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Book ChapterDOI

A Four-Point Bending Test for the Bonding Evaluation of Composite Pavement

01 Jan 2012-pp 51-60

Abstract: The aim of this paper is to present a specific four-point bending test with a specific model to help investigate the crack initiation and propagation at the interface between layers of composite pavements The influence of the geometry on the delamination phenomenon in specimens is analyzed Considering the deflection behavior of specimens, both experimental and analytical results are compared Two different types of interface (concrete / asphalt and asphalt / concrete) are tested in static conditions Different failure mechanisms whose mainly delamination is observed The crack mouth opening displacement is monitoring by means of linear variable differential transducer (LVDT) The strain energy release rate is provided and compared successfully to the literature
Topics: Asphalt concrete (56%), Strain energy release rate (53%), Deflection (engineering) (52%), Test method (51%)

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A four-point bending test for the bonding evaluation of
composite pavement
Manitou Hun, Armelle Chabot, Ferhat Hammoum
To cite this version:
Manitou Hun, Armelle Chabot, Ferhat Hammoum. A four-point bending test for the bonding eval-
uation of composite pavement. 7th Rilem International Conference on Cracking in Pavements, Jun
2012, France. p.51-60, g., graphiques, ill. en couleurs, bibliogr., �10.1007/978-94-007-4566-7_6�.
�hal-00845902�

A four-point bending test for the bonding evaluation of
composite pavement
M. Hun
1
, A. Chabot
1
, F. Hammoum
1
1
LUNAM Université, IFSTTAR, Route de Bouaye, CS4, F-44344
Bouguenais Cedex, France
Abstract. The aim of this paper is to present a specific four-point bending test with
a specific model to help investigate the crack initiation and propagation at the
interface between layers of composite pavements. The influence of the geometry
on the delamination phenomenon in specimens is analyzed. Considering the
deflection behavior of specimens, both experimental and analytical results are
compared. Two different types of interface (concrete / asphalt and asphalt /
concrete) are tested in static conditions. Different failure mechanisms whose
mainly delamination is observed. The crack mouth opening displacement is
monitoring by means of linear variable differential transducer (LVDT). The strain
energy release rate is provided and compared successfully to the literature.
Introduction
Due to shrinkage phenomenon occurred in cement materials, the existing vertical
crack through the cement concrete layer combined to environmental and traffic
loadings affects the durability of composite pavements made with asphalt and
cement materials. Two main problems have to be investigated: i) debonding
mechanisms at the interface between two layers; ii) reflective cracking
phenomenon through asphalt overlay or corner cracks in concrete overlay. This
paper deals with the study of debonding. Previous research works have proposed
some experimental devices to characterize the bond strength of asphalt-concrete
interface in mode I [1]. But the combined normal and shear stresses near the edge
of the layer as the vertical crack usually initiates and propagates the delamination
[1]. The optimum design incorporating these variables has not been done yet.
Mixed mode test to evaluate the delamination resistance is needed. On site, only
few devices [4-5] allow testing the bond strength in mixed-mode. The literature
review offers interesting ideas especially those on reinforced concrete beams and
on concrete beams strengthened with composite materials [6].

