MB - IFSTTAR Actions incitatives

COMPORTEMENT DES ENROBES BITUMINEUX ET
PROPRETE DES SABLES : APPROCHE PHYSICOCHIMIQUE
Chi-Wei CHEN (PhD 2ème année),
Myriam DUC (Ifsttar/GERS –SRO),
Clôture de l’opération AGREGA
Ifsttar (centre de Nantes) - Mardi 10 décembre 2013
PLAN DE LA PRÉSENTATION
• Contexte de l’étude
• Objectif
Valorisation des sables non conformes contenant des fines
argileuses dans les bétons bitumineux.
• Le phénomène de désenrobage dans les bétons bitumineux contenant
des fines argileuses lors la pénétration de l’eau dans le matériau
– Essai Duriez
– Nocivité des fines d’argile
– Corrélation Duriez - nocivité (MB)
• Essais préliminaires
2
CONTEXTE
Étude à l’origine du projet de recherche (LR Autun)
Sable FLETY / MONTAUTE
(étude au LR Autun) :
MB 2, MB 3, MB 4
Non-qualified Montaute
sand in AC pavement (2006)
In situ testing = NO PATHOLOGY DURING
5-6 YEARS on the portion of road realized
with non-qualified Montaute or Fléty sands
Thèse de Chi Wei Chen (Octobre 2012 – octobre 2015) financée par l’IFSTTAR
Physical-chemical study of the possibilities for using the non-qualified
clay-rich sands in asphalt concrete pavement
Encadrement (GERS/ MAST):
Erwan HAMARD (Ifsttar/MAST – GPEM), Yannick DESCANTES (Ifsttar/MAST – GPEM),
Vincent GAUDEFROY (Ifsttar/MAST – MIT), Ferhat HAMMOUM (Ifsttar/MAST – MIT)
Contrat UNPG en marge de la thèse
3
OBJECTIF
Valorisation des sables non conformes contenant des fines
argileuses dans les bétons bitumineux :
utilisation d’une approche physico-chimique en couplant les
propriétés d’usage et les propriétés des granulats
Stripping potential in asphalt concrete (AC) pavement :
the main problem to understand/solve to use non qualified sands
Impermeable
stripping in
contact with
water
Sources of moisture in pavement systems (FHWA 1999)
4
DÉSENROBAGE EN PRÉSENCE D’ARGILE
Mineral
Electrostatic bonding (polar forces)
Bitumen reactive
components
Stripping = loss of adhesive
bond between the aggregate
surface and asphalt binder due
to WATER intrusion (Tarrer 1986)
Clays that coat aggregate surface, severely
weakens the bonding with bitumen, and then
accelerates the stripping in AC pavement.
(Kanitpong and Bahia 2003;
Hicks et al. 2003)
5
SENSIBILITÉ A L’EAU : ESSAI DURIEZ
Duriez test NF EN 12697-12
2008 = degradation of AC
specimen from stripping
Preheated fractions and
bitumen in the mixer
measuring specimens
=
compressive strength i of the sample conditioned under air
compressive strength C of the sample immersed in water
2 minutes’ mixing
storing in water with
vacuum 2hrs
compacting
cooling down over night
28days in air and water
respectively (ref 9% montm.)
calibration
de-moulding
after Duriez test
(28days’ 9%
montm. in water)
6
NOCIVITÉ DES FINES D’ARGILE : ESSAI MB
ClStructure of MB molecule
MB value
= measure of the specific surface area - SSA
(or cation exchange capacity - CEC )
= indirect measure of mineralogy
Molar mass: 319.85g/mol
Rectangular (projected area):17Å x7.6 Å x3.25 Å
Clay type
Largest surface:130Å2 / (until 135 Å2)
Kaolinite
Illite
MB molecule
(Hang and Brindley, 1970)
( Hahner et al., 1996)
Theoretical covering of
clay particle by a
monolayer of MB
molecule
The
interlayer
cations
//
K
CEC
MB
(meq/100 (meq/100
g)
g)
3-15
0.5-2
SSA
(m2/g)
5-20
10-40
3-5
50-200
Montmorillonite Ca, Na…
70-120
6-13
700-800
Chlorite
Sepiolite
Palygoskite
10-40
20-30
3-5
n/a
n/a
//
//
Threshold : MB = 2
7
NOCIVITÉ DES FINES D’ARGILE : ESSAI MB
Influence de la méthode de mesure sur la valeur de bleu
Conformed
M B 0 / 2 drop m ethod (g/k g)
4
Drop method (EN13043, NF EN 933-9)
Non-conformed
Unconform Flety
DROP METHOD
3
Unconform Montaute
(GEOTECHNICAL FIELD)
TUBIDIMETRIC METHOD
(AGGREGATES FIELD)
