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Steel Fibre‐Reinforced Roller‐Steel Fibre‐Reinforced Roller‐Compacted Concretep
Dr Kyriacos Neocleous / Harris AngelakopoulosDepartment of Civil and Structural EngineeringThe University of Sheffield, United Kingdom
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
1
http://ecolanes.shef.ac.uk – http://www.shef.ac.uk/civil
OutlineOutline• Steel Fibre Reinforced (SFR) ConcreteSteel Fibre Reinforced (SFR) Concrete
• Roller‐Compacted Concrete (RCC)
• EcoLanes work on SFR‐RCC
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
2
SFRC is conventional concrete reinforced with discontinuous steel fibres
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
Steel Fibre Reinforced Concrete: Why use?
Concrete has low tensile strength.Hence, use SFRC:• Tensile & flexural strength improvement• Control cracking (shrinkage and structural)• Increase toughness Extended post crackingg• Enhance surface characteristics
Extended post-cracking behaviour
d
Enhanced flexural strengthFibre t
Load
SFRCtypes: •Asbestos
Deflection
High first crack strength
plain concreteAsbestos• Glass•
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
DeflectionPolymers• Steel
Steel Fibre Types: Industrially Produced
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
5
Indented Cone End Paddle End Hooked Button End Crimped
Steel Fibre Types: RecycledSteel Fibre Types: Recycled
Steel fibres extracted from post consumer tyres:Steel fibres extracted from post consumer tyres:
M h i l sing
Mechanical shredding
Pro
ces
Removal of bead wire ss
ing
bead wire from truck
tyres Pro
cesIndustry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09
Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield© 6
Steel Fibre Types: RecycledSteel fibres produced from post‐consumer tyres(http://www.shef.ac.uk/tyre‐recycling):
60
70
40
50
60
oad
[kN
]
20
30PRSF 6%ISF-1 6%ISF 2 6%
Ben
ding
lo
research proved that these fib b ff ti
0
10
0 1 2 3 4
ISF-2 6% fibres can be as effective as industrially‐produced fibres (ISF)
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
7
0 1 2 3 4Mid-span deflection [mm] (ISF)
SFRC Applications: Cast insitu & PrecastI d i l flIndustrial floors(slabs‐on‐grade) Highway pavements
Composite slabs
Shaft segments Barrier segmentsPipes
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
8
SFRC properties: Generalp pFactors affecting performance of FRC:
V l f i f i i l• Volume fraction of constituent materials
• Aspect ratio (L/d) of fibre
• Physical properties of fibres and matrix
• Bond strength between constituents
Post‐cracking performance of FRC important:
• Matrix cracks long before fibre fractures• Matrix cracks long before fibre fractures
High volume fraction & L/d high performance, b d ff k bili
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
but adverse effect on workability
SFRC Properties: Fresh‐stateS l d fib
Fibres tend to ball:Fib i t l ki
pSteel tyre‐cord fibres
• Fibre interlocking• Prior to mixing
3
rix)
• During mixing with concreteff t d b fib t
2
2.5
nt (%
vol
of m
atr– affected by fibre geometry
– relative volume proportions of fibre and coarse aggregate
1
1.5
Max
fibr
e co
ntenfibre and coarse aggregate
– mixing sequence and duration of mixing
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
10
10 10 20 30 40
Coarse aggregate content (% volume of mix)
M
SFRC Properties: Fresh‐state
Fibres balling examples
Wet‐consistency concrete
D iDry‐consistency (Roller‐compacted) concrete
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
SFRC Properties: Compressive Behaviour•SFRC keeps integrity after failure
•Maximum strength slightly enhanced, but ‐Maximum strength slightly enhanced, but due to increase of voids ‐ decreases for high volume ratiosvolume ratios
P t k t th h dIndustry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09
Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield© 12
•Post‐peak strength enhanced
SFRC Properties: Tensile Behaviour
•Increase tensile concrete strengthStress
SFRC
Plain
Increase tensile concrete strength •Improve post‐peak tensile concrete behaviour, which is dependent on
Tensile
S
pthe effective fibres crossing the crack
Tensile Strain
•There is no standard test for tensile σ‐ε of SFRC
•Flexural tests used to measure post‐cracking capacity
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
13
4‐point flexural test
R ll C t d C tRoller Compacted Concrete
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
14
A different kind of t !
