mechanical behavior of fiber reinforced compacted concrete...
TRANSCRIPT
Mechanical behavior of fiber reinforced compacted concrete with incorporation of reclaimed asphalt pavement K. Bilodeau EIFFAGE Travaux Publics, Research & Development Division, 8 rue du dauphiné BP 357, F-69960 Corbas Cedex, France Université de Lyon, ENTPE, DGCB (FRE CNRS 3237), Rue Maurice Audin, Vaulx-en-Velin, F-69518, France C. Sauzéat & H. Di Benedetto Université de Lyon, ENTPE, DGCB (FRE CNRS 3237), Rue Maurice Audin, Vaulx-en-Velin, F-69518, France F.Olard EIFFAGE Travaux Publics, Research & Development Division, 8 rue du dauphiné BP 357, F-69960 Corbas Cedex, France D. Bonneau EIFFAGE Travaux Publics, Ciry Central laboratory, 9 route du condé, F-02220 Ciry-Salsogne, France ABSTRACT: A composite material “Steel fiber reinforced compacted concrete (FRCC©) mixed with reclaimed asphalt pavement (RAP) materials” is investigated for road structure. It is intended to use this composite for heavy traffic road below the surface layer made with asphalt concrete. Monitoring of pavement structure behavior and experimental studies in laboratory are both conducted. First, the new innovative material combining cement concrete, fiber and RAP is presented. It is a compacted concrete with a low cement content compared to a standard cement concrete. Fibers are used in FRCC© to minimize crack width and RAP is added to preserve material and respect sustainable development. Four mixes have been placed on site. Different fibers and RAP contents are used in FRCC©. These structures are also compared with a reference structure composed of classical granular material treated with road hydraulic binders. In order to select the formulations used on site, experimental investigations are performed in laboratory. A total of nine different combinations were tested. In the laboratory, a traditional characterization for design is conducted. This part, made at EIFFAGE Travaux Publics laboratory, includes the following tests: compressive strength, tensile strength, tensile splitting strength, Proctor and immediate bearing ratio (IPI). The first results and analyses from lab investigations are presented in this paper. KEY WORDS: Roller Compacted Concrete, Pavement, Steel Fiber, FRCC©, Reclaimed Asphalt Pavement. 1 INTRODUCTION This research is a part of a French National Research Agency (ANR) project named “Recyroute”. This 2.3 million-euro project intends to propose a new high performance and long-lasting pavement using “Steel fiber reinforced roller compacted concrete” (FRCC©) road
bcallRs
emw(
d
T(
o 2 Th2(pcaF
F
RaooT
bacham’É’O
Rhstu
exmwe(c
de
Th(b
ob
2 M
Thhy28(LplcoarFi
Fi
RAagobofTa
ashamoÉtOhiud
TxpecerlaF
ev
hebe
Tbt
M
heyd80Ligas
one ib
ig
AAggbtf ab
se araonta
OuindiTpechreasFRve••••
e twTai
MA
e dr0kgest
nte6
be
gu
AAPgraifibl
lacngat uen ieh
erihae ussR
elo• • • • n
whin
A
Frakgexticen6crs
ure
AsP creginible
lactg (stR
eshe imanuic
RCop
neee
he ne
AT
FRaug/x cintcms
e1
mcoganebe 3
aytet
(Et Rh af
mnisecaCCpeHWFP
ewen
ed
TE
RRuli/m
Fiztsmar
1:
monateder 3)
yererithEN
Phôarfir
menicedal C©
edHyWFiPlw n fo
d r
ER
Ric
m³FPzes a
m lre
: D
mentted
a).
r ize
NTPaônre rsnt
cad B
© d yd
Wab
laa0
olre
R
RC b³ PLr arloe a
D
entee man
inza
iT
arinep
st ta
al fo
BB
bdr
ateerst
asp0%lloes
IA
C©
bioLa
reonad
Dra
ntien
(mand
ncatin
TPise pes
al p
forB(F
byraerrsticpe% owsu
A
© inf
L2ade ingdd
am
ionts(reatd
clio
nvPEsie
(erste
par TFi
y Caur cs ccieca
wult
AL
cnd
c2) dming de
m
ons esterR
luonvoE)en(trfoepsi
arath
TMicCulcocoizctan
wints
LS
codeco
imnvaed
mix
nemspri
RA
udn lv
), n,oorp iteamheMchTicononzet indng
s a
S
omeronis
mixveand
x
edmapeiaA
dinanveL
, llrmoesme
M fheTI c bntnt
er ind g an
mpr cnc
cxtesnd
d
8
d patecalsAP
ngnedLaC
l mof s.
