LIFE-365

Service Life Prediction Model for Concrete Structures

LIFE-365

Computer Program for predicting the service life and life-cycle costs of reinforced concrete exposed to chlorides

Strategic Development Council (SDC)

• Formed by ACI International in 1997

• Collaborative Problem Solving

SDC Mission

• To form alliances of concrete industry leaders dedicated to expanding the total market potential for concrete.

• To leverage the efforts and resources through consortia.

SDC Consortium #26

• Service life prediction model LIFE-365

Consortia Funding

• Grace

• MBT

• PCA

• SFA

SLPM Phases

• Phase I– Version 1.0 July 2000

• Phase II– Consensus Test Procedures 2001

• Phase III– ACI International acceptance, 5 years

Phase I Beta Testers

Walker Parking

Structural Preservation Systems

Cagley & Associates

Caruthers & Wallace

Reid Crowther

AGRA

CCIA

FHWA AGRA

NST MTO

CTL NYDOT

FDOT NCDOT

CCIA WJE

AET

Virginia Tech

Levelton

Concrete Corrosion Inhibitors Association

Cortec

Master Builders

Grace

Sika

Axim

Phase II Testing

• Corrosion Threshold Values

• Chloride Diffusion Values

Service Life

• Construction to First Repair

Two Stage Service Life Model

• Page 32

• Figure 4.1

• Tuuti

Initiation period, ti Propagation period, tp

End of service life

Dam

age

Time

Cl , CO2 penetration

O2 diffusion,resistivity

Figure 4.1 Two-Stage Service Life Model Proposed by Tuutti (1982)

Initiation Period

• Time for Chloride to penetrate to the rebar, accumulate to threshold to initiate corrosion.

Initiation Period Model• Diffusion Mechanism

• Fick’s Second Law

• Finite Element Model

• Inputs– Cover

– Quality

– Exposure

– Threshold

Propagation Period

• Time necessary for sufficient corrosion to require repair

Propagation Period Model

• Assign a fixed value - will be modeled in the next version

Input Parameter• Cs Surface concentration of chloride ion

• D Diffusion coefficient

• M Diffusion decay coefficient

• Dult Ultimate diffusion coefficient

• Ct Chloride threshold

• tp Propagation period

• T Temperature

Parking Ramp

Jessi 2001/4/3

Description of Structure Properties of Scenarios

8.0

Design Life = 75 years

Discount Rate = 3.0

15% FlyAsh

Mix Design : w/cm = 0.45, Cost 68 $/yd3

Fly ash = 15 %

D28 = 1.05x10-11

m2/s , m = 0.32 , Ct = 0.05 %wt conc

Black Steel (0.45 $/lb) , Propagate = 6 years

222+ Mix Design : w/cm = 0.45, Cost 87 $/yd3

D28 = 9.42x10-12

m2/s , m = 0.20 , Ct = 0.12 %wt conc

Black Steel (0.45 $/lb) , Propagate = 6 years

Rheocrete 222+ : 1 gal/yd3

5% SilicaFume

Mix Design : w/cm = 0.45, Cost 87 $/yd3

Silica fume = 5 %

D28 = 4.60x10-12

m2/s , m = 0.20 , Ct = 0.05 %wt conc

Black Steel (0.45 $/lb) , Propagate = 6 years

Base Case Mix Design : w/cm = 0.45, Cost 70 $/yd3

D28 = 1.05x10-11

m2/s , m = 0.20 , Ct = 0.05 %wt conc

Black Steel (0.45 $/lb) , Propagate = 6 years

DCI 3 Gal Mix Design : w/cm = 0.45, Cost 87 $/yd3

D28 = 1.05x10-11

m2/s , m = 0.20 , Ct = 0.24 %wt conc

Black Steel (0.45 $/lb) , Propagate = 6 years

DCI / Rheocrete CNI : 3 gal/yd3

Epoxy Mix Design : w/cm = 0.45, Cost 70 $/yd3

D28 = 1.05x10-11

m2/s , m = 0.20 , Ct = 0.05 %wt conc

Epoxy Coated Steel (0.60 $/lb) , Propagate = 20 years

User - MCI2005

Cost 86 $/yd3 , D28 = 1.05x10

-11 m

2/s

m = 0.20 , Ct = 0.18 %wt conc , Propagate = 30 years

Clear Cover= 2.00 in

Volumetric = 1.2 %

Sur

face

Con

c (%

wt c

onc)

years

Surface History (Total)

