Low Temperature Bending Test Research Articles

Investigation of the Performance of Ceramic Fiber Modified Asphalt Mixture

Ceramic fiber (CF) is a novel thermally resistant material with the potential to improve the high-temperature performance of asphalt mixture. In this study, asphalt mixtures with 0%, 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% CFs were prepared. The Marshall test, wheel tracking test, Marshall immersion test, freeze-thaw splitting test, and low-temperature bending test were conducted to evaluate the performance of the CF-modified asphalt mixture. The morphologies of these asphalt mixtures were observed using scanning electron microscopy to analyze the modification mechanism. The results showed that the CFs could improve the mechanical properties, high-temperature stability, moisture susceptibility, and low-temperature cracking resistance of asphalt mixture, with the optimum CF content being 0.4%. Further microscopic analysis showed that the CFs improved the performances of asphalt mixture through forming three-dimensional network structure, asphalt absorption, bridging cracks, and pulling-out effect.

Determination of volumetric criteria for designing hard asphalt mixture

The current mix design method that is established based on the volumetric properties works well for conventional hot-mixed asphalt (HMA), but does not satisfy the design of hard HMAs. Hard HMAs refer to the mixtures designed using hard asphalt binder whose penetration is less than the conventional one (70#). Increasing asphalt content is regarded to be an effective way to design hard HMAs and keeps them away from thermal cracking problem. Therefore, this research explored the suitable volumetric criteria for designing hard HMAs. The principle of establishing the volumetric criteria is to ensure hard HMAs can achieve the equivalent performance as conventional ones. Eleven groups of AC16 containing three penetration grades of asphalt binders (70#, 50#, and 30#) were designed, and the volumetric properties, uniaxial penetration shear test (UPST), low-temperature bending test (LTBT) and four-point bending test (4PBT) were then conducted. Based on experiment data, two key volumetric criteria of AFT and VMA are established for hard HMAs. It can be seen that when the ranges of AFT maintain within the 10–11.2 µm and 12.9–13.4 µm, respectively, the 50# and 30# hard HMAs can reach the equivalent high- and low- temperature performance as 70# conventional HMAs. Correspondingly, the ranges of criteria in VMA for 50# and 30# hard HMAs need to maintain within 15.6–17.5% and 17.6–19.5%, respectively. Overall, a higher value of volumetric criteria is required for designing hard HMA compared with conventional one. In addition, the results of 4PBT indicate that hard HMAs can also exhibit good fatigue resistance when they are designed within these criteria.

Pavement conductive wearing surface with graphite heating film de-icing potential and performance experimental study

It is known that the freezing of the road brings high risks to the traffic in winter. However, Traditional deicing technology has low deicing efficiency and severe damage to the road surface. Therefore, the new develop pavement conductive wearing surface with graphite heating film (PCWSG) could be one option to solve this problem. So the main objective of this paper is to investigate the road performance (high-temperature, low-temperature, moisture susceptibility, friction-resistance) of pavement conductive wearing surface with graphite heating film (PCWSG) and then evaluate its deicing potential. In this paper, several tests are conducted to evaluate the performance of PCWSG. The high-temperature performance is conducted by the laboratory wheel-tracking rut test. Low-temperature performance is characterized by the low-temperature bending test. Moisture susceptibility is studied by the freeze-thaw split test. Friction-resistance performance is estimated by the pendulum type friction coefficient measuring instrument and the small acceleration loading device. Furthermore, removing ice potential is studied by asphalt rutting slabs (various gradations) with graphite conductive wearing surface. The results show that pavement conductive wearing surface with graphite heating film (PCWSG) could improve the high-temperature, low-temperature, and friction-resistance compared with the original asphalt mixture. Although moisture susceptibility and wear performance decrease lightly but also satisfy the specification requirement. Moreover, removing ice potential of asphalt slabs with PCWSG results shows that AC-20 asphalt concrete with higher porosity has better deicing and snow removal effect. The PCWSG has lower heating and deicing cost and more effective deicing effects.

