Low Temperature Bending Test Research Articles

Study and Application on Cold Blended Epoxy Asphalt Mixture for Steel Bridge Deck Pavement

New cold blended epoxy asphalt material and ERS pavement structure were used for steel deck pavement of Zhijiang bridge. In this paper, the material and structural performance were evaluated by laboratory tests. For the cold blended epoxy asphalt, the optimum composition ratio, construction time and temperature requirements were determined through viscosity and tensile performance test. The road performance of epoxy asphalt mixture was evaluated by high temperature rutting test, low temperature bending test and moisture damage test. Through 45 ° oblique shear test and composite beam fatigue test. The structural properties such as interlayer bonding state and fatigue performance were evaluated. The experimental results showed that the new type of cold blended epoxy asphalt had high breaking elongation, high tensile strength and loose construction time under normal temperature;RA05 mixture had excellent road performance; The shear strength of ERS waterproof adhesive layer reached 5MPa at 25°C and 2MPa at 70°C; RA05 and SMA10 had close bonding，good cooperative performance and great fatigue property to resist large deformation. Overall, ERS material and structure had excellent road performance and mechanical properties. The effect of the application in Zhijiang bridge was great.

The Research on Preparation and Properties of the Petroleum-Based Color Asphalt Binder

The petroleum-based color asphalt binder was prepared through physical blending method with domestic references and international experience. The property was carried out and close to or more than similar products at home and abroad. The best aggregate ratio of the petroleum-based color asphalt binder mixture was determined by Marshall Test. The merits of the road performance were analyzed for the petroleum-based color asphalt binder mixture by Rutting Test, Trabecular Low-Temperature Bending Test, the immersion Marshall Test and Freeze-Thaw Splitting Test. The results showed: the petroleum-based color asphalt binder mixture had excellent pavement performance compared with the performance of ordinary road asphalt mixture.

Research on Performance of Recycled Mixture with High RAP Content from Central Plant Hot Recycling and Evaluation Method of Its Durability

Based on pavement maintenance project of the national road, a series of laboratory tests were conducted to investigate the road performance of recycled mixtures with different RAP content by wheel tracking test, immersing Marshall test, freeze-thaw splitting test and low temperature bending test. During these tests, virgin mixture without RAP is used as a control group. Furthermore, the durability of recycled mixture was verified by a new test method by which the impact-freeze-thaw damage degree can be obtained. On the basis of laboratory experiments, three types of trial sections have been successfully paved on the national road. The results show that the performance of recycled mixture with 30% RAP is better while recycled mixture with 50% RAP can also satisfy the existing standards by adding the recycling agent and reinforcing agent. The new test method is efficient to distinguish the durability difference between different mixtures. The performance of these recycled trial sections meet the existing standards, and recycled mixture with high RAP content can be used in national road project on a large-scale.

Laboratory evaluation of pavement performance using modified asphalt mixture with a new composite reinforcing material

As a new way of modifying asphalt or asphalt mixture, composite modification has obvious effects. In order to improve the performance of asphalt pavement in a simple, fast and efficient way, a new kind of composite reinforcing material (CRM) is used in this study. The Marshall Immersion test, the freeze–thaw splitting test and low-temperature bending test were conducted to evaluate the pavement performance of the asphalt mixture with different CRM contents. Test results show that the pavement performance of modified asphalt mixtures is better than unmodified asphalt mixture. When the CRM content increases, resistance to rutting at a high temperature increases significantly, low temperature cracking resistance and moisture damage resistance first rise and then fall. In consideration of other pavement performance, such as dynamic stability (DS), indirect tensile strength ratio (TSR) and maximum tensile strain, the suggested optimal CRM dosage is 5.9‰ to 7.9‰.