0.0

0.2

0.4

0.6

0.8

0 20 40 60

Tem

pera

ture

(deg

F)

Month Number

Annual Temp. History

0

20

40

60

0 2 4 6 8 10

Project Title: Parking Ramp Date: 2001/4/3 - 5:17 pm

Performed by: Jessi

Structure: 1D slab/wall structure Exposure: Parking Garages

Location: MINNEAPOLIS , Minnesota 1 %wt conc @ 13 years

Clear cover: 2.00 in

Design Life: 75 years Discount Rate: 3.0 %

Scenario Initial Repair Repair Repair Time to Time to Total LifeName Cost Cost Area Interval Initiation 1

st Repair Cycle Cost

($/ft2) ($/ft

2) (%) (years) (years) (years) ($/ft

2)

Epoxy 4.09 25.00 10 10 8.1 28.1 7.38

222+ 3.93 25.00 10 10 18.6 24.6 7.57

DCI 3 Gal 3.93 25.00 10 10 18.2 24.2 7.62

15% FlyAsh

3.46 25.00 10 10 11.9 17.8 8.24

5% SilicaFume

3.93 25.00 10 10 13.6 19.5 8.48

Base Case 3.51 25.00 10 10 8.1 14.1 8.86

*User -MCI 2005

3.90 25.00 10 10 15.1 45.1 5.42

* Input Parameters (D, m, Ct) selected by user.

Mike's Parking Ramp

Jessi 2001/4/3

Description of Structure Properties of Scenarios

8.0

Design Life = 75 years

Discount Rate = 3.0

Mpls Ramp Mix Design : w/cm = 0.37, Cost 104 $/yd3

Silica fume = 4 % Fly ash = 21 %

D28 = 3.48x10-12

m2/s , m = 0.37 , Ct = 0.24 %wt conc

Epoxy Coated Steel (0.60 $/lb) , Propagate = 20 yearsDCI / Rheocrete CNI : 3 gal/yd3

User -2005 + 3%SF/21%FA

Cost 96 $/yd3 , D28 = 4.11x10

-12 m

2/s

m = 0.37 , Ct = 0.18 %wt conc , Propagate = 30 years

Clear Cover= 2.00 in

Volumetric = 1.2 %

Sur

face

Con

c (%

wt c

onc)

years

Surface History (Total)

0.0

0.2

0.4

0.6

0.8

0 20 40 60

Tem

pera

ture

(deg

F)

Month Number

Annual Temp. History

0

20

40

60

0 2 4 6 8 10

Project Title: Mike's Parking Ramp Date: 2001/4/3 - 5:20 pm

Performed by: Jessi

Structure: 1D slab/wall structure Exposure: Parking Garages

Location: MINNEAPOLIS , Minnesota 1 %wt conc @ 13 years

Clear cover: 2.00 in

Design Life: 75 years Discount Rate: 3.0 %

Scenario Initial Repair Repair Repair Time to Time to Total LifeName Cost Cost Area Interval Initiation 1

st Repair Cycle Cost

($/ft2) ($/ft

2) (%) (years) (years) (years) ($/ft

2)

Mpls Ramp 4.93 25.00 10 10 > 75 > 75 4.93

*User -2005 + 3%SF/21%FA

4.15 25.00 10 10 62.4 92.4 4.15

* Input Parameters (D, m, Ct) selected by user.