Concrete Performance Evaluation on MTO Projects Webinar ... · 45 minute webinar with 15 minutes Q...
Transcript of Concrete Performance Evaluation on MTO Projects Webinar ... · 45 minute webinar with 15 minutes Q...
Concrete Performance Evaluation on MTO Projects Webinar
Oct. 23rd, 2018
Facilitators
Bart Kanters, P.Eng.PresidentConcrete Ontario
Alen Keri, P.Eng.Technical Services EngineerConcrete Ontario
Housekeeping
45 minute webinar with 15 minutes Q & A All participants are muted Questions? Use ‘Questions’ Pane Webinar will be recorded and posted on the Concrete Ontario
YouTube channel. www.ConcreteOntario.org PDF version of the presentation and the link to the YouTube video will
be emailed to all participants
PresenterHannah SchellHead, Concrete SectionMTO Materials Engineering and Research Office The Concrete Section is responsible for development of technical policy and
standards for concrete and related products for Ontario’s Provincial highway structures and pavements.
Hannah is a graduate of Queen’s University at Kingston and a licensed Professional Engineer in the Province of Ontario.
She is the past Chair of Canadian Standards Association (CSA) Technical Committee A283 which is responsible for the qualification code for concrete testing laboratories, and is a member of the CSA A23.1/23.2 standard committee, on concrete materials and methods of construction, and test methods.
She is also a member of American Concrete Institute (ACI) Committee 201, Durability of Concrete.
Concrete Performance Evaluation on Ministry of Transportation (MTO)
Contracts
Hannah SchellHead, Concrete Section
MTO Materials Engineering and Research Office
5
September 26, 2018
Overview
• Results from Quality Assurance testing on MTO Contracts
during 2017
• Trends in referee testing on MTO contracts
• Specification changes and updates for 2018
• Current issues in concrete construction
6
MTO Quality Assurance — Acceptance of Concrete
• Compressive strength: as specified in the contract (30MPa, 35MPa)
• Air void system (AVS) of hardened concrete:• Air content: minimum 3.0%
• Spacing factor:• Cast-in-place concrete: maximum 0.23 mm
• Precast concrete: maximum 0.20 mm
• Rapid chloride permeability (RCP)• Maximum 2500 Coulombs when tested at 28-32 days.
7
Compressive Strength — 30 MPa and 35 MPa2017 Results – OPSS 1350 Acceptance Method A
Notes:-Data incomplete (does not include all MTO contracts)- Includes forecasts for ongoing contracts- No penalties were reported for these contracts
0
10
20
30
40
50
60
70
30MPa 35MPa
No
of M
TO C
ontr
acts
Compressive Strength
No BonusWith Bonus $1-$5/m3
8
Compressive Strength — 30 MPa2017 Results – OPSS 1350 Acceptance Method A
9
Notes:- Data incomplete (does not include all MTO contracts)- Includes forecasts for ongoing contracts- No penalties were reported for these contracts
0
5
10
15
20
25
30
35
Central East West
No
of M
TO C
ontr
acts
MTO Region
No Bonus
With Bonus $1-$5/m3
Air Void System (AVS) — Air Content2017 Results - Cast-in-place Concrete
10
0.0
2.5
5.0
7.5
10.0
12.5
15.0
17.5
20.0
22.5
0.0-
2.9
3.0-
3.9
4.0-
4.9
5.0-
5.9
6.0-
6.9
7.0-
7.9
8.0-
8.9
9.0-
9.9
10.-1
0.9
11.0
-11.
9
12.0
-12.
9
13.0
-13.
9
>14.
