PROGRESS REPORT GCCETR 11-12 PROJECT Project Title: Improving the self-healing properties of concrete materials by using composite action with fiber reinforced polymers PI: Michele Barbato Department of Civil and Environmental Engineering Louisiana State University and A&M College 3418H Patrick F. Taylor Hall Ph: 225-578-8719 E-mail: [email protected]Co-PI: Marwa Hassan Department of Construction Management Louisiana State University and A&M College 3130A Patrick F. Taylor Hall Ph: 225-578-9189 E-mail: [email protected]This document is a progress report for the research project “Improving the self-healing properties of concrete materials by using composite action with fiber reinforced polymers.” Please find below: (1) the research accomplishments to date, (2) the research tasks to be completed and their expected completion date. Accomplishments to date: The research accomplishments achieved to date are: • Successful production of microcapsules of dicyclopentadiene (DCPD) and sodium silicate in the laboratory. • Successful control of size, morphology and shell thickness of the microcapsules of DCPD and sodium silicate. • Experimental validation of the self-healing process of concrete due to the addition of DCPD and sodium silicate microcapsules. • Identification of appropriate analytical models for prediction of strength, stiffness, and ductility of concrete confined with fiber reinforced polymers (FRP). • Extension of the previously identified material constitutive models to cyclic loading conditions. • Implementation of the aforementioned material constitutive models into a general purpose code for nonlinear finite element analysis. • Preparation of one paper that has been accepted for presentation at the 2013 TRB Annual Meeting (see attached copy of the submitted paper). • Submission of a proposal to NSF (Division: CMMI, Program: Structural Materials and Mechanics, Title: “COLLABORATIVE RESEARCH: A NEW GENERATION OF
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PROGRESS REPORT GCCETR 11-12 PROJECT
Project Title: Improving the self-healing properties of concrete materials by using composite action with fiber reinforced polymers PI: Michele Barbato Department of Civil and Environmental Engineering Louisiana State University and A&M College 3418H Patrick F. Taylor Hall Ph: 225-578-8719 E-mail: [email protected] Co-PI: Marwa Hassan Department of Construction Management Louisiana State University and A&M College 3130A Patrick F. Taylor Hall Ph: 225-578-9189 E-mail: [email protected] This document is a progress report for the research project “Improving the self-healing properties of concrete materials by using composite action with fiber reinforced polymers.” Please find below: (1) the research accomplishments to date, (2) the research tasks to be completed and their expected completion date. Accomplishments to date: The research accomplishments achieved to date are: • Successful production of microcapsules of dicyclopentadiene (DCPD) and sodium silicate in the laboratory. • Successful control of size, morphology and shell thickness of the microcapsules of DCPD and sodium silicate. • Experimental validation of the self-healing process of concrete due to the addition of DCPD and sodium silicate microcapsules. • Identification of appropriate analytical models for prediction of strength, stiffness, and ductility of concrete confined with fiber reinforced polymers (FRP). • Extension of the previously identified material constitutive models to cyclic loading conditions. • Implementation of the aforementioned material constitutive models into a general purpose code for nonlinear finite element analysis. • Preparation of one paper that has been accepted for presentation at the 2013 TRB Annual Meeting (see attached copy of the submitted paper). • Submission of a proposal to NSF (Division: CMMI, Program: Structural Materials and Mechanics, Title: “COLLABORATIVE RESEARCH: A NEW GENERATION OF
INFRASTRUCTURE ELEMENTS MIMICKING SELF-HEALING MECHANISMS OF LIVING ORGANISMS”). This proposal is based on the preliminary results obtained in this current research project (see attached copy of the summary of the proposal, which is currently under review). • Preparation of the self-healing concrete specimens, both with and without FRP confinement. • Repair of the MTS machine to allow the testing of self-healing concrete specimens confined with FRP. Research tasks to be completed and their expected completion date: The research tasks to be completed are: • Experimental compressive test of self-healing concrete confined with FRP. • Complete the final report. The PI and co-PI expect to complete both research tasks before the end of February 2013. Reason for delay: The experimental compressive test requires the use of the large MTS machine of the CEE Department. However, this machine was not in working condition due to a problem with the adaptor of the load cell. Repairing the machine proved to be much more complex than originally expected and required the design of new components for the machine. This issue has been resolved recently, and the machine was successfully tested on November 29th, 2012. Benefits gained to the project from the granting of this extension: The investigators will complete all research tasks proposed for the funded project and will include the results obtained in the final report. These results will also be included in a second journal paper. It is noteworthy that, from the point of view of self-healing material production and property control, the PI and Co-PI have already completed a significant amount of research and obtained important research results, which are even beyond what originally proposed in the project.
