Low Temperature Rheological Properties Research Articles

Study on the Rheological Performance and Microscopic Mechanism of PPA/SBS/SBR Composite-Modified Asphalt Cold Replenishment Liquid

To prepare high-performance asphalt cold replacement liquids, a composite modification preparation process was used to synthesize a styrene–butadiene–styrene (SBS) block copolymer, styrene–butadiene–rubber (SBR) copolymer, and polyphosphate acid (PPA), erucamide/diesel/acrylic ester as surfactants/diluents/reinforcing agent respectively. These six were blended to prepare an asphalt cold replenishment liquid (ACRL), and its modification effect on base asphalt was studied using base asphalt as the control group. A comparative study was conducted on the high- and low-temperature rheological properties and microstructure. The modification mechanisms of high-temperature asphalt cold replenishment liquid (H-ACRL) and low-temperature asphalt cold replenishment liquid (L-ACRL) were studied through dynamic shear rheometry, bending beam rheometry, Fourier-transform infrared spectroscopy, fluorescence microscopy, and atomic force microscopy. The results showed that the optimal dosages of PPA/SBS/SBR in H-ACRL and L-ACRL were (1.2%/5%/3%) and (0.9%/4%/4%), respectively. Within the optimal dosage range, the particles in the cold replenishment fluid were uniformly dispersed in the asphalt to form a dense and continuous network. No new functional groups were generated during the preparation of H-ACRL and L-ACRL, showing that the modifiers (surfactants/diluents/reinforcing agent) were only physically blended with the asphalt.

Preparation and properties of a newly developed devulcanized and pyrolytic crumb rubber modified asphalt

Purpose The purpose of this article is to determine the parameters of the preparation process for devulcanized and pyrolytic crumb rubber modified asphalt (DCRMA) and then study the rheological and microscopic properties of DCRMA through experiments.Design/methodology/approach In this study, a new preparation process for DCRMA was developed, then the penetration, softening point and viscosity tests were employed to determine the parameters of the preparation process. The crumb rubber (CR) solubility, Fluorescence microscopy (FM), Fourier Transform Infrared (FTIR) spectroscopy and thermogravimetric analysis tests were conducted to verify the devulcanized and pyrolytic effectiveness of the preparation process. Furthermore, dynamic shear rheometer and bending beam rheometer were used to characterize the high and low-temperature rheological properties of DCRMA.Findings The results showed that the penetration balanced the CR degradation and the virgin asphalt aging well and thus could be used as a main parameters control indicator. The CR solubility, FM and FTIR tests proved that the CR has been fully devulcanized and pyrolytic via the preparation process. The DCRMA exhibited better low-temperature and fatigue performance and lower rutting performance than the conventional crumb rubber modified asphalt (CRMA) with the same CR content. Finally, the time–temperature superposition principle could be employed for all binders in this study.Originality/value A new preparation process for DCRMA was developed.

Combined modification of asphalt with organic attapulgite (OATT) and polyurethane (PU): preparation, properties and modification mechanisms

Polyurethane (PU) and attapulgite (ATT) have been proven to have good effects on asphalt modification. This study proposes to use both PU and organic attapulgite (OATT) to prepare a modified asphalt, aiming to improve the comprehensive performance of asphalt and study the synergistic modification effect of PU and OATT on asphalt. Firstly, the structure and composition of ATT and OATT were determined by X-ray diffraction, scanning electron microscope, and Fourier transform infrared spectroscopy. Then the OATT/PU modified asphalt was investigated in terms of compatibility, basic physical properties, high- and low-temperature rheological properties, and high-temperature stability. Results indicated that the organic modifier was successfully grafted onto ATT. OATT and PU present a good synergy in asphalt and play a significant role in improving the high- and low-temperature performance of modified asphalt. The addition of OATT led to significant and consistent improvement in the high-temperature performance of the OATT/PU modified asphalt. At the same time, the increase of OATT content also helps to improve the low-temperature performance of the modified asphalt. Finally, the optimum contents of modifiers are recommended. The modified asphalt 3 wt%OATT/7wt%PU is suggested for areas with long duration of high temperatures, while 3 wt%OATT/9wt%PU is suggested for areas with long duration of low temperatures.