mepfrero
cbitetea
ntr80
nd
pcocrcotuti
d 0du
80
pterctis P
g d d abCh
hed
f t
etepaomoucoin
enenadro0%se
d
ononretomurig0
uri
0/
reriivarc
rr
tebohahigdthSer
avmul
omndnt nt dmod%ecd
nnttemre ga.7in
6
eviavereo
reroeaoraugh.
heSors
vemm ll
mpde: :
midu
% ct
dis
entee
mpi
ate75ng
0
vialselye n
ecoaamratushw
e pom omFe perfrb
ixucotiosc
ntenw
poised5mg
B
ios y n
nte
laadmto
sséw
prmeof
meFre
anr cfrobextuceof oncu
tsnt whoss d:mmth
BN
ouar
naen
aid s:oiée
wa
roe f Fenenannycoometwuredth
nsus
s i
heedf 0mhe
N
uslre0
amnt
mst: Eiree
ay
ogs
Fnt ncndy.onmwred hes si
aisend
fix0
m e
N f
lye %
mets,
metrEe T
ys
grstRd
chd . nt
m 9wee cine p
io
re n
oxekdfi
fi
y,st
%,ed,
edru
EIFC
Tec
ramtanRCdeh
HF
ten90eecon a
pron
e fiu
ofedkgdiain
b
ttu, d 8
d uctFF
Ceecco
mn
CCesdH
FRnt0 enonth
agrens
pixusf d g/mam
na
er
thud
3F
8
atuFAenchom
m dCsigdeHeRCt to
n 2nthe
ggess.
prxese5a
mm
al
rs
hedie36F0d
spurA
nthnm
isar
C©
gnsi
enC: o 25tee
gresen
reeded52at
m3
mem
s u
e ied6%0%dif
phre
AGtrani
mp
s rd
© mn.ig
ninCC
b1
5 enpegnt
sed d w2%
, etemi
us
ind.%%ff
hae cGEaliqpa
tod m. Cgnn
C©
et15to
nt progat
enatw
% 02erix
se
nn. T
%, fer
alcaEl dquan
o t
maCn g
2© tw
50o : ogatt
ntt
wic
.520r x p
ed
noTaFre
lt al
E Tde
ueny
dteateCh
gu2isw0 l6bgrteth
te1thcl5%0 k(Dpr
d
ovh
anF4en
plcTres e
y,
dester
houi0s ceel/m
60bera
e mhe
ed12h lin%kgDro
in
vae
nd40nt
pacuras etE
estsriaosid0coenm
0 ketwamme
d 2%
nnk
% g/
Draoc
n
atc
d 0%t F
avulaavPt E
igs alen
de4omn
m³kgwm
mate
in% nakein
/mamce
F
ivco7
%F
veatvaPo
InEIF
gnwlsn e L) m1
³ og/
wem iasses
n i
atuern
m3
mes
FR
veon70
% aR
emtioauonnnFF
n wes t
wLi
mp18of/meeis s)st
tinurr,
m3
mixs
RC
e nte0%an
RR
meonuxntsnoFA
aertowe
LCispo80f cm³en
t). te
thn ra2
manx a
C
aen
% ndRC
enn x Ps ovA
anreo bea
CPs os0 tco³
n 0th
d
hism
al 21
man8
an
C
aspnt
d C
nta
Peva
AG
nde barPCa
setoono0.he
d
s ma
a1%asd 80nd
C©
petsoF©
t (arut atGE
d sthe rinC-a d
o 4ncf 3
e a
m
sasag%ss
30/d a
© m
ecs aof F8 f
(Rre ub
CtioE
sehep
ng-Sro
d o40crc%an
ma
sessgg
% o
30/6ar
m
ctarf80fo
RAp
liChon
E
elenplg SEolof00reo
% na
at
cts grflof0 60re
ma
t ireag
0%or
Apaichan su
ecn acc
ETllef: 0k
etento
al
te
tiore
flyf k
0 e n
ate
ise fgg%rm
APar, au
(ub
ctp
cecoTer
kge,
ncro y
eri
oof egy
hkgBno
er
s fixgr
% (mu
P)rt É
us(Cb
t tpeedouTRr
g/ re1
ysi
ia
nf ggaa
hyg/mBNot
ri
thxere(sul
). o
ÉcssCTsi
therd urRA