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Evaluation of Microencapsulation of Dicyclopentadiene (DCPD) and Sodium Silicate for Self-Healing Concrete
LCDR James Gilford III1, CEC, USN, Marwa M. Hassan2, Tyson Rupnow3, Michele Barbato4, Ayman Okeil5, and Somayeh Asadi6
ABSTRACT
Considerable interests have been given in recent years to utilize self-healing materials in
concrete. The concept of microcapsule healing is based on a healing agent being encapsulated
and embedded in the concrete. The objective of this study was to evaluate the effects of
preparation parameters, namely, temperature, agitation rate, and pH on the shell thickness and
size (diameter) of the microcapsules. Two healing agents were evaluated in this study,
dicyclopentadiene (DCPD) and sodium silicate. Based on the results of the experimental
program, it was determined that as the pH was reduced, the shell thickness increased for sodium
silicate. Unlike DCPD, sodium silicate shell thickness was almost twice the amount of DCPD.
The more uniform and coherent microcapsules were produced at a temperature of 55°C. For the
DCPD microcapsules and at 49°C, the solution remained an emulsion and no encapsulation took
place. The increase in agitation rate resulted in a decrease in the average diameter of the
microcapsules for DCPD. This is due to the large microcapsules being broken up into smaller
ones when high shear is applied. On the other hand, the diameter of the microcapsules remained
1 Graduate Research Assistant, Department of Construction Management and Industrial Engineering, Louisiana State University,3218 Patrick F. Taylor,Baton Rouge, LA 70803, e-mail: [email protected]. 2 Assistant Professor, Department of Construction Management and Industrial Engineering, Louisiana State University, 3218 Patrick F. Taylor, Baton Rouge, LA 70803, e-mail: [email protected]. 3 Concrete Research Engineer, Louisiana Transportation Research Center, 4101 Gourrier Ave., Baton Rouge, LA 70808, e-mail: [email protected] 4 Department of Civil and Environmental Engineering, Louisiana State University, 3418H Patrick F. Taylor, Baton Rouge, LA 70803, e-mail: [email protected] 5 Department of Civil and Environmental Engineering, Louisiana State University, 3418H Patrick F. Taylor, Baton Rouge, LA 70803, e-mail: [email protected] 6 Assistant Professor, Department of Civil and Architectural Engineering, Texas A&M University-Kingsville, MSC 194. 700 University Blvd, Kingsville, TX 78363, email: [email protected]
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constant for sodium silicate microencapsulation as the agitation rate increased. Testing of
concrete specimens modified with the two healing agents showed that DCDDbased
microcapsules were effective in enhancing the modulus of elasticity of un-cracked concrete and
increasing its modulus of elasticity after healing. For sodium silicate, an optimum pH value
should be identified in order to produce microcapsules that enhance the modulus of elasticity of
and Technology, Vol. 65, Is. 15-16, 2005, pp. 2466-2473.
13. Brown, E.N., S.R. White, and N.R. Sottos. Retardation and repair of fatigue cracks in a
microcapsule toughened epoxy composite-Part II: In situ self-healing. Composites Science
and Technology, Vol. 65, Is. 15-16, 2005, pp. 2474-2480.
14. Nonat, A. Structure and Stoichiometry of C-S-H. Cement and Concrete Research, Vol. 34, Is.
9, 2004, pp. 1521-1528.
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List of Tables and Figures
Table 1. Required Chemicals for Interfacial Polymerization Synthesis
Table 2. Experimental Test Factorial
Fig.1 Schematic of the Components of a Microcapsule
Fig.2 DCPD Microencapsulation Process.