Impact of Salt Freeze-Thaw Cycles on Low Temperature Performance of Asphalt Mixture Based on the Strain Energy Density

With the use of snow-thawing salt in the cold winter, asphalt pavement is damaged easily by salt freeze-thaw cycles. The aim of this research is to study the impact of salt freeze-thaw cycles on low temperature performance of asphalt mixture. Through low temperature bending test, the decay law of strain energy density of asphalt mixture under the conditions of salt freeze-thaw cycles was analyzed, and strain energy density was used for regression by the exponential model, what’s more, the improvement of fiber, anti-stripping agent and slaked lime on the low temperature performance of the mixture were investigated. The results of low temperature bending test showed that the strain energy density of asphalt mixture decreased rapidly after salt freeze-thaw cycles, moreover, the more the times of salt freeze-thaw cycles, the higher the concentration of salt solution and lower the change of freezing temperature, the larger the influence on strain energy density of asphalt mixture. Regression analysis results revealed that the exponential model could well reflect the variation of strain energy density of the mixture with the times change of the salt freeze-thaw cycles. The improvement of basalt fiber on the low temperature performance of the asphalt mixture was very significant under the condition of salt freeze-thaw cycles.

Mechanical properties of gutta-percha sulfide modified asphalt

Gutta-percha is the isomer of caoutchouc and can be used to enhance the performance of asphalt. In this paper, the produce proceedings of gutta-percha sulfide and gutta-percha sulfide modified asphalt are introduced. The performance indices of gutta-percha sulfide modified asphalt samples with different proportions are examined based on laboratory tests and the optimum ratio of gutta-percha and sulfur is decided.The micromechanism, temperature sensitivity, high and low temperature properties and viscoelasticity of the polymer modified asphalt are analyzed to discuss the modified mechanism and to decide the optimal polymer content. Low temperature bending tests are carried out to verify the low temperature performance of gutta-percha sulfide modified asphalt mixture. Research results showed that gutta-percha sulfide modified asphalt has good low temperature performance and a promising application prospect in the cold regions.

The Pavement Performance Research on the Powder Colored Asphalt Mixture

The high-strength powder colored asphalt was studied by sieve analysis, density and cone penetration test in order to study technical performance. Secondly, the mixing process of colored asphalt mixture was put forward through the Marshall Compaction test. The best whetstone of the colored asphalt mixture was determined by Marshall Test design method. Finally, the variation of pavement performance for colored asphalt was analyzed by the rutting test, immersion Marshall Test split and freeze-thaw test and low-temperature bending test. The results showed: the high temperature performance of colored asphalt mixture was outstanding, but the low temperature performance was lower. Therefore the high-strength powder colored asphalt mixture is suitable to be used in high temperature areas.

Study of factors influencing gussasphalt mixture performance

Effects of mixture content, binder type, mixture gradation, modifier, and stirring time on properties of gussasphalt mixtures are investigated by fluidity, penetration, high-temperature rutting, and low-temperature bending tests. It is found that gradation and asphalt content have a strong influence and should therefore be strictly controlled during the preparation of gussasphalt mixtures. The use of a macadam coating and the addition of a modifier have strong effects on the dynamic stability of gussasphalt mixtures. The preparation technique has a strong influence on the quality of the mixture, with the optimal stirring time in the cooker being about 3h.

Testing and assessing the performance of a new warm mix asphalt with SMC

Warm mix asphalt (WMA) is a new technology which asphalt mix is produced and placed at normal temperature. It has advantages including low cost, environmentally friendly, haul-convenience, and so on. WMA has been widely tested and applied in the USA in the last decade, but it has just started in China. Recently, a new WMA using a new plastic-macromolecule-normal temperature additive, which was called “SMC” by the production company, was introduced as asphalt modifier. Based on discussing the strength forming process of this new WMA with SMC, a series of laboratory tests, including Marshall stability test (MST), boiling test (BT), modified immersion Marshall test (MIMT), freeze-thaw splitting test (FTST), rutting test (RT), low-temperature bending test (LTBT), and abrasion loss test (ALT), were conducted in this study to assess the performance of this WMA and the capability of applying it on low volume roads in China. SMC modified asphalt mixed under normal temperature is used in testing samples. It was found that this WMA product exhibited merits on its strength, which was about 6.7 kN bigger than the requirement of 5.0 kN in the JTG F40-2004, on high-temperature stability, which is about 1100 times/mm greater than the requirement of 600–1000 times/mm in the JTG F40-2004, and on its storage stability. Based on these indicators, it is recommended that this product could be used for low volume low class roads construction. However, due to the relatively lower water resistance and low-temperature cracking resistance, this product is suggested to be applied first in the areas with warm weather and little rainfall. In order to improve the performance of this WMA with SMC, further research on this SMC asphalt modifier should be continued.

