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Extending the Season for ConcreteConstruction and Repair
Charles Korhonen
U.S. Army Cold Regions Researchand Engineering Laboratory
(CRREL)
NESMEANortheastern States Materials Engineers’ Association
October 19-20, 2004, Portsmouth, NH
Research Civil EngineerCold Regions Research and Engineering Laboratory
72 Lyme RdHanover, NH 03755
Current Practice
Winter Concreting (review)
• Not changed since the 1930s• Thaw substrate• Pre-heat materials• Use insulation and heated enclosures
1990s
• Demonstrated antifreeze admixtures
• No acceptance standard for antifreeze admixtures. * Tort Liability * Market Size * Inertia
• No single commercial admixture significantly lowersthe freezing point of fresh concrete.
Problem
• Combine Off-the Shelf Admixtures
– Already Meet Standards
– Familiar & Available
– No Limit on the # of Admixtures
Solution
POOLED-FUND STUDY
FHWA TPF 5-(003)
Objective: develop
concrete that can fully cure
at below freezing
temperatures
Product: tools to design,mix, place, and cureconcrete in below-freezingweather
October 2000 – October 2003(ID, MI, MT, NH, NY, PA, UT, VT, WI, WY)
How Normal Concrete Performs
Time (min)Time (min)
–5C
40C
How Antifreeze Admixtures Work
• Depress the freezing point
• Accelerate the hydration rate of cement
20
10
0
-100 200 1000 1200 1400400 600 800
ControlMix 1
Tem
pera
ture
(C)
20
10
0
-10
20
10
0
-100 200 1000 1200 1400400 600 8000 200 1000 1200 1400400 600 800
ControlAntifreeze
Tem
pera
ture
Freeze Point
DaysDays0
8000
6000
4000
2000
7 28 56 84
Stre
ngth
psi
AntifreezeAntifreeze
ControlControl
20C 5C–5C
20C
0 56 84
Stre
ngth
psi
ControlControl
20C
“Antifreeze Concrete”
-5°C
Combine admixtures to:
0
10
20
30
40
50
60
70
80
90
100
0 50 100 150 200 250 300
Completed Freeze-Thaw Cycles
Rel
ativ
e D
ynam
ic M
od
ulu
s o
f E
last
icit
y (%
)
fig 10 from TR-04-2
CONTROL
Admixtures do not reduceconcrete’s freeze-thaw durability
-
S1
0
100
200
300
400
500
In-p
lace
Co
st$/
m3
Su
mm
er
An
tifr
eeze W
inte
r
Year Round
120 Days
60 Days
• 1/3 less cost
• Extends the season
ANTIFREEZE ADMIXTURES: Cut Time & Cost
–5°C Capability
Field Tested
Littleton, NH 10 Dec ’01 Bridge Curbing
Rhinelander, WI 27 Feb ’02 Pavement
North Woodstock, NH 12 Dec ’02 Footing
West Lebanon, NH 18 Dec ’02 Bridge Curbing
Concord, NH 14 Feb ’03 Sidewalk
New York, NY 18 Feb ’04 Streets & Sidewalks
Grand Forks AFB, ND 23 Feb ’04 Airfield slab
FHWA Study
Others
CASE STUDY
–15°C
32m L x 46cm W x 38cm D
Bridge Curbing, W. Lebanon, NH 18 December 2002
10 a.m.
Preconstruction Trial Batches
First Trial Second Trial Job Mix
FP = -4.3ºC
Adjustments Needed:
• Workability * Cements Vary Widely * Batching Plant Setups Differ
• Zero in on freezing point * Agg. Moisture Varies• Optimize Batch Sequence * All at mixing plant * Some at plant, rest at job * All at job
FP = -4.7ºC FP = -5.1ºC
Ingredient
Cement
Aggregate
Sand
AEA
Type A
Cor. Inh.
Type E
W/C
Air Content
Slump
Amount
392 kg/m3
1083 kg/m3
804 kg/m3
77 ml/m3
584 ml/100kg
30 L/m3
5.87 L/100kg
0.37
8.0%
200mm
Ready-Mix PlantBATCHING
9:45 – 10:15 A.M.
