Experimental Study on Mix Ratio Design and Road Performance of Medium and Small Deformation Seamless Expansion Joints of Bridges

Abstract

Expansion joints are a weak and fragile part of bridge superstructure. The damage or failure of the expansion joint will lead to the decline of bridge durability and endanger the bridge structure and traffic safety. To improve the service life and performance of bridge expansion joints, the ideal method is to use seamless expansion joints. In this study, starting from the commonly used asphalt mixture gradation of seamless expansion joint, and taking into account the actual situation of bridge expansion joint structure and environment in China, the gradation and asphalt-aggregate ratio are preliminarily designed. Through a Marshall test, the corresponding asphalt mixture is evaluated and analyzed according to the stability, flow value, and void ratio, and the optimal gradation and asphalt-aggregate ratio are determined. Finally, the asphalt mixture is prepared with the mixture ratio design, and the test results of an immersion Marshall test, fatigue performance test, and full-scale test verify that the asphalt mixture meets the road performance requirements of seamless expansion joints. On the basis of the experimental data, the performance of large sample asphalt mixture is continuously tested, compared, and optimized. The results show that the asphalt mixture ratio designed is true and reliable, which can provide reference for the optimal design of seamless expansion joint filler.

Currently, the level of economic development in China has greatly improved. As an indispensable and important foundation of economic development, the transportation industry has been developing rapidly and comprehensively, putting greater emphasis on the quality and performance of highway bridges ( 1 ). The bridge expansion joint is used to meet the requirements of bridge deck deformation at the intersection of two beam ends, the beam end and the abutment, or at the hinge position of the bridge ( 2 ). The significance of the expansion joint lies in its ability to connect the upper structure of the bridge and mitigate the displacement caused by the physical properties of the bridge structure.

The bridge expansion joint is a weak link in bridge structures that can be easily damaged and is difficult to maintain. In the 1990s, 556 bridges (22.3% of the total) of 2,490 bridges in 13 cities were surveyed in China. From these, 271 bridges had damaged expansion joints, accounting for 48.7% of the total bridges surveyed ( 3 ). Other countries suffer similar situations. For example, according to statistics from the end of the 20th century, approximately 250,000 of the 570,000 bridges surveyed in the United States have some form of structural or functional defect or failure, and more than half of the problems are observed on the expansion joints ( 4 ). Similar results from European countries such as France and Portugal show that the cost of repairing joints accounts for approximately 7%–22% of the cost of maintenance of the entire bridge ( 5 ). It can be concluded that the vulnerability of bridge expansion joints and their maintenance difficulties are a common global problem.

To avoid various problems caused by the damage of the simply supported beam bridges, high-quality expansion joints can be used, improving the construction quality. The expansion joint is an important element in bridge structures, which is mainly used to adjust the deformation caused by temperature change, concrete shrinkage and creep, uneven settlement, vehicle impact, and so forth; to prevent the bridge deck rainwater and road residue from entering the bridge structure; and to ensure the smooth passage of vehicles. However, while it can improve quality to a certain extent, the inherent issue cannot be solved fundamentally. If the bridge expansion joint can be eliminated, the problem can be solved. Globally, bridge scholars and experts are striving to find the best expansion joint structure, and they conclude that “the best expansion joint is no expansion joint” ( 6 ). Seamless expansion joints mostly refer to the function of absorbing the beam displacement by the deformation of the elastomer, which varies with the materials and structures used. The most common form of bridge seamless expansion joint is the asphalt-filled expansion joint. It contains a type of asphalt mixture with high elasticity and high viscosity formed by mixing modified asphalt binder and aggregate ( 7 ).

At present, a series of researches on asphalt mixture have been carried out, but not enough of these studies have considered the performance of modified asphalt mixtures ( 8 – 11 ).