Fig.3 Sodium Silicate Microencapsulation Process
Fig. 4 Effect of pH Values on the Shell Thickness for (a) Sodium Silicate and (b) DCPD
Microcapsules
Fig.5 Effect of pH Values on the Morphology of Microcapsules for (a) and (b) DCPD and (c)
and (d) Sodium Silicate
Fig. 6 Effect of Temperature on the Shell Thickness for (a) Sodium Silicate and (b) DCPD
Microcapsules
Fig.7 Effect of Temperature on the Morphology of Microcapsules for (a) and (b) DCPD and (c)
and (d) Sodium Silicate
Fig.8 Effect of Agitation Rate on the Diameter of the (a) Sodium Silicate and (b) DCPD
Microcapsules
Fig.9 Effect of Agitation Rate on the Morphology of Microcapsules for (a) and (b) DCPD and
(c) and (d) Sodium Silicate
Fig. 10 Effect of Microcapsules on Modulus of Elasticity before and after Healing for (a) SS and
DCPD Microcapsules and (b) for SS Microcapsules Prepared at Different pH
Fig.11 Effects of (a and b) DCPD and (c and d) Sodium Silicate (1%) on Crack Healing after 1-
Week Recovery
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Table. 1 Required Chemicals for Interfacial Polymerization Synthesis
Chemical Function Manufacturer Urea Creates endothermic reaction in water The Science Company Ammonium Chloride Assists with curing Process The Science Company
Resorcinol (Technical Grade Flake) Reacts with formaldehyde and is a chemical intermediate for the synthesis process
NDSPEC Chemical Corporation
ZeMac E60 Copolymer Improves mechanical properties Vertellus Specialties, Inc. ZeMac E400 Copolymer Improves mechanical properties Vertellus Specialties, Inc. Octanol Prevents surface bubbles Oltchim Hydrochloric Acid Lowers pH The Science Company Sodium Silicate Reacts with Ca(OH)2 The Science Company Sodium Hydroxide Increases pH The Science Company
Formaldehyde Reacts with urea during synthesis process
The Science Company
Grubbs Catalyst Reacts with DCPD and polymerizes Materia, Inc. DETA (diethylenetriamine) Mix with EPON 828
Used in synthesis of catalysts, epoxy curing agent, and corrosion inhibitors
Temperature 49,52, and 55 51,53, and 55 pH value 3.1, 3.4, and 3.7 3, 3.1, and 3.2
Fig. 1. Schemmatic of the Componennts of a Micrrocapsule
20
21
DI Water
Add EMA 400 or 60 Co-polymer
Add Formaldehyde
Add DCDP
Add UreaAdd Resorcinol
Add Ammonium Chloride
Allow 4 hours to Cook and 2 hours to cool to room
temperature
Filter and Wash 3 X 500 ml using Vacuum Filtration System
Begin Agitation
Turn on and Set Desired
Temperature
Adjust Agitation/ Adjust pH
Fig. 2. DCPD Microencapsulation Process
22
Fig. 3. Sodium Silicate Microencapsulation Process
DI Water
Add EMA 400 or 60 Co-polymer
Add Formaldehyde
Add Sodium Silicate
Add UreaAdd Resorcinol
Add Ammonium Chloride
Allow 4 hours to Cook and 2 hours to cool to room
temperature
Filter and Wash 3 X 500 ml using Vacuum Filtration System
Begin Agitation
Turn on and Set Desired
Temperature
Adjust pH
Adjust Agitation/ Adjust pH
Fig. 4.