Rheological properties of SBS-modified asphalt containing aluminum hydroxide and organic montmorillonite

The composite flame retardant composed of aluminum hydroxide (ATH) and organic montmorillonite (OMMT) is of potential application value in the tunnel asphalt pavement. To investigate the effect of ATH and OMMT on the rheological properties of SBS modified asphalt at high and low temperatures. In this study, the composite ATH/OMMT/SBS modified asphalt was subjected to multiple stress creep recovery (MSCR), linear amplitude sweep test (LAS), and Bending beam rheometer (BBR) experiments. Analysis of high and low temperature rheological properties and fatigue properties of composite ATH/OMMT/SBS modified asphalt under the conditions of single incorporation and composite modification. The findings of the tests suggest that ATH can significantly improve the fatigue life but has adverse impact on the creep recovery property of asphalt materials, OMMT has a significant improvement effect on the low-temperature performance, however, the detrimental effect of OMMT on fatigue performance is greater than the improvement of ATH. The research results provide a reference for the practical application of flame retardants.

Research on low temperature properties and physical hardening effect of asphalt components

It is generally recognized in current research that asphalt binder is composed of four components, i.e., saturates, aromatics, resins and asphaltenes, and the physicochemical properties of asphalt binder are closely related to the properties of the components. In this paper, solvent precipitation and chromatographic column method were used to extract and separate a sufficient amount of four components, and different components were recombinant according to the original ratio to form components recombinant materials. Using Fourier Transform Infrared, dynamic shear rheometer and differential scanning calorimetry to characterize the chemical composition and low temperature rheological properties of single component and components recombinant materials, including amplitude sweeping, temperature sweeping, time sweeping temperature-frequency sweeping and relaxation test. The response of the material to the physical hardening effect at low-temperature isothermal storage was also explored. The test results show that, within the test temperature range, the aromatics does not produce physical hardening effect, while the saturates and resins produced a certain degree of physical hardening effect. The free volume, phase angle, and complex shear modulus have different response times to the physical hardening effect, so the free volume theory alone is not sufficient to explain the physical hardening effect. This paper proposes to use the method of area integral to evaluate the degree of response of materials to physical hardening, and to rank the materials.

Thermal Aging Degradation of High-Viscosity Asphalt Based on Rheological Methods.

With the acceleration of the construction of sponge cities in China, porous asphalt pavement (PA) is has been widely used. High-viscosity asphalt (HVA) is the core material in building PA because it has good rheology properties, which can provide good raveling and rutting resistance. However, due to the open-graded structure of PA, HVA was more susceptible to rapid aging, which significantly affects the durability of PA. To investigate the thermal aging effect on the rheological properties of self-modified HVA (SHVA), five types of asphalts were aged using a rolling thin film oven (RTFO) and pressure aging vessel (PAV). Then, rheological tests were adopted, such as temperature sweep test (TS), repeated creep and recovery test (RCR), and bending beam rheometer test (BBR). The results indicate that during the aging process, the oxidation-induced hardening effect of neat asphalt and the degradation-induced softening effect of the modifier changes the rheology properties of HVA significantly. As the aging progresses, the contribution of the modifiers of HVA to anti-aging performance is greatly reduced. At high temperatures, HVA demonstrates better anti-aging performance than conventional styrene-butadiene-styrene (SBS)-modified asphalt (Guo Chuang, GC). The change of the high-temperature rheological indices of the two HVA types (SHVA and TAFPACK-super HVA (TPS)) showed a smaller activation energy index (EAI), a more considerable viscous component of binder creep stiffness (Gv), and more minor accumulated stain (racc), indicating a more significant anti-short-term and long-term aging performance, which is beneficial to the high-temperature performance of asphalts. However, the changes in low-temperature rheological properties do not align with those in high-temperature rheological properties after long-term aging. The BBR test results reveal that TPS exhibits worse low-temperature performance than GC and SHVA. During the thermal aging process, the contribution rate of the modifiers in SHVA against RTFO and PAV aging is higher than that of the modifiers in TPS, which contributes to the superior anti-aging property. Overall, SHVA demonstrates the best anti-aging performance among the five asphalts tested.