Study on pavement performance of basalt fiber asphalt concrete under different pavement environment

In order to study the basalt fiber in the road with the performance, the test of matrix asphalt concrete, basalt fiber reinforced asphalt concrete and the SBS modified asphalt concrete applying ultraviolet aging, high and low temperature alternating cycle change, after the freeze-thaw cycle and salt freezing and thawing cycle road environment for rutting test, low-temperature bending test and immersion Marshall test. The test results show that basalt fiber plays an important role in improving the high-temperature stability, low-temperature crack resistance and water stability of asphalt concrete under different road conditions. The degree of influence of pavement environment on the deterioration of pavement performance of basalt fiber asphalt concrete is as follows: ultraviolet aging > high and low temperature alternating cycle > freeze-thaw cycle > salt freeze-thaw cycle.

Laboratory Study on the Performance of Asphalt Mixes Modified with a Novel Composite of Diatomite Powder and Lignin Fiber

The performance and the fundamental weaknesses of asphalt mix under environmental temperature and water effects have made researchers try to modify the asphalt mix properties by using the proper additives. For this reason, this paper aims to improve the anti-cracking performance and water stability of asphalt pavement by adding a novel composite of diatomite and lignin fiber in asphalt mixes. Four types of asphalt mixes, including control asphalt mix (CAM), diatomite modified asphalt mix (DMAM), lignin fiber modified asphalt mix (LFMAM), and diatomite-lignin fiber composite modified asphalt mix (DLFMAM) were prepared in the laboratory. Low-temperature bending test, Marshall Immersion test, and freeze-thaw splitting test were employed to evaluate the performance of the asphalt mixes. Results reveal that the use of the lignin fiber in reinforced asphalt mixes combined with diatomite led to an enhancement in the asphalt pavement performance more than the other three types of mixes. Diatomite has an important influence on the water damage resistance of asphalt mix more than lignin fiber. On the other hand, diatomite has a small effect on the anti-cracking performance; meanwhile, lignin fiber showed a significant improvement in the cracking resistance of asphalt mixes. DLFMAM has the best traveling performances among all asphalt mixes. Thus, this work provides a good reference for the design of composite asphalt mixes.

Study of Pavement Performance of Thin-Coat Waterborne Epoxy Emulsified Asphalt Mixture

Waterborne epoxy emulsified asphalts (WEEA) have high densities, good chemical stabilities, and high viscosities. However, they have problems in terms of overly high stiffness and low-temperature brittleness when applied as thin-coat asphalt mixtures. In this study, testing was conducted to obtain the optimal mixing ratio for WEEA. Anti-sliding, rutting, water stability, Cantabro, and low-temperature bending tests were carried out to evaluate the performance of thin coating layers formed from open graded friction course (OGFC)-5 WEEA mixtures, with the results indicating that the optimal ratio of waterborne epoxy resin emulsion and curing agent was 2:1 and that the dosage of waterborne epoxy resin should be maintained between 15 and 30%. The surface texture depth and British Pendulum Number (BPN) of the OGFC-5 WEEA mixtures were larger than 0.91 mm and 77.4, respectively, and the WEEA mixtures had better water stabilities and spalling resistance performance than a mixture without WEEA. Waterborne epoxy resin dosages of 15 and 30% resulted in WEEA mixture stabilities of up to 4,285 and 8,798 times/mm, respectively, and tensile strengths at -10 ℃ of 2.204 and 4.727 MPa, respectively. The relatively good pavement functional and low-temperature performance of the optimized OGFC-5 WEEA mixture suggest its usefulness as a pavement maintenance material.

