Temperature Sensitivity Of Asphalt Research Articles

Study on the Performance of SBS/Polyphosphoric Acid Composite Modified Asphalt

To address the issue of bad compatibility between a single polymer modifier and asphalt and high preparation cost, the composite modified asphalt with polyphosphoric acid (PPA) and SBS as a modifier was prepared. Basic properties, viscosity characteristics, high-temperature and low-temperature rheological performance, and aging-resistant performance of SBS/PPA composite modified asphalt were comprehensively evaluated, and the best content of PPA was obtained through the experimental results below. By performing an infrared spectrum test and a scanning electron microscope test, structural changes and modifying mechanisms of composite modified asphalt were analyzed. The results indicate the optimal PPA content is 0.75%. After adding PPA, the penetration and ductility of composite modified asphalt were reduced, while the softening point increased. At 135 °C, the viscosity was 1.2 times that of SBS modified asphalt. The average weight loss ratio was 0.163%. When the content of PPA was 0.75% and 1%, the rutting factor increased significantly. Therefore, PPA can not only improve the thermal oxidation aging resistance of asphalt, it can also improve the shear resistance, high-temperature performance, and temperature sensitivity of asphalt. Between 1027 and 1150 cm−1, the composite modified asphalt forms a new absorption peak, and from 1610 cm−1, the absorption peak presents an upward trend, suggesting that PPA reacts chemically with asphalt, produces the new substance, and also increases a large number of hydrocarbon components with chain structure. The surface appearance of the compound modified asphalt gradually presents a smooth wrinkle state due to the increase of PPA, so the issue of easy segregation of SBS in asphalt is improved.

Study on the Performance and Modification Mechanism of Polyphosphoric Acid (PPA)/Styrene–Butadiene–Styrene (SBS) Composite Modified Asphalt

In order to address the high preparation cost of styrene–butadiene–styrene block copolymer (SBS) modified asphalt, four kinds of polyphosphoric acid (PPA) content (0%, 0.5%, 0.75%, and 1% PPA by weight of the matrix asphalt) were selected to prepare composite modified asphalt with better high-temperature performance. The physical properties of composite modified asphalt were evaluated by conventional performance tests. The rheological properties of composite modified asphalt were evaluated by dynamic shear rheometer (DSR) test and bending beam rheometer (BBR) test. The synergistic modification mechanism of PPA and SBS was revealed by the Fourier transform infrared spectroscopy test. The results show that with the increase of PPA content, the penetration of PPA/SBS composite modified asphalt is reduced by 20.92%, 25.07% and 28.94%, respectively, compared with matrix asphalt, and the softening point is increased by 5.46%, 22.69% and 34.03%, respectively. In addition, PPA can improve the thermal oxidative aging resistance of asphalt. PPA can improve the shear resistance, high-temperature performance and temperature sensitivity of asphalt. At 82 °C, compared with SBS modified asphalt, the phase angle of PPA/SBS composite modified asphalt can be decreased by 8.63%, 13.23% and 19.24%, respectively, and G*/sinδ can be increased by 41.97%, 67.62% and 70.97%, respectively. SBS mainly exists in asphalt in the form of physical blending, and PPA has a new chemical reaction with asphalt, which increases the macromolecules and chain hydrocarbon components in asphalt, and the macroscopic performance is the improvement of high-temperature performance of asphalt. However, PPA has a negative effect on the low-temperature performance of the SBS modified asphalt.

Study on the rheological properties and phase-change temperature regulation of asphalt modified by high/low-temperature phase change material particles

The temperature sensitivity of asphalt can be improved by blending phase change materials into asphalt through the effect of phase change temperature control. In this study, two types of phase change material particles with excellent heat resistance were prepared by vacuum adsorption method. Based on material preparation, phase change material particles with different phase change temperature intervals were blended into asphalt to prepare a composite modified asphalt. Furthermore, the composite modified asphalt's rheological properties and temperature regulation effects were analyzed. The results showed that the incorporation of phase change material particles improved the rutting factor of the composite modified asphalt. The aging resistance of the composite modified asphalt increased significantly with the increase of the proportion of low-temperature phase change material particles. Bending beam rheometer (BBR) test results showed that incorporating high/low-temperature phase change material particles did not significantly affect the low-temperature rheological properties. According to temperature regulation simulation, it was found that the temperature change rate affects the temperature regulation effect of the composite modified asphalt. With increasing the temperature change rate, the maximum temperature difference increases, the latent heat accumulation temperature value (LHATV) decreases, and the latent heat temperature regulation index (LHTI) increases.