c
/m
et1.is
als
, grateashydmN t c
al
heedegsela
PofcoéeTid
herfoa
rseA co
m
te 8%
s o
s,
arae hdr
m3 f
co
ls
e d:gaeeati
Paf oleesI)
dia
e forase 1
om
m³
a%of
asan
o, rao
froon
s
u: 0atee Tio
avthe s ), ar
mrm ri
19m
o
an% f
th
s wnuon6
auofomns
us0%esTon
veheN(LP
ry
mamros 99
mp
of
ndinth
he
wulanl6%ulif cmsi
e %s+ab
ns
eme NaLPay)
atmeoaa
97ac
f c
d, n he
e
wearly%icco
m d
o%, + bls
med
atLCar).
terd
ada t7)ct
co
me
s
ellr
y. s
c onB
der
of4h
lear
endetioCPriB
rid d bth). te
on
mau
st
l pT
slb
ncBere
f 40hye re
ntevonPCs B
iainba
hin
ed
nc
asuse
ta
apaThlabincreced
R0%yd2e
t dvenaC)C
o
al n asn
d
cre
sse
an
as artheagndreckd
RA%dr).s
deloal),Cith
fo
seb
c
et
s oo
nd
tt. e
g ade
etekafo
AP% a
ra. Cstu
esople Lith
forore bi
co
te
ofof
dar
thIc
anere.aeor
P anauCud
sipme dLty
i
rmrdlatu
on
e,
f tf d
rd
heItchndr. T
ertr c
andul
Codi
igmdeab
y ain
mdeayum
nc
thdi
d
e t hod
Tht co
asd ic
onie
gnmeesboan
n
muer yem
cre
heif
t
mco
os2
ThCon
s 8
c nsed
n, ens Tornds
ulat
ermin
et
e hffe
te
maor
se21
The
Conc
an0b
idd
mntsTrad
sit
atto
r. no
te
hyer
es
atrrn1%hre
comcr
n 0%bide(s
mas
Traat
Atu
tioo T
ou
e
ydre
ts
tere
n h%eechmre
a% inerse
attoavoAu
ond
Thus
w
dren
s
eriesphy
% e ho
mpete
agb
ndrinee
teo vair
Aua
n dehes
wi
rant
c
iapoydlid
ospae
ggbydenge
erib
aureutoan
tefesc
ith
auR
ca
al ondrimdisend
gry wer g s
iabeuxe Ror
nd
o finseon
h
ulRA
am
dndra
meifny
de
rew
mcec
al e x Rro
d
bne pn
icA
mp
dedsaues
ffen s,
esi
egwe
mcoct
pcP
Régoula
bee pacr
st
c bAP
pa
ess ulsterstFig
gaeigmaomtio
prcoPug
uteab
e c
arre
te
bP c
ai
sit
ictoreee
Fign
ateghasmbon
roonubioesbo
uclraet
ee
inco
ig
gntoc onnelgu
n.
e.htssbin
opndblions or
uselaame
l
ndon
gn
no
bnent l fur
Tt o).in3
peduicnaP
ra
edss
mel
f
dent
n,
. ab
bin. f
fire
Tof. na3
rtuccsal Paato
d sietay
fib
erte
TbondT
fibibe
hf T
atia
tiete dd
aror
oicteye
be
r en
th
Thoude
Thbe
be1
reth
Thioan
eseddederisry
onalrser
er
nts
he
heuterheerrs
1)
eeheheonnd
s d e e s y
n l s r
r
s
e
e t r e r s .
e e e n d
A material developed by EIFFAGE Travaux Publics (ERTALH) is used as reference to evaluate the properties of the FRCC© materials. This reference material is made with the same Ligex FPL2 hydraulic binder (the content of which being fixed at 5% by weight of the aggregate) and contains 70% of the same RAP (in mass of aggregates + hydraulic binder).