Laboratory Performance Evaluation of Hot-Mix Asphalt Mixtures with Different Design Parameters

Aggregate gradation and asphalt type are traditional variables that affects mix design of Hot-Mix Asphalt (HMA). Recently, the number of design gyrations (Ndes) has been increasingly accepted as another variable parameter during the design process. Due to the growing shortage of high-quality raw materials, it is necessary to make full use of the combined roles between these design parameters, instead of solely relying on their individual effect, to improve the HMA properties. Therefore, this study comprehensively explored the effect of aggregate gradation, Ndes, and asphalt type on the performance of HMAs. Seven different combinations of aggregate gradation, Ndes, and asphalt type were evaluated. The volumetric indicators, uniaxial penetration shear test (UPST), unconfined compression test (UCT), low-temperature bending test (LBT), four-point bending test (FPBT), and dynamic modulus test (DMT) were used to assess the performance of HMAs designed by various parameter combinations. It was found that the contribution of adopting harder asphalt binder was able to make up for the high-temperature resistance loss caused by lower Ndes or coarser gradation. The dynamic modulus exhibited the similar phenomenon. By contrast, the harder asphalt binder led to the worse tenacity of HMAs at low temperature; however, the tenacity can be restored through using lower Ndes or coarser gradation by increasing asphalt content. In addition, the fatigue life of HMAs went up significantly by about 36 ~ 41%, when both Ndes and asphalt penetration grade decreased to one lower level.

Investigation of the Performance of the Ecofriendly Fiber-Reinforced Asphalt Mixture as a Sustainable Pavement Material

This article presents a study to evaluate the performance of the ecofriendly calcium sulfate whisker fiber- (CSWF-) reinforced asphalt mixture as a sustainable pavement material. Asphalt mixtures containing 0.2 wt.%, 0.4 wt.%, 0.6 wt.%, and 0.8 wt.% of the CSWF were designed by the Marshall method. Asphalt mixtures without fiber were also prepared as control samples. The Marshall test, wheel-tracking test, low-temperature bending test, water sensitivity test, and fatigue test were conducted to evaluate the performance of the CSWF asphalt mixture. And the mechanism of fiber reinforcement was discussed. The results showed that the CSWF could improve the high-temperature stability and low-temperature crack resistance of the asphalt mixture. Water stability of asphalt mixtures in the presence of the CSWF was also improved. When the CSWF content was 0.4 wt.% of the total mixture, the performance of the asphalt mixture is the best. Compared with the conventional asphalt mixture, the CSWF asphalt mixture not only utilized power plant waste effectively to preserve ecosystems but also improved the performance of the pavement, which is suggested to be used in sustainable pavement construction and rehabilitation.

Investigation of the Microwave Absorption of Asphalt Mixtures Containing Magnetite Powder

This article is intended to investigate the microwave heating performance of asphalt mixtures containing magnetite powders (MPAM). For this purpose, the surface temperatures of asphalt mixtures containing different dosages of magnetite powders were measured during microwave heating. The low-temperature bending test and water sensitivity test were also conducted to evaluate the performance of MPAM. Heating rate and reflection loss of different thicknesses of MPAM were determined using a microwave heating test and arch reflectivity test, respectively. The results showed that because its main components are triiron tetroxide and iron oxide, which have excellent microwave-absorbing properties, magnetite powders can be used as microwave absorbers to improve the ability of microwave absorption and increase the heating rate of asphalt mixtures. The heating rate of the asphalt mixtures increased with the increase of the amount of magnetite powder. The addition of magnetite powder improved the low-temperature properties of the asphalt mixture, but it reduced the water stability of the asphalt mixture. Considering that the microwave-absorbing asphalt mixture used for melting snow and ice should have good water stability, the recommended dosage of magnetite powders was 60%. The microwave-absorbing properties of MPAM were related to its thickness in the pavement structure and frequency of microwaves. In order to greatly enhance the absorbing efficiency, future work should be focused on matching thickness and matching frequency.