Currently, the commonly used asphalt mixture design methods mainly include the Marshall design method, the gyratory testing machine (GTM) design method, and the Superpave design method ( 12 ). In China, the mixture design mainly adopts the Marshall design method, while the Superpave design method is adopted in the United States ( 13 ). Changheng et al. compared and evaluated the differences between the Marshall and Superpave design methods based on the standards of asphalt mixture forming methods, volume calculation methods, and short-term aging ( 14 ). According to the current technical specifications for asphalt pavement construction in China, Xiaojiang used the Marshall method to verify other design methods of asphalt mixture, and compared the volume indexes of different design methods ( 15 ). Xin systematically studied the differences between the Superpave and Marshall design methods against the prediction of binder content and the determination of the maximum theoretical density, and then optimized the design method of the mixture ( 16 ). Wayne Lee et al. used Superpave gyratory compactor (SGC) to improve the Marshall design method for the in situ cold recycled asphalt mixture, and proposed a new volumetric asphalt mixture mix design method ( 17 ). The indoor test proved that the asphalt mixture has good road performance. Field tests were performed in five different regions of North America. Soohyok et al. also proposed a new asphalt mixture design method based on reclaimed asphalt pavement (RAP) ( 18 ). This method is also called the asphalt mixture balance design method, and it is used to determine the optimal asphalt content. Indoor and field experiments show that the method can effectively solve the cracking and rutting problems of asphalt mixture pavement. Bressi et al. introduced a new asphalt mixture design method ( 19 ). By analyzing the influence of the specific surface area of aggregate and its particle shape when determining the asphalt-aggregate ratio of asphalt mixture, the optimum asphalt content and critical filler content are determined, which strengthens the theory of determining the optimum asphalt content in asphalt mixture design.

The above design theory has been further developed and is widely used in asphalt mixture design methods. However, for seamless expansion joint asphalt mixture, the above design theories are not fully applicable because of its special expansion deformation. In China, the technology of seamless expansion joint system began only recently, so no relevant specification is available in China at present. Therefore, this study draws lessons from asphalt mixture design abroad, specifically the mature Marshall test design method; adjusts and optimizes the design according to the actual situation of bridge expansion joint structure and environment in China; obtains a more reasonable mix ratio of new asphalt mixture; and, through a Marshall test, evaluates the effects of different aggregate gradation and asphalt-aggregate ratio on the performance of seamless expansion joint asphalt mixture comprehensively against gross volume density, mineral clearance ratio, stability, and flow value. Finally, combined with relevant tests, the optimum aggregate gradation and asphalt-aggregate ratio are given. The results of this study lay a foundation for the research and development of seamless expansion joint material with high-elasticity and high-resistance, and provides reference for the optimization of the design of expansion joint structures.

Proportion Design of Asphalt Mixture

Materials

Asphalt

Presently, there are many types of modified asphalt locally in China and abroad. Finding an asphalt binder suitable for the preparation of bridge expansion joint mixture is crucial. The basic requirement when selecting a binder is that the asphalt mixture, when mixed with asphalt binder, must meet the stress performance of the bridge expansion joint. The important performance control indexes for an asphalt binder when used as raw material for expansion joint mixture in test are ductility, penetration, softening point, elastic recovery, viscosity, and so on. Only when these requirements are met can the performance of expansion joints be guaranteed. Based on these parameters, three types of modified asphalt were selected as samples: Matrix 502, styrene-butadiene block copolymer (SBS), and Colas. The basic conditions of the three types of asphalt are as follows.

(1) Matrix 502 Asphalt

Matrix 502 asphalt is said to be a representative of seamless expansion joint cements in the United States. Seamless Expansion Joint of Matrix 502 Asphalt Reinforced Bridge and Tunnel is mainly composed of three different temperature grade sealants and two different particle size grades. It was developed and introduced into China by the Coreford Company from the United States. The Matrix 502 system can be used for expansion of bridge slab joints or fixed joints at both sides of the bridge head, and also for new construction or repair of various single and multi-span bridges.