Table 1 presents the properties of RAP used for FRCC© and ERTALH. RAP bitumen content was obtained following the standard NF EN 12697-3. A penetration test, as well as a ring and ball temperature test were done according to standard NF EN 1426 and NF EN 1427 on the bitumen extracted by distillation (NF EN 12697-3). Grading curves of all used aggregates (alluvial sand 0/4 Gurgy, crushed sand 0/6 Crain, crushed gravels 6/14 Crain and RAP) are presented in Figure 2.
Figure2: Grading curves of aggregates used in FRCC© and ERTALH materials Table 1: Properties of used Reclaimed Asphalt Pavement
Aggregates Bitumen Size (mm) Content (%)
NF EN 12697-3 Penetration at 25°C (1/10 mm)
NF EN 1426 Ring & Ball temperature (°C)
NF EN 1427 0-14 3.51 12 69.4
To obtain FRCC© and ERTALH final design the following procedure is used. First the
cement content and grading envelop (Figure 3) are fixed. Cement content is fixed at 12% in mass for FRCC© materials and at 5% for ERTALH mix. Then the aggregate fractions are adjusted to give a grading curve inside the grading envelop specification. Figure 3 shows the selected grading envelops and grading curves of all mixes. The water content is then determined from the modified Proctor test (NF EN 13286-2) and immediate bearing ratio (IPI) test (NF P 94-078) on materials without steel fiber. Figure 4 presents Proctor and IPI curve and the selected water content of each mixes. Finally Table 2 gives the mix proportions (without fiber) of the tested materials.
a) b)
Figure3: Grading curves and grading envelops for a) FRCC© b) ERTALH®
0.1 1 100
20
40
60
80
100Pa
ssin
g %
Diameter (mm)
0/4 Gurgy 0/6.3 Crain 6/14 Crain 0/14 RAP
0.1 1 100
20
40
60
80
100 F0% F40% F80% Grading envelop
Pass
ing
%
Diameter (mm)0.1 1 10
0
20
40
60
80
100 ERTALH Grading envelop
Pass
ing
%
Diameter (mm)
a) b) Figure4: a) Proctor and b) IPI curves and selected water content values of each mixes Table 2: Mixes component (without fiber)
F0% F40% F80% ERTALH
Alluvial sand 0/4 Gurgy 23.0% 20.0% 18.0% 0.0%
Crushed sand 0/6.3 Crain 35.0% 20.0% 0.0% 25.0%
Crushed gravel 6/14 Crain 30.0% 12.0% 0.0% 0.0%
RAP (0/10 Yonne enrobés) 0.0% 36.0% 70.0% 70.0%
Hydraulic binder (FPL2) 12.0% 12.0% 12.0% 5.0%
Total 100.0% 100.0% 100.0% 100.0%
Additive1 (Sika) 0.06% 0.06% 0.06% None Water content2 6.1% 6.2% 6.2% 6.9%
Bitumen content (%) from RAP 0.0 1.26 2.46 2.46
Dry Density 2.240 2.190 2.128 2.105
water/cement ratio 0.508 0.516 0.516 1.380 1 by weight of concrete 2 by weight of aggregates 3 CLASSICAL STANDARD TEST CAMPAIGN Experimental campaign was performed with standard tests at EIFFAGE Travaux Publics central laboratory in Ciry-Salsogne. The reference material ERTALH and eight FRCC© with different combinations of steel fibers and RAP content were tested. The nine different materials are listed in Table 3 where Fx% (yy) means FRCC© having x% RAP content of the aggregates mass and yy fibers content in kg/m³ of concrete.
Samples were molded using vibrocompression method (NF EN 13286-52) and stored in constant relative humidity (90% RH) and temperature (20°C) room.
