# Experimental Study on the Interfacial Bonding Performance of a New Steel Bridge Deck Interface-Bonding Agent

Authors: Chaohua Zhao; Ya Li; Zhijian Yi; Kang Su
Journal: Advances in Materials Science and Engineering
 (2022)

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## Abstract

The construction of steel deck pavements is still considered difficult worldwide, and interfacial bonding is a major factor influencing this construction. With the recent developments in the field of pavement materials, high-performance cement-based concrete is used to construct steel bridge deck pavements. However, ensuring adequate interface-bonding strength remains particularly complex and difficult. In this study, with the aim of striking the right balance between rigidity and flexibility, an interface-bonding material was formed using modified epoxy resin, cement, and rubber powder. Polymer lattice porous concrete was used as the paving material, and the interface-bonding effect was studied experimentally by employing three methods using the material: pull-off, dual-interface shear, and flexural tensile tests. The results showed that (1) the interface pull-off strength was higher than 4 MPa, that is, higher than twice that of epoxy asphalt pavements used currently on steel bridge decks, and the failure surface was located on the pavement material rather than on the bonding interface; (2) the interface flexural strength and tensile strength were significantly higher than those of epoxy asphalt at room temperature and those of the ordinary epoxy resin; (3) the dual-interface shear strength was nearly four times higher than that of epoxy asphalt. Therefore, the modified epoxy resin composite interface-bonding material suggested in this study is an excellent bonding material that can serve as a reference for interface-bonding of steel bridge deck pavements.


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## Body

## 1. Introduction

The construction of a steel deck pavement has long remained a technical issue worldwide, and interfacial bonding is the key process in this construction. Developed countries such as the United States and Japan started research on steel deck pavements earlier than other countries; such studies have focused on structures and pavement materials such as epoxy asphalt concrete and Guss asphalt [1–6]. This research has made progress in pavement materials and structures, but the low elastic modulus and poor stability of asphalt have hindered the development of steel deck pavements. In terms of pavement materials, some great studies on porous concrete and its mechanical properties have been reported [7, 8]. In recent years, concrete pavement materials, such as polymer concrete [9–11] and ultrahigh performance concrete (UHPC) steel deck pavement materials [12, 13], have emerged. There are also studies on composite structures made of concrete and steel structures [14–16]. One such popular material—cement-based concrete—is brittle and has poor deformability [17]. Consequently, when it is used in steel deck pavements, interfacial bonding between the materials remains inadequate.Strong interfacial bonding is extremely essential in steel deck pavements. If interfacial bonding fails, the pavement starts to damage. Most existing studies on interfacial bonding have focused on the bonding performance [18–23], that is, the bonding strength, of the interface. The thickness of the interface and the deformation coordination mechanism of the interfacial bonding have not been studied in detail. Therefore, the gradual stress transition and deformation coordination of the interface layer are not well understood. This explains why there has been no substantive breakthrough in ensuring the firmness and durability of steel deck pavement interfacial bonding.A new type of polymer concrete studied by the author’s research team in the early stage is a pavement material with excellent performance. This new pavement material can be used to modify cement by adding a flexible organic polymer to realise the combination of organic and inorganic materials. We successfully developed a new pavement material with high strength, large deformation, and high stability in the early stage. Based on this new pavement material, a new pavement structure was proposed. Theoretical, experimental, and pilot engineering studies have shown that this new pavement structure can be used to combine the advantages of the existing cement concrete pavement and asphalt concrete pavement [24–27]. In the early stage, the author also studied polymer steel fibre concrete, which is also an optional steel deck pavement material, with good mechanical properties, such as strength, deformation, toughness, and environmental durability [28]. In this paper, one type of polymer alloy concrete was used as the representative of cement-based pavement materials [28] to study the interfacial bonding of the cement-based pavement with the steel bridge deck pavement structure.The interface-bonding material used in this study is a modified self-made material that is of rigidity and flexibility. It is obtained by mixing a flexible-modified polymer resin with cement. The modified flexible epoxy resin is used to improve cement brittleness, and cement is used to retain the environmental stability of the interface-bonding material. This polymer-interface-bonding material can enhance the deformation coordination ability of interfacial bonding and realise durable and firm bonding between cement-based concrete and steel.


## 2. Materials and Methods

### 2.1. Selected Pavement Materials

We selected a new polymer-modified cement concrete pavement material as a representative of the cement-based pavement material. The pavement material has good mechanical properties [28].SBR latex, ordinary Portland cement, and single-graded granite (4.75–9.5 mm) are used as raw materials for making the pavement material. They are mixed in an SBR latex : ordinary Portland cement : single-graded granite ratio of 135 : 400 : 1650.