0
Perc
enta
ge o
f Occ
urre
nce
(%)
Hardened Air Content (%)
Total no. of AVS tests = 14452.4% 97.6%
3.0%
Air Void System (AVS) — Spacing Factor2017 Results - Cast-in-place Concrete
11
0.0
2.5
5.0
7.5
10.0
12.5
15.0
Perc
enta
ge o
f Occ
urre
nce
(%)
Spacing Factor (mm)
Total no. of AVS tests = 1445
0.23mm
2.1%97.9%
Air Void System (AVS) — Air Content and Spacing Factor2017 Results - Cast-in-place Concrete
12
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0.400
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Spac
ing
Fact
or (m
m)
Hardened Air Content (%)
0.23mm
Total no. of AVS tests = 1435
Air Void System (AVS) — Air Content and Spacing Factor2017 Results - Cast-in-place Concrete
13
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0.400
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0
Spac
ing
Fact
or (m
m)
Hardened Air Content (%)
0.23mm
Total no. of AVS tests = 1435
BonusBonus $5/m3
Air Void System (AVS) — Specific Surface2017 Results - Cast-in-place Concrete
14
0.0
2.5
5.0
7.5
10.0
12.5
15.0
17.5
Perc
enta
ge o
f Occ
urre
nce
(%
)
Specific Surface (mm-1)
Total no. of AVS tests = 130925 mm-1
18.1% 81.9%
Air Void System (AVS) — Spacing Factor Evolution
15
0.0
2.5
5.0
7.5
10.0
12.5
15.0
17.5
20.0
Perc
enta
ge o
f Occ
urre
nce
(%)
Spacing Factor (mm)
Year End Results - 2017 (1445 AVS tests) Year End Results - 2014 (853 AVS tests)Year End Results - 2006 (1005 AVS tests)
0.23mm
Air Void System (AVS) – Spacing Factor2006, 2014 and 2017 Results - Cast-in-place Concrete
16
0.0
2.5
5.0
7.5
10.0
12.5
15.0
17.5
20.0
Perc
enta
ge o
f Occ
urre
nce
(%)
Spacing Factor (mm)
Year End Results - 2017 (1445 AVS tests) Year End Results - 2014 (853 AVS tests)Year End Results - 2006 (1005 AVS tests)
0.23mm
2006 Avg. = 0.165mm2017 Avg. = 0.125mm
2014 Avg. = 0.145mm
Rapid Chloride Permeability (RCP) — Lowest to Highest2017 Results - Cast-in-place Concrete
17
Note: Each RCP test is the average of two slices
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
0 30 60 90 120 150 180 210
RC
P T
est V
alue
s (C
oulo
mbs
)
RCP Test Number
Total no. of RCP tests = 204
Rapid Chloride Permeability (RCP)2017 Results - Cast-in-place Concrete
18Note: Each RCP test is the average of two slices
172
24
30
20
40
60
80
100
120
140
160
180
200
No
of R
CP
Test
s
Central, West, and East Regions
Less than or equal to 2500 CoulombsMore than 2500 Coulombs and less than or equal 3500 CoulombMore than 3500 Coulombs
Rapid Chloride Permeability (RCP) — Results by Supplier (multiple plants)2017 Results - Cast-in-place Concrete
19
Note: Each RCP test is the average of two slices
0
10
20
30
40
50
60
70
80
90
A b c d e f (single plant)
No.
of R
CP
Test
s
Concrete Supplier
Less than or equal to 2500 CoulombsMore than 2500 Coulombs
Air Void System (AVS) — Air Content2017 Results - Cast-in-place Concrete and Precast Concrete
20
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
Perc
enta
ge o
f Occ
urre
nce
(%)
Hardened Air Content (%)
Cast-in-place Concrete (No. of samples 1445)Precast Concrete (No. of Samples 36)
Air Void System (AVS) — Air Content2017 Results - Cast-in-place Concrete and Precast Concrete
21
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
Perc
enta
ge o
f Occ
urre
nce
(%)
Hardened Air Content (%)
Cast-in-place Concrete (No. of samples 1445)Precast Concrete (No. of Samples 36)
3.0%
Air Void System (AVS) — Spacing Factor2017 Results - Cast-in-place Concrete and Precast Concrete
0.0
2.5
5.0
7.5
10.0
12.5
15.0
17.5
20.0
22.50.
0-0.
059
0.06
-0.0
690.
07-0
.079
0.08
-0.0
890.
09-0
.099
0.1-
0.10
90.
11-0
.119
0.12
-0.1
290.
13-0
.139
0.14
-0.1
490.
15-0
.159
0.16
-0.1
690.
17-0
.179
0.18
-0.1
890.
19-0
.199
0.2-
0.20
90.
21-0
.219
0.22
-0.2
290.
23-0
.239
0.24
-0.2
490.
25-0
.259
0.26
-0.2
690.
27-0
.279
0.28
-0.2
890.
