Numerical Analysis for the Mechanism of Deterioration of Mortar by Chemical Attacks D2 Yuji OIWA

Numerical Analysis for the Mechanism of Deterioration of

Mortar by Chemical Attacks

D2 Yuji OIWA

Today’s Topics

• Background & purpose

• Last presentation

• Research results

Background of my research

Recently, it seems that… ・ Decrease of natural aggregate resource ・ Increase of waste concrete in the future

New disposal system are developing.

Aggre

gate

resu

mpt

ion

Neutralize waste water

Functionality materialWaste concrete

Purpose of my research

Aggre

gate

resu

mpt

ion

Neutralize waste water

Functionality materialWaste concrete

1.Clarify the mechanism of deterioration of mortar by chemical attacks2.Simulation of deterioration of mortar numerical analysis

My research associate red zone. In concrete teams,

Purpose of my research

102 [m]

101 [m]

100 [m]

10-1 [m]

Structure

Member

Element (meso-scale)(Member=homogeneous)

(Element=homogeneous)

Verification

Constitutive model

10-2 [m]

Microscopic phenomena e.g. cracking and stress concentration can be simulated.

Because of the heterogeneity, environmental effects are easy to be introduced and combined with the mechanical action.

Chloride ion

Referenced Matsumoto paper

0 0.02 0.04 0.06 0.08 0.10

1

2

3

4

Stress(MPa)

width(mm)

Last presentation

Our RBSM can not simulate all of 3 kind experiment (bending, compression, tension) quantitatively. Only Compression. But other 2 experiment cannot be.

Modification of constitutive law is necessary.

Constitutive law is re-evaluated.

0 0.1 0.20

100

200

ExperimentAnalysis

Laod(kg)

Displacement(mm)Bending Tension

Last presentation

Parametric analysis

First, Tensile constitutive law is modified

Constitutive law is re-evaluated.

Kind ofanalysis

Affection of constitutive law

tension Compression Shear Variation

Tension ◎ △ △ △

Compression ○ ○ ◎ ◎

Flexure ◎ △ △ △

Tension

0 0.02 0.04 0.06 0.08 0.10

1

2

3

4

ExperimentModified model

Stress(MPa)

width(mm)Bending

0 0.1 0.20

100

200

ExperimentModified model

Laod(kg)

Displacement(mm)

Last presentation

Other constitutive law is not determined.Because, there are multi-pairing of shear and variation.

Parametric analysisKind ofanalysis

Affection of constitutive law

tension Compression Shear Variation

Tension ◎ △ △ △

Compression ○ ○ ◎ ◎

Flexure ◎ △ △ △

Shear model changed

0 0.001 0.002 0.0030

10

20

30

40

50

0 0.001 0.002 0.0030

10

20

30

40

50

Variation put

Almost same

≒

Constitutive law is re-evaluated.

Stress(MPa)

Displacement(mm)

Stress(MPa)

Displacement(mm)

Research results

Some problems are not solved yet.

1.Variation and shear spring model is not determined. There are multi-pairing of shear and variation.

2.My constitutive law are determined from other researchers. And three experiment data is not same mortar.

・ Experiment is necessary using same mortar in our laboratory.

Research results

Current bending test system have some gaps ofDisplacement.

0 0.1 0.2 0.30

2

4

6

8

Displacement (mm)

fb (

MPa

)

AnalysisExperiment1Experiment2Experiment3Experiment4

Experiment Analysis

gapSteel plate

Research resultsComparison of analysis data with good experimental data (Miura kun’s data)

Research resultsComparison of analysis data with good experimental data (Miura kun’s data)

Environmental control room

Research results

Grade up universal testing machine in Q laboratory

Before After

Research resultsFollowing box are made for setting displacement measurer.

DisplacementMeasurer

Thank you for your kind attention !