Storage Stability Of Asphalt Binders Research Articles

Laboratory Evaluation of Storage Stability for Asphalt Binder Modified with Crumb Rubber and Styrene-Isoprene-Styrene Depending on Evaluation Factors and Blending Condition.

Modified asphalt binders are still considered important in asphalt pavement. However, the comprehensive use of various modifiers is limited due to storage stability issues. Moreover, there is a scarcity of detailed analyses regarding the degree of separation for asphalt binders among each method despite the utilization of various methods to assess the storage stability of binders. Therefore, a comprehensive analysis was conducted to assess the storage stability of asphalt binder modified with a crumb rubber modifier (CRM) and styrene-isoprene-styrene (SIS), utilizing five evaluation factors following the ASTM D7173 guidelines based on four mixing methods (A: high-shear mixing method, B: low-speed agitating method, C: high-shear mixing method + low mixing method, D: low-speed agitating method + low mixing method). To produce the modified asphalt binder, the proportions of the CRM were 5% and 10% for each binder, and 10% SIS was added to all binders. The results in this study convey that (1) the addition of the modifier led to an increase in G*/sin δ with different mixing methods, but using mixing methods (C and D) for a relatively long time resulted in a lower G*/sin δ, indicating suboptimal performance; (2) through the multiple stress creep recovery (MSCR), rheological properties of Jnr and % rec exhibited trends similar to G*/sin δ evaluation, highlighting an improved elastic recovery with a higher modifier content; (3) storage stability assessment revealed consistent trends in high-shear mixing groups (A and C), while low-speed mixing groups (B and D) exhibited an elevated separation index (SI), suggesting a sensitivity to modification conditions; (4) evaluation using the MSCR method indicated that % rec with a 3.2 kPa load is effective for the sensitive assessment of binder storage stability and Jnr showed a limited sensitivity across varying loads, advocating for % rec for precise evaluation; and (5) despite permitting various tests, achieving consistent results remains challenging. Future research should explore diverse modifiers and optimal evaluation methods to enhance knowledge of binder behavior and separation dynamics.

A Laboratory Investigation Regarding Storage Stability of the CRM-Modified Bitumen—CRM Processing Method (Untreated vs. Treated)

The aim of this study is to analyze the phase separation that occurs between treated and untreated rubber crumb particles produced by wet processes in the laboratory. The percentage of replacement used for both the treated and untreated crumb rubber-modified asphalt (CRMA) was 5%, 10%, 15%, and 20%. Tests to evaluate binder properties were performed using a rotational viscometer and a DSR, and the following properties were determined—viscosity, G*/sinδ, % recovery, and Jnr. The phase separation study was analyzed using the viscosity and G*/sinδ results. In general, the results of the study show the following. (1) The treated CRMA binders had higher viscosity values than untreated CRMA binders, although some values could not be measured due to the high viscosity values. (2) The G*/sinδ, % recovery and Jnr results also had a similar trend with viscosity results. (3) The viscosity and G*/sinδ phase separation values demonstrate that treated CRMA binders perform better than untreated CRMA binders. (4) Different experimental methods have shown variations in the calculated SI value; hence, a more improved approach should be explored to accurately assess the storage stability of asphalt binders containing various additives.

Investigation of the Effect of Combined Nanosilica and Iranian Natural Binder on the Rheological Behavior of Mastics and Performance of Asphalt Mixtures

The aim of this study was to evaluate the impact of nanosilica (NS) and gilsonite on the behavior of asphalt binders and stone matrix asphalt (SMA) samples. An asphalt binder with 60/70 penetration grade, 0%, 3%, 5%, and 7% gilsonite, and 0%, 2%, 4%, and 6% NS by the weight of the asphalt binder were used. The rotational viscosity (RV), linear amplitude sweep (LAS), bending beam rheometer (BBR), multiple stress creep recovery (MSCR), and dynamic shear rheometer (DSR) tests were applied to evaluate the physical and rheological behaviors of modified asphalt binders. Also, the wheel track, dynamic creep, indirect tensile strength (ITS), resilient modulus (Mr), and four-point bending (FPB) fatigue tests were utilized to examine the performance characteristics of mixtures. Moreover, a two-factor analysis of variance (ANOVA) was used to analyze the data. The rheological test results showed that gilsonite and NS enhanced the rutting and fatigue resistances of asphalt binders. Gilsonite also reduced the low-temperature resistance of asphalt binders, while NS improved that. The storage stability test showed that gilsonite enhanced the storage stability of asphalt binders. Also, adding NS led to an improvement in phase separation. MSCR test indicated an improvement in the high-temperature performance of base asphalt binder at different stress levels by the addition of gilsonite and NS. Based on the LAS test, gilsonite and NS enhanced the fatigue characteristics of asphalt binders. The sample test results also showed that gilsonite and NS improved the permanent deformation resistance, MR, ITS, fracture energy, and intermediate-temperature properties of samples.