Dynamic mechanical characterizations and road performances of flame retardant asphalt mortars and concretes

To research the dynamic mechanical properties and road performances of flame retardant asphalt mortars and mixtures, four different asphalt mortars/mixtures were prepared: a reference group and three asphalt mortars/mixtures containing composite flame retardant materials (M-FRs) of different proportions. Temperature sweep, frequency sweep, repeated creep test, force ductility test and bending beam rheological test were carried out to research the dynamic mechanical properties of asphalt mortars containing M-FRs; wheel-tracking test, low-temperature bending test and freeze-thaw split test were used to study the road performances of asphalt mixtures containing M-FRs. The results show that high-temperature performances of the three flame retardant asphalt mortars improve greatly, while low-temperature cracking resistances decline. Both high-temperature performances and water stabilities of asphalt mixtures containing M-FRs are quite good and exceed the specification requirements. However, their low-temperature performances decline in different degrees. In summary, besides their good flame retardancy, the flame retardant asphalt mortars and mixtures also exhibit acceptable road performance.

Low temperature property and salt releasing characteristics of antifreeze asphalt concrete under static and dynamic conditions

This research reports the low temperature properties and salt releasing characteristics of antifreeze asphalt concrete (AFAC) under different moisture conditions, such as static condition (wetting–drying cycles), static loading and dynamic loading conditions. Therefore, low temperature bending test and conductivity test were carried out to estimate the performance of antifreeze asphalt concrete. Results show that the low-temperature properties and salt releasing characteristics of antifreeze asphalt concrete are affected by salt content, continuously immersion time, wetting–drying cycles, solution temperature and, as expected, loading condition. A static/dynamic loading and conductivity test system was developed to simulate the traffic flow on pavement in working condition. It is revealed that loading condition also influences the salt releasing characteristics, especially that the dynamic loading will enhance the salt dissolving in water. In AFACs, the salt location is divided into three zones which are related with the salt releasing characteristics.

Research on Fiber Micro-Surfacing Mixture Design and Pavement Performance in Interchange’s Connections

In order to use the micro-surfacing which is the existing micro-surfacing technology guide that has some technical defects, the method to determine the optimal dosage of emulsified asphalt and best whetstone is not very reasonable, and it impedes the application and development of micro-surfacing technology to improve the performance of the pavement. In this paper, the “graphical method” is first used to determine the optimal dosage range of emulsified asphalt. Nowadays, a large number of expressways reach the stage of repair and maintenance. Interchange ramp exit and entrance are always the accident-prone sections and, it’s easy to over-look the pavement’s skid resistance of those areas. Micro-surfacing can significantly improve the performance of pavement, especially the skid resistance. Verified with laboratory tests, it recommends that the dosage of emulsified asphalt corresponding to the peak of flexural strain measured with low temperature bending test as OAC of micro-surfacing mixture shows technical superiority. The use of fiber micro-surfacing at the ramp’s exit and entrance can reduce the braking distance.