She
ll T
hick
ness
(nm
)S
hell
Thi
ckne
ss (
nm)
Effect of p
0
100
200
300
400
500
600
700
800
900
1000
0
50
100
150
200
250
300
350
400
H Values on
3.01
3.1
n the Shell TMic
(a)
(b) Thickness focrocapsules
3.12
pH
3.4
pH
for (a) Sodiu
3
um Silicate
3.2
3.7
and (b) DC
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Yie
ld S
tren
gth
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Yie
ld S
tren
gth
23
PD
g
Fig. 5. E
599.8 μ
Effect of pH
289.1 μm
μm
218.5
320.6 μm
319.7 μm
(
(b
(c
(d
H Values on
5 μm
3
(a) pH = 3.1
b) pH = 3.7
c) pH = 3.0
d) pH = 3.2
the Morpho(c) and (d
987.1 μm
315.9 μm
313.9 μm
247.4 μm
1 (250 rpm,
(250 rpm, T
(251 rpm, T
(255 rpm, T
ology of Mid) Sodium S
m
m
T = 55°)
T = 55°C)
T = 55°C)
T = 55°C)
icrocapsulesilicate
786.8
315.9 μm
181.3
1
s for (a) and
8 μm
3 μm
133.8 μm
d (b) DCPD
24
and
Fig.6. EEffect of Tem
0
100
200
300
400
500
600
700
800
She
ll T
hick
ness
(nm
)
0
50
100
150
200
250
She
ll T
hick
ness
(nm
)
mperature
51
49
on the ShellMic
Temp
Shell T
Tem
Shell T
(a)
(b) l Thickness crocapsules
53
perature (°C)
Thickness Y
52
mperature (°C
Thickness Y
for (a) Sod
55
)
Yield
55
C)
Yield
dium Silicate
0%
20%
40%
60%
80%
100%
0%10%20%30%40%50%60%70%80%90%100%
e and (b) DC
%
Yie
ldS
tren
gth
%
Yie
ld S
tren
gth
25
CPD
Fig. 7.
599.8 μ
847.5 μ
311.4
530.4 μ
Effect of Te
μm
μm
4 μm
μm
(a
(b
(c)
(d) emperature
a
31
293
5
a) T = 55° (p
b) T = 52° (p
) T = 55°C (
T = 51°C (e on the Morand (c) and
5.9 μm
858
3.9 μm
540.6 μm
pH = 3.7, rp
pH = 3.7, rp
(pH = 3.2, rp
(pH = 3. 2, rrphology of(d) Sodium
.9 μm
pm = 250)
pm = 250)
pm = 255)
rpm = 255)f Microcaps
m Silicate
672.2 μm
701.4 μm
489.6 μm
sules for (a)
and (b) DC
26
CPD
Fi
Di
t(
)
g. 8. Effect
1
10
100
1000D
iam
eter
(µ
m)
1
10
100
1000
Dia
met
er (
µm
)
of Agitation
250 3
1
0
0
0
250
n Rate on thand (b)
349 451
Ag
Dia
350
Agi
Dia
(a)
(b) he DiameterSodium Sili
1 549
gitation Rate
ameter Yeil
451
itation Rate
ameter Yeil
r of the (a) Dicate
800
e (RPM)
ld
552
(RPM)
ld
DCPD Micr
01234567891
1000
0%
20%
40%
60%
80%
100%
2
rocapsules
0%0%
20%0%
40%0%
60%70%0%
90%00%
Yie
ld S
tren
gth
%
Yei
ld S
tren
gth
27
Fig. 9. E
Effect of Ag
599.8 μm
165.7 μm
591.
498.1 μm
(a) Agita
(b) Agita
(d) Agita
(d) Agitati
gitation Ratea
.6 μm
m
ation Rate =
ation Rate =
ation Rate =
ion Rate = 5
e on the Moand (c) and
786.8 μm
609.9 μm
= 250 rpm (p
= 549 rpm (p(c)
= 257 rpm (p(e)
551 rpm (pH
orphology o(d) Sodium
315.9 μm
81.4 μm
pH = 3.7, T
pH = 3.7, T
pH = 3.2, T
H = 3.2, T =
of Microcapm Silicate
265.2 μm
701.4
46
T = 55°C)
T = 55°C)
T = 55°C)
= 55°C)
sules for (a)
672.2 μm
4 μm
67.5 μm
) and (b) DC
28
CPD
29
(a)
0
1000
2000
3000
4000
5000
6000
7000
8000
Control SS 0.5%pH=3.1
SS 1%pH=3.1
SS 2.5%pH=3.1
SS 5%pH=3.1
DCDP0.25%pH=3.1
DCDP0.25%pH=3.4
DCDP0.25%pH=3.7
Mod
ulus
of
Ela
stic
ity
(ksi
)
Sample ID
Before HealingAfter Healing
Fig. 10. (a) SS
(a) BeforFig. 1
2
3
4
5
6M
odul
us o
f E
last
icit
y (k
si)
Effectand DCPD
re healing 11. Eff
0
1000
2000
3000
4000
5000
6000
t of MicrocaMicrocapsu
fects of (a aH
Control
B
apsules on Mules and (b)
nd b) DCPDHealing afte
SS 5% p
Before Healing
(b) Modulus of ) for SS Mic
D and (c ander 1-Week R
pH=3.0 S
Sample ID
g After
Elasticity bcrocapsules
(b) Afterd d) Sodium
Recovery
SS 5% pH=3
D
r Healing
before and aPrepared a
r 1-week of hm Silicate (1
.1 SS 5%
after Healinat Different
healing 1%) on Crac
% pH=3.2
30
ng for pH
ck
A. PROJECT SUMMARY COLLABORATIVE RESEARCH: A NEW GENERATION OF INFRASTRUCTURE