### 2.2. Raw Materials and Parameters

Two basic raw materials used for the three interfacial bonding materials compared in this paper are shown in Figure1, and the basic physical and mechanical parameters are presented in Tables 1 and 2.Figure 1
Raw materials for producing the interface-bonding material: (a) E-51; (b) T-31.
(a)(b)Table 1
Basic parameters of E-51.
AppearanceNo visible mechanical impurityEpoxide value (eq/100 g)0.48–0.54Unhydrolytic chlorine (eq/100 g)≤0.0008Hydrolytic chlorine (eq/100 g)≤0.014Volatile 150°C, 40 min (%)≤1.5Colour number≤2Viscosity 40°C (mPa s)≤2500Table 2
Basic parameters of T-31.
AppearanceLight brown viscous liquidFlashpoint75°CRefractive index1.525–1.530Density 20°C1.08–1.09 g/cm3Net weight10 kgViscosity 25°C (mPa s)1000–1300


### 2.3. Interface-Bonding Materials

Polymer lattice porous concrete (PLPC) is bonded with a steel plate by using a polymer interface binder. The polymer interface binder is formed by mixing a modified epoxy resin (which acted as the binder) with cement and a rubber powder filler. The modified epoxy resin : ordinary Portland cement :  80 mesh rubber powder mixing ratio was 1 : 0.5 : 0.1.A cement paste was prepared using the forming method, and specimens were of the size 40 mm × 40 mm × 160 mm. The flexural and tensile strength and other properties of the cement concrete bonding material specimens were determined using the three-point loading test method on the universal testing machine.


### 2.4. Test Methods

Several methods are employed for testing the interface-bonding performance of a bonding material, which results in relatively large measurement errors. To accurately determine the bonding performance of the interface between polymer-modified cement lattice concrete and a steel bridge deck, we designed three different test methods, namely pull-off, dual-interface shear, and flexural tensile tests, by using the existing test methods as reference.


### 2.5. Pull-Off Test

The instrument and method used in this test were based on those used for testing the bonding strength of facing bricks. The instrument used was HC-6000, a modified pull-off instrument for testing the interfacial bonding strength of facing bricks. The test method was similar to that used for determining the interfacial bonding strength of facing bricks, as detailed in reference [29]. One major modification was that the pull-off test piece in this study was fixed using a self-made chuck. The test piece and the test instrument are shown in Figure 2.Figure 2
Pull-off test of interfacial bonding. (a) Test piece. (b) Test instrument.
(a)(b)Samples used in the test were first formed onto the steel plate with an interface size of approximately 40 mm × 40 mm, and their actual size was measured later.Three types of interface-bonding materials were selected: (1) test group: a self-made special polymer interface binder for steel bonding, (2) control group: ordinary epoxy resin, and (3) control group: epoxy asphalt. Three pieces from each group were tested, and the mean value of the observed force was considered. If the difference between a single test force and the average force value was greater than 15%, the test result was discarded.It should be mentioned that the number of specimens was referred to the standard test procedures (i.e., concrete bending and tensile or compressive tests) [30]. During testing, the authors found that the experimental results were relatively uniform in a group of three concrete specimens, so the design and testing specimens were finally adopted in this number.