(2) SBS Modified Asphalt

SBS modified asphalt is widely used in China. The SBS modifier is uniformly dispersed in the base asphalt by shearing and stirring. At the same time, a certain proportion of exclusive stabilizer is added to form SBS blend. The material is modified by the good physical properties of SBS.

(3) Modified Asphalt Colas

Modified asphalt Colas is a representative of seamless expansion joint cements in South Korea. With its excellent rheological and fatigue properties, it can meet the flatness requirements of seamless expansion joints, ensure the integrity of the bridge, and effectively solve the problem of vehicle bumping at the bridge head.

The technical indexes of three kinds of asphalt are shown in Table 1.

Table 1.

The Technical Indexes of Three Kinds of Asphalt

	Softening point/°C	Tensile strength at 25°C/%	Ductility at 25°C/mm	Penetration at 25°C/mm	Fluidity at 25°C/mm	Resilience at 25°C/%
Matrix 502	≥95	>700	>400	<7.5	<3.0	40–70
Styrene-butadiene block copolymer	≥64	≥800	≥400	NA	NA	≥95
Colas	≥95	≥750	≥400	≤9.0	≤3.0	≥40

Note: NA = not available.

There are a wide variety of modified asphalts, and many are specifically used for seamless expansion joints. However, they have their own conditions of use. According to the actual application environment, this study selects modified asphalt Colas, as the cement for seamless expansion joint, for further testing and application performance research.

Aggregate

For better quality control of the bridge seamless expansion joint asphalt mixture, it is necessary to strictly control the quality index of aggregate in the mixture. Seamless expansion joints of bridges require hard aggregates and good bonding with asphalt binders to ensure that expansion joints have sufficient strength to resist the load of vehicles in use, while ensuring that expansion joints do not crack and cause damage. This study selects a single particle size grading, and the aggregate technical requirements are shown in Table 2.

Table 2.

Aggregate Performance Index

Performance index	Technical requirement
Crushing value (%)	≤26
Los Angeles wear loss (%)	≤28
Apparent density (g/cm³)	≥2.6
Water absorption rate (%)	≤2.0
Adhesion (level)	≥4 level
Needle-like particle content (%)	≤15

Preliminary Design of Mix Proportion

Gradation Primaries

This study analyzes the blending ratio of bridge joint expansion joint fillers disclosed at home and abroad. The screening rate of mineral materials is shown in Table 3.

Table 3.

Screening Pass Rate

Sieve pore size (mm)	19	16	13.2	9.5	4.75
Passing rate (%)	100	90–100	50–70	25–40	0–10

Within the above gradation range, three types of mineral aggregate gradation—A, B, and, C—are selected initially. The three gradation curves are shown in Figure 1.

Figure 1.

The three gradation curves.

Marshall Test

This study uses the Marshall test to conduct the preliminary design of the mixture ratio. The production method is referred to as the “T 0702-2011 Asphalt Mixture Test Piece Manufacturing Method (Compacting Method)” in “Test Procedure for Highway Engineering Asphalt and Asphalt Mixture” (JTG E20-2011) ( 20 ). The compactor and Marshall experimenter are shown in Figure 2.

Figure 2.

Marshall test main equipment.

The stability and flow value of asphalt mixture are the main reference indicators when selecting the appropriate asphalt-aggregate ratio. Stability refers to the ability of the asphalt mixture to remain stable under high temperature conditions after molding, measured by the strength of the specimen in the Marshall test. Flow value refers to the deformation ability of the asphalt mixture, measured by the deformation of the test piece in the Marshall test.

The Marshall test was carried out on A, B, and C aggregate gradation. The asphalt-aggregate ratios were 1:10, 1:9, 1:8, 1:7, and 1:6, with four specimens in each group. In addition, the Marshall test was carried out for the three aggregate gradations of D, E, and F, and the asphalt-aggregate ratios are 1:7 and 1:6. The results of the Marshall specimens are shown in Figure 3. The gross volume density (g/cm³), mineral clearance ratio (%), stability (KN), flow value (mm), and other indicators were tested to determine the appropriate asphalt-aggregate ratio. The test results of asphalt mixtures with different mix proportions are shown in Table 4.

