•The anti-rutting efforts focus on improving the rheological properties of asphalt.•Semi-flexible and cool asphalt pavements can help reduce rutting depth.•The applicability of wheel tracking test ...was systematically analyzed.•It is unnecessary to perform rutting tests at a rather high temperature.•Multiple-stress mode should be considered in performing laboratory rutting test.
Permanent deformation, mainly referring to rutting, is one of the main distress modes of asphalt pavement. Exploring effective methods to mitigate the rutting distress is of great significance for providing a long-life and safe road. The rutting solutions were first reviewed. It was found that the efforts from academic and engineering industries focused on enhancing the rheological properties of asphalt binder by adding modifying powder, fiber or mixture into binder or mixture, as well as strengthening aggregate interlock and applying novel pavement structure. Semi-flexible asphalt pavement was suggested to be a promising method to fight the rutting distress, because it has a high mechanical property without scarifying the flexibility of asphalt pavement. In order to consider the influence of temperature on rutting occurrence, cool asphalt pavements, especially heat-transfer induced structures, were reviewed and deemed to be a new strategy for reducing rutting susceptibility of asphalt pavement. In order to evaluate the effectiveness of above rutting solutions, many tests, such as multi-stress creep recovery test for asphalt binder and wheel tracking test for asphalt mixture, were reviewed. By linking the reported results of wheel tracking test with high-temperature rutting mechanism it was advised to develop a test method that could reproduce the real field pavement environment, including multiple stress mode, temperature gradient control system and pavement structure, to assess the rutting response of asphalt mixture. This review is expected to provide an overall insight on the existing rutting solutions and test methods, and recommend future studying areas relevant to rutting distress.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•Steel fiber was used to prepare high-thermal-conductivity asphalt mixture.•Steel fiber could increase the air voids content of asphalt mixture.•Greater compaction work could induce a lower air voids ...content of asphalt mixture.•Using steel fiber asphalt mixture could reduce the temperature of asphalt pavement.
High-temperature asphalt pavements will intensify urban heat island effect and cause many pavement distresses. In order to cool asphalt pavement, two types of steel fiber, curved hook steel fiber (CH-SF) and long sawtooth steel fiber (LS-SF), were used to increase the thermal conductivity of asphalt mixture. The results show that the addition of steel fiber increased the air voids content of asphalt mixture, of which CH-SF had a stronger influence. Six compaction levels were used to investigate the compaction characteristic of steel fiber asphalt mixture. It is found that greater compaction work would induce the mixtures to be further compacted. When the steel fiber asphalt mixtures were compacted to have an air voids content of about 4.0%, CH-SF was more effective to increase the thermal conductivity and splitting strength of asphalt mixture than LS-SF. The indoor irradiation test shows that using 1.0% CH-SF asphalt mixture below the top asphalt layer could reduce the temperature at the depth of 4 cm by 1.8 ℃. The findings in this study indicate that using CH-SF can increase the thermal conductivity of asphalt mixture, on the condition that the CH-SF asphalt mixture is compacted to have an appropriate air voids content.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Display omitted
•The composite PCM was prepared by mixing PEG-water solution with cement.•PEG was well incorporated in cement hydration products.•PEG did not participate in the hydration reaction of ...cement.•The composite PCM had phase transition enthalpy as high as 37.47 J/g.•The surface temperature of the composite PCM could reduce by 6.2 °C.
Utilizing phase change materials (PCMs) in building envelope has been proved to be able to effectively reduce the indoor temperature variations, of which the preparation of composite PCMs is rather important due to the leakage of PCMs. This work proposed a novel fabrication approach of cement-based composite phase change materials (CCPCMs) by means of the water solubility of polyethylene glycol (PEG) and the hydraulicity of cement. The microstructure, mineral component and latent heat storage capacity of CCPCMs were characterized by a series of experiments, including scanning electron microscopy (SEM), Fourier transform infrared rheometer (FTIR), X-ray diffraction (XRD), differential scanning calorimeter (DSC), thermal gravimetric analyzer (TGA) and leakage test. The potential cooling effect of the CCPCMs was also verified using an indoor irradiation test. The result of SEM test shows that PEG was well incorporated into cementitious matrix, which was also confirmed by the leakage test. The FTIR and XRD results indicate that PEG did not react with cement. In the DSC test, the prepared CCPCMs were observed to have phase transition enthalpy as high as 37.47 J/g. The TGA test reveals that CCPCMs had excellent thermal stability below the temperature of 300 °C. Furthermore, compared to control cement paste, the surface temperature of CCPCMs sample reduced by a maximum of 6.2 °C, showing that CCPCMs had a good thermal storage capacity. The findings of the paper indicate that the prepared CCPCMs have great potentials to be applied in thermal energy storage buildings.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•Steel rods were implanted in asphalt layers to construct thermal channels.•Approximately 30.6% more solar heat was induced to be absorbed by asphalt pavement.•The heat in pavement was induced to ...fast transfer to the base layer through steel rods.•The surface and inner temperatures reduced by maximums of 3.5 °C and 6.4 °C, respectively.•The maximum rutting depth decreased by 49.2%.