Four different standard tests were carried out: compressive strength (Rc), compressive modulus (Ec), tensile splitting strength (Rit) and direct tensile strength (Rt). The same specimens were used for Ec and Rit. The tests were performed at different curing periods. As mentioned in Table 3, the curing time was slightly longer than forecasted for 3 specimens. Table 3 shows the specimen size, the determined parameters and the performed tests for each considered materials.
4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.02.00
2.05
2.10
2.15
2.20
2.25
2.30
Dry
Den
sity
(Mg/
m³)
Water content (%)
F0% F40% F80% ERTALH Selected value
4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.00
50
100
150
200
250
300
IPI
Water content (%)
F0% F40% F80% ERTALH Selected value
Table 3: Experimental campaign (at least 3 replicates for each condition)
TESTS Name Curing period (days)
F0%
F0%
(20)
F0%
(30)
F40%
F40%
(20)
F80%
F80%
(20)
F80%
(30)
ERTA
LH
Compressive Strength Rc (NF EN 13286-41)
Rc1 1 ● ● ● ● Rc7 7 ● ● ● ● Rc28 28 ● ● ● ● ● ● ●2 ● ●
Compressive Modulus Ec (NF EN 13286-43)
Ec28 28 ●1 ● ● ● ● ● ● Ec63 63 ● ● ● ● ● ● ● ● ●
Tensile Splitting Strength Rit (NF EN 13286-42)
Rit28 28 ●1 ● ● ● ● ● ● Rit63 63 ● ● ● ● ● ● ● ● ●
Tensile Strength Rt (NF EN 13286-40)
Rt28 28 ● ● ● ● ● ●
Rt63 63 ● ● ●3
1 curing time 30 days; 2 curing time 35 days; 3 curing time 66 days 4 RESULTS AND DISCUSSIONS Results of performed tests (Table 3) are presented in sections 4.1 to 4.4. Each data point represents the average of three specimens and the error bar is the standard deviation. Section 4.5 gives a comparison between different types of test results. 4.1 Compressive strength (Rc) The compressive strength test was made according to the standard NF EN 13285-41. Figure 5a shows the compressive strength of each material at different curing times. As no clear influence of the fiber content appears, the same data are transposed into Figure 5b, considering four groups of materials (ERTALH, F0%, F40% and F80%) without distinguishing the fiber content.
a) b) Figure5: Compressive strength at different curing times a) All mixes separately b) Grouped by
RAP content In Figure 5, the influence of the RAP content appears clearly for FRCC mixes. Regardless of the curing time, compressive strength decreases considerably when increasing the RAP content. This result is obtained by other authors (Kolias, 1996 and Mathias, 2004). Compressive strength results for 28 days are also presented as a function of RAP content at
10cm
20cm
32cm
32cm
16cm
0 5 10 15 20 25 30 35 40 4505
10152025303540 F0%
F0% (20) F0% (30) F40% F40% (20) F80% F80% (20) F80% (30) ERTALH
Com
pres
sive
Stre
ngth
(MPa
)
Curing Time (days)
Standarddeviation
0 5 10 15 20 25 30 35 40 4505
10152025303540
F0% + (20) + (30) F40% + (20) F80% + (20) + (30) ERTALH
Com
pres
sive
Stre
ngth
(MPa
)
Curing Time (days)
Standarddeviation
Figure 6b. Considering F80% and ERTHAL materials, which have the same RAP contents and respectively 12% and 5% cement contents, it can be noted that the cement content has an obvious effect on the compressive strength. At 7 and 28 days, FRCC 80% is much stronger than ERTALH. Figure 6a shows the compressive strength ratio between Rcd and Rc28. It appears that normalized compressive strength evolution is the same at any RAP (and fiber) content.
a) b) Figure6: Compressive strength a) ratio of specimen without fiber (Rcd/Rc28) at different curing
times b) of different RAP contents at 28 days 4.2 Compressive modulus (Ec) The compressive modulus test was made according to the standard NF EN 13286-43. Figure 7 presents the compressive modulus as a function of the curing times. Figure 7a shows all data, and Figure 7b represents the same data when considering four groups of materials (ERTALH, F0%, F40% and F80%) without considering the fiber contents. Figure 8 shows the ratio between compressive modulus at 28 and 63 days. The average ratio is 0.9.