What is Roller‐compacted Concrete (RCC)?concrete!
p ( )• ‘A relatively stiff mixture of aggregates, cementitious materials and water that is compactedcementitious materials and water that is compacted by vibratory rollers and hardened into concrete.’
• 0 slump• 0 slump
• No formwork required
• Adequate compaction is
critical
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
15
RCC: Performance
• Flexural strength: 3.5 ‐ 7.0 MPa• Compressive strength: 25 ‐ 70 MPa • Satisfactory shear strength • High density • No formwork or finishing Main RCC
F tg
• Low water content, low w/c ratio • Aggregate interlock
Features
Aggregate interlock• Hard, durable, light‐coloured surface• Sawed joints may not be required
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
16
• Sawed joints may not be required
RCC construction3.Placing of RCC pavement
L 100 200 t 2501.Placing of RCC
in a haul truck Layers: 100-200mm, up to 250 mm (with high density paver)
in a haul truck
2.Loading RCC in the paver
4.Rolling of RCC pavement
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
17
F r o m m i x i n g t o r o l l i n g < 1 5 m i n u t e s
RCC: Applicationspp
DamsDamsDams
Heavy-load PavementsHeavy-load PavementsHeavy-load Pavements
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
18Road PavementsRoad PavementsRoad Pavements
RCC Pavements: Tackling Common Problemsg
• Span soft localised subgrades • No deformation under heavy, concentrated loads N d t i ti f ill f f l d• No deterioration from spills of fuels and hydraulic fluids
• No softening under high temperatures• No softening under high temperatures • Early strength gain• No rutting• No rutting • No settlement• No raveling of surface
Rutting
RavellingBearing capacity
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
19
• No raveling of surface Bearing capacity failure
RCC Pavements: Proportioning of MaterialsRCC Pavements: Proportioning of Materials
dry enough for rollingg
wet enough for costgcement hydration
cost
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
20
RCC Pavements: Constituent Materials• Binders (e.g. OPC, PFA)12 ~ 16% by mass12 16% by mass Aggregates (fine ≤ 5mm coarse ≤ 20mm)(fine ≤ 5mm, coarse ≤ 20mm)75 ~ 80% by mass
• Water 4 5 ~ 6% by massSelection criteria:
• Water 4.5 6% by masswater/cement = 0.3 ~ 0.45
• Admixtures (e g water
• Design strength
• Durability • Admixtures (e.g. waterreducing, retarding)
Diffi lt t dd fib / i f t
• Application
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
21
• Difficult to add fibres / reinforcement
RCC Pavements: Laboratory Testing
Compaction curve
Maximum dry density, Ga = 2.81
y g
Compaction curve
2 6
2.8M
g/m
3
2.4
2.6
C d
ensi
ty, M
Compressive
2.20 2 4 6 8 10 12
RC
C
Dry density curveWet density curve
0 2 4 6 8 10 12Moisture content, %
BendingOptimum moisture content
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
22
E L kEcoLanes work on
SFR‐RCC
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
23
RCC Pavements: Mechanical Limitations
• Post cracking behaviourHigher deformations required by RCC industry
• Increase spacing of joints• Increase spacing of jointsAttain spacing similar to industrial floors (40 metres)?