2
Conform Flety
PHOTOMETRIC METHOD
MB0/2mmdrop method (Autu n)
MB 0/2mm Photom etric method (stud y)
(LABORATORY FIELD)
(Chi Wei
‘s method
thesis)
MB 0/2mmChen
tubidimetric
(Na nte)
Conform Montaute
1
1
1.5
2
2.5
3
3.5
4
0-2 mm fraction – undried
MB0/2 (g/kg)
Turbidimetric method (NF P 18-545)
Batch Spectrophoto. method (IFSTTAR Paris)
(2 hours contact of 0-2mm fraction of sand with MB,
centrifugation, concentration of MB remaining in
solution >> concentration of MB molecules that were
adsorbed)
8
NOCIVITÉ DES FINES D’ARGILE : ESSAI MB
Effet du séchage avant essai MB
Natural sand
undried, air dried, heating at 110°C
2.00
1,40
7.00
1,20
6.00
1,00
5.00
0,80
4.00
(IFSTTAR Nantes study, 2012)
Drop method
1.80
1.60
1.40
MB (g/kg)
M B ( g /k g )
MB (g/kg)
1.20
1.00
3.00
0,60
0.80
0.60
0,40
2.00
0,20
1.00
0.40
0.20
0.00
0.00
0,00
Sans séchage
Air libre
Etuve 110°C
Sans séchage
Air libre
Mode de séchage
Mode de séchage
Sand
Effet du séchage - Sable1
Averton
Effet du séchage - Sable de Mantallot
Sand 2
Etuve 110°C
Sans séchage
Air libre
Etuve 110°C
Mode de séchage
Sand
3
Effet du séchage - Sable Mallet
Increase of the temperature of drying >> decrease of the MB
(irreversibility or partial reversibility of deshydratation)
9
NOCIVITÉ DES FINES D’ARGILE : ESSAI MB
Effet de différents paramètres sur la valeur de bleu
•No effect of filter paper (IFSTTAR study in 2012)
•Effect of MB concentration,
•Age of the MB solution
•Variation of MB UV-visible spectrum with pH
and salinity (Na, Ca…)
( Pentrák M. et al., 2012)
Effect of contact time
( Neumann. et al., 2002)
Immediately
Bentonite SWy-1
5 hours
30 days
(Bujdák J., 2006)
High
energy
Low
energy
Variation of UV-vis. spectrum but
is there a variation of MB value
measured by drop method?
10
CORRÉLATION DURIEZ-MB
The same MB value but different results in Duriez test
TSR: Tensile Strength Retaining
Qualified
Non-qualified
No stripping
?
Severe stripping
Effect of clay
mineralogy ?
Effect of
cations on
clays ?
(KANDHAL, 1998)
11
CORRÉLATION DURIEZ-MB
Effet du type de cation échangeable
TOT clay structure
cations
bind with
bitumen
P e r c e n t a g e o f p o la r f o r c e s f r o m s u r f a c e
e n e r g y (% )
56
54
52
MB > SSA and CEC
Impact of the nature of exchangeable cations
>> polar forces (stripping) depends on cations on clay
surface that bind with bitumen
Tension surface energy: γ = γ D + γ P
Polar forces measured by
drop shape method on
saturated Mont. with various
cations
(Neumann et al., 2002)
Polar force of study (Sardaigne, hum.66%)
Polar force of reference (SAz1, hum.33%)
(Chi Wei
Chen thesis)
Ca2+.
50
48
46
Na+
//
Mg2+
44
Litterature
K+
42
minimum
40
Montm. water commercial
K-Montm. commercial
Na-Montm. commercial
Ca-Montm. commercial
Mg-Montm. commercial
Variation of UV - visible spectrum of MB
absorbed on SWy-1 bentonite exchanged
with different cations, measured
immediately after mixing.
12
ESSAIS PRÉLIMINAIRES
Essais Duriez
Aggregate content
100%
Aggregate size
6mm
EB6 (BBTM 0/6 discontinue):
Diorite 2/6mm 75%;
Sand 0.063/2mm 16%
Filler 0.01/0.063 mm is limestone,
Binder 35/50;
richness 3.5;
BCmin5 (25 gyration);
Vmin12 max20;
ITSR80;
Diorite
Diorite
4mm
2mm
0.063mm
0.001mm
25%
Washed sand
Washed
sand
Fines
Fines
9%
0%
Aggregate proportions and sizes
(Delorme 2007)
of EB6 discontinue
Fine 0/0.063 mm = 9% in mixture with bitumen (= 35% in sand)
9% Filler
9% kaolinite
9 % illite
9% Montmorillonite
Water sensitivity
13
ESSAIS PRÉLIMINAIRES
Premiers résultats : essais Duriez
No degradation of water resistance
when there is no clay (Ref)
i/C = 100xCW/CD
Lowest water resistance
28 days Duriez test
Reference without clay
1.00
1.00
9% raw kaolinite
100%
for swelling clay (Mont.)