Figure 3.

Marshall specimen.

Table 4.

Marshall Test Results of Three Graded Asphalt Mixtures with Different Asphalt-Aggregate Ratios

Gradation	Asphalt-aggregate ratio	Gross volume density (g/cm³)	Gap ratio VMA (%)	Stability (KN)	Flow value (mm)
Gradation A	1:10	2.06	28.76	4.32	2.70
	1:9	2.15	25.60	5.18	2.63
	1:8	2.11	26.75	5.32	5.85
	1:7	2.02	29.98	4.76	6.24
	1:6	1.92	33.33	4.63	3.46
Gradation B	1:10	1.80	37.44	5.88	4.78
	1:9	1.90	34.01	4.58	3.48
	1:8	1.88	34.97	5.44	3.26
	1:7	2.04	29.16	4.47	5.42
	1:6	1.96	32.15	4.46	6.28
Gradation C	1:10	2.03	29.46	5.38	3.57
	1:9	1.98	31.26	5.71	4.06
	1:8	1.87	35.26	4.99	5.85
	1:7	2.09	27.51	5.12	5.51
	1:6	2.01	30.41	6.19	4.72

Note: VMA = voids in the mineral aggregate.

Analysis of Test Results

Figure 4 shows the Marshall test results for the different asphalt-aggregate ratios under gradation A, B, and C.

Figure 4.

Marshall Test Results

To better analyze the effect of gradation on the performance of mixtures, the longitudinal comparison of the test results of different gradation mixtures was performed. The coarse aggregate of A grade is relatively small, while the fine aggregate is relatively large. This is reflected in the physical index of the specimen as relatively good compactness of the mixture. According to conventional road asphalt mixture design theory, asphalt mixture with good compactness has good stability, but the flow value is small. However, the stability of A-grade mixture is between B and C, and the flow value did not show a significantly lower trend than the other two grades. This may be because of the weakening of the skeleton between the aggregates and the performance of the mixture depending on the properties of the asphalt binder itself. The coarse aggregate of C grade is relatively large, and the fine aggregate is relatively small. However, its stability is higher than the A grade. In normal asphalt mixture design theory, the increase of the asphalt-aggregate ratio reduces the mixture stability and increases flow value. However, with the C grade, the flow value of the mixture decreases as the asphalt-aggregate ratio increases. This is contrary to the current asphalt mixture design theory, which is initially determined to be because of experimental error. As can be seen from Figure 1, the B grade is between A and C, and the experimental results are in line with the design theory of asphalt mixture. However, when the flow value is large, the stability of the mixture may not meet the requirements. The more flow value, the less the stiffness of asphalt mixtures. The strength of asphalt mixture increases with the increase of the stability value. Reflected in the actual road performance, the asphalt mixture can adapt to the displacement of the bridge deck, but cannot bear the vertical load of the vehicle ( 21 ). Therefore, it is necessary to further adjust the gradation of mixtures.

Mix Ratio Optimization

The preliminary tests show that when the proportion of coarse aggregate and asphalt-aggregate ratio is large, the overall performance of the mixture will be better. To determine the optimal proportion of coarse aggregate, three gradations (D, E, and F) were selected for verification tests, and Figure 5 shows the Marshall test results for the different asphalt-aggregate ratios under gradation D, E, and F. The detailed proportions of these three gradations are shown in Table 5. In addition, when the asphalt-aggregate ratio is 1:6, the gross volume density, stability, and flow value of grade C are higher than those of grade A. Therefore, the subsequent tests were carried out directly under the asphalt-aggregate ratio of 1:7 and 1:6. The test results are shown in Table 6.

Figure 5.

Marshall test results.

Table 5.

