

Ca

rbon

ati

on s

pee

d

Permeability speed Kt（kPa/s）

Ne=2.4461ln(Kt)+6.6394 (1) RDM=-0.49(Ne/Ni)+1.4997 (2)

y = x

80%

100%

120%

mea

sure

d v

alu

e）


Experimental results

y = 0.9007x

R = 0.73

0%

20%

40%

60%

0% 20% 40% 60% 80% 100% 120%

RD

M （

mea

sure

d v

alu

e

RDM （estimation value）

Cover depth

Carbonation depth(cm)

Ni：Initial estimation valueNt：Measured value at tNe：Estimation value by permeability at t

Carbonation speed: N


ＤｅｔｅｒｉｏｒａｔｉｏｎＤｅｔｅｒｉｏｒａｔｉｏｎＤｅｔｅｒｉｏｒａｔｉｏｎＤｅｔｅｒｉｏｒａｔｉｏｎａｓｓｅｓｓｍｅｎｔａｓｓｅｓｓｍｅｎｔａｓｓｅｓｓｍｅｎｔａｓｓｅｓｓｍｅｎｔ and life time prediction

ttttmaxmaxmaxmax(Life time)(Life time)(Life time)(Life time)

Age (√year)

tttt ttttmaxmaxmaxmax’’’’(Life time)(Life time)(Life time)(Life time)

Carbonation depth(cm)

RDM=-0.49(Ne/Ni)+1.4997

Ne=2.4461ln(Kt)+6.6394

After t years, measure permeability Kt, carbonation depth Ct

ＤｅｔｅｒｉｏｒａｔｉｏｎＤｅｔｅｒｉｏｒａｔｉｏｎＤｅｔｅｒｉｏｒａｔｉｏｎＤｅｔｅｒｉｏｒａｔｉｏｎａｓｓｅｓｓｍｅｎｔａｓｓｅｓｓｍｅｎｔａｓｓｅｓｓｍｅｎｔａｓｓｅｓｓｍｅｎｔ and life time prediction

Mixture, environmental condition Initial carbonation speed: Ni


Calculate estimation carbonation speed Ne

from permeability Kt by eq(3.2)

Calculate RDM from Ne/Ni by eq(3.3)

Assessment of frost deterioration

Life time prediction

Future Study:

Life cycle prediction of structures


Permeability



Mixture Materials

Neutralization


Pore structure


Diagnosis

technique



Frost damage



33 Mechanism of deterioration due to frost damage and ...

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