### 2.6. Interfacial Shear Test

It is difficult to accurately simulate a pure interface shearing test, and no uniform criteria have been developed. Considering the interface bond strength test principle and the test methods used by other researchers [31], a dual-interface shear test method was designed to determine the interface shear strength of the samples. Each sample consisted of two pieces of 100 mm × 100 mm × 10 mm steel plates and one brick of 100 mm × 100 mm × 80 mm polymer-modified cement lattice concrete. During sample preparation, the steel plate was first placed into a preprocessed test mould after rust removal and cleaning. For comparison, different interfacial agents were used to treat the bonding interfaces. Polymer-modified cement lattice concrete samples were formed in the test mould. Dual-interface shear specimens were formed after interfacial bonding with the steel plate.The shear test was conducted on the universal testing machine in the Structural Laboratory of Chongqing Jiaotong University, China. The loading device and the loading diagram are shown in Figure3.Figure 3
Loading device and diagram of the shearing test for the steel plate and polymer-modified cement lattice concrete interface. (a) Test device. (b) Loading diagram.
(a)(b)The test was conducted in accordance with the standards for a compressive test of cubic concrete as described in the Testing Methods of Cement and Concrete for Highway Engineering (JTG E30-2005) [32]. The steps involved in the test are as follows.(1)
Place the test piece on the steel base plate of the experimental machine support such that their centre positions are aligned. Place the steel base plate also on the upper surface of the test piece and manually hold the steel base plate and the test piece.(2)
Turn on the testing machine, and supply oil at a constant speed. Once the compression device touches the test piece, carefully adjust the test piece manually so that the bonding surface remains vertical, and the polymer-modified cement lattice concrete stays at the centre.(3)
Apply load at a constant and slow speed until the interface is separated. In this instance, the specimen is damaged, and the corresponding load is the maximum load that the bonding interface can bear.The average shear stress of the two shearing surfaces when the specimen is damaged is taken as the shear strength of the bonding surface.(1)τ=VA1+A2,where V is shear failure load (N), and A1 and A2 are the areas of the two bonding surfaces (mm).Specimens with a symmetrical shape were used in this study to reduce the effect of instability and peeling. However, the stress state of the interface remained different from the position of the bonding interface in the specimen. The test results obtained in this study may not completely reflect the strength of the bonding interface. However, it is certain that due to the use of a dual interface, if the specimen is sheared, the failure first occurs at the interface on the weaker side. Therefore, the obtained shear strength can be less than the actual interface shear strength, and the design based on these results is safe and conservative.Meanwhile, it shall be noticed that the failure of the specimen was not only the shear failure of the interface, and the specimen did have a bending and pulling-off effect for the concrete block, only 10 cm. The bending moment is small, and lateral shear failure was the main form of failure. Therefore, flexural and tensile stress can be ignored during the whole test.


### 2.7. Interface Flexural Test

The interface flexural test is a new interface test method designed in this study. This test can objectively reflect the tensile strength of the interface. The test principle and method are based on the concrete flexural and tensile strength test. The preparation and testing of the sample follow the guidelines mentioned in the Testing Methods of Cement and Concrete for Highway Engineering (JTG 3420-2020-2005) [32]. The polymer-modified cement lattice concrete samples used in the flexural tests were right-angle beams with a size of 100 mm × 100 mm × 400 mm.The size of the steel plate was 100 mm × 100 mm × 6 mm. Polymer lattice porous concrete is a steel deck pavement material made by mixing a special polymer emulsion, cement, and pebbles in predetermined ratios. The steel plate was placed at the half-length position of the polymer-modified cement lattice concrete, and its bonding surface was a square with a size of 100 mm × 100 mm.When building the test piece, the precut steel plate was first cleaned and then vertically placed on the bonding surface, as shown in Figure4. The bonding surface was placed at the centre of the steel mould, the size of which was 100 mm × 100 mm × 400 mm. The inner walls of the steel mould were coated with engine oil. As shown in Figure 5, the polymer-modified cement lattice concrete material was poured on both sides of the bonding surface of the steel plate. Hammering vibrations were used to assist the sample formation.Figure 4
Flexural failure status of different interface binders. (a) Self-made polymer steel interface binder, (b) common epoxy resin, (c) epoxy asphalt.
(a)(b)(c)Figure 5
Formation of the polymer-modified cement lattice concrete and the steel plate interface for the interface flexural test (unit: mm).The test was conducted on a 1,000 kN universal mechanical testing machine. The test device and loading diagram are shown in Figure6.Figure 6
Test device and loading diagram for the flexural test (unit: mm). (a) Test device. (b) Loading diagram.
(a)(b)The loading test followed the guidelines of the Testing Methods of Cement and Concrete for Highway Engineering (JTG E30-2005) [32] issued by the Ministry of Transport. During the interfacial flexural strength test, failure generally occurs near the bonding interface and is located between the two loading points. The interfacial flexural strength (Rb) is calculated according to the following equation:(2)Rb=PLbh2,where Rb is the interfacial flexural and tensile strength (MPa), P is the maximum failure load of the sample (N), L is the distance between supports (L = 300 mm), b is the width of the cross section (b = 100 mm), and h is the height of the cross section (h = 100 mm).


## 2.1. Selected Pavement Materials

We selected a new polymer-modified cement concrete pavement material as a representative of the cement-based pavement material. The pavement material has good mechanical properties [28].SBR latex, ordinary Portland cement, and single-graded granite (4.75–9.5 mm) are used as raw materials for making the pavement material. They are mixed in an SBR latex : ordinary Portland cement : single-graded granite ratio of 135 : 400 : 1650.