a) b) Figure7: Compressive modulus at different curing times a) All mixes separately b) Grouped by
RAP content
Figure8: Compressive modulus ratio Ec28/Ec63
0.0
0.2
0.4
0.6
0.8
1.0
0 5 10 15 20 25 30
Rat
io R
c d /
Rc 2
8
Curing Time (days)
F0%F40%F80%ERTALH
0 10 20 30 40 50 60 70 800
5
10
15
20
25
30
35
R2 = 0,95
FRCC (0 kg/m³ fiber) FRCC (20 kg/m³ fibers) FRCC (30 kg/m³ fibers) ERTALH Trendline FRCC
Com
pres
sive
Stre
ngth
at 2
8 da
ys (M
Pa)
RAP content (%)
Standarddeviation
25 30 35 40 45 50 55 60 65 70 75 80 85 90
10000
20000
30000
40000
50000
Com
pres
sive
Mod
ulus
(MPa
)
Curing Time (days)
F0% F0% (20) F0% (30) F40% F40% (20) F80% F80% (20) F80% (30) ERTALH
Standarddeviation
25 30 35 40 45 50 55 60 65 70
10000
20000
30000
40000
50000
Com
pres
sive
Mod
ulus
(MPa
)
Curing Time (days)
F0% + (20) + (30) F40% + (20) F80% + (20) + (30) ERTALH
Standarddeviation
F0%
F0%
(20)
F0%
(30)
F40%
F40%
(20)
F80%
(30)
ERTA
LH
0.00.20.40.60.81.01.2
Ec28
/Ec6
3
Average = 0,9
The same conclusion as for the compressive strength can be formulated: incorporating RAP in FRCC decreases the compressive modulus. The cement content affects the compressive modulus. It decreases at the same time as the cement content does. The fiber content has no significant influence on the modulus (Figure 7a). In addition, the evolution of Ec between 28 and 63 days is low. 4.3 Tensile splitting strength (Rit) The tensile splitting strength test was made according to the standard NF EN 13286-42 with the same specimens tested as the compressive modulus. Figure 9a presents the evolution of the tensile splitting strength of each material at different curing times, and Figure 9b groups FRCC by RAP content. In Figure 9b), all values for F0% are grouped at 28 days, despite distinct curing times (28 and 30 days). Figure 10 shows the tensile splitting strength ratio. The average ratio is 0.81.
The same conclusion as for Rc and Ec can be drawn for tensile splitting strength: Rit decreases with incorporation of RAP, but the scattering is higher (Figure 9a) than for Rc and Ec. There is no effect of fiber content. The evolution between 28 and 63 days is more important than for compressive strength (Figure 10).
a) b) Figure9: Tensile splitting strength a) All mixes separately b) Grouped by RAP content
Figure10: Tensile splitting strength ratio (Rit28/Rit63) 4.4 Tensile strength (Rt) This section presents results from tensile strength tests. The tensile strength test was made according to the standard NF EN 13286-40. Figure 11 shows results and standard deviations of all available data. RAP and cement contents have the same effect on Rt values as that presented for the three other parameters (Rc, Ec Rit). The few results for tensile strength don’t allow us to obtain either strength evolution at different curing times or effect of fiber content.