Pass Rate Indicators

Sieve pore size (mm)		19	16	13.2	9.5	4.75
Passing rate (%)	D	100	99	70	40	0
	E	100	95	60	32.5	0
	F	100	91	50	25	0

Table 6.

Marshall Test Results of Asphalt Mixtures with Different Asphalt-Aggregate Ratios

Gradation	Asphalt-aggregate ratio	Gross volume density (g/cm³)	Gap ratio VMA (%)	Stability (KN)	Flow value (mm)
D	1:7	2.16	25.10	5.12	5.00
	1:6	2.14	25.96	4.97	6.55
E	1:7	2.02	29.82	4.67	5.18
	1:6	1.98	31.24	4.55	6.42
F	1:7	2.16	25.03	4.82	5.10
	1:6	2.10	27.25	5.06	6.87

Note: VMA = voids in the mineral aggregate.

By comparing the two indexes of stability and flow value, it can be seen that for the same gradation, with the increase of asphalt-aggregate ratio, the stability change is not obvious, but the flow value increases correspondingly. Therefore, 1:6 is selected as the best asphalt-aggregate ratio. When comparing different gradations vertically, it can be seen that the flow value of F-grade mixture, with a larger proportion of coarse aggregate, is larger. The results show that high elastic performance of asphalt mixture increases with the grading of coarse aggregate, so the final gradation is selected as F. In this study, it can be found that the strength and deformation capacity of asphalt mixture depend more on the characteristics of the asphalt binder itself. Based on these findings, the asphalt mixture specimens were prepared with F gradation and 1:6 asphalt-aggregate ratio, and its road performance was verified.

Asphalt Mixture Performance Verification

Water Stability Test and Analysis

This study uses the water-immersed Marshall test to evaluate the water stability of the asphalt mixture. The standard Marshall test piece is placed in a 60°C constant temperature water bath for 30 min. After being taken out, it is loaded on the Marshall tester to determine the stability and flow value of the test piece, so as to reflect the water stability of the asphalt mixture.

In this experiment, 30°C, 40°C, 50°C, and 60°C were used as test temperatures. The test piece was molded by the Marshall standard compaction method with a diameter of 101.6 mm and a height of 63.5 mm. The water-immersed Marshall test and the standard Marshall test were conducted at each test temperature to record the stability of the specimen after 48 h of water immersion, and the average value was obtained as MS₁ and MS. The stability of residual immersion is obtained as follows:

M S_{0} = \frac{M S_{1}}{MS}

(1)

where

MS ₀ = Residual stability of immersed specimens, %;

MS ₁ = Stability of the specimen after 48 h of water immersion, KN;

MS = Marshall stability of specimens, KN.

The water immersion residual stability was calculated according to Equation (1), and the test results are shown in Table 7.

Table 7.

Water Stability Test Data

Temperature	30°C	40°C	50°C	60°C
Marshall stability MS/KN	16.06	11.24	8.05	6.56
Water immersion Marshall stability MS₁/KN	13.76	9.86	7.79	6.37
Residual stability of immersion MS₀/%	85.70	87.70	96.80	97.10

The annual rainfall in Zhejiang Province of China exceeds 1,000 mm, which classifies it as a humid area. “Technical Specifications for Construction of Highway Asphalt Pavements” (JTG F40-2004) stipulates that the water stability of modified asphalt mixture should not be less than 85% ( 22 ). The test results show that with the increase of temperature, Marshall stability and water Marshall stability decline significantly. However, the stability of water immersion residue does not decrease, both being higher than 85%. The results at 50°C and 60°C are higher than 95%. This shows that the water stability of the asphalt mixture is good.

Fatigue Performance Test and Analysis

Fatigue refers to the phenomenon where the material is damaged before the stress reaches the ultimate strength of the material when subjected to repeated cyclic stress changes for a long time. For the test piece fabrication and test cycle, this study uses an indirect tensile fatigue test to evaluate the fatigue properties of the mixture.