## 2.2. Raw Materials and Parameters

Two basic raw materials used for the three interfacial bonding materials compared in this paper are shown in Figure1, and the basic physical and mechanical parameters are presented in Tables 1 and 2.Figure 1
Raw materials for producing the interface-bonding material: (a) E-51; (b) T-31.
(a)(b)Table 1
Basic parameters of E-51.
AppearanceNo visible mechanical impurityEpoxide value (eq/100 g)0.48–0.54Unhydrolytic chlorine (eq/100 g)≤0.0008Hydrolytic chlorine (eq/100 g)≤0.014Volatile 150°C, 40 min (%)≤1.5Colour number≤2Viscosity 40°C (mPa s)≤2500Table 2
Basic parameters of T-31.
AppearanceLight brown viscous liquidFlashpoint75°CRefractive index1.525–1.530Density 20°C1.08–1.09 g/cm3Net weight10 kgViscosity 25°C (mPa s)1000–1300


## 2.3. Interface-Bonding Materials

Polymer lattice porous concrete (PLPC) is bonded with a steel plate by using a polymer interface binder. The polymer interface binder is formed by mixing a modified epoxy resin (which acted as the binder) with cement and a rubber powder filler. The modified epoxy resin : ordinary Portland cement :  80 mesh rubber powder mixing ratio was 1 : 0.5 : 0.1.A cement paste was prepared using the forming method, and specimens were of the size 40 mm × 40 mm × 160 mm. The flexural and tensile strength and other properties of the cement concrete bonding material specimens were determined using the three-point loading test method on the universal testing machine.


## 2.4. Test Methods

Several methods are employed for testing the interface-bonding performance of a bonding material, which results in relatively large measurement errors. To accurately determine the bonding performance of the interface between polymer-modified cement lattice concrete and a steel bridge deck, we designed three different test methods, namely pull-off, dual-interface shear, and flexural tensile tests, by using the existing test methods as reference.


## 2.5. Pull-Off Test

The instrument and method used in this test were based on those used for testing the bonding strength of facing bricks. The instrument used was HC-6000, a modified pull-off instrument for testing the interfacial bonding strength of facing bricks. The test method was similar to that used for determining the interfacial bonding strength of facing bricks, as detailed in reference [29]. One major modification was that the pull-off test piece in this study was fixed using a self-made chuck. The test piece and the test instrument are shown in Figure 2.Figure 2
Pull-off test of interfacial bonding. (a) Test piece. (b) Test instrument.
(a)(b)Samples used in the test were first formed onto the steel plate with an interface size of approximately 40 mm × 40 mm, and their actual size was measured later.Three types of interface-bonding materials were selected: (1) test group: a self-made special polymer interface binder for steel bonding, (2) control group: ordinary epoxy resin, and (3) control group: epoxy asphalt. Three pieces from each group were tested, and the mean value of the observed force was considered. If the difference between a single test force and the average force value was greater than 15%, the test result was discarded.It should be mentioned that the number of specimens was referred to the standard test procedures (i.e., concrete bending and tensile or compressive tests) [30]. During testing, the authors found that the experimental results were relatively uniform in a group of three concrete specimens, so the design and testing specimens were finally adopted in this number.