25 30 35 40 45 50 55 60 65 70 75 800.00.51.01.52.02.53.03.54.04.55.0
Tens
ile S
plitt
ing
Stre
ngth
(MPa
)
Curing Time (days)
F0% F0% (20) F0% (30) F40% F40% (20) F80% F80% (20) F80% (30) ERTALH
Standarddeviation
25 30 35 40 45 50 55 60 65 700.00.51.01.52.02.53.03.54.04.55.0
Tens
ile S
plitt
ing
Stre
ngth
(MPa
)
Curing Time (days)
F0% + (20) + (30) F40% + (20) F80% + (20) + (30) ERTALH
Standarddeviation
F0%
F0%
(20)
F0%
(30)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Rit2
8/R
it63
F40%
F40%
(20)
Average = 0.81 σ = 0.05
F80%
(30)
ERTA
LH
Figure11: Tensile strength at different curing times 4.5 Comparison between different tests In this section different types of results are compared. When designing road base layer in roller compacted concrete according the French design guide, the tensile strength and the elastic modulus are needed. The French design guide proposes different ratios that can approximate tensile strength and elastic modulus from tensile splitting strength. For roller compacted concrete, these values are 0.8 for Rt-Rit ratio and 12000 for Ec-Rit ratio both at 360 days. In order to know these ratios for FRCC and ERTALH mix, tensile splitting strength is compared to tensile strength and compressive modulus. Then, compressive strength is compared to Rt and Ec at 28 days. 4.5.1 Comparison between Rt and Rit Figure 12 shows the Rt-Rit ratio for all available data at 28 and 63 days. It seems to have a slighter influence of RAP and fiber (Figure 12a) at 28 days. For F0%, adding fibers increases the Rt-Rit ratio. At equal fiber content for F0% and F40% at 20kg/m³ or F0% and F80% at 30kg/m³ the incorporation of RAP increases the Rt-Rit ratio. As a first approximation and considering error ranges, all formula can be linked by a common value of 0.7. At 63 days, there is no influence of cement content (Figure 12b). The ratio at 28 days is lower than the French design guide ratio at 360 days. At 60 days, it has the same value (LCPC-SERTA 1997).
a) b) Figure12: Ratio between Rt-Rit a) 28 days b) 63 days and indication of French design guide
ratio at 360 days 4.5.2 Comparison between Ec and Rit Figure 13 shows the Ec-Rit ratio for all available data at different curing times. The cement content has a significant effect on Ec-Rit ratio. The ratio increase when decreasing the cement content. Because the evident difference between the ratio Ec-Rit of FRCC and ERTALH, ERTALH is separated from FRCC. The average for FRCC is given for 28 and 63 days. There is no influence of fiber. A small effect of the RAP content is observed. The ratio slightly decreases when incorporating RAP in FRCC©. The French design method proposes a 12000
0.0
0.6
1.2
1.8
2.4
25 35 45 55 65 75
Tens
ile st
reng
th
(MPa
)Curing Time (Days)
F0%F0% (20)F0% (30)F40%F40% (20)F80% F80% (20)
F0%
F0%
(20)
F0%
(30)
F40%
(20)
F80%
(30)
0.00.10.20.30.40.50.60.70.80.91.01.1
Average = 0.66 σ = 0.08Guide ratio at 360 days
Rt2
8/R
it28
Standarddeviation
F80%
ERTA
LH
0.00.10.20.30.40.50.60.70.80.91.01.1 Average = 0.81
σ = 0.01
Rt6
3/R
it63
Guide ratio at 360 days
ratio at 360 days (LCPC-SETRA 1997). The lower level of the ratio found at 28 and 63 days shows that the actual guide value at 360 days is not valid for FRCC. Ec-Rit ratio at 360 days is needed before given a conclusion for ERTALH.
a) b) Figure13: Ec-Rit ratio of all mixes and French design guide ratio at 360 days a) 28 days b) 63
days 4.5.3 Comparison between Rc and Rt Figure 14 shows the Rc-Rt ratio for all available data at 28 days. Previously, the same effect of the RAP content is seen on Rc and Rt. The strength decreases with incorporation of RAP. The RAP content has also an effect on the Rc-Rt ratio. This ratio decreases by increasing the RAP content. The decrease of the ratio when increasing the RAP content shows a more significantly effect of RAP content on Rc than Rt. No fiber effect is observed.
Figure14: Ratio between compressive strength and direct tensile strength at 28 days for FRCC
materials 4.5.4 Comparison between Ec and Rc Figure 15 shows the Ec-Rc ratio at 28 days for all available data. Cement content has a significant effect on Ec-Rc ratio. Less the cement content is, higher is the ratio. Because of this difference, an average value for FRCC is calculated and added to figure 15. The RAP and fiber contents don’t significantly affect the Ec-Rc ratio.