An indirect tensile fatigue test using the Marshall standard compaction method was used to form test pieces with a diameter of 101.6 mm and a height of 63.5 mm. For the test, the control test load is set to 800 N at a loading frequency of 2 Hz (one cycle loading 100 ms, stop for 400 ms). Under repeated loading, the microscopic defects inside the test piece will gradually increase, resulting in the gradual decrease of the stiffness modulus of the test piece. The deformation gradually increases until the test piece is broken. The final load times are the fatigue life. The fatigue test instrument is shown in Figure 6, and the test results are shown in Figure 7.

Figure 6.

Indirect tensile fatigue test equipment.

Figure 7.

Indirect tensile fatigue strain-cycle curve.

Analyzing the tensile fatigue strain-cycle curve, of the specimen in Figure 5, it can be known that: As the number of cycles increases, the cumulative rate of horizontal to permanent strain gradually decreases, and the recovery capacity decreases. It may be that, under load, the gap inside the mixture is compacted, so its ability to resist deformation increases. After 10,000 load cycles, the cumulative permanent deformation is 13,428 μm/m, and the recovery capacity approaches 30 μm/m. This shows that the asphalt mixture has good resistance to fatigue damage.

Test and Analysis of Interfacial Bonding Properties

Design of Test Scheme

In this study, the full-scale simulation test is used to simulate the force deformation behavior of the seamless expansion joint in the field. By compressing the expansion joint to a certain displacement and observing the expansion and failure mode (cohesive cracking or interfacial cracking) during the failure, the bonding performance can be determined. Compared with drawing and shearing tests, this method is more intuitive, accurate, and reasonable.

The specific scheme is as follows: first, prefabricate two reinforced concrete test blocks, and then use a cutter, electric hammer, or other tools to leave a space of 400 mm in the longitudinal direction, 1,000 mm in the lateral direction, and 100 mm in the vertical direction between the two test blocks. The asphalt mixture is poured into these spaces. According to the construction method of seamless expansion joints, the asphalt mixture test piece is whitened with a layer of white paint to facilitate observation of deformation. The white paint has no deformability. When the asphalt mixture expands and deforms, the paint will crack, and the deformation of each part of the mixture is analyzed according to the cracks in the paint layer. The expansion joint was stretched and compressed at a deformation loading speed of 1.5 mm/min, at amplitudes of 5 mm, 7.5 mm, 10 mm, 15 mm, and 20 mm, respectively. The amplitude was cycled five times. During the test, the adhesion of the expansion joint to the cement concrete junction was observed.

Figure 8 shows some of the field devices used in the bridge joint expansion joint test. In this test, the longitudinal length of the seamless expansion joint is only 400 mm, and the width of the vibrating plate is slightly larger. Only an asphalt mixture higher than the concrete test block can be pressed into the tank, because of which effective compaction cannot be performed, so manual weight is used for compaction. Because of this, there is a certain gap between the final compaction effect and the actual construction compaction effect.

Figure 8.

Interface bonding performance test device.

Result Analysis

Figure 9, a–e, indicate the adhesion of the asphalt mixture to the concrete at displacements of +5 mm, +7.5 mm, +10 mm, +15 mm, and +20 mm, respectively. Figure 9f shows the adhesion of the test piece at a displacement of –20 mm.

Figure 9.

Interface bonding performance test device.