The Optimization Design of Mixing Ratio of ARAC-13 Rubber Asphalt Mixture based on Low Temperature Crack Resistance

The representative ARAC-13 mineral grading range was calculated by power curve grading, combining with the climatic characteristics of Gannan high-altitude and damp areas. The gradation of five kinds of ARAC-13 rubber asphalt mixture was designed based on representative grading. Different grade rubber asphalt mixtures were studied by the freeze-thaw splitting test and low temperature bending test to optimize the mix design of ARAC-13 mixture.

Laboratory Performance of Hot Mix Asphalt with High Reclaimed Asphalt Pavement (RAP) and Fine Reclaimed Asphalt Pavement (FRAP) Content.

Recently, there has been an increasing interest in the applications of recycled mixtures with a high reclaimed asphalt pavement (RAP) content. However, many government departments are hesitant about the applications of that due to being worried about the durability of its pavement, and few findings has been reported in terms of the percentage of fine reclaimed asphalt pavement (FRAP, 0~5 mm) in recycled mixtures. In this paper, 25% or more RAP by the weight of aggregates is defined as high RAP and high FRAP refers to 10% or more FRAP by the weight of aggregates. This paper examines the laboratory performances of mixtures with high RAP (30%, 40%, and 50%) and FRAP (10%, 15%, and 20%). Performance evaluations have been conducted by conventional tests, including the low-temperature bending test, fatigue test, and the moisture susceptibility test. The results show that with the increasing RAP and FARP contents, 41% (30-R-10) to 63% (50-R-15) of virgin asphalt can be saved, both the low-temperature and fatigue performance decrease, and the moisture performance firstly increases and then decreases. The results of analysis of variance (ANOVA) in terms of low-temperature and moisture performance show that RAP contents in recycled mixtures have a significant effect on the performance, while the effect of FRAP contents on the performance of recycled mixtures is insignificant.

Expansion inhibition of steel slag in asphalt mixture by a surface water isolation structure

To inhibit volume expansion of steel slag and improve pavement performance of steel slag asphalt mixture, a surface water isolation structure was proposed by employing three surface treatment approaches. Properties of the surface modified steel slag were tested including water absorption, expansion ratio, crush value and adhesion. X-ray diffraction, X-ray fluorescence and scanning electron microscope were used to analyse the physical and chemical properties of steel slag. Results showed that three approaches could reduce the volume expansion of the surface modified steel slags at a certain extent, and the silicone waterproof agent had the best treatment effect, with expansion ratio reduced by 34%. Subsequently, three asphalt mixtures (surface modified steel slag, original steel slag and basalt) were prepared. Rutting test, low-temperature bending test, mixture immersion expansion test, Marshall test and freeze–thaw split test were achieved to determine their pavement performances. Compared with control groups, the high-temperature performance and water stability of the asphalt mixture composed of surface modified steel slag had significant enhancement. The dynamic stability increased by 20% and the 72 h mixture expansion ratio decreased by 44%. This surface water isolation structure is valuable for inhibiting the volume expansion of steel slag and improving the performances of steel slag asphalt mixture.

Study on Road Performances of Ultra-thin Wearing Layer Small Particle Size Asphalt Mixture

In order to find out that if it is available to apply the asphalt mixture with small particle size and large porosity to the ultra-thin wearing layer, a kind of open-graded asphalt mixture whose nominal maximum aggregate size is 4.75mm and void ratio is greater than 20% is designed in this article. The rutting test, low-temperature bending test, freeze-thaw split test, pendulum friction coefficient test, manual sand patch test and permeability test are conducted to evaluate the road performance and surface behavior like high-temperature stability, low-temperature, water stability, friction and permeability. The test results shows that the asphalt mixture’s 60℃ dynamic stability is 8201 times /mm, ultimate bending strain is 2896 μe, the residual strength ratio of freeze-thaw split is 83.94%, BPN is 69, the texture depth is 0.71mm, and water permeability coefficient is 6857mL/min. It can be concluded that the asphalt mixture with small particle sized aggregate and large porosity has good road performance, whose high-temperature stability, anti-skid performance and drainage performance are excellent. Compared with road performance of OGFC-13, small particle asphalt mixture can also be used as ultra-thin wearing course.