29-0
.299
0.3-
0.30
9>0
.31
Perc
enta
ge o
f Occ
urre
nce
(%)
Spacing Factor (mm)
Cast-in-place Concrete (No. of samples 1445)Precast Concrete (No of samples 36)
22
Air Void System (AVS) — Specific Surface2017 Results - Cast-in-place Concrete and Precast Concrete
23
0.0
2.5
5.0
7.5
10.0
12.5
15.0
17.5
20.0
22.5
25.0
27.5
30.0
Perc
enta
ge o
f Occ
urre
nce
(%
)
Specific Surface (mm-1)
Cast-in-place Concrete (No. of samples 1306)Precast Concrete (No. of samples 36)
Rapid Chloride Permeability (RCP)2017 Results - Cast-in-place Concrete and Precast Concrete
24
Note: Each RCP test is the average of two slices
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 30 60 90 120 150 180 210
RC
P Va
lue
(Cou
lom
bs)
No. of RCP Tests
Cast-in-place Concrete (No. of RCP Test = 204)
Precast Concrete (No of RCP tests = 151)
Referee Testing on 2017 Contracts — Summary
• Air Void System (AVS) in Hardened Concrete - 66 (55 QA failures) total
• 31 confirmed QA result, 24 overturned
• Compressive Strength – 15 total• 11 confirmed QA result, 4 overturned
• Rapid Chloride Permeability (RCP) – 9 total• 1 confirmed QA result, 8 overturned
• Admixture Properties – 15 total• 6 confirmed QA result, 9 overturned
25
2017 Referee Requests — Summary
Type of Test
Region – Lots [Sublots or samples]
All-In CR WR ER NER NWRTotal 78 12 31 7 10 18
AVS 44 [66] 3 [4] 24 [42] 4 [4] 5 [8] 8 [8]
Strength 14 [15] 2 [2] 3 [3] 1 [1] 3 [4] 5 [5]
Admixture 11 [15] 0 [0] 3 [3] 1 [1] 2 [2] 5 [9]
RCP 9 [9] 7 [7] 1 [1] 1 [1] 0 [0] 0 [0]
26
Number of Referee Requests Each Year
Type of referee test invoked
Year
2013 2014 2015 2016 2017
Compressive Strength 1 28 20 17 14
Air Void System (AVS) 32 15 24 39 44
Rapid Chloride Permeability (RCP) 4 7 14 5 9
Admixtures 4 3 4 12 11
27
Compressive Strength
• 15 QA tests failed to meet the specified strength (ranging
from 30 to 60 MPa). Except for one, specimens were
cylinders.
• Out of the 15 referee tests, only 4 did not confirm the QA
result (i.e., at least 10% difference between QA & REF per
OPSS 1350); eleven test results were not compliant.
28
Compressive Strength
29
Air Void Analysis (AVS)
• Out of 59 QA failures, 28 were related to deficient air
content (i.e. below the specified 3.0%) and 31 due to high
spacing factor (i.e. above that specified for the application).
• The referee results confirmed 7 out of the 28 QA failures
due to deficient air content, and 30 out of 31 QA failures
due to high spacing factor.
30
Air Void Analysis (AVS)
31
Air Void Analysis (AVS)
32
Rapid Chloride Permeability (RCP)
• 9 QA tests failed to meet the specified requirement of 2500
coulombs, for concrete mixes with a specified compressive
strength of 30 MPa.
• The referee results confirmed 1 out of the 9 QA failures (i.e.
QA results were overturned in 8 cases).
33
Rapid Chloride Permeability (RCP)
34
35
Specifications and Standards
• Modifications related to elimination of Quality VerificationEngineer (QVE) requirements
• Contractor must submit “Request to proceed”; receive “Permissionto proceed” before going on to next operation
• Inspection by MTO will replace QVE inspection in some cases e.g.reinforcing steel placement for structures
• Manufacturer’s Engineer sign-off required for manufacturedproducts e.g. precast concrete components
• Updated OPSS PROV 1002 and SP110S17 for concreteaggregates
• Expanded use of permeability (RCP) requirement instructural concrete
• Developing new Special Provision for precast structuralculverts (>3m span)
36
Current Issues
• Temperature concerns
• Impacts of aggregate gradation
• Significant quality deficiencies related to workmanship
37
Detection of internal voids using ground-penetrating radar (GPR) technology
Surface and Internal Voids
Void (90mm long and 40mm wide) extends from 50mm to 90mm below the surface
Exposed void
Void (85mm long and 35mm wide) extends from 40mm to 70mm below the surface
Cold Joints
Cold Joints
Lack/Loss of Concrete Workability
44
OPSS PROV 904 “No material shall be applied to the concrete surface or the finishing tools to aid in the finishing.”