Effect of short-term aging on rheological properties of bio-asphalt/SBS/PPA composite modified asphalt

Substituting petroleum asphalt with bio-asphalt produced by biological waste recycling can mitigate the dependence on non-renewable resource oil. This study aimed to investigate the effectiveness of bio-asphalt as a substitute for petroleum asphalt by analyzing its rheological properties. Therefore, in this study, modified asphalt was prepared using styrene-butadiene-styrene copolymer (SBS), polyphosphoric acid (PPA), and bio-asphalt (BA) as modifiers, and the short-term aging test of the modified asphalt was carried out. Then the rheological properties of the modified asphalt were analyzed through the Temperature Scanning (TS) test, the Multiple Stress Creep Recovery (MSCR) test, and the Bending Beam Rheometer (BBR) test; finally, the Fourier Transform infrared spectroscopy (FTIR) test, Fluorescence Microscopy (FM) test to study the modification mechanism and microscopic characteristics of asphalt. The results show that adding BA improved the low-temperature rheological properties of modified asphalt while reducing the high-temperature rheological properties of PPA modified asphalt. The BA, SBS, and PPA combination exhibited excellent performance in high and low-temperature conditions. The short-term aging process enhances the high-temperature rutting resistance of modified asphalt but adversely affects its low-temperature performance. Fluorescence microscopy tests have demonstrated that BA improves the compatibility of SBS and PPA in asphalt. Meanwhile, FTIR has revealed that BA and SBS are physically mixed, and BA and PPA undergo a chemical reaction. This study suggests that BA could be a viable and sustainable alternative to petroleum asphalt, with promising performance characteristics when combined with SBS and PPA modifiers.

Rheological Properties of Desulfurized Crumb Rubber Modified Warm Mix Asphalt

In order to study the rheological properties of warm mix asphalt modified by desulfurized rubber powder with different meshes, the desulfurized rubber powder was mixed with matrix asphalt at the best content. Dynamic shear rheological test (DSR) was used to study the high temperature rheological properties of asphalt modified by waste rubber powder. Multi-stress creep test (MSCR) was used to study the high temperature deformation resistance of asphalt modified with waste rubber powder. The low temperature rheological properties of Sasobit and crumb rubber modified asphalt with different mesh numbers were evaluated by bending beam rheological test (BBR). The test results show that compared with the base asphalt, the complex modulus and rutting factor of CRMA 60 are significantly improved, and the effect is more obvious than that of CRMA 40 and CRMA 80. With the addition of Sasobit, the high temperature performance of WCRMA first increased and then decreased. With the addition of Sasobit, the creep stiffness modulus of WCRMA decreases, the creep rate increases, and the low-temperature properties first increase and then decrease. From the atomic force microscope (AFM), it can be seen that Sasobit promotes the compatibility between rubber powder and asphalt, and the performance of asphalt modified by 60 mesh rubber powder is best. When the mass fraction of Sasobit is 2.5%, WCRMA has the best comprehensive performance.

Preparation and performance of self-healing SBS modified bitumen based on dynamic disulfide bonds

In this study, self-healing SBS (S-SBS) was first synthesized by introducing dynamic disulfide bonds into the molecular structure of SBS. Subsequently, a self-healing SBS modified bitumen (S-SMB) was prepared by blending of S-SBS and bitumen. The chemical structure of S-SBS and S-SMB was charactered by Fouriertransform infrared spectrometer (FTIR) and Raman spectrometer. The physical properties, low-temperature rheological properties and self-healing performance of S-SMB were investigated. The results of FTIR and Raman showed that dynamic disulfide bonds were successfully introduced into the molecular structure of SBS. With the increase of dynamic disulfide bonds content in SBS molecular structure, the softening point and ductility of S-SMB enhanced, and the penetration was decreased. Fluorescence microscope showed that the S-SBS in S-SMB formed a complete crosslinking network structure compared to SMB. The bending beam rheometer illustrated that the low-temperature rheological properties and the cracking resistance of SMB were improved by introducing dynamic disulfide bonds. The fluorescence microscopy observation indicated that the crack in S-SBS can self heal. The fracture healing test and fatigue healing test demonstrated that dynamic disulfide bonds endow S-SMB with great self-healing performance. The fracture healing rate of S-SMB reached 58.7% after 4 h of healing, and the fatigue healing index reached 0.93 after 1 h of healing.