Low-Temperature Performance and Evaluation Index of Gussasphalt for Steel Bridge Decks

Gussasphalt is widely used in steel deck pavement in cold regions; thus, it should have good low-temperature performance. A method for evaluating the low-temperature performance of gussasphalt is presented in this paper. Low-temperature bending, bending creep, and splitting tests were used to study the performance of different types of gussasphalt. The sensitivity and correlation between low-temperature indices obtained from three methods were compared and analyzed with sensitivity factors and the grey relational coefficient, respectively, and the low-temperature evaluation index and standard of gussasphalt in cold regions were determined. Flow, penetration at 50°C, low-temperature bending, and bending fatigue tests of the trabeculae were carried out after secondary mixing of gussasphalt asphalt concrete. Degradation of the material performance after different storage times was studied. Finally, taking the strain energy density as the main control index and considering the fluidity, the high-temperature performance, fatigue characteristics, technical requirements for storage, and mixing time of gussasphalt in cold weather after two mixing procedures are discussed.

Performance evaluation and material optimization of Micro-surfacing based on cracking and rutting resistance

Abstract To improve the cracking resistance and rutting resistance performance of Micro-surfacing, the conventional test, low temperature bending test and Hamburg Wheel-Track Testing (HWTT) were conducted to analyze the improvement effect of waterborne epoxy modified emulsified asphalt (WEMEA), Styrene Butadiene Styrene (SBS) modified emulsified asphalt and fiber stabilizer on Micro-surfacing performance. The influence degree and significance level of fiber type and fiber dosage on Micro-surfacing properties were discussed to optimize the material composition of fiber Micro-surfacing. The results show that the Micro-surfacing performance is improved by selecting optimum binder or the addition of fiber, and the comprehensive improvement effect of fiber is better. Compared to other materials, the fiber significantly improves the low temperature performance, and also takes into account other properties of Micro-surfacing. Moreover, the fiber type and fiber dosage both significantly influence the properties of Micro-surfacing, and the influence degree of fiber dosage is higher. The compound use of polypropylene fiber and basalt fiber can show the technical advantages of different fiber to improve the overall performance of Micro-surfacing and reduce the cost of material. Combining with the performance change and economic influence for Micro-surfacing, the optimal dosage of fiber is recommended as 0.10%–0.20% by the weight of asphalt mixture. The research results will provide some reference for the further promotion and application of fiber Micro-surfacing.

Aggregates breakage introduction to optimize gradation of multi-supporting skeleton asphalt mixtures

This research provides a method for introducing the broken rate of the coarse aggregates to optimize gradation of multi-supporting skeleton asphalt mixtures (MSSAM). The MSSAM was designed and then verified by comparing the measured volume parameters with designed criterion. Single Marshall tests were performed on single and multiple sized aggregates to find the boundary of coarse and fine aggregates. The tamping method replaced the Marshall compaction to measure accumulated density of the coarse aggregates. The broken rate of the coarse aggregates was introduced to optimize gradation of MSSAM. The wheel-tracking and low-temperature bending tests were finally performed to evaluate the pavement performances of the modified MSSAM. The results indicated that the gradation degeneration of MSSAM introduced by the crushed coarse aggregates resulted in the volume parameters to deviate from the designed criterion. The grain size of 4.75 was identified as the boundary of coarse and fine aggregates. Introduction of the broken rate of the coarse aggregates neutralized the gradation degeneration in the Marshall compaction, and brought the measured volume parameters nearer to the designed criterion. The modified MSSAM had a high dynamic stability and met requirements of low-temperature performance at minus 9 °C, was a good choice for the southeast China with heavy traffic.