According to Figure 9: (1) When the displacement is +5 mm, there is no obvious tensile deformation in the bonding part of the specimen, and no cracks are produced in the white coating, which indicates that the specimen is in good condition; (2) When the displacement is +7.5 mm, there is no obvious tensile deformation in the bonding part of the specimen, but the local cracks appear in the white coating near the bonding part, which indicates that the asphalt mixture near the bonding part begins to deform first; (3) When the displacement is +10 mm, slight tensile deformation occurs at the bonding part of the specimen, and more cracks appear on the white coating near the bonding part; (4) When the displacement is +15 mm, obvious tensile deformation occurs at the bonding part of the specimen. In addition, the cracks produced in the white coating near the bonding part extend outward, indicating that the deformation of the asphalt mixture near the bonding part is expanding outward; (5) When the displacement is +20 mm, the local debonding phenomenon occurs in the bonding part of the specimen, and the cracks produced in the white coating are all over the surface of the test piece, which indicates that the limit working state of the specimen has been exceeded and it is not suitable for further use. The relative displacements at the interface under different deformations are shown in Table 8.

Table 8.

Relative Displacements at the Interface Under Different Deformations

Deformation	+5 mm	+7.5 mm	+10 mm	+15 mm	+20 mm
Relative displacement	0.1 mm	0.18 mm	0.32 mm	0.89 mm	1.52 mm

In conclusion, in the case of small and medium deformation, there is no obvious damage at the interface between asphalt mixture and concrete, which indicates that the bonding performance of the asphalt mixture is good.

Conclusion

Based on the gradation of seamless expansion joint asphalt mixture used in previous studies, the mix proportion of seamless expansion joint asphalt mixture was designed by adjusting the gradation and asphalt-aggregate ratio, and the effectiveness of the mix proportion was verified by Marshall tests. The current section intends to summarize the overall conclusions achieved through this study. The significant findings of this study are presented as follows:

(1) In the preliminary test, three aggregate gradations and five asphalt-aggregate ratios were selected, such as gross volume density (g/cm³), gap ratio VMA (%), stability (KN), flow value (mm), and other indicators were considered. It was determined that when the amount of asphalt was larger and the coarse aggregate occupied a certain proportion, the performance of the mixture could meet the requirements of the deformation of the seamless expansion joint.

(2) Based on the preliminary test, the gradation was adjusted, and Marshall test pieces were prepared in the ratios of 1:7 and 1:6, and their stability and other indexes were determined. The final gradation arrived at was F and the optimum asphalt-aggregate ratio observed was 1:6.

(3) The water-immersed Marshall test results showed that with the increase of temperature, the stability of water immersion residue did not decrease, both being higher than 85%. The results at 50°C and 60°C were higher than 95%. This showed that the water stability of the asphalt mixture was good.

(4) After 10,000 load cycles, the cumulative permanent deformation of the asphalt mixture was 13,428 μm/m, and the recovery capacity approached 30 μm/m. This showed that the asphalt mixture had good resistance to fatigue damage.

(5) In the case of small and medium deformation, there was no obvious damage at the interface between the asphalt mixture and concrete by the full-scale simulation test, which indicated that the bonding performance of the asphalt mixture was good.

This study was based on experimental test data of the performance of many mixtures, continuous testing, comparative analysis, and optimization. The results were true and reliable, and the study laid a foundation for the research and development of high-elasticity and high-resistance joint filler materials for seamless expansion joints in China and provides a reference for the optimization of the design of the mix proportion.

Footnotes

Author Contributions

The authors confirm contribution to the paper as follows: study conception and design: P. Lu, C. Zhou; data collection: Y. Pan; analysis and interpretation of results: S.Huang; draft manuscript preparation: Y. Shen. All authors reviewed the results and approved the final version of the manuscript.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The authors gratefully acknowledge financial support provided by the Science Foundation of China Postdoctor (Grant No. 2016M600352), and the Science and Technology Agency of Zhejiang province (Grant No. LGF19E080012).

References

Xuemei

Chuanjun

Research on the Application of Seamless Expansion Joint Technology of Highway Bridge. Pearl River Water Transport, Vol. 17, 2018, pp. 68–69.

Xiaping

Tianlai

Boyong

Bridge Engineering. Science Press, Beijing, China, 2007.

Yanghai

Chaoyang

Weigang

Xuezhen

Expansion Device of Highway Bridge. China Communications Press, Beijing, China, 2007.