## 2.6. Interfacial Shear Test

It is difficult to accurately simulate a pure interface shearing test, and no uniform criteria have been developed. Considering the interface bond strength test principle and the test methods used by other researchers [31], a dual-interface shear test method was designed to determine the interface shear strength of the samples. Each sample consisted of two pieces of 100 mm × 100 mm × 10 mm steel plates and one brick of 100 mm × 100 mm × 80 mm polymer-modified cement lattice concrete. During sample preparation, the steel plate was first placed into a preprocessed test mould after rust removal and cleaning. For comparison, different interfacial agents were used to treat the bonding interfaces. Polymer-modified cement lattice concrete samples were formed in the test mould. Dual-interface shear specimens were formed after interfacial bonding with the steel plate.The shear test was conducted on the universal testing machine in the Structural Laboratory of Chongqing Jiaotong University, China. The loading device and the loading diagram are shown in Figure3.Figure 3
Loading device and diagram of the shearing test for the steel plate and polymer-modified cement lattice concrete interface. (a) Test device. (b) Loading diagram.
(a)(b)The test was conducted in accordance with the standards for a compressive test of cubic concrete as described in the Testing Methods of Cement and Concrete for Highway Engineering (JTG E30-2005) [32]. The steps involved in the test are as follows.(1)
Place the test piece on the steel base plate of the experimental machine support such that their centre positions are aligned. Place the steel base plate also on the upper surface of the test piece and manually hold the steel base plate and the test piece.(2)
Turn on the testing machine, and supply oil at a constant speed. Once the compression device touches the test piece, carefully adjust the test piece manually so that the bonding surface remains vertical, and the polymer-modified cement lattice concrete stays at the centre.(3)
Apply load at a constant and slow speed until the interface is separated. In this instance, the specimen is damaged, and the corresponding load is the maximum load that the bonding interface can bear.The average shear stress of the two shearing surfaces when the specimen is damaged is taken as the shear strength of the bonding surface.(1)τ=VA1+A2,where V is shear failure load (N), and A1 and A2 are the areas of the two bonding surfaces (mm).Specimens with a symmetrical shape were used in this study to reduce the effect of instability and peeling. However, the stress state of the interface remained different from the position of the bonding interface in the specimen. The test results obtained in this study may not completely reflect the strength of the bonding interface. However, it is certain that due to the use of a dual interface, if the specimen is sheared, the failure first occurs at the interface on the weaker side. Therefore, the obtained shear strength can be less than the actual interface shear strength, and the design based on these results is safe and conservative.Meanwhile, it shall be noticed that the failure of the specimen was not only the shear failure of the interface, and the specimen did have a bending and pulling-off effect for the concrete block, only 10 cm. The bending moment is small, and lateral shear failure was the main form of failure. Therefore, flexural and tensile stress can be ignored during the whole test.


## 2.7. Interface Flexural Test

The interface flexural test is a new interface test method designed in this study. This test can objectively reflect the tensile strength of the interface. The test principle and method are based on the concrete flexural and tensile strength test. The preparation and testing of the sample follow the guidelines mentioned in the Testing Methods of Cement and Concrete for Highway Engineering (JTG 3420-2020-2005) [32]. The polymer-modified cement lattice concrete samples used in the flexural tests were right-angle beams with a size of 100 mm × 100 mm × 400 mm.The size of the steel plate was 100 mm × 100 mm × 6 mm. Polymer lattice porous concrete is a steel deck pavement material made by mixing a special polymer emulsion, cement, and pebbles in predetermined ratios. The steel plate was placed at the half-length position of the polymer-modified cement lattice concrete, and its bonding surface was a square with a size of 100 mm × 100 mm.When building the test piece, the precut steel plate was first cleaned and then vertically placed on the bonding surface, as shown in Figure4. The bonding surface was placed at the centre of the steel mould, the size of which was 100 mm × 100 mm × 400 mm. The inner walls of the steel mould were coated with engine oil. As shown in Figure 5, the polymer-modified cement lattice concrete material was poured on both sides of the bonding surface of the steel plate. Hammering vibrations were used to assist the sample formation.Figure 4
Flexural failure status of different interface binders. (a) Self-made polymer steel interface binder, (b) common epoxy resin, (c) epoxy asphalt.
(a)(b)(c)Figure 5
Formation of the polymer-modified cement lattice concrete and the steel plate interface for the interface flexural test (unit: mm).The test was conducted on a 1,000 kN universal mechanical testing machine. The test device and loading diagram are shown in Figure6.Figure 6
Test device and loading diagram for the flexural test (unit: mm). (a) Test device. (b) Loading diagram.
(a)(b)The loading test followed the guidelines of the Testing Methods of Cement and Concrete for Highway Engineering (JTG E30-2005) [32] issued by the Ministry of Transport. During the interfacial flexural strength test, failure generally occurs near the bonding interface and is located between the two loading points. The interfacial flexural strength (Rb) is calculated according to the following equation:(2)Rb=PLbh2,where Rb is the interfacial flexural and tensile strength (MPa), P is the maximum failure load of the sample (N), L is the distance between supports (L = 300 mm), b is the width of the cross section (b = 100 mm), and h is the height of the cross section (h = 100 mm).