3.5 m3
Type E dosed but not mixeduntil truck arrived at jobsite
10:40 – 10:10 A.M.
3.5 m3
First Load
Second Load
PLACING&
FINISHING
Traffic Control
10:15 A.M–12°C
CURING… but for how long?
10
15
20
25
500 550 600 650 700 750 800 850 900
Maturity (C-hrs)
Str
eng
th (
MP
a)
MaturityFast-Track
Measuring theFreezing Point• Quality Assurance
• Back-calculatewater/cement Ratio(Critical to Strength)
Is it good concrete?
0
5
10
15
20
25
30
0 200 400 600 800 1,000 1,200 1,400
Maturity (C-hr)
Str
en
gth
(M
Pa)
Cold Concrete\Final Report\Maturity Datum\TruesBrookRT12A_Maturity.xls\Strength (MPa) FR
Maturity Curve
0
5
10
15
20
25
30
0 1 2 3 4 5 6 7 8 9 10Age (days)
Esti
mate
d S
tren
gth
(M
Pa)
Cold Concrete\Field\RT12A\TruesBrookRT12A_Maturity.xls\cjk - psi #3
TOP
INTERFACE
Strength Development Curve
ActualPerformance
7 Days
Cost ComparisonTrues Brook, West Lebanon, NH
18 Dec ‘02
Erect Shelter: 96 mhrDismantle: 36 mhr
βHeat Shelter: 364 gal LPMaterials: 48 ea – 2x4x8
120 m – 1x8 pine120 m – strapping2 rolls – poly
βAdmixture #1 = $58.69/m3
βAdmixture #2 = $3.52/m3
βAdmixture #3 = $52.34/m3
Heat = $748.47 Admixtures = $700.64
… a chemical substitute for heat.
The ProductFHWA Pooled-Fund Study
TPF-5(003)
… developed an antifreeze technology that produces concretethat can fully cure while its internal temperature is belowfreezing, and that is as strong and durable as normal concretecured during the summer.
http://www.crrel.usace.army.mil/concrete
What We Still Don’t Know
Phase I – Establishing the Technology “… demonstrated the practicality of antifreeze admixtures”
Phase II – Determining Engineering Parameters• Enhanced Durability• Thermal Safety• Quality Assurance Tools• Other Cements
SP&R Pooled-Fund Study TPF-5(075)
Extending the Season for Concrete Construction and Repair
Defining Engineering Parameters
Phase II Continuation of TPF-5(003)
US Army Cold RegionsUS Army Cold RegionsResearch and Engineering Research and Engineering LaboratoryLaboratory
US Army CorpsUS Army Corpsof Engineers ®of Engineers ®ERDCERDC
SP&R Pooled-Fund Study TPF-5(075)
Extending the Season for Concrete Construction and Repair
Defining Engineering Parameters
Phase II Continuation of TPF-5(003)
US Army Cold RegionsUS Army Cold RegionsResearch and Engineering Research and Engineering LaboratoryLaboratory
US Army CorpsUS Army Corpsof Engineers ®of Engineers ®ERDCERDC
US Army Cold RegionsUS Army Cold RegionsResearch and Engineering Research and Engineering LaboratoryLaboratory
US Army CorpsUS Army Corpsof Engineers ®of Engineers ®ERDCERDC
US Army CorpsUS Army Corpsof Engineers ®of Engineers ®ERDCERDC
0.00
0.20
0.40
0.60
0.80
1.00
0 20 40 60 80 100 120 140 160 180
F/T Cycles
Dyn
amic
Mo
du
lus
of
Ela
stci
ty
Control
Antifreeze
C:\mydocuments\from sherri\antifreeze durability\antifreeze concrete 0.xls
Objective: The freeze-thawdurability of concrete seems toimprove whenever high doses ofchemical admixtures are used. Thisneeds to be investigated.
Enhanced Freeze-Thaw Durability
Phase II:
US Army Corpsof Engineers
Engineer Research & Development CenterCold Regions Research & Engineering Laboratory
Charles [email protected]
http://www.crrel.usace.army.mil/concrete
Extending the Season for ConcreteConstruction and Repair