Performance Characteristic of Cold Recycled Mixture with Asphalt Emulsion and Chemical Additives

Three types of chemical additives were used to modify asphalt emulsion recycled mixture. These chemical additives include composite Portland cement (CPC), hydrated lime (HL), and a combination of hydrated lime and ground-granulated blast-furnace slag (GGBF). The influence of different additives on the recycled mixture performance was investigated by volumetric and strength tests, moisture susceptibility test, rutting resistance test, and low temperature bending test. To better understand its performance characteristic, the microstructure images of the recycled mixture were observed by environmental scanning electron microscope (ESEM). Test results demonstrate that the performance improvement of the emulsion recycled mixture depends on the types and content of chemical additives. Several recommendations are presented for the selection of chemical materials. Based on ESEM image analysis, the interface bonding mechanism is proposed to explain the performance characteristic of the recycled mixture with asphalt emulsion and cementitious materials.

Fatigue property of basalt fiber-modified asphalt mixture under complicated environment

The fatigue property of asphalt mixtures under complicated environment (low-temperature bending performance, chloride penetration, freezing-thawing cycle and their coupling effect) and the improvement effect for relevant property of basalt fiber-reinforcing asphalt mixture under complicated environment are studied. Two grading types of asphalt mixtures, AC-16I and AC-13I, are chosen, whose optimum asphalt-aggregate ratio and optimum dosage of basalt fiber are determined by the Marshall test. The standard specimens are made firstly, and then the low temperature bending tests of asphalt mixture and basalt fiber-reinforced asphalt mixture under the coupling effect of the chloride erosion and freezing-thawing cycle have been carried out. Finally, the fatigue property tests of asphalt mixture and basalt fiber-reinforced asphalt mixture under complex environment are performed on MTS material testing system. The results indicate that the tensile strength, the maximum curving tensile stress, the curving stiffness modulus, and fatigue properties of asphalt mixture are influenced by the coupling effect of the chloride erosion and freezing-thawing cycle. The low-temperature bending performance and fatigue property of asphalt mixtures under complicated environment can be greatly improved by adding moderate basalt fiber. The dense gradation asphalt mixture possesses stronger ability to resist adverse environmental effects under the same condition.

The Influence of Coarse and Fine Ratio on ATB Asphalt Mixture Performance

Through the freeze-thaw splitting test, rutting test, low temperature bending test, comprehensive analysis the affect of coarse and fine ratio on ATB asphalt mixture performance. The results showed that: the ratio of change have a significant effect on water stability, high temperature stability, low temperature stability. Reasonable coarse and fine ratio have a higher degree of stability; Smaller coarse and fine ratio can effectively improve the asphalt mixture water stable performance, with coarse and fine ratio increased, freeze-thaw splitting strength ratio decreases; Larger coarse and fine ratio have an adverse effect on the high temperature stability, dynamic stability after the first increase and then decrease with increasing coarse and fine ratio; Smaller coarse and fine ratio can significantly improve the low temperature stability.

Laboratory investigations of activated recycled concrete aggregate for asphalt treated base

Asphalt treated base ATB-25 was designed containing recycled concrete aggregate (RCA), which was pretreated with three types of activators in various amount. Crushed value, water absorption, density and adhesion with asphalt of RCA were tested. Four mixtures of ATB-25 were designed containing different contents of RCA: 0%, 30%, 60% and 100%. Marshall test, rutting test, water stability test and low-temperature bending test were conducted to evaluated road performances of above mixtures. It was found that the voids and microfractures existing in RCA led to large water absorption and crushed value and low density and strength. Application of activator effectively decreased crushed value and water absorption and enhanced adhesiveness with asphalt due to closing of voids in RCA. The activation effect of organic silicon resin was superior to that of metatitanic resin acceptor and silane resin acceptor. Because of asphalt absorption by microfractures, asphalt content and oil absorption of ATB increased as RCA content increasing. While effective asphalt content of different mixture were basically the same, indicating that RCA and natural aggregate had the same effective thickness of asphalt film. Residual Marshall Stability, tensile strength ratio and low-temperature bending strain of ATB decreased with RCA content increasing. Low-temperature bending strain decreased to 1728.5με when RCA content increased to 100%, which was less than the required value of specification of China. No obvious relationship was found between dynamic stability and RCA content, but dynamic stability of all ATB mixtures containing RCA satisfied the requirement in specification of China. ATB-25 mixtures containing less than 60% of RCA satisfied all the requirements of specification of China.