Figure15: Ratio between compressive modulus and the compressive strength at 28 days
F0%
F0% (20)
F0% (30)
F40%
F40% (20)
F80% (30)
Average FRCC
ERTALH
02000400060008000
100001200014000160001800020000 Average for FRCC = 11390 σ = 1344
Ec28
/Rit2
8 Guide ratio at 360 days
Standarddeviation
F0%
F0%
(20)
F0%
(30)
F40%
F40%
(20)
F80%
F80%
(20)
F80%
(30)
Ave
rage
FRC
C
ERTA
LH
02000400060008000
100001200014000160001800020000
Guide ratio at 360 days
Ec63
/Rit6
3
Standarddeviation
Average for FRCC = 9860 σ = 1175
F0%
F0%
(20)
F0%
(30)
F40%
(2
0)
F80%
(2
0)
F80%
(3
0)
0
5
10
15
20
Rc2
8/R
t28 Average = 13.4 σ = 3.02
F0%
F0% (20)
F0% (30)
F40%
F40% (20)
F80% (30)
Avg. FRCC
ERTALH
0
500
1000
1500
2000
2500
3000
Standarddeviation
Ec28
/Rc2
8
Average = 1277 σ = 117
5 CONCLUSIONS Results on compressive modulus Ec, tensile and compressive strength (Rt, Rit, Rc) on FRCC© (with and without RAP) and ERTALH are presented. RAP content has an effect on the strength and the compressive modulus of FRCC© mixes. The higher the RAP content is, the weaker all three strengths and the modulus become. There is no influence of the fibers for the considered tests. Fiber plays a role only when the anchor of the fiber is in action. A further testing investigation after the first crack is required to view the influence of fibers after cracking. At equal RAP content (80%), there is a hydraulic binder content effect. With a rising of cement content, the strength and the modulus of the specimen are both increased. The increase of RAP content influences the strength, according to the temperature (which has to be taken into consideration). REFERENCES Ficheroulle, B. and Henin, M., 2004. Compacted Rolled Fibre-Reinforced Concrete
composition and method for producing a pavement based on same. Patent EP1278925B1. Kolias, S., 1996. Mechanical properties of cement-treated mixture of milled bituminous
concrete and crushed aggregates. Materials and Structures, Vol 29, August/September, page 411 to 417.
LCPC SETRA, 1997. French design manual for pavement structures – technical guide. LCPC, 250 p.
Mathias, V. et al., 2004. Recycling reclaimed asphalt pavement in concrete roads. RILEM Conference on the Use of Recycled Materials in Building and Structures, Barcelona.
Mathias, V., 2004. Recyclage des fraisats d'enrobés dans les bétons routiers. PhD Thesis, Ecole Centrale de Nantes and Université de Nantes.
NF EN 12697-3, 2005. Bituminous mixtures - Test methods for hot mix asphalt - Part 3: bitumen recovery: rotary evaporator. Afnor, 16 p.
NF EN 13286-40, 2003. Unbound and hydraulically bound mixtures - Part 40: test method for the determination of the direct tensile strength of hydraulically bound mixtures. Afnor, 9 p.
NF EN 13286-41, 2003. Unbound and hydraulically bound mixtures - Part 41: test method for the determination of the compressive strength of hydraulically bound mixtures. Afnor, 12 p.
NF EN 13286-42, 2003. Unbound and hydraulically bound mixtures - Part 42: test method for the determination of the indirect tensile strength of hydraulically bound mixtures. Afnor, 10 p.
NF EN 13286-43, 2003. Unbound and hydraulically bound mixtures - Part 43: test method for the determination of the modulus of elasticity of hydraulically bound mixtures. 14 p.
NF EN 1426, 2007. Bitumen and bituminous binders - Determination of needle penetration. Afnor, 15 p.
NF EN 1427, 2007. Bitumen and bituminous binders - Determination of softening point - Ring and Ball method. Afnor, 17 p.
NF P 94-078, 1997. Soils : investigation and tests. CBR after immersion. Immediate CBR. Immediate bearing ratio. Measurement on sample compacted in CBR mould. Afnor, 12 p.