Dawen

Zhiping

Jinxiang

Research and Practice of Jointless Bridges. Highway, Vol. 8, 2006, pp. 53–65.

Joao

Jorge

D. B.

Inspection Survey of 150 Expansion Joints in Road Bridges. Engineering Structures, Vol. 31, 2009, pp. 1077–1084.

Baochun

Yizhou

Briseghella

Jointless Bridge. China Communications Press, Beijing, China, 2013.

Linfeng

Pengzhen

Ting

Dong

Application of Seamless Expansion Joint Technology in Bridge Engineering. Northern Communications, Vol. 4, 2018, pp. 2–5.

Shaowen

Zhihui

Evaluation of Elastic Resilience of Rubber Asphalt by Rebound Recovery. Journal of Highway and Transportation Research and Development, Vol. 26, No. 7, 2009, pp. 22–26.

Donglin

Research on Preparation and Properties of Bridge Seamless Expansion Joints Material. Wuhan University of Technology, Wuhan, China, 2012.

10.

Tianlai

Tao

Sigang

Study on Low Temperature Performance of Modified Asphalt Expansion Joints and Mixtures. China Journal of Highway and Transport, Vol. 18, No. 2, 2005, pp. 18–23.

11.

Gongjian

Kang

Experimental Study on Bond Performance of Warm Rubber Asphalt as Waterproof Cohesive Layer of Bridge Deck. Petroleum Asphalt, Vol. 25, No. 5, 2011, pp. 24–27.

12.

Qingfeng

Menghao

The Comparative Analysis of Optimum Asphalt-Aggregate Ratio Based on Superpave and Marshall Method. Shanxi Science & Technology of Communications, Vol. 2, 2018, pp. 1–5.

13.

L. J.

Zhang

J. Y.

The Road-Test of High Performance Asphalt Mixture with Superpave. Applied Mechanics & Materials, Vol. 361, 2013, pp. 1576–1579.

14.

Changheng

Ping

Comparative Study on Superpave and Marshall Asphalt Mixture Design Methods. Journal of China & Foreign Highway, Vol. 2, 2005, pp. 115–117.

15.

Xiaojiang

Comparison of Superpave and Marshall Mix Design Methods. Transpo World, Vol. 5, 2011, pp. 142–143.

16.

Xin

Study on Optimization Design of Asphalt Mixture Based on Superpave and Marshall Method. Chang’an University, Xi’an, China, 2008.

17.

Wayne Lee

Brayton

T. E.

Mueller

Singh

Rational Mix-Design Procedure for Cold In-Place Recycling Asphalt Mixtures and Performance Prediction. Journal of Materials in Civil Engineering, Vol. 28, No. 6, 2016.

18.

Soohyok

Pravat

Fujie

Development of New Mix Design Method for Asphalt Mixtures Containing RAP and Rejuvenators. Construction and Building Materials, Vol. 7, No. 115, 2016, pp. 727–734.

19.

Bressi

Dumont

A. G.

Partl

M. N.

An Advanced Methodology for the Mix Design Optimization of Hot Mix Asphalt. Materials Design, Vol. 3, No. 3, 2016, pp. 264–275.

20.

JTG E20-2011. Standard Test Methods of Bitumen and Bituminous Mixtures for Highway Engineering. Highway Research Institute of the Ministry of Transport, China, 2011.

21.

Jaya

R. P.

Hainin

M. R.

Hassan

N. A.

Yaacob

Satar

M. K. I. M.

Warid

M. N. M.

Mohamed

Abdullah

M. E.

Ramli

N. I.

Marshall Stability Properties of Asphalt Mixture Incorporating Black Rice Husk Ash. Materials Today: Proceedings, Vol. 5, No. 10, 2018, pp. 22,056–22,062.

22.

JTG.F40-2004. Tehnical Specifications for Construction of Highway Asphalt Pavements. Ministry of Communications Highway Science Research Institute, China, 2004.