M. Hun, A. Chabot, F. Hammoum
2
In this paper, we propose to adapt existing four-point bending test (4PB) to bi-
material specimens made with asphalt and cement material layers as illustrated in
Figure 1. By using a specific elastic model, the influence of the specimen geometry
and the material characteristics on internal stresses is presented. Then,
experimental program is described and a discussion on static results is given.
x
z
o
a
L/3
L
L-a
2L/3
2
1
a
f
1
f
2
a
a
a
2
z
F/2F/2 F/2F/2
e
2
e
1
b
F
L
F
L
FF
L
2
1
x
o
a
L
L-a
2
1
1
Zone I Zone II Zone III
Asphalt concrete
Cement concete
A B C D
Asphalt concrete
Cement concete
(a)
(b)
Figure 1. (a) Schematic of test configuration, (b) Schematic adapted for calculating
strain energy release rate calculation
Quasi-analytical investigation
The Multi-particle Model of Multi-layer Materials with 5 equilibrium equations
per layer (M4-5n, n: total number of layers) [2] used to calculate stress and strain
energy release rate on the 4PB test (Figure 1.b) is briefly presented. Considering
homogenous, elastic and isotropic material assumptions, the specimen design is
studied in order to optimize stresses to cause delamination between layers.
Introduction to the M4-5n
The M4-5n has five kinematic fields per layer i (
{
}
ni ,...,1
): the average plane
displacement
(
)
yxU
i
,
α
, the average out of plane
(
)
yxU
i
,
3
and the average rotations
(
)
yx
i
,
α
Φ
{
}
(
)
2,1
α
. Stress field is assumed to be written with polynomial
approximation in z (vertical direction) per layer i (characterized by
iii
Ee
υ
,,
, its
thickness, Young modulus and Poisson ratio parameters). Its coefficients are
expressed with the use of the classical Reissner generalized stress fields in
(
)
yx,
per layer i. These polynomial approximations have the advantage to define the
normal stresses
(
)
yx
ii
,
1, +
ν
and the shear stresses
(
)
yx
ii
,
1, +
α
τ
at the interface
between i and i+1 layers. Theses stress fields are responsible for the delamination
between layers at the edge or cracking location points. Hellinger-Reissner's
formulation reduces the real 3D problem to the determination of regular plane
fields (x,y) per layer i and interface i, i+1 (and i-1, i). This model can be viewed as
superposition of n Reissner’s plates, connected by means of an elastic energy that
depends on the interlaminar stress fields [2]
.
The M4-5n advantage is to
give finite
value of stresses near the edge or crack permitted to identify easily delamination
criteria [3].

A four-point bending test for the bonding evaluation of composite pavement
3
In order to simplify the analysis, the 4PB test presented in Figure 1.a is simulated
under the assumption of plane strain. Then, the mechanical fields depend only on
the variable x. The problem is divided in three zones (see Figure 1.b). By mean of
shear forces
(
)
xQ
i
1
of layers 1 and 2, linking conditions of displacements, forces
and moments between zones, the first and last single layer zone (
],0[
1
ax
and
],[
2
LaLx
) allow to pass on the support conditions of the beam at the
bilayer zone
(
)
],[
21
aLax
. On this central zone (where
2
=
n
), different
manipulations of M4-5n equations let to put finally into a system of second order
differential equations in function of x only with the form Eqn. (1)
( ) ( ) ( )
(
)
( )
( )
( )
( )
Φ
Φ
==+
x
xU
xQ
x
xU
xXwithCxBXxAX
2
1
2
1
1
1
1
1
1
1
"
(1
)
where A, B, and C are the analytical matrices functions of geometric parameters,
elastic characteristics of material behaviors and loading conditions specified
(Figure 1.a). The expression of A, B, and C are given in Eqn. (2-4):
( ) ( )
( )
( )
( )
( )
( )
( )
( ) ( )
+
+
+
+
+
+
=
0
1
00
1
112
000
12
00
35
13
0
15
1
15
0000
1
1
1
15
4
000
11212
22
2
3
2
2
2
2
2
3
2
2
2
22
1
11
2
22
1
121
2
2
1
1
12
211
1
1
12
2121
1
1
2
11
1
11
υυ
υυ
υ
υ
υ
υ
υ
υ
υυ
EeEe
EeEee
E
e
E
e
E
Eee
E
Eeee
EeEe
A
(2
)
( ) ( )
( )
×
×
+
×
+
=
+
+
+
+
+
=
3
,,
0
10002
100025
112
100025
1
0
;
00000
00100
10
5
112
5
112
10
2
1
5
1
5
1
2
1
00100
1
22
2
2
2
22
2
11
1
2
2
2
1
11
L
axif
F
F
Ee
F
E
C
EeEe
e
EE
e
B
υ
υ
υυ
υυ
(3
)
( )
×
×
+
×
+
=
=
2
22
2
2
2
,
3
2
,
0
10002
100025
112
100025
1
0
;
3
2
,
3
,
0
0
0
0
0
aL
L
xif
F
F
Ee
F
E
C
LL
xifC
υ
υ
(4
)