• Better optimisation of materials/ technologies currently required to tackle global environmental issues
Possible solution SFR‐RCC
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
24
FRC‐RCC: Challengesg
• Fibre dispersion in the mixp
• Compaction
• Specimen preparation
• Monitoring fibre dispersionMonitoring fibre dispersion
• Use of recycled fibres
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
25
EcoLanes progress: Fibre dispersionp g p
Successful dispersion of recycled fibre at y
laboratory conditions
(up to 225 kg of fibres per m3 of RCC))
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
26
EcoLanes progress: SFR‐RCC compactionEcoLanes progress: SFR RCC compaction
After compaction,After compaction,
recycled fibres
do not spring
backback
Compacted SFR‐RCC cube
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
27
EcoLanes progress: Flexural characterisationp g
4‐point bending tests according to RILEMaccording to RILEM
recommendations and Japanese standardsJapanese standards
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
28
EcoLanes progress: Bending test setupp g g p
A
150 150 150
150
125
150
25
150
AA-A
150
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
29
EcoLanes progress: Typical 4‐point bending testp g yp p g
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
30
EcoLanes progress: Flexural characterisation• Flexural behaviour SFR‐RCC: industrial fibres
p g
40
45
Fr: 3%
Button end: BE1/54Hooked end: HE1/50
N
25
30
35
KN) Fr: 2%
Fr: 3%
Fr: 2%
ding
load, kN
10
15
20Load
(K
Fr: 1% Fr: 1%
4‐po
int be
nd
0
5
-2 -1.5 -1 -0.5 0 0.5 1 1.5 2Average vertical displacement (mm)
Average vertical displacement mm
4
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
31
Average vertical displacement, mm
EcoLanes progress: Flexural characterisation• Flexural behaviour SFR‐RCC: recycled fibres
p g
500100%50 %: by mass of concrete
N
300
400
requ
ency
40%
60%
80%
tive
Dist
ribut
ion
FrequencyCumulative %
30
40
Load
(kN
)
9% Fibres
6% Fibresding
load, kN
0
100
200Fr
0%
20%
40%
Cum
ulat
0
10
20
Bend
ing 6% Fibres
2% Fibres
1% Fibres
4‐po
int be
nd
0 5 10 15 20 25 30
Length, mm
00 0.2 0.4 0.6 0.8 1
Ver tical displacement (mm)
4
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
32
EcoLanes progress: Recycled Concrete AggregatesEcoLanes progress: Recycled Concrete Aggregates
1st stage 2nd stage1 stage 2 stage
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
33
EcoLanes progress: Flexural characterisation of SFR‐RCC with RCA
40 R‐300LECr‐28d‐RTC4‐24‐R6‐(30r‐70na)RCC with 100% na
30
35
40 R‐300LECr‐28d‐RTC4‐24‐R6‐(30r‐70na)
R‐300LECr‐28d‐RTC4‐24‐R6‐(70r‐30na)
R‐300LECr‐28d‐RTC4‐24‐R6‐(100r‐0na)
R‐300LECr‐28d‐R0‐(30r‐70na)
R 300LEC 28d R0 (70 30 )
20
25
ng load, kN
R‐300LECr‐28d‐R0‐(70r‐30na)
R‐300LECr‐28d‐R0‐(100r‐0na)
R‐LEcr300‐R0‐28d‐na
R‐LECr300‐RTC1‐15‐R6‐28d‐na
10
15Bend
in
0
5
0 1 2 3 4 5 6 7
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
34
0 1 2 3 4 5 6 7
Vertical displacement, mm
EcoLanes progress: Flexural characterisation of SFR‐RCC with RA RCC with 100% na
5
6
7
Pa) 5
6
7
N
R-LECr300-RTC6-25-R6-7d-ra a
R-LECr300-RTC6-25-R6-7d-ra b
R-LECr300-RTC1-15-R6-7d-na b
2
3
4
Flex
ural
stre
ss (M
P
R-LECr300-R0-7d-na bR-LECr300-R0-7d-ra aR-LECr300-R0-7d-ra bR-LECr300-RTC6-25-R6-7d-ra a
2
3
4
5
Ben
ding
load
(kN
0
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
R-LECr300-RTC6-25-R6-7d-ra b
0
1
2
0 1 2 3 4 5 6 7 8
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
35
Net midpoint deflection (mm)Net midpoint deflection (mm)
EcoLanes progress: DurabilityAccelerated corrosion tests 0, 5 & 10 months
p g y
recycledindustrial
5 months of corrosion0 months of corrosion 10 th f i5 months of corrosion simulation shows that
specimens with recycled fibres are the most
0 months of corrosion simulation shows RCC
specimens with 6% recycled fibres already
10 months of corrosion simulation shows an increase of
rust at the specimens with recycled fibres – specimens with
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
fibres are the most corroded
recycled fibres already corroded
recycled fibres specimens with industrial fibres show corroded
fibres near surface
EcoLanes progress: Durability
R-CEMII/A-L300- RTC3-11-R6 – internal viewAccelerated corrosion tests 0, 5 & 10 months
p g y
R CEMII/A L300 RTC3 11 R6 internal view
150 mm
m15
0 m
m
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
5 months 10 months
EcoLanes progress: DurabilityAccelerated corrosion tests 0, 5 & 10 months
p g y
Compressive strength Flexural strength14a]
.
120a] .