## 3. Results and Discussion

### 3.1. Interface Pull-Off Test

The strength and failure mode of interfacial bonding formed by different interface materials are listed in Table3.Table 3
Results of the pull-off tests of polymer-modified cement lattice concrete-steel deck interfaces formed by different interface binders.
Type of structureType of binderAverage of the pull-off strength (MPa)Failure modePolymer concrete-steel pavementSelf-made polymer interface binder I4.16Shear failure, that is, the failure occurred within the concrete specimen, and the bonding material was attached to the steel plate.Polymer concrete-steel pavementCommon epoxy resin（E51）1.31The failure occurred at the interface, and most of the steel plate surface was exposed.Epoxy resin-steel pavementEpoxy asphalt1.07Interface failure, that is, the epoxy asphalt was attached to the steel plate, and the failure process is long.The pull-off test of the paving material—steel bridge deck pavement interfaces formed by different binders—showed the following results .(1)
The pull-off strength of the interface between the polymer-modified cement lattice concrete and the steel bridge deck formed by the self-made binder is significantly higher than that of the epoxy resin interface agent and the epoxy asphalt interface agent, and its pull-off strength is three times higher than that of the two agents.(2)
According to the failure mode, after using the self-made interface binder, the pull-off failure of the interface between the polymer-modified cement lattice concrete and the steel bridge deck did not occur at the interface itself (Figure7(a)), indicating that the strength of the interface material and bonding exceeded the strength of the polymer-modified cement lattice concrete and that the interfacial binder between the polymer-modified cement lattice concrete and the steel bridge deck can completely meet the bonding requirements of pavement material.(3)
Damage occurred to interfacial bonding between the ordinary epoxy resin at the interface during pull-off, suggesting that the pavement material and steel bridge deck were not firmly bonded (Figure7(b)). The damage to the epoxy asphalt (Figure 7(c)) showed that although it remained bonded to the steel plate, its deformation was considerably large (temperature was 35°C during the test). Moreover, although the pavement material remained bonded with the steel plate after pull-off failure, the pavement layer could actually move and lost the function of interfacial bonding. Consequently, regardless of the pull-off strength and failure mode, the epoxy asphalt interface binder could not meet the requirements of an interface-bonding material for use in the steel bridge deck pavement.Figure 7
Pull-off failure of steel plate-polymer-modified cement lattice concrete interface formed by different interfacial binders. (a) Self-made polymer-bonded steel interface, (b) common epoxy resin, and (c) epoxy asphalt.
(a)(b)(c)


### 3.2. Interface Shear Test

In this test, common epoxy resin and epoxy asphalt were used as control groups to analyse the interface-bonding effect between the polymer-modified cement lattice concrete and the steel bridge deck pavement produced using the self-made polymer steel bridge deck pavement interface binder. The results of the interface shear test for different interface binders are shown in Table4.(1)
When the self-made polymer steel bridge deck interface binder was used as the interface-bonding material, the damage did not occur at the interface but within the polymer-modified cement lattice concrete, as shown in Figure8(a). This shows that the interfacial shear strength between the polymer-modified cement lattice concrete and steel bridge deck was greater than the flexural and tensile failure of the polymer-modified cement lattice concrete. Thus, the self-made polymer steel bridge deck pavement interface binder can meet the shear requirements of the interface between the polymer-modified cement lattice concrete and the steel bridge deck pavement.(2)
The interface shear strength of the self-made polymer steel bridge deck interface binder was much greater than the bonding strength of common epoxy resin and epoxy asphalt. The damage of interfacial bonding between the ordinary epoxy resin and epoxy asphalt occurred at the interface itself during shearing, suggesting the pavement material and the steel bridge deck were not firmly bonded, as shown in Figure8(b) and Figure 8(c).Table 4
Interface shear test results for different interface binders.
Type of structureType of binderAverage of the pull-off strength (MPa)Failure modePolymer concrete-steel pavementSelf-made polymer interface binder I4.21Shear failure, that is, the failure occurred within the concrete specimen, and the polymer concrete was attached to the steel plate.Polymer concrete-steel pavementCommon epoxy resin interface binder1.99The failure occurred at the interface, and most of the steel plate surface was exposed.Epoxy resin-steel pavementEpoxy asphalt1.11Interface failure, that is, a small amount of epoxy asphalt was attached to the steel plate, and the interface failure showed slip traces.Figure 8
Interfacial shear failure of different interface binders. (a) Self-made polymer steel bridge deck pavement interface agent, (b) ordinary epoxy resin, and (c) epoxy asphalt.
(a)(b)(c)