Investigation of Usability of Brucite Fiber in Asphalt Mixture

The objective of this study is to investigate the usability of brucite fiber in asphalt mixture. In order to compare the characteristics of brucite fiber with other fibers usually used in asphalt mixtures, the water absorption test, oven heating test, Mesh-basket draindown test, and scanning electron microscopy are conducted on brucite fiber, lignin fiber, basalt fiber, and polyester fiber. Also, the Marshall test, wheel tracking test, low temperature bending test, water sensitivity test, and fatigue test are used to evaluate the performance of different fiber-reinforced asphalt mixtures. These experimental results show that brucite fiber has a good state of preservation in the moist storage environment, and its thermo-stability is better than lignin fiber. Its absorption and adhesion of asphalt is better than basalt fiber and polyester fiber. The best performance of asphalt mixtures are obtained for 0.40% brucite fiber content. Asphalt mixture prepared with brucite fiber also has excellent high temperature stability, water sensitivity, and fatigue property, especially low temperature properties. Addition of brucite fiber is feasible to improve major performance properties of asphalt mixture.

Study on the Effect of Warm Mix Modifiers on the Performance of Guss Asphalt

In order to comparatively study the effect of warm mix modifiers on the road performance of guss asphalt, the guss asphalt mixtures, whose asphalt aggregate ratio were 8.5%,9.0%,9.5% respectively, were mixed with 0%,1%,2%,3% of the RH and Sasobit warm mix modifiers. Then by means of Lueer test, penetration test, wheel track test and low-temperature bending test, the performance of guss asphalt were evaluated. The test results show that: RH and Sasobit can effectively improve the workability of guss asphalt; RH is better than Sasobit in reducing viscosity of guss asphalt; RH reduces the high-temperature properties of guss asphalt; On the contrary, Sasobit can improve the hightemperature performance of guss asphalt; RH and Sasobit have an adverse impact on the crack resistance of guss asphalt in low temperature, so their content should not too high. Guss asphalt has characteristics of high construction temperature and energy consumption. In order to reduce construction temperature, based on energy conservation, low-carbon emission environment, reduce the aging of asphalt principle, warm modifiers could be used to reduce the viscosity of guss asphalt at high temperatures[1-5]. Sasobit modifiers imported from Germany are used much more to improve the workability of guss asphalt. In this paper, 0%, 1%, 2%, 3% RH and Sasobit warm mix modifier were mixed with the aggregate ratio of 8.5%, 9.0%, and 9.5% of the Guss asphalt to compare and analyzed the performance of those two warm modifiers on Guss asphalt.

The Application of High Modulus Mixture of EME2 on Qin Lin Expressway Test Road

This paper used the design method of EME high modulus HMA from France to carry out the mix design of EME2(0/14) HMA, and carried out Duriez test, HWTD, dynamic modulus test and low temperature bending test. The test result showed that this kind of HMA had excellent water resistance, high temperature rutting resistance, high dynamic modulus and low temperature cracking resistance. This EME high modulus HMA was applied in the test road on Qing Lin expressway.

The Analyze Study of Compacting Temperature and Road Performance of Warm Mix Asphalt Mixture (LEADCAP)

This paper used one kind of organic additive LEADCAP to reduce the compacting temperature of SBS WMA mixture, and compared the WMA mixture compacted by superpave gyratory compactor (SGC) with HMA mixture to determine the compacting temperature of WMA mixture. Rutting test, low temperature bending test, freeze-thaw indirect tension test, Hamburg Wheel-Track test and dynamic modulus were carried out to evaluate the road performance of WMA mixed with LEASCAP. The test result showed that the WMA mixed with LEADCAP had well performed high temperature stability, low temperature stability, water stability, rutting cracking resistance, and high dynamic modulus, the compacting temperature were 127 °C, and affectively reduced the compacting temperature of SBS WMA mixture.