68
101214
reng
th [M
Pa
6080
100120
engt
h [M
Pa
0246
t l 28 5 th 10 thFl
exur
al st
r
02040
pres
sive
stre
W-LEC380-I2C1/54-R2W-LEC380-RTC3-11-R6R CEMII/A L300 I2C1/54 R2
control - 28days
5 monthscorrosion
10 monthscorrosion
control - 28days
5 monthscorrosion
10 monthscorrosionC
omp
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
R-CEMII/A-L300-I2C1/54-R2R-CEMII/A-L300- RTC3-11-R6
EcoLanes remaining work on SFR‐RCC
• Parametric study for SFR RCC mixes
g
• Parametric study for SFR-RCC mixes
• Durability tests (corrosion, freeze-thaw)y ( )
• Fatigue bending tests
• Modelling of SFR-RCC
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
This research has been financially supported by the 6th FP of the European Community within thethe 6 FP of the European Community within the framework of specific research and technological development programme “Integrating and strengthening the European Research Area” understrengthening the European Research Area , under contract number 031530.
Thank You!Thank You!Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09
Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
Background Notes
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
41
Steel Fibre Types: RecycledSize-reduction processes (e.g. tyre shredding):reduces tyres to steel fibres & granulated rubber.
Thermal degradation processes (e.g. microwave pyrolysis):breaks down tyres into steel, char, liquids and gases.AMAT LTD™
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
42
SFRC Properties: Flexural Behaviour
C
Phase 1
CNA
Phase 2
CT1
NA
Phase 3C
T1T2
NA MSMM
Phase 4
T1NA
MS
T1
T2
NA
MMMS
T1
T3
T2MSMM
T2
T3
T4
MM
MS
F
Microcrack initiation
MMCrack resisted
through fibre pullout
F
Crack with not muchresistance from fibres
FFfc
NA
Ffc
Fft
NAFfc
Fft
NAFfc
Fft
NAMSMM
FZ
C: Compressive zone NA: Position of the neutral axisT1: Uncracked tensile zone MS: Max Tensile strain at σt l
Fft
FftFZ FZ FZ
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
43
T1: Uncracked tensile zone MS: Max. Tensile strain at σt,calT2: Aggregate and fibre bond bridging zone MM: Micro-Macro zones axisT3: Fibre pull-out zone FZ: Fracture zoneT4: No resistance from fibres
SFRC Properties: Flexural BehaviourFour-point flexural tests of ISF and steel tyre-cord fib (SRSF & PRSF)fibres (SRSF & PRSF):
• Behaviour of beams 60
70
PRSF 1.5%
N]
with PRSF similar toth ith ISF
40
50 PRSF 3%
PRSF 6%
SRSF 0.5%ge lo
ad [k
N
those with ISFs
• Flexural strength 10
20
30SRSF 1%
SRSF 2%
ISF 1 6%
Ave
rag
Flexural strengthincreases with fibre content
0
10
0 1 2 3 4Average mid-span deflection [mm]
ISF-1 6%
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
44
content g p [ ]
SFRC Design: Methods
Lack of universally accepted design standards:
g
ac o u e sa y accepted des g sta da ds• Similar concepts to conventional reinforced concrete• Provisions for flexure, shear and crackingRILEM technical committee on “Test and designRILEM technical committee on Test and design methods of steel fibre reinforced concrete”:
St k th d (f t h i )• Stress-crack, σ-w, method (fracture mechanics)• Stress-strain, σ-ε, method (based on Eurocode-2)
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
45
( )
RCC Pavements: Construction Process
Transported by trucks
Produced in a pugmill or central mix plant or dry
trucksPlaced and compacted with an asphalt paver
central mix plant or dry batch plant
Joint spacing:
9 20 metresIndustry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09
Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield© 46
Roller compactionCuring9-20 metres
RCC Pavements: Design
Thickness design approach
g
• Portland Cement Association
• US Army Corps of Engineers• US Army Corps of Engineers
• minimise, within acceptable limits, the flexural f ti d d b th h l l d thfatigue damage caused by the wheel load on the pavement over the design life
• Information required for sub‐grade, sub‐base, vehicle characteristics, RCC mechanical properties
Industry Seminar “Economical and sustainable pavement infrastructure for surface transport”, Pafos Cyprus, 08/04/09Fibre‐reinforced roller‐compacted concrete ‐ Dr Kyriacos Neocleous / Harris Angelakopoulos – University of Sheffield©
47