M. Hun, A. Chabot, F. Hammoum
4
The shear stresses
(
)
x
2,1
1
τ
and normal stresses
(
)
x
2,1
ν
of M4-5n at the interface
between layer 1 and 2, are obtained analytically in function, respectively, of the
unknowns of the system of Eqn. (1) and their derivative by the Eqn. (5) of interface
behavior, and the equilibrium equation of shear forces of Eqn. (6). The sum of
shear force of layers has to verify the condition as indicating in Eqn. (7).
( )
( ) ( ) ( ) ( ) ( ) ( )
( ) ( )( )
212121
2
1
2
2
1
1
1
1
2
1
2
1
1
1
1
1
2
1
212,1
1
114
5
1
5
1
22
15
υυ
υυ
τ
+++
+
+
+
+ΦΦ
=
EeEe
xQ
E
xQ
E
x
e
x
e
xUxU
EEx
(5)
(
)
(
)
xQx
'1
1
2,1
=
ν
(6)
( ) ( )
×
×
=+
21
2
1
1
1
,
3
2
10002
;
3
2
,
3
0;
3
,
10002
aL
L
xif
FLL
xif
L
axif
F
xQxQ
(7)
Eqn. (8) gives the M4-5n elastic energy W
e
. According to linear elasticity theory
for a system under constant applied load, the energy release rate can be expressed
as in Eqn. (9) in case of the crack propagation along the interface (Figure 1.b).
(
)
(
)
( )
[ ]
( )
[ ]
( )
[ ]
( )
[ ]
[ ]
( )
( )
( )
[ ]
( )
[ ]
( ) ( )
( ) ( )
( )
( )
( )
( )
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
++
Φ
+
++Φ
+
+
+
+
=
2
22
2
2
3
2
2
22
2
2
"1
1
1
11
2
22
1
11
"1
1
1
11
2
1
2
2
1
1
1
1
2
2
1
22
2
2
1
1
11
1
2
'2
1
2
'2
1
'1
1
2
2
2
'1
1
1
1
2
'2
1
2
2
22
2
'2
1
2
22
2
'1
1
2
1
11
2
'1
1
1
11
2
22
1
2
3
1
2
22
2
1000
10
13
1000
2
1
1
11
15
2
1
11
5
1
5
16
5
16
140
17
4
2
270
13
112
12
112
12
1000
10
13
1000
2
1
3
2
2
1
2
2
1
2
2
1
2
1
2
1
2
1
2
1
2
3
2
1
2
2
1
2
3
2
1
23
2
F
Ee
aL
aL
F
Ee
dxU
Ee
E
e
E
e
dxU
Ee
Q
E
Q
E
dxQ
Ee
dxQ
Ee
dxQ
QQ
E
e
dxQ
E
e
dx
Ee
dxU
Ee
dx
Ee
dxU
EeF
Ee
a
a
F
Ee
W
x
x
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
x
x
e
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
υ
υ
υ
υυ
υ
υυυυ
υ
υ
υ
υ
υ
υ
(8)
A
W
G
e
=
(9)
Both the methods of adimentionalisation and numerical resolution of equations by
the Newmark finite difference scheme used by Pouteau [4] and Le Corvec [7] are
adapted to this test. This method is programmed under the free software Scilab. For
a symmetrical case, the excellent convergence of normal and shear stresses at the
interface between layers at
1
ax =
and
2
ax =
is obtained in [8]. It has shown that
the discretization of the x variable into 1200 elementary segments is sufficient.
One simulation takes few seconds (CPU time). Interface ruptures are expected in
mixed mode (mode I and II). The results have been compared successfully with
finite element calculations and different static tests on Alu/PVC structure [8].

Citations
More filters

Journal ArticleDOI
Armelle Chabot1, Manitou Hun1, Ferhat Hammoum1Institutions (1)
Abstract: In order to investigate interlayer debonding near skrinkage cracks or joints of “composite” pavements, a four-point bending test on bi-layer structures is performed. Before mixed mode failure, the quasi-analytical calculations obtained by a specific elastic model match experimental results under static and controlled displacement conditions. Both the interface normal and shear stress intensities determined at the specimen edge lie within the range of values found in the literature for cement concrete overlays on a bituminous material type of interface. The strain energy release rate is calculated. Results are discussed relative to both data provided in the literature and testing campaigns.

34 citations


Journal ArticleDOI
Abstract: The degradation of the bituminous pavement structures is due to the several external loads (climatic conditions and traffic) and the weak bond between layers. Thus, it is important to take into account the interface behavior in the pavement computational design which is never considered actually. In order to provide reliability and efficiency of the design methods, the interface characterization study is required. In this study, a monotonic tensile test was performed for better understanding of the global and local structure behavior by using the Digital Images Correlation (DIC) analysis. The obtained results allow us to characterize the constitutive law of interface and mechanical parameters such as: stiffness, damage evolution, and release rate energy.