High-temperature asphalt pavements contribute to the development of urban heat island, rutting distress and asphalt aging, etc. Implanting steel rods in the middle and bottom asphalt layers was proved to be able to construct thermal channels, but it was difficult to reduce surface and inner temperatures simultaneously. To increase solar absorption and accelerate heat release in asphalt pavement, a novel strategy of oriented heat induction was proposed according to the effect of rod-implanting mode on temperature profile. The simulation results show that the proposed structure absorbed 30.6% solar heat more than control structure. The implanting of steel rods changed the heat flow characteristics as well. The heat in the asphalt mixture in the top layer was absorbed by steel rods, which was then released to the asphalt mixture in the bottom layer after a period of fast downward heat transfer. The surface and inner temperatures reduced by maximums of 3.5 °C and 6.4 °C, respectively, compared to the control structure. The temperature reduction was verified by an indoor irradiation test. As a result, the maximum rutting depth of the proposed structure decreased by 49.2%. The proposed strategy of heat induction is expected to be used to cool asphalt pavement by inducing solar absorption and accelerating heat release.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•Asphalt prevents the phase change process of polyethylene glycol.•Polyethylene glycol has a complicated effect on the rheological property of asphalt.•The asphalt mixture containing polyethylene ...glycol is cooled by a maximum of 3.3 °C.•Polyethylene glycol has an adverse effect on the shear strength of asphalt mixture.
Polyethylene glycol (PEG) has been used as a phase change material in asphalt mixture to cool asphalt pavement in summer. However, the PEG is much likely to leak and then influence its performance. This study aimed at studying the interaction between PEG and asphalt for phase change effect. Laboratory tests were conducted to evaluate the influence of PCM on asphalt/asphalt mixture performance, including microscopic test, dynamic shear rheometer test, indoor irradiation test and shear strength test. The results showed that the measured phase change enthalpy of PEG/asphalt composite was lower than theoretical results. Based on the observed FTIR spectra and fluorescence images, the PEG was found evenly distributed in the asphalt at a low content. The results of frequency and temperature sweep tests indicated that the liquid state of PEG could improve the elastic property of PAC. Furthermore, the zero shear viscosity at 40–60 °C and the non-recoverable compliance at 3.2 kPa and 12.8 kPa both increased due to the addition of PEG. The peak temperature of the PEG/asphalt mixture with 20% PEG was 3.3 °C lower than control asphalt mixture. However, the shear strength of PEG/asphalt mixture decreased by 20.3%, compared with control asphalt mixture. The study findings indicate that it is desired to propose an effective method to incorporate phase change material in asphalt mixture in order to reduce the influences of PCM leakage on performance.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•The effect of ECC construction method on shear properties of ECC-to-concrete interface was studied.•The construction method of spraying ECC had an obvious decreasing effect on interface tensile ...strength.•A shear strength mechanical model and a shear stress-slip model of ECC-to-concrete interface were proposed.
This paper reveals an investigation of the influences of ECC mixture construction method (i.e., common casting and spraying ECC), ECC strength grade, interface roughness of concrete substrate, and polyvinyl alcohol (PVA) fiber type on shear properties of ECC-to-concrete interface. The test results show that two failure modes of interface shear failure and ECC failure were observed. The roughness degree of concrete substrate had a strong effect on the failure mode, while ECC strength grade, ECC mixture construction method, and PVA fiber type had almost no influence on the failure mode. The shear load-slip curves of all specimens were basically similar. Compared to the casting ECC, the spraying ECC had an obvious decreasing effect on interface shear strength. The ECC strength grade and roughness degree of concrete substrate had a significant influence on interface shear strength, and higher ECC compressive strength and coarser interface could cause higher interface shear strength. On the contrary, PVA fiber type had a slight influence on interface shear strength. Based on the micro-bonding mechanism and test results of shear load-slip curves, a shear strength mechanical model and a shear stress-slip model of ECC-to-concrete interface were proposed to predict interface shear strength and shear stress-slip curve, respectively.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•Fly ash ceramsites with different particle size ranges were used to incorporate PCM.•AC-13 and SMA-13 were used to prepare phase change asphalt mixtures.•Cooling and strength performances were used ...to select gradation of composite PCMs.
