performances of concrete repairs in practice graham …
TRANSCRIPT
CON REP NETCON REP NET
PERFORMANCES OF CONCRETE REPAIRS IN PRACTICE
Graham Tilly, Gifford and Partners
STRUCTURESSTRUCTURES
0
10
20
30
40
50
60
70
80
90
Buildings Bridges Dams Powerstations
Car parks Other
Num
ber
Ages ofAges of StructuresStructures
0
10
20
30
40
50
60
0-10 11-20 21-30 31-40 41-50 51-60 61-70 71-80 81-151
Years (to 2003)
Num
ber
ENVIRONMENTSENVIRONMENTS
01020304050607080
Urban Rural Highway Coastal Industrial
Num
ber
WP2 Past Performances
DETERIORATION AND REPAIR
Types of Original DeteriorationTypes of Original Deterioration
0
20
40
60
80
100
120
140
Corrosio
n
Frost
Cracks AAR
Deterio
rated co
ncrete
Poor constr
uction
OtherNu
mbe
r
Ages of Structures when RepairedAges of Structures when Repaired
0
10
20
30
40
50
60
0-10 11-20 21-30 31-40 41-50 51-60 61-70 71-100
Years (to 2003)
Num
ber
Types of RepairTypes of Repair
0
20
40
60
80
100
120
140
Patch Coating Crackinjection
Strengthen Sprayedconcrete
Electro-chemical
Other
Num
ber
PatchesPatches
01020
30405060
7080
Cementitious Polymer modified Other
Num
ber
CoatingsCoatings
05
101520253035404550
Barrier Hydrophobic Anti-carbonation
Other
Num
ber
PERFORMANCES OF REPAIRS
• Successful• Evidence of deterioration• Failed
Performances of all RepairsPerformances of all Repairs
0
20
40
60
80
100
120
Successful Evidence ofdeterioration
Failed
Num
ber
Repair Performances, BCA 1997
0
10
20
30
40
50
60
Good Fair Poor Failure
Per c
ent
Performances of PatchesPerformances of Patches
05
101520253035
Cementitious Polymermodified
Other
Num
ber
Successful Evidence of deterioration Failed
Performances of CoatingsPerformances of Coatings
0
5
10
15
20
25
30
35
Successful Evidence ofdeterioration
Failed
Num
ber
Performances of Repairs to CorrosionPerformances of Repairs to Corrosion
0
2
4
6
8
10
12
14
16
18
20
Patch Patch + coating Crack injection
Num
ber Successful
Evidence of failureFailed
Performances in Relation to Ages of RepairsPerformances in Relation to Ages of Repairs
0
5
10
15
20
25
30
35
40
0-5 6-10 11-15 16-20 21-52
Years
Num
ber Successful
Evidence of failureFailed
Failure of Patch Repair
Failure of sprayed coating
Continued ASR
WP2 Past Performances
MODES AND CAUSES OF FAILURE
Modes of FailureModes of Failure
0
5
10
15
20
25
30
35
Corrosion Cracking Debonding AAR Other
Num
ber
Causes of FailureCauses of Failure
05
101520253035404550
Incorrect d
esign
Material
Poor Workm
anshipWrong diag
nosis
Weather
Unknown
Other
Num
ber
Deterioration and Repair Model
Repair Performances
Damage Level Detection
SUMMARY
• 229 Case Histories Analysed
• Disappointing Repair Performances– 25% fail in 5 years– 75% fail in 10 years– 95% fail in 25 years
Summary Continued
• Modes of Repair Failure : continued corrosion, cracking, debonding
• Causes of Repair Failure: wrong diagnosis, wrong design, wrong material and poor workmanship
Recommendations
• Repair materials should be compatible with the substrate
• Repair materials should be flexible
• Repair materials should be forgiving