Rheological Properties of Composite Inorganic Micropowder Asphalt Mastic

Graphene Tourmaline Composite Micropowder (hereinafter referred to as GTCM) modified asphalt was prepared by the ball milling method. The effects of different temperatures and different frequencies on the high-temperature performance of composite-modified asphalt were evaluated by dynamic shear rheological test, and the viscoelastic properties of composite-modified asphalt under different stresses and different temperatures were analyzed. The low-temperature rheological properties of GTCM-modified asphalt were analyzed by bending beam rheological test, and its mechanism was analyzed by Fourier transform infrared spectroscopy (FTIR) test. The results show that the temperature sensitivity and anti-aging resistance of GTCM-modified asphalt are significantly higher than that of tourmaline-modified asphalt. The improvement effect gradually increases with the increase in graphene powder content, and its addition does not change the viscoelastic properties of asphalt. The complex shear modulus and phase angle of GTCM-modified asphalt at appropriate temperatures are more conducive to tourmaline-modified asphalt and matrix asphalt, which can improve the rutting resistance of asphalt. In the same type, with the increase in composite modified micropowder content, the rutting resistance of modified asphalt is better. The improvement of rutting resistance of GTCM-0.5, GTCM-1.0 and GTCM-1.5-modified asphalt can reach 12.95%, 10.12% and 24.25%, respectively; the improvement range is more complicated due to temperature and frequency changes. The GTCM-modified asphalt has good low-temperature crack resistance. The creep stiffness modulus of GTCM-modified asphalt decreases with the increase in load time under different types and dosages, and its stiffness modulus is smaller than that of tourmaline-modified asphalt and mineral powder asphalt mastic. The creep rate increases with the extension of load time, which is greater than that of tourmaline-modified asphalt and mineral powder asphalt mastic. When the load was 60 s, the creep stiffness modulus of GTCM-0.5, GTCM-1.0 and GTCM-1.5-modified asphalt decreased by 5.75%, 6.97% and 13.73%, respectively, and the creep rate increased by 1.37%, 2.52% and 4.35%, respectively. After adding GTCM or tourmaline to the matrix asphalt, no new functional groups were produced due to the chemical reaction with the asphalt.

Evaluation on recycling effect of a novel rejuvenator combined with fresh asphalt on field-aged SBS modified asphalt by rheological and micro characteristics

Styrene-butadiene-styrene block copolymers (SBS) modified asphalt has been the main binder applied in the surface course of high-grade asphalt pavement. However, as more and more pavements are entering into the maintenance period, a mass of waste SBS modified asphalt mixtures are produced. To effectively restore the performance of field-aged SBS modified asphalt (SBSMA), a novel rejuvenator (RA) combined with fresh SBSMA was used in this research. The rheological properties of recycled SBSMA were investigated using dynamic shear and bending beam rheometer tests, and the micro characteristics were characterized by fluorescence microscopy, Fourier transforms infrared spectroscopy and chemical composition tests. The results indicate that RA can lessen the aging behavior of recycled SBSMA from themolecularstructure, enhance the compatibility between SBS modifier and asphalt in recycled SBSMA. The combined utilization of RA and new SBSMA can effectively recover the high, intermediate and low temperature rheological properties of recycled SBSMA. Moreover, when the ratio of aged SBSMA with RA to new SBSMA is 0.45:1, the recycled SBSMA has the closest continuous performance grade to new SBSMA.