Research on design and performance of sasobit warm mixed reclaimed asphalt mixture

In order to evaluate road performance of Warm mixed reclaimed asphalt (WMRA), the tests are carried out. Different blended ratio(10%, 30%, 50%) of RAP(recycled asphalt pavement) is selected, and WMRA and Hot mixed reclaimed asphalt mixture (HMRA) are designed respectively. Through the test analysis, the method to determine WMRA optimal mixed temperature, molded temperature and heated temperature of new aggregate is established. Marshall test, rutting test, low temperature bending test, residual stability test and freeze-thaw splitting test are conducted, and Marshall indicators and road performance of HMRA and WMRA are finally evaluated.

Studying of the Influence of Mesh Material between 6.3 ~ 4 mm on the Performance and Design of EME2(0/14) High Modulus Asphalt Mixture

This paper used the design method of EME high modulus HMA from France for the mix designing of EME2 (0/14) HMA. We studied the influence of critical sieve between 6.3 ~ 4mm for EME high modulus asphalt mixture, and tested the volume indicators of the test specimen. We found that the optimum asphalt content of the asphalt mixture which had 6.3 and 4 gap graded graduation was 5.2% which was 0.5% lower than optimum asphalt content of the asphalt mixture which had continuous gradation. Meanwhile, AASHTO T283 test, HWTD, low temperature bending test were carried out for comparing the performance of the above two graduation type. The test results showed that the gap graded asphalt mixture and the continuous gradation of EME-14 high modulus asphalt mixture performance were basically the same, we could also concluded that the amount of material from sieve 6.3 to 4 could significantly influenced the asphalt content of the asphalt mixture.

Laboratory evaluation of composed modified asphalt binder and mixture containing nano-silica/rock asphalt/SBS

As SBS modified asphalt has the disadvantages of high initial cost, difficult processing and poor storage stability, many researches have been conducted experiments on composed modified asphalt to get a more satisfactory pavement performance. This study proposed an asphalt mixture modified by nano-silica, rock asphalt and SBS. Basic performance tests of asphalt, rutting tests, low-temperature bending tests, moisture susceptibility tests, fatigue tests and durability tests of asphalt mixtures modified by SBS, rock asphalt, nano-silica/rock asphalt and nano-silica/rock asphalt/SBS were performed to evaluate their pavement performance. Comparing these tests results with the properties of unmodified asphalt mixture, nano-silica and rock asphalt cause an improvement in pavement performance. nano-silica/rock asphalt/SBS modified asphalt mixture had higher temperature stability, low-temperature cracking resistance, moisture susceptibility and durability than 5% SBS modified asphalt except the similar fatigue life. Furthermore, economic analysis indicated that the nano-silica/rock asphalt/SBS modified asphalt mixture had higher cost effectiveness.

A lab study to develop a bridge deck pavement using bisphenol A unsaturated polyester resin modified asphalt mixture

To improve the low-temperature and anti-fatigue performances of the bridge deck pavement and decrease its cost, an unsaturated polyester resin (UPR) modified asphalt mixture is put forward in this paper. First the optimum formula of UPR modified asphalt is determined through several tests. Second the ductility, bending beam rheometer (BBR), dynamic shear rheometer (DSR) and tensile tests are conducted for matrix asphalt, and SBS, epoxy and UPR modified asphalts. Finally, Marshall, rutting, low temperature bending, freeze-thaw splitting and fatigue tests are conducted for their mixtures. Test results show that the laboratory performances of UPR modified asphalt mixture are more excellent than those of SBS modified asphalt mixture and have advantages over those of epoxy modified asphalt mixture in low-temperature crack resistance, water stability and anti-fatigue ability. The maximum flexural-tensile strain, stripping inflectionpoint and fatigue life of UPR modified asphalt mixture are 2.54, 1.25 and 1.08 times of those of epoxy modified asphalt mixture, respectively. Whereas the cost of UPR modified asphalt is only 62% of that of epoxy modified asphalt. Although the BPA will have a certain impact on the health of BPA unsaturated polyester resins production workers and construction workers, this impact can be controlled by limiting BPA concentrations within reasonable ranges and taking effective protective measures.