ELEMENTS MIMICKING SELF-HEALING MECHANISMS OF LIVING ORGANISMS The objective of this project is to test the hypothesis that dual-action healing can drastically improve the self-repairing properties of reinforced concrete (RC) structures. The dual-action healing will be obtained by combining concrete prepared with microcapsules self-healing agents with Shape-Memory Alloy (SMA) reinforcement. The new class of RC composite material will mimic biological systems by partially healing moderate crack damage and by recovering from large deformations. The basic hypothesis is that the SMA can mechanically reduce the size of permanent cracks associated with yielding of the reinforcing steel, and the self-healing microcapsules can heal these cracks, thus recovering most of the stiffness and strength loss due to damage. A comprehensive experimental plan will characterize the mechanical and microscopic properties of the new class of RC composite materials using standard and advanced material characterization techniques. Size and morphology of self-healing microcapsules will be characterized using Scanning Electron Microscopy (SEM) coupled with Energy Dispersive X-Ray Spectroscopy (EDX). Self-healing processes in the concrete surface cracks will be characterized over time using SEM coupled with EDX and Atomic Force Microscopy (AFM). Material specimen tests will be used to identify and optimize the properties of the microcapsules and SMA. Laboratory testing will measure the recovery of flexural strength, stiffness and deformation for the new class of RC members after loading damage. Educational activities will enhance the knowledge and understanding of advanced materials’ applications among high school and undergraduate students. To achieve this objective, six undergraduate students from underrepresented groups (from Texas A&M University, Kingsville, a historically Hispanic institution, and from Southern University, a historically Black institution, and two from LSU) will receive summer internships that will expose them to innovative laboratory research activities and encourage them to pursue graduate studies related to advanced construction materials. Additional instruction/outreach activities for undergraduate students, high school students and teachers, and the general public will be performed through collaboration with several well-established and already successful diversity programs at LSU.
Intellectual Merits: This research project will introduce a new class of RC members that mimic living organisms with self-repair and damage restoration capabilities. The proposed project will innovatively combine the benefits of self-healing microcapsules (which have the ability to heal concrete after damage) with SMAs (which have the ability to recover large deformations and steel yielding upon heating and removal of stress). The basic hypothesis is that composite action can improve the self-repair capabilities of RC structures. Experimental and microscopic results will fill the gap in our knowledge by addressing the following issues: (1) Validate that the proposed approach can provide a superior class of RC composite materials; (2) Quantify the recovery in mechanical properties of damaged RC members that are built based on the proposed approach; (3) Determine the optimal properties and ratio with cement of self-healing microcapsules for the proposed application; and (4) Identify the benefits and limitations of the proposed preparation approach and its potential applications in structural and bridge engineering.
Broader impacts: This research proposal innovatively addresses the important societal need to reduce costs associated with inspection, maintenance, and repair of RC structures by introducing a new paradigm of RC elements that are designed to autonomously self-repair up to moderate damage levels. The proposed experimental activities will provide the necessary fundamental knowledge to facilitate the practical implementation of this new class of RC members in Civil Engineering applications. Results from this research could lead to the design/construction of new bridges and upgrade of existing bridges, a more efficient use of taxpayers’ dollars, creation of new jobs in the construction industry, and reduction of the cost associated with traffic restrictions on degraded bridges in the US. This research is characterized by a strong multidisciplinary component and proposes a significant and well-coordinated effort for involvement/education of undergraduate and K-12 students especially from underrepresented groups.