UV Aging Resistance Of Bitumen Research Articles

Preparation and Characterization of Lignosulfonate Intercalated Layered Double Hydroxides and Their Application in Improving Ultraviolet Aging Resistance for Bitumen

In order to develop economically anti-ultraviolet (UV) aging additives to bitumen and extend the comprehensive utilization of lignin materials, lignosulfonate (LS) was selected to intercalate into layered double hydroxides (LDHs), then the LS intercalated LDHs (LS-LDHs) were applied to improve UV aging resistance of bitumen. With the characterization of X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, chemical analysis and scanning electron microscopy (SEM), LS was successfully intercalated into the galleries of LDHs. The ultraviolet and visible (UV-vis) absorbance curves showed LS-LDHs had excellent UV absorptive ability from 200 to 400 nm. Thermogravimetry and differential scanning calorimetry (TG-DSC) indicated LS-LDHs could have a good thermal stability during the processing of bitumen. Compared with the LDHs, the LS-LDHs exhibited better performance in UV aging resistance of bitumen.

Effect of Layered Double Hydroxides with Different Particle Size on Properties of Bitumen

The crystal structure, microscopic morphology, particle size distribution and UV shielding properties of layered double hydroxides (LDHs) with different particle size were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), laser particle size analysis and ultraviolet and visible (UV-vis) spectrophotometer. The effects of LDHs with different particle size on the physical, rheological properties and UV aging resistance of bitumen were investigated by conventional physical properties and dynamic rheological characteristics. The results indicated that the particle size of LDHs had a little effect on the physical properties, and it had some influence on rheological properties of bitumen, but its influence on the UV aging resistance of bitumen was different significantly. When UV aging time was 9d, the viscosity aging indexes of bitumen modified by LDHs with different particle size (80nm, 115nm and 180nm) decreased by 48.2%, 58.1% and 63.8% compared with the pristine bitumen, respectively. LDHs with the particle size of 180 nm showed better improvement than other two kinds of LDHs on UV aging resistance of bitumen.

Influence of UV aging on the rheological properties of bitumen modified with surface organic layered double hydroxides

Triethoxyvinylsilane surface organic modified layered double hydroxides (TEVS-LDHs) were prepared and applied to improve the ultraviolet aging resistance of bitumen. The effect of TEVS-LDHs and LDHs on the temperature susceptibility and rheological properties of bitumen before and after UV aging were thoroughly investigated. The storage stability test showed that the difference in the softening point (ΔS) of LDHs modified bitumen (the LDHs content at 2%) decreased from 1°C to 0.4°C after TEVS surface organic modification, and the descending trend was more obvious with the content of LDHs increase, which implied that TEVS-LDHs dispersed better and existed more stably in bitumen than LDHs. The introduction of TEVS-LDHs significantly alleviated the temperature susceptibility of bitumen and increased the rutting factor (G∗/sinδ) of bitumen, indicating that TEVS surface organic modification were favorable to the improvement of high-temperature performance for LDHs modified bitumen. After UV aging, bitumen became more hard and brittle, compared with LDHs, the addition of TEVS-LDHs alleviated obviously the deterioration tendency of bitumen, which suggested that LDHs surface organic modified by TEVS were far superior to unmodified LDHs in enhancing the UV aging resistance of bitumen.

Effect of Silane Coupling Agent Surface Modified Layered Double Hydroxides on Properties of Bitumen

Layered double hydroxides (LDHs) surface modified by silane coupling agent KH550 were prepared to modify bitumen, the surface modified LDHs (KH550-LDHs) were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD). The effect of KH550-LDHs and LDHs on physical and anti-ageing properties of bitumen was evaluated by means of physical test. The results of FTIR showed that KH550 had successfully grafts onto the surface of LDHs, and XRD result showed that KH550 had little effect on the crystal structure of LDHs. The storage stability test showed that KH550-LDHs dispersed better homogeneously and existed more stable than LDHs in bitumen. The physical properties tests indicated that high and low temperature properties of bitumen were improved compared with LDHs. After UV aging with the addition of KH550-LDHs, the increase rate of softening point slowed remarkably, the reduction rate of ductility declined evidently compared with LDHs. Aging indices (softening point increment and ductility retention rate) show that KH550-LDHs exhibited better improvement than LDHs in UV aging resistance of bitumen, implying more effective modification of KH550-LDHs which is due to the enhanced compatibility between KH550-LDHs and bitumen.