Physico-chemical and mechanical properties of asphalt binders blended with waste bio-shell powder

ABSTRACT Bio-shell is a renewable bio-waste resource being used to develop sustainable and environmentally friendly pavement materials. In this study, bio-shell was mixed with asphalt to prepare bio-shell-modified asphalt. The modified asphalt was divided into four groups with 0%, 5%, 10% and 15% of waste bio-shells. The morphology of the bio-shell was investigated by scanning electron microscopy tests. Penetration, softening point, and ductility tests were performed to analyse the basic physical properties of bio-shell asphalt. Dynamic shear rheometer and bending beam rheometer were used to high and low-temperature rheological properties of the bio-shell-modified asphalt. Fourier transform infrared spectroscopy and nuclear magnetic resonance hydrogen spectroscopy were used to analyse the atomic distribution and relative content of bio-shell-modified asphalt and reveal the modification mechanism. Atomic force microscopy was employed to observe the nano-microscopic morphology of the bio-shell-modified asphalt, and to analyse the changes of the bee structures in the asphalt. The results showed that the high-temperature rheology of 15% bio-shell asphalt was the best. The rutting factors of the asphalt increased by 38%, 43%, 45%, 50%, 55% and 63% at temperatures of 40°C, 46°C, 52°C, 58°C, 64°C and 70°C, respectively, compared to the matrix asphalt.

Research on High- and Low-Temperature Rheological Properties of High-Viscosity Modified Asphalt Binder

This study evaluates the critical high- and low-temperature rheological properties of a high-viscosity modified asphalt (HVMA) binder by analyzing one neat and three high-viscosity modified binders (B-type, Y-type, and H-type) using temperature sweep tests and multi-stress creep recovery tests (MSCR) through the dynamic shear rheometer (DSR), and low-temperature creep stiffness properties by the bending beam rheometer (BBR). Technical indexes such as the softening point temperature, dynamic viscosity, rutting factor, unrecoverable creep compliance, and the creep recovery rate are measured and calculated for high-temperature properties, while the m/S value, dissipation energy ratio, relaxation time, elongation, creep stiffness, and creep speed are used as technical indexes for low-temperature properties. The results show that the incorporation of high-viscosity modifiers reduces the unrecoverable creep compliance and increases the creep recovery rate of the asphalt binder. Non-recoverable creep compliance is found to be a reliable indicator for high-temperature performance, while at low temperatures, the relaxation time decreases, the dissipation energy increases, and the stress relaxation ability improves. The dissipation energy ratio and m/S value are suggested to evaluate the low-temperature performance of HVMA binders using the Burgers model based on the BBR bending creep stiffness test. Therefore, this study recommends using the unrecoverable creep compliance via MSCR to evaluate high-temperature properties and dissipation energy ratio and m/S value for low-temperature properties in the evaluation of HVMA binders.

Study on rheological and micro-structural properties of different modified asphalt by using organic and inorganic modifier

In order to evaluate the high and low temperature rheological properties of different modified asphalt, this paper prepared different types of modifiers and short-term aging modified asphalt (RTFOT), using dynamic shear rheometer (DSR) and bending beam rheological test (BBR) to compare and analyze the deformation resistance and stress sensitivity of different types (organic and inorganic) modified asphalt, determine its PG classification, and evaluate its fitting parameters with the help of Burgers model. The low-temperature mechanical properties of the fitting parameters were evaluated by the Burgers model; the chemical composition of different modified asphalts was analyzed by Fourier transform infrared spectroscopy (FTIR), and the microscopic state of the modified asphalts was observed by fluorescence microscopy. The results show that: with the increase of temperature, the high temperature deformation resistance of organic modified asphalt is better than that of inorganic modified asphalt, and PE modified asphalt is the best, and the low temperature performance of inorganic modified asphalt is poor, and the addition of SBS It will improve the low temperature crack resistance of asphalt. The road performance of different modified asphalts from strong to weak are PE modified asphalt, SBS modified asphalt, diatomite modified asphalt, montmorillonite modified asphalt. The research results have certain reference value for further research on different types (organic and inorganic) of modified asphalt.