9% Avrel illite
0.90
9% Avrel montm.
0.80
0.74
0.70
74%
Kaol. = raw material from
0.77
quarries
77%
Illite / Mont. = commercial
0.60
products (crushed and dried)
I/C ratio 0.50
0.40
Specimens for Duriez test
0.30
plays a role on AC water
0.20
0.11
0.10
0.00
MB 0-2mm
The history of clay (treatments)
11%
Ref.
Kao.
MB 2.7
Illite
resistance
Montm.
MB 15
MB 68
14
ESSAIS PRÉLIMINAIRES
Clay location and water intrusion in asphalt concrete (AC)
Microstructural observation
Pores
Clay at
interfaces
Clay and stripping location
Use of tracer
X-ray tomography coupled
with synchrotron (Ifsttar 2012)
Clay in
Mastic
Sand
Coarse grain
2mm
ESSAIS PRÉLIMINAIRES
Clay location and water intrusion in asphalt concrete (AC)
Mont. / sand / coarse fraction - bitumen mixtures put in contact with MB solution
68
Bitumen
M B a b so rb ed b y M o n tm . in A C m ix tu re (g /k g )
67.6
Mastics: montm. + bitumen
67
Water may reach clay in
bitumen matrix
66
Water intrudes through
-Bitumen
interfaces
bitumen
-Mastics:
themontm.+
mastic
coats sand+
coarse fracion+ bitumen
-Montm.
clay
agregates
65
Montm. coats sand
all fractions separeted
Montm. coats coarse fracion+ sand+ bitumen
Montm. coats coarse fraction
Montm balls+ sand+ coarse fraction+ bitumen
Montm.+ sand+ coarse fraction+ bitumen
Montmorillonite balls in bitumen
show the fastest intrusion of water
Montm. Balls' mixture
64
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Day of AC mixture contacts water
16
ESSAIS PRÉLIMINAIRES
Identification et quantification de l’argile dans les sables
MB value is not enough to establish the conformity
For a MB value > possibility of several clay mineralogies in sand
XRD measurements
qualified sand
Identification / quantification
of clay fraction
Non qualified sand
Size distribution
(wet sieving)
Sample
< 2µm %
Sand + 4%
3%
3%
Montmorillonite Arvel
< 63 µm
%
18.6%
Amount of < 2 µm particles
partial control of the sand qualification
Master (TUC)
Semi-quantification
(fromSEMI
< 2 µm Rietveld
RIETVELD
oriented
lamella
Quantification
QUANT
and particle size
distribution)
Minerals
97.1%
72.4%
Quartz
9.5%
Calcite
4.6/%
Mordenite
0.4%
hornblend
20%
Feldspars
37.9%
Swelling clay
2.9%
5.7%
2,9%
5.7%
Smectite group
2.9%
5.7%
Non-swelling clay 0.07%
22%
Mica group
0.01%
5.5%
Kaolinite group
0.01%
2.2%
chlorite group
0.05%
14%
Minerals
96.8%
70.4%
minerals
The method to
quantify clay has to
be chosen carefully
The accuracy of
quantification has to
be discussed
17
ESSAIS PRÉLIMINAIRES
Traitement à la chaux (1/2)
Indirect tensile test (IFSTTAR, Nantes)
Different preparation of sands
Bitumen mixture with 9%
of montmorillonite in sand
(35% of mont. in sand)
Lime treated sand
MB = 68
MB after treatment decreases
18
ESSAIS PRÉLIMINAIRES
Traitement à la chaux (2/2)
EFFECT of LIME
• Exchanged clay with Ca2+
• flocculation of clay
• Calcium effect on claybitumen bonding
• Formation of hydrates (?)
Layered structure of calcium silicate
hydrates (Richardson, 2007)
May C-H-S structure be formed in AC mixture or is there a
pH effect on MB UV-visible spectrum ? Validation in course
Methylene blue adsorption
on lime treated AC
Monomers
H-dimers
H-aggregates
lime marinating
Adsorption of MB as a
descriptor of C–S–H
nanostructure (2010)
586
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Merci pour votre attention
14-20 Boulevard Newton
Cité Descartes, Champs sur Marne
F-77447 Marne la Vallée Cedex 2
Tél. +33 (0)1 81 66 85 25
Fax. +33 (0)1 40 43 54 98
PhD student : [email protected]
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