Synthesis and characterization of triethoxyvinylsilane surface modified layered double hydroxides and application in improving UV aging resistance of bitumen

Layered double hydroxides (LDH) surface modified by triethoxyvinylsilane (TEVS) was prepared and characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and Ultraviolet and visible (UV–Vis) spectrophotometry. FTIR and XRD showed that TEVS has been successfully grafted onto the surface of LDH. Compared with LDH, the agglomeration between the TEVS surface modified LDH (TEVS-LDH) particles was obviously weakened according to SEM. UV–Vis reflectance and absorbance analyses indicated that TEVS-LDH possessed better UV reflectance and absorbance than that of LDH. Then the effects of TEVS-LDH and LDH on the physical and anti-aging properties of bitumen were thoroughly evaluated. The storage stability test showed that TEVS-LDH existed more stably than LDH in bitumen, which was due to the surface modification of LDH which improved the compatibility between LDH and bitumen. The results of physical properties tests showed that TEVS-LDH improved high-temperature behavior and had a less pronounced effect on the low temperature ductility of bitumen in contrast with LDH. Aging indices (viscosity aging index, softening point increment and ductility retention rate) and FTIR showed that TEVS-LDH exhibited better improvement than LDH on anti-ultraviolet aging of bitumen.

Synthesis and characterization of layered double hydroxides intercalated by UV absorbents and their application in improving UV aging resistance of bitumen

Two different types of UV absorbents, 2-hydroxybenzoic acid and 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, were intercalated into layered double hydroxides (LDHs) to synthesize organic LDH by anion-exchange method, and then the synthesized organic LDHs were applied to modify bitumen aiming to improve UV aging resistance of bitumen. According to the characterization with X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM), the two UV absorbents were successfully intercalated into the galleries of LDH, leading to the expansion of interlayer distance of LDH. Thermogravimetry and differential scanning calorimetry (TG–DSC) and UV–vis absorbance analyses indicated that the thermal stability and UV absorptive ability of UV absorbents were enhanced significantly. Compared with LDH, organic LDH exhibited better improvement in UV aging resistance of bitumen by restraining the oxidation of bitumen and generation and stacking of asphaltenes cluster during UV exposure, which was due to the enhanced UV absorptive ability of organic LDH and compatibility between organic LDH and bitumen.

Effect of salicylic acid intercalated layered double hydroxides on ultraviolet aging properties of bitumen

Salicylic acid intercalated layered double hydroxides (Sa-LDHs) were prepared by ion-exchange method. X-ray diffraction (XRD), Fourier transform infrared (FTIR) and ultraviolet and visible (UV–Vis) spectrum were applied to characterize the Sa-LDHs. The increase of basal spacing illustrated in XRD and presence of characteristic peak of salicylic acid observed in FTIR demonstrate that the salicylic acid is favorably intercalated into the interlayers of LDHs. UV–Vis curves of Sa-LDHs reveal the salicylic acid intercalated in LDHs dramatically improves the UV absorption ability, therefore, Sa-LDHs possess both excellent physical reflection and chemical absorption to UV rays. And then the effects of Sa-LDHs and LDHs on UV aging properties of bitumen were investigated. Compared with LDHs modified bitumen after UV aging, Sa-LDHs modified bitumen exhibits smaller changes in physical indexes (softening point and viscosity) and rheological parameters (complex modulus and phase angle), indicating Sa-LDHs can further improve the UV aging resistance of bitumen. The enhanced anti UV aging performance of bitumen mainly attribute to the dramatic improvement in UV absorption ability.

Effect of 4,4′-stilbenedicarboxylic acid-intercalated layered double hydroxides on UV aging resistance of bitumen

UV aging is the main cause of the deterioration of bitumen pavement.

Investigation of Anti-UV Aging of Bitumen Modified with Layered Double Hydroxides

Layered double hydroxides (LDHs) were used to modify bitumen. Effect of LDHs on physical properties and chemical compositions of bitumen was investigated. Fourier transform infrared (FTIR) spectroscopy was carried out to analyze the structural change of LDHs modified bitumen after UV aging. The results show that LDHs is effective in improving the UV aging resistance of bitumen since the viscosity aging index (VAI) and softening point increment (SPI) of bitumen decrease while the retained penetration ratio (RPR) increases with increasing LDHs contents. The carbonyl and sulfoxide of LDHs modified bitumen presented a smaller increase after UV aging in comparison with unmodified bitumen according to FTIR analysis, and the changing rate of carbonyl and sulfoxide index of aromatics and asphaltenes reduced obviously compared with the slight changes of saturates and resins after the introduction of LDHs during UV aging, which demonstrated that LDHs mainly inhibit the oxidation of aromatics and asphaltenes during the UV aging.