Rheological properties of composite DTDM/DOP/SBS modified asphalt and its effect on high and low temperature performance

To investigate the effect of crosslinker (DTDM) and plasticizer (DOP) on the rheological properties of SBS modified asphalt at high and low temperatures. In this study, the composite DTDM/DOP/SBS modified asphalt was subjected to infrared spectroscopy, dynamic shear rheology, and low-temperature bending beam rheology experiments. Analysis of microscopic properties and high and low temperature rheological properties of composite DTDM/DOP/SBS modified asphalt. The findings of the tests suggest that the cross-linking agent (DTDM) and plasticizer (DOP) have a better chemical response with SBS modified asphalt. It may significantly increase SBS modified asphalt's high-temperature deformation resistance, elastic recovery capacity, low-temperature fracture resistance, and aging resistance. The research findings have theoretical and practical significance for enhancing asphalt high and low temperature performance.

Aging Resistance Evaluation of Asphalt Modified by BRA/NA/AA Composite Modified Asphalt Based on the Rheological and Microscopic Analysis

In this study, Buton rock asphalt (BRA), nano-aerogel (NA), and an antiaging agent (AA) were selected to modify base asphalt to improve its aging resistance. Based on the preliminary performance test results, the optimum dosage of the three modifiers was determined. The asphalt’s rheological properties and microscopic properties were tested under different aging methods. Its high- and low-temperature rheological properties were characterized by dynamic shear rheological tests and bending beam rheological tests. Fourier transform infrared spectroscopy (FTIR) analyzed changes in the asphalt’s functional groups before and after aging. The ultraviolet absorption capacity of the asphalt before and after aging was studied by an ultraviolet-visible spectrophotometer (UV-VIS). The results showed that the optimal dosing of the modifiers was 2% NA, 10% BRA, 0.3% antioxidant 1010, and 0.4% UV-327. Compared with the base asphalt, the composite modified asphalt with BRA, NA, and AA showed improvement in high- and low-temperature performance. The aging index of both the rheological test and the infrared spectroscopy test showed that the composite modified asphalt had the best resistance to aging. Its resistance to UV radiation was higher than that of the base asphalt, and the BRA/NA modified asphalt. Therefore, the addition of BRA and NA effectively improved the asphalt’s high- and low-temperature performance. Addition of the antioxidants 1010 and UV-327 effectively improved its aging resistance.

Analysis of Low-Temperature Rheological and Mechanical Properties of Steel Slag Asphalt Mixture Based on Direct Tensile Test

Due to the high resource requirements for specimen preparation and testing equipment, the direct tensile test method is seldom used to study the cracking behavior of asphalt mixture at low temperatures. In this study, three asphalt mixtures were prepared in which all of the basalt or part of the basalt and basalt aggregate was replaced by steel slag. Through the direct tensile creep test and direct tensile relaxation tests including the measurement of creep rate, cumulative strain change rate, and relaxation time, the variation law of rheological properties of low-temperature steel slag asphalt mixture was analyzed and the variation law of viscoelastic properties was explored. Meanwhile, based on the traditional viscoelastic constitutive model, the creep compliance and relaxation modulus were fitted. The mechanical response of the transformation from creep compliance to relaxation modulus of steel slag asphalt mixture was analyzed by a numerical method. The results show that, with the decrease of temperature, the creep rate εs and cumulative strain change rate of the three asphalt mixtures gradually decline, and the relaxation time gradually increases. In particular, when the temperature was reduced from −20°C to −30°C, the cumulative strain change rate of all three asphalt mixtures reached the minimum, which was less than 10%. Moreover, none of them relax to 75% σ0 within 3,600 s at −30°C. The mixture specimens with steel slag replacing all basalt exhibited the best low-temperature deformation adaptation performance under different temperature conditions. Mixture specimens with basalt as aggregate have the worst low-temperature deformation adaptation performance. The relaxation modulus obtained by the measurement of creep compliance is similar to that obtained by testing, and the relaxation modulus calculated through the direct tensile test is more accurate.