### 3.3. Interface Flexural Test

The results of the flexural test of the interface flexural tensile specimens formed by different interface-bonding materials are listed in Table5. The failure mode of interfacial bonding between the self-made polymer interface-bonding materials and common epoxy resin and epoxy asphalt is shown in Figure 4.Table 5
Interfacial flexural properties of different interface-bonding materials.
Type of binderFlexural strength (MPa)Average flexural strength (MPa)Status of the damaged interfaceCommon epoxy resin1.90 (removed)2.82For all three samples, the failure occurred at the interface. One sample was not bonded with any polymer-modified cement lattice concrete material on the steel plate, while the other two specimens were bonded with a small amount.2.513.13Epoxy asphalt3.13.37For all three samples, the failure occurred at the interface. Some parts of the steel were attached to the paving materials while other parts were exposed.4.03.0Self-made polymer interface binder I7.407.73The failure occurred within the polymer concrete near the steel plate, and the interface was intact.7.528.24By comparing the interfacial flexural and tensile strength and the bonding effects between the self-made polymer binder and conventional binders for steel bridge deck pavements, the following observations can be made.(1)
The flexural strength and tensile strength of the self-made polymer steel interface binder were significantly higher than those of other existing steel plate interface binders. Moreover, the binding strength of the former was about twice that of common epoxy resin and epoxy asphalt.(2)
The failure of the flexural samples bonded by the self-made polymer steel interface binder did not occur at the interface (Figure4(c)), and the polymer-modified cement lattice concrete was attached to the steel plate at a large number of bonding points, indicating that the interfacial bonding formed by the self-made polymer binding agent had higher strength than the flexural and tensile strength of the polymer-modified cement lattice concrete. Thus, the interface could be firmly bonded.


## 3.1. Interface Pull-Off Test

The strength and failure mode of interfacial bonding formed by different interface materials are listed in Table3.Table 3
Results of the pull-off tests of polymer-modified cement lattice concrete-steel deck interfaces formed by different interface binders.
Type of structureType of binderAverage of the pull-off strength (MPa)Failure modePolymer concrete-steel pavementSelf-made polymer interface binder I4.16Shear failure, that is, the failure occurred within the concrete specimen, and the bonding material was attached to the steel plate.Polymer concrete-steel pavementCommon epoxy resin（E51）1.31The failure occurred at the interface, and most of the steel plate surface was exposed.Epoxy resin-steel pavementEpoxy asphalt1.07Interface failure, that is, the epoxy asphalt was attached to the steel plate, and the failure process is long.The pull-off test of the paving material—steel bridge deck pavement interfaces formed by different binders—showed the following results .(1)
The pull-off strength of the interface between the polymer-modified cement lattice concrete and the steel bridge deck formed by the self-made binder is significantly higher than that of the epoxy resin interface agent and the epoxy asphalt interface agent, and its pull-off strength is three times higher than that of the two agents.(2)
According to the failure mode, after using the self-made interface binder, the pull-off failure of the interface between the polymer-modified cement lattice concrete and the steel bridge deck did not occur at the interface itself (Figure7(a)), indicating that the strength of the interface material and bonding exceeded the strength of the polymer-modified cement lattice concrete and that the interfacial binder between the polymer-modified cement lattice concrete and the steel bridge deck can completely meet the bonding requirements of pavement material.(3)
Damage occurred to interfacial bonding between the ordinary epoxy resin at the interface during pull-off, suggesting that the pavement material and steel bridge deck were not firmly bonded (Figure7(b)). The damage to the epoxy asphalt (Figure 7(c)) showed that although it remained bonded to the steel plate, its deformation was considerably large (temperature was 35°C during the test). Moreover, although the pavement material remained bonded with the steel plate after pull-off failure, the pavement layer could actually move and lost the function of interfacial bonding. Consequently, regardless of the pull-off strength and failure mode, the epoxy asphalt interface binder could not meet the requirements of an interface-bonding material for use in the steel bridge deck pavement.Figure 7
Pull-off failure of steel plate-polymer-modified cement lattice concrete interface formed by different interfacial binders. (a) Self-made polymer-bonded steel interface, (b) common epoxy resin, and (c) epoxy asphalt.
(a)(b)(c)