20 citations


Journal ArticleDOI
Abstract: Considering that water may cause a separation of interfaces between layers of pavement structures, specific test on bi-layer specimens is performed in a water bath. For the study of the bond between layers made of cement concrete overlay on bituminous material, four-point bending results show a competition between different failure mechanisms. Actually a very good bond resistance between layers compared to the fracture tension resistance of the cement concrete layer is preliminary observed in dry conditions. In this work, first results of the water effect on the behaviour of such a material interface are presented. The final fracture length of the specimen and the corresponding curve of force-displacement highlight the influence of water immersion on the debonding failure mode. The field displacement measurement obtained by Digital Image Correlation is used to improve the understanding of the fracture scenario.

17 citations


Journal ArticleDOI
Abstract: A bonded concrete overlay consists of a concrete layer poured over a deteriorated pavement. Its mechanical performance depends on the quality of the bond between the lower and the uppermost layers. This paper reports an extensive experimental program to evaluate bond strength between Conventional Concrete (CC) and Asphalt Concrete (AC) substrates and Self-Compacting High-Performance Concrete (SCHPC) overlays. In all, 8 interface treatments are tested under Direct Tension, pure shear “LCB”, and compressive Slant Shear tests. The results show that direct pouring of the SCHPC overlay over CC and AC substrates produces similar or higher strengths than the other treatments analyzed.

17 citations


Book ChapterDOI
01 Jan 2018-
Abstract: The performance and durability of multi-layered pavements strongly depend on interlayer bonding between layers, especially for pavements with a thin or ultra-thin surface course. These pavements, comprised of several differing material layers, are often subjected to premature distresses (corrugation, peeling, slippage or fatigue cracking, etc.) caused by poor interface bonding. This chapter summarizes the different bond characterization tests available around the world (mostly in the laboratory) available to characterize the bond between pavement layers. Many of the tests can be performed on specimens prepared in the laboratory or on cores or slabs obtained from the pavement. Mostly, “pure” fracture mode test methods (opening mode I or in-plane, shear mode II or out-of-plane, shear mode III) are currently used worldwide for determining the interlayer bond of pavement layers. Most of the mixed-mode test methods (mainly for the combination of Modes I and II) were developed by a few research teams and there are therefore no standard tests. Although tack coat type and content are the main parameters studied by researchers and engineers, surface roughness, moisture, freezing, and presence of dust or debris on the interface are additional parameters that may decrease bonding performance.

12 citations


References
More filters

Journal ArticleDOI
Abstract: To approach the three-dimensional stress state in multi-layered composites, a laminate theory which considers a kinematic field per layer (particle) is used. Thus, interlaminar stresses are naturally introduced to carry out the equilibrium conditions of the plies. These stresses have a physical meaning and represent the exact out-of-plane 3D stresses calculated at the interface between two layers. These simplified models are able to provide finite interfacial stresses, even at the free edge of a structure. The first part of the paper describes the model and shows its validation by means of a comparison with finite element calculations. The model can involve inelastic strain fields in the layers and fields of displacement discontinuities at the interfaces. These inelastic fields, such as interface sliding, are assumed to be known by the user. The second part proposes some relevant criteria able to predict delamination initiation in some angle-ply laminates based on the model results. The laminates considered here are elementary cross-plies ±(θ n ) s with 0 < 30° to avoid more complicated phenomena as fiber rotation, transverse cracking or other non-linearity. The three criteria proposed herein integrate naturally interface stresses, and have been confronted to experimental results in mode III, for a ±(θ n ) s . The first criterion is based on the calculation of the maximum interfacial shear stresses. The second criterion is based on the analytical calculation of the strain energy release rates in a delaminated multi-layer. The third criterion is based on an experimental observation: a critical interface sliding value seems to govern delamination onset during tensile tests. Two plastic models were proposed for relating the interface sliding with the interfacial stresses: perfect plasticity and plasticity with a linear softening. Brittle linear elastic (criteria 1 and 2) and plastic analyses both provide accurate predictions. A more detailed study of this presumptive contradictory assertion is lastly led.