Study on the Low-Temperature Rheology of Polar Drilling Fluid and Its Regulation Method

Drilling fluid is the blood of drilling engineering. In the polar drilling process, the ultra-low temperature environment puts high demands on the rheological performance of drilling fluids. In this paper, the effects of temperature, ice debris concentration and weighting agent on the rheological properties of drilling fluids were studied. It was found that the lower the temperature and the higher the ice debris concentration, the higher the drilling fluid viscosity, but when the ice debris concentration was below 2%, the drilling fluid rheology hardly changed. Secondly, the low temperature rheological properties of drilling fluid were adjusted by three different methods: base fluid ratio, organoclay, and polymers (dimer acid, polymethacrylate, ethylene propylene copolymer, and vinyl resin). The results showed that the base fluid rheological performance was optimal when the base fluid ratio was 7:3. Compared with polymers, organoclay has the most significant improvement on the low temperature rheological performance of drilling fluid. The main reason is that organoclay can transform the drilling fluid from Newtonian to non-Newtonian fluid, which exhibits excellent shear dilution of drilling fluid. The organoclay is also more uniformly dispersed in the oil, forming a denser weak gel mesh structure, so it is more effective in improving the cuttings carrying and suspension properties of drilling fluids. However, the drilling fluid containing polymer additives is still a Newtonian fluid, which cannot form a strong mesh structure at ultra-low temperatures, and thus cannot effectively improve the low-temperature rheological performance of drilling fluid. In addition, when the amount of organoclay is 2%, the improvement rate of the yield point reaches 250% at -55 °C, which can effectively improve the cuttings carrying and suspension performance of drilling fluid at ultra-low temperature.

Preparation and curing properties of waterborne epoxy emulsified asphalt/DMP-30 composites

The objective of this paper is to investigate the effect of DMP-30 on the curing rate and mechanical properties of waterborne epoxy emulsified asphalt (WEREA). WEREA/DMP-30 composites were prepared and the high temperature rheological properties, low temperature rheological properties, adhesion properties, tensile properties and fluorescence microscopy images of DMP-30 modified WEREA were investigated. Results showed that DMP-30 can effectively reduce the curing time of WEREA. There are positive and negative effects of DMP-30 on the mechanical properties of WEREA.The 1% and 2% DMP-30 dosing showed an enhancement of the high temperature performance and tensile strength, while the 3% DMP-30 dosing showed a weakening effect. In addition, the ductility and flexibility of WEREA are improved with the addition of DMP-30. The above results provide a reference for material optimization design of waterborne epoxy resin modified emulsified asphalt.

Evaluation of the Physicochemical Properties and Antiaging Properties of Bitumen Mastic Modified by Layered Double Hydroxides

Layered double hydroxides (LDHs) can shield polymeric materials from UV light, which allows reducing material aging and erosion damage of bituminous pavement under physical and chemical action. In this study, the physicochemical properties, aging resistance, and erosion resistance to the aqueous solution of LDHs modified bitumen mastic (BM) were characterized by Fourier-transform infrared spectroscopy, basic physical tests, viscosity tests, a dynamic shear rheometer, and a bending beam rheometer. The results show that few chemical reactions occurred between LDHs and BM, indicating that a physical mechanism underlay the modification of BM by LDHs. Moreover, LDHs could increase the flow activation energy of BM by 0.12%, increase the high failure temperature from 69.07 °C to 71.07 °C, and decrease the low failure temperature from −10.50 °C to −12.39 °C. Therefore, LDHs could slightly reduce the temperature sensitivity of BM, while slightly enhancing the high and low-temperature rheological properties of BM. Compared with short-term aging and long-term aging, LDHs could significantly improve the UV aging resistance of BM. The above results are consistent with previous studies of LDHs-modified bitumen. Furthermore, water and pH 3 acidic solutions had the greatest degree of erosion to BM, and LDHs could improve the resistance to aqueous solutions. Overall, this study can help to investigate the effects of various environmental factors on the performance of LDHs modified bitumen pavements during long-term use.