## 3.2. Interface Shear Test

In this test, common epoxy resin and epoxy asphalt were used as control groups to analyse the interface-bonding effect between the polymer-modified cement lattice concrete and the steel bridge deck pavement produced using the self-made polymer steel bridge deck pavement interface binder. The results of the interface shear test for different interface binders are shown in Table4.(1)
When the self-made polymer steel bridge deck interface binder was used as the interface-bonding material, the damage did not occur at the interface but within the polymer-modified cement lattice concrete, as shown in Figure8(a). This shows that the interfacial shear strength between the polymer-modified cement lattice concrete and steel bridge deck was greater than the flexural and tensile failure of the polymer-modified cement lattice concrete. Thus, the self-made polymer steel bridge deck pavement interface binder can meet the shear requirements of the interface between the polymer-modified cement lattice concrete and the steel bridge deck pavement.(2)
The interface shear strength of the self-made polymer steel bridge deck interface binder was much greater than the bonding strength of common epoxy resin and epoxy asphalt. The damage of interfacial bonding between the ordinary epoxy resin and epoxy asphalt occurred at the interface itself during shearing, suggesting the pavement material and the steel bridge deck were not firmly bonded, as shown in Figure8(b) and Figure 8(c).Table 4
Interface shear test results for different interface binders.
Type of structureType of binderAverage of the pull-off strength (MPa)Failure modePolymer concrete-steel pavementSelf-made polymer interface binder I4.21Shear failure, that is, the failure occurred within the concrete specimen, and the polymer concrete was attached to the steel plate.Polymer concrete-steel pavementCommon epoxy resin interface binder1.99The failure occurred at the interface, and most of the steel plate surface was exposed.Epoxy resin-steel pavementEpoxy asphalt1.11Interface failure, that is, a small amount of epoxy asphalt was attached to the steel plate, and the interface failure showed slip traces.Figure 8
Interfacial shear failure of different interface binders. (a) Self-made polymer steel bridge deck pavement interface agent, (b) ordinary epoxy resin, and (c) epoxy asphalt.
(a)(b)(c)


## 3.3. Interface Flexural Test

The results of the flexural test of the interface flexural tensile specimens formed by different interface-bonding materials are listed in Table5. The failure mode of interfacial bonding between the self-made polymer interface-bonding materials and common epoxy resin and epoxy asphalt is shown in Figure 4.Table 5
Interfacial flexural properties of different interface-bonding materials.
Type of binderFlexural strength (MPa)Average flexural strength (MPa)Status of the damaged interfaceCommon epoxy resin1.90 (removed)2.82For all three samples, the failure occurred at the interface. One sample was not bonded with any polymer-modified cement lattice concrete material on the steel plate, while the other two specimens were bonded with a small amount.2.513.13Epoxy asphalt3.13.37For all three samples, the failure occurred at the interface. Some parts of the steel were attached to the paving materials while other parts were exposed.4.03.0Self-made polymer interface binder I7.407.73The failure occurred within the polymer concrete near the steel plate, and the interface was intact.7.528.24By comparing the interfacial flexural and tensile strength and the bonding effects between the self-made polymer binder and conventional binders for steel bridge deck pavements, the following observations can be made.(1)
The flexural strength and tensile strength of the self-made polymer steel interface binder were significantly higher than those of other existing steel plate interface binders. Moreover, the binding strength of the former was about twice that of common epoxy resin and epoxy asphalt.(2)
The failure of the flexural samples bonded by the self-made polymer steel interface binder did not occur at the interface (Figure4(c)), and the polymer-modified cement lattice concrete was attached to the steel plate at a large number of bonding points, indicating that the interfacial bonding formed by the self-made polymer binding agent had higher strength than the flexural and tensile strength of the polymer-modified cement lattice concrete. Thus, the interface could be firmly bonded.


## 4. Conclusions

This paper proposed a new bonding material for connecting cement-based paving materials and steel bridges and experimentally compared the bonding performance of the proposed material with two existing bonding materials in experiments to illustrate its superiority of the performance of the proposed material. The main conclusions are summarized as follows.(1)
The interfacial pull-off strength between the polymer lattice concrete pavement material and the steel deck was larger than 4 MPa, which was more than twice that of epoxy asphalt pavements currently used. Moreover, for polymer interface-bonding materials, cohesive failure occurred at the interface; that is, the failure surface was located within the pavement material.(2)
The flexural strength and tensile strength of the interface between the polymer lattice concrete pavement material and the steel deck were larger than 7.73 MPa, which was considerably greater than that of the epoxy asphalt interface (3.37 MPa) at room temperature and that of the common epoxy resin (2.82 MPa).(3)
The dual-interface shear strength between the polymer lattice concrete pavement material and the steel bridge deck was larger than 4.21 MPa, which was nearly four times that of the epoxy asphalt interface shear strength (1.11 MPa), and cohesion failure occurred at the interface.In conclusion, the bonding strength of the interface-bonding material proposed in this study is substantially higher than that of the existing conventional steel bridge deck interface-bonding materials, indicating that the interface-bonding system can completely meet the bonding requirements of the cement-based concrete-steel bridge deck pavement materials (represented by the polymer-modified cement lattice concrete).



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*Source: 9953146-2022-05-04.xml*