53 citations


Dissertation
24 Jun 1997-
Abstract: La these a pour but de concevoir un outil simple d'utilisation, pour l'ingenieur, capable d'analyser les champs de contraintes tridimensionnels responsables de delaminage au bord ou de fissuration transverse dans les materiaux multicouches. Dans la premiere partie du memoire, nous construisons des modelisations multiparticulaires (M4) a partir de champs de contraintes tridimensionnels approches ecrits sous forme de polynomes de Legendre en z par couche. Les coefficients de ces polynomes sont des champs en (x,y) relies aux efforts generalises. Nous utilisons la formulation d'Hellinger-Reissner pour en deduire les deplacements et les deformations generalisees associees. Par stationnarite de la fonctionnelle, nous donnons les equations d'equilibre, les conditions aux limites et le comportement ecrit en souplesse. La richesse plus ou moins grande des champs de contraintes approches ainsi construit mene a 7n, 5n, 3n et (2n+1) (n: nombre de couches) equations d'equilibre dans le plan. Dans la seconde partie de la these, nous testons quatre modeles sur le probleme de la traction simple pour des stratifies non troues d'empilement quelconque et troues d'empilement (0°, 90°)s. Nous posons analytiquement les systemes d'equations qui par combinaison se condensent en un systeme d'equations differentielles de degre 2 en y et dont la resolution se fait par le logiciel de calcul formel MATHEMATICA. Sur le cas du stratifie (0°, 90°)s non troue, nous montrons que l'energie due aux efforts manquants dans les modeles reduits ne disparait pas completement mais est transferee sur celles des efforts restants. Dans le cas du modele multiparticulaire M4_(2n+1)M (M: pour membrane) le plus simple, pour assurer l'equilibre global de la plaque, nous proposons un concept, generalisable, d'effort lineique de type Dirac dont l'intensite est relie au maximum des cisaillements au bord. Nous pensons que l'intensite du Dirac peut servir de base a un critere sur le delaminage.

51 citations


Journal ArticleDOI
Mithila Achintha1, CJ Burgoyne2Institutions (2)
Abstract: The debonding of FRP plates from concrete beams is not amenable to finite-element analysis; fracture mechanics, based on a global energy balance, offers a better alternative. An analytical model with energy calculations based on a revised version of Branson’s model (to take account of the reaction to the force in the FRP) has already been developed. This paper presents comparisons with a variety of experiments reported in the literature and shows that the model can correctly determine both the failure load and the failure mechanism. The paper shows that debonding often propagates in the concrete, just above the interface, and hence the failure load is dependent on the Mode I fracture energy of concrete. The method can also be used to determine when premature adhesive failure occurred prior to debonding within the concrete substrate.

30 citations


Dissertation
03 Dec 2004-
Abstract: Ce travail a pour but d’etudier la durabilite mecanique du collage blanc (beton) sur noir (enrobe) sans lequel deux structures de chaussee innovantes – le beton de ciment mince colle (BCMC) et le beton arme continu sur grave bitume (BAC sur GB) –, constituees d’une couche de blanc mise en oeuvre sur une couche de noir, n’ont aucun interet. Tout d’abord, on s’attache a identifier, a partir d’une analyse bibliographique, un mode de ruine du collage sous l’action du trafic. On etablit que les fissures de retrait de la couche de beton constituent le point a partir duquel s’initie et se propage le delaminage. Dans un second temps, ce mode de ruine est simule par un essai mecanique de fatigue en laboratoire, qui permet d’observer un delaminage progressif. Dans cet essai, le grenaillage de l’interface, compare au non grenaillage, apporte un collage plus durable. Une analyse mecanique de l’essai est proposee et necessite d’etre validee avec plus d’essais dans l’avenir. Ensuite, on met au point d'une methodologie de suivi « in situ » de la qualite du collage par CND, basee sur l’utilisation d’un systeme d’auscultation mecanique dynamique. Finalement, l’analyse des essais echelle 1:1 montre deux evolutions du collage. Pour la RN4, chaussee epaisse presentant un engrenement mecanique au niveau des fissures, on ne note aucune evolution du decollement initial apres 2 ans. Pour la maquette de structure reelle, a couches amincies et ne presentant pas d’engrenement mecanique dans les fissures, on observe, apres 1 million de cycles de sollicitation des simulateurs de trafic accelere FABAC, le mode de ruine attendu soit un delaminage s’initiant au niveau des fissures de retrait.

22 citations


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