Evaluation of temperature sensitivity of recycled asphalt based on numerical analysis model and thermal analysis kinetics

The use of recycled asphalt not only consumed a large amount of reclaimed asphalt pavement (RAP), but also brought significant economic and social benefits. However, recent research mainly focused on the engineering properties of recycled asphalt, without paying attention to the temperature sensitivity of recycled asphalt in service. At present, the temperature sensitivity of asphalt was mostly studied in matrix asphalt, while the quantitative analysis of the temperature sensitivity of recycled asphalt was still lacking, and this study aimed to propose an effective quantitative analysis method of temperature sensitivity of recycled asphalt. For this, a self-developed rejuvenator was used to prepare recycled asphalt, and then the recycled asphalt was analyzed by conventional performance test, rotational viscosimeter (RV) test, dynamic shear rheometer (DSR) test and differential scanning calorimetric (DSC) test. The results showed that the temperature sensitivity of aged asphalt was improved by the addition of rejuvenator, and several evaluation indexes suggested that the temperature sensitivity of recycled asphalt was influenced by the dosage of the rejuvenator, to have excellent temperature sensitivity, a reasonable dosage of rejuvenator should be selected for recycled asphalt. In addition, the VTS equation most applicable to recycled asphalt was selected by the gray relation analysis (GRA) model, and the temperature sensitivity index most applicable to recycled asphalt was evaluated by principal component analysis (PCA) model. Finally, considering that the temperature sensitivity indexes were derived from the matrix asphalt, to more effectively study the temperature sensitivity of recycled asphalt, based on the DSC test, thermal analysis kinetics was used to analyze the test results, and an effective quantitative analysis method of temperature sensitivity of recycled asphalt was proposed.

High-Temperature Rheology Characteristics of Hard Petroleum Asphalt Used in China

Hard petroleum asphalt, which is a high modulus asphalt binder material, is used for improving asphalt pavement rutting distress. This property is attributed to the good high-temperature rheological characteristics of hard petroleum asphalt. The study investigates the performance of hard petroleum asphalt and Styrene-Butadiene-Styrene polymer modified asphalt (SBSPMA) based on three aspects: asphalt oil source, asphalt grade, and aging degree. The short-term and long-term aging of four hard petroleum asphalts and SBSPMA of comparative samples were measured using the rolling thin film oven test (RTFOT) and the pressure aging test (PAV). Firstly, the viscosity-temperature curve of hard petroleum asphalt was obtained using the Brookfield viscosity test at different temperatures combined with the improved REFUTAS formula. The complex shear modulus ( G ∗ ), phase angle (δ), and rutting factor ( G ∗ / sin δ ) of each asphalt sample were then measured by the dynamic shear rheometer test (DSR). Furthermore, the temperature sensitivity of each asphalt sample was calculated using the complex modulus index method (GTS). The compaction and paving temperature ranges of each asphalt were then confirmed. The results showed that the high-temperature rheological characteristics of hard petroleum asphalt were similar to those of SBSPMA. The temperature sensitivity of hard petroleum asphalt was basically the same as that of SBSPMA, while the influence of aging on the G ∗ of hard petroleum asphalt was greater than that of SBSPMA. In addition, the hard petroleum asphalt construction temperature was lower than that of SBSPMA.

Effect of phenolic resin on the rheological, chemical, and aging properties of SBR-modified asphalt

In this study, the effects of phenolic resin (PF) on the permanent deformation and short-term aging resistance of SBR-modified asphalt binder were investigated. Multiple stress creep recovery (MSCR) tests, Fourier transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC) were performed to investigate the effect of PF on the deformation resistance and aging resistance of SBR-modified asphalt with PF (S4P3). The results show that PF can significantly improve the permanent deformation resistance and aging resistance of the asphalt binder. In addition, S4P3 showed different molecular weight changes during the aging process, and the percentage of large molecular size (LMS) in asphalt has a significant impact on the deformation recovery ability and temperature sensitivity of asphalt.

Fatigue Behavior of Cement Asphalt Emulsion Mortar

As one of the key components of non-ballast slab track in high speed railway, cement asphalt emulsion mortar (CAM) has low compressive strength and low elastic modulus. This makes CAM possible to be served as supporting, height-adjusting, vibration-dissipating and deformation-fitting sandwich-layer between pre-stress slab and concrete roadbed. To study the fatigue behavior of the CAM, fatigue tests were conducted at room temperature and negative temperature, respectively. The permanent strain, elastic modulus and yield strength of fatigue-tested specimens were compared to the reference one. The results showed that the small permanent deformation lead to very little displacement differences among the slab track system. Secondly, the elastic modulus and yield strength of fatigue test specimens were both higher than that of reference one. Because the fatigue process might strengthen the CAM by compacting micro-cracks. Additionally, arising from the temperature sensitivity of asphalt, viscosity behavior of asphalt mortar at room temperature is changed to brittleness behavior at negative temperature.

The Influence of Nano-Montmorillonite on High Temperature Performance of Asphalt

In order to increase the life of bituminous pavement, quality of bitumen needs to be enhanced and modified. Different dosages of nano-organic montmorillonite (nano-OMMT) were used as modifier for base asphalt. The effect of the contents of nano-OMMT on high temperature performance of asphalt was investigated. Experimental results showed that with the increase of nano-OMMT of content, the high temperature performance of asphalt was gradually improved. And the high temperature sensitivity of asphalt is also enhanced. The nano-OMMT modified asphalt is expected to possess superior rutting resistance to the base asphalt.