Phase change materials (PCMs) can regulate the temperature of asphalt pavement through latent thermal energy storage. Composite phase change materials using lightweight aggregate as supporting material have been used in asphalt pavement. This work aims at investigating the effect of lightweight aggregate gradation on latent heat storage capacity of asphalt mixture for achieving satisfactory cooling effect. Polyethylene glycol (PEG) was incorporated in three kinds of fly ash ceramsite (FACS) with different particle size ranges (2.36–4.75 mm, 4.75–9.5 mm and 9.5–13.2 mm) to prepare composite PCMs (PEG/FACS) by a vacuum adsorption method. The results of differential scanning calorimeter test showed that the composite PCMs with smaller particle size had larger latent heat. The leakage experiment confirmed that the composite PCMs coated with cement paste (C-PEG/FACS) had good thermal exudation stability. Two kinds of asphalt mixture, AC-13 and SMA-13, were prepared by replacing aggregate with C-PEG/FACS. For AC-13 gradation, the asphalt mixture prepared with C-PEG/FACS (2.36–4.75 mm) presented the best cooling effect and the lowest strength reduction, compared with control asphalt mixture. As for SMA-13 gradation, the asphalt mixture using C-PEG/FACS (4.75–9.5 mm) had the best cooling effect, but the asphalt mixture prepared with C-PEG/FACS (2.36–4.75 mm) presented the lowest strength reduction. The results of the paper indicated that it is necessary to select reasonable lightweight aggregate gradation as PCM-supporting material for different types of asphalt mixture, in order to achieve satisfactory cooling performance and minimize the strength reduction of asphalt mixture.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
In order to reduce the solar absorption of pavement and accelerate the downward heat conduction, two bidirectional heat induced structures were designed, one named G-BHIS (only gradient thermal ...conductivity) and the other named G + R-BHIS (the combination of gradient thermal conductivity and heat reflective layer). Compared with the contrast structure, the heat absorption was reduced by 12.73% for the G-BHIS and 35.02% for the G + R-BHIS, respectively. The heat accumulation within the pavement was reduced by 15.9% for the G-BHIS and 37.6% for the G + R-BHIS, respectively. The coupling effect of the decreased heat absorption and accumulation reduced pavement temperature. The maximum temperature differences, 2.38 °C (for the G-BHIS) and 7.76 °C (for the G + R-BHIS), both appeared at the depth of 4 cm. Rutting results showed that the maximum rutting depth could be reduced by 41.0% for the G-BHIS and 65.0% for the G + R-BHIS, respectively. The two structures are expected to decrease heat accumulation and reduce pavement temperature, and furthermore, reducing rutting.
•The designed structures can prevent heat into the pavement.•They can allow the heat in the pavement fast to conduct to the base layer.•Pavement temperature can get reduced and rutting problem can also be solved.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Steel fiber was used to prepare high-thermal-conductivity asphalt mixture.•Steel fiber could increase the thermal conductivity of asphalt mixture by 15.2%.•The deformation resistance of asphalt ...mixture reduced with the addition of steel fiber.•Steel fiber could improve the low-temperature and fatigue performance of asphalt mixture.•It is recommended to use 1.0% curved hook steel fiber to reinforce asphalt mixture.
In order to accelerate the heat flow in asphalt pavement, two types of steel fiber, curved hook steel fiber and long sawtooth steel fiber, were used to prepare steel fiber asphalt mixture (SFAM). The results show that all the SFAM specimens presented higher air voids contents at the two ends, compared with control asphalt mixture. From the results of dynamic modulus and creep test it is found that the deformation resistance of SFAMs gradually reduced with the increase of steel fiber content, which could be explained by the air voids distribution characteristics of SFAM specimens. On the contrary, SFAM showed excellent low-temperature cracking resistance and fatigue performance. Combining the above results, it is recommended to use 1.0% curved hook steel fiber to reinforce asphalt mixture for improving the thermal conductivity and road performances of asphalt mixture. Because of the reduced deformation resistance of SFAM, the cooling performance of SFAM asphalt pavement needs to be investigated in future studies, based on which the rutting depth can be simulated by means of finite element analysis to determine the actual influence of steel fiber on the rutting resistance of asphalt pavement.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•The designed structure absorbed less 9.3% solar radiation heat.•The structure can induce inner accumulated heat to subgrade.•The structure releases less 12.1% heat into the atmosphere during ...nighttime.
In this paper, a highly oriented heat conduction structure of asphalt pavement, with a combination of low thermal conductivity layer and three-layered gradient heat conduction structure, was proposed to reduce pavement temperature and decrease nighttime heat release into the atmosphere in summer. The structure was formed by modifying contrast asphalt pavement by adding different dosages of low thermal conductivity powders to each layer. Also, it made full use of principles of thermal insulation and gradient heat conduction, and extended the scope of thermal gradient in asphalt layers. The results showed that, compared with contrast structure, the highest temperature of upper surface of bottom layer, which was used to represent the average temperature of middle and bottom layers, reduced by 2.3°C (simulation result) and 2.4°C (test road result). The average temperatures of middle and bottom layers reduced by 1.6°C (at 2:30pm) and 1.5°C (at 6:00pm), respectively, which were validated by test road results. Calculations of simulation result displayed that the structure released less 12.1% of heat to the atmosphere during nighttime than contrast structure. According to the results summarized above, it is concluded that the structure has a continuous cooling capacity, and is expected to reduce high temperature rutting of asphalt pavement and help to reduce high air temperature at night.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