Rheological, chemical and short-term aging properties of waste polyurethane particles modified asphalt binder with or without SBS

In order to effectively dispose of waste polyurethane (WPU) and obtain modified asphalt binders with excellent properties, WPU particles are used to modify asphalt binder. Conventional properties and thermal storage stability of asphalt binders are analyzed, their rheological properties and creep recovery properties are tested by the dynamic shear rheological (DSR). Microstructure, molecular weight and chemical structure of the asphalt binders are analyzed by fluorescence microscopy (FM), gel permeation chromatography (GPC) and fourier transform infrared spectroscopy (FTIR) respectively. Results show that low temperature crack resistance of base asphalt binder is improved due to WPU particles addition, which impairs the property of SBS modified asphalt binder. After short-term aging, the Jnr at 3.2 kPa (Jnr3.2) of modified asphalt binder with WPU particles is less than 2.0 kPa−1. And Jnr3.2 of base asphalt binder decreases by 52.4 % due to WPU particles addition, it is 25.5 % for SBS modified asphalt binder. The thermal storage stability of WPU particles modified asphalt binder is poor and improved by 42.3 % due to the SBS use. The rod-shaped WPU particles are found in modified asphalt binder without SBS, and their structure is destroyed during aging, forming numerous small particles and small molecular products, which improve rutting resistance of asphalt binder. When aged at 150 °C, 163 °C and 180 °C, addition of WPU particles makes aging resistance of base asphalt binder increase by 0.9 %, 1.5 % and 1.2 % respectively, which impairs the aging resistance of SBS modified asphalt binder by 0.9 %, 5 % and 5.3 % respectively. FTIR results manifest decomposition reaction presented in WPU during preparation and aging, forming products with CO.

Compatibility and Storage Stability of Asphalt Binder Modified by Styrene-Butadiene-Styrene (SBS) Graft Copolymer

A styrene-butadiene-styrene triblock copolymer (SBS) was grafted with an unsaturated polar monomer (monomer A) composed of maleic anhydride (MAH) and methoxy polyethylene (MPEG) via a ring-opening reaction after epoxidizing styrene-butadiene-styrene triblock copolymer (ESBS). The microscopic changes of SBS before and after grafting has been characterized with Fourier transform infrared spectrum (FT-IR), X-ray photoelectron spectroscopy (XPS) and gel permeation chromatography (GPC). The results revealed that the monomer A was successfully grafted on SBS backbone, and the maximum graft ratio (GR) was 20.32%. To verify the compatibility between SBS and asphalt, solubility parameters and surface free energy (SFE) of SBS, grafted SBS and asphalt were measured. It was found that the solubility parameter and SFE of grafted SBS were closer to asphalt compared with SBS. It also has been confirmed from storage stability that the temperature susceptibility of grafted SBS modified asphalt was reduced in compare with SBS modified asphalt binder. As consequence, the use of grafted copolymer can be considered a suitable alternative for modification of asphalt binder in pavement.

Thermal Storage Stability of Bio-Oil Modified Asphalt

AbstractThis study investigates and evaluates the storage stability of asphalt binder modified by bio-oil at high temperature. Five bio-asphalts are prepared by adding 10, 15, 20, 25, and 30% bio-o...

Evaluation and Analysis of Variance of Storage Stability of Asphalt Binder Modified by Nanotitanium Dioxide

To investigate the effects of nanoparticle content, storage time, and storage temperature on the storage stability of asphalt binders modified by nanoparticles, hot tube storage tests, softening point tests, and dynamic-shearing rheometer (DSR) tests were adopted to evaluate the properties of two kinds of nanotitanium dioxide (TiO2) modified asphalt binders. A statistical one-way analysis of variance (ANOVA) test was employed to analyze the effects of those variations on the storage stability of the nano-TiO2 modified asphalt binders. The results indicated that the softening point, the failure temperature, the dynamic-shear viscosity, and G⁎/sinδ of the binders increased with nanoparticle content. The storage stability of the binders decreased with nanoparticle content. The impact of storage time on the storage stability of the binders was remarkable when the storage time was more than 48 h. Moreover, the storage stability of the binders at low temperatures was better than that at high temperatures. Based on the one-way ANOVA, the size of nanoparticle had little influence on the storage stability of the nano-TiO2 modified asphalt binders in this study. Reducing the nanoparticle size cannot effectively enhance the storage stability of the nanoparticle modified asphalt binder due to the agglomeration of nanoparticle.

Influence of graphite on the thermal characteristics and anti-ageing properties of asphalt binder

Hydronic asphalt pavement (HAP) is an emerging technology for the purpose of harvesting solar energy in the summer and deicing the pavement in the winter. Increasing the thermal conductivity of pavement material is a fundamental technology to improve the operation efficiency of such novel system. In this paper, the influences of graphite on the thermal characteristics and anti-ageing properties of asphalt binders were experimentally investigated. A control asphalt binder (CAB) sample was prepared by the same weight ratio of asphalt and mineral filler. Experimental results indicated that the thermal conductivity and diffusivity increased linearly with the increasing of graphite content, while the specific heat presented a descending trend correspondingly. Although the storage stability of asphalt binders with graphite were better than the CAB sample, binders with mineral filler or graphite showed bad high temperature storage stability. Differences between the physical and rheological properties of the original asphalt binders and the aged samples illustrated that graphite improved the anti-ageing properties of asphalt binders.

Investigation of the rheological modification mechanism of crumb rubber modified asphalt (CRMA) containing TOR additive

Crumb rubber obtained from scrap tires has been incorporated with asphalt binder to improve the performance of asphalt mixtures in the past decades. However, rubber asphalt mixtures demand higher production temperatures than conventional asphalt binders due to the higher viscosity of asphalt rubber binder. The objective of this paper is to evaluate the rheological properties of crumb rubber modified asphalt by adding trans-polyoctenamer rubber (TOR) additives and investigate the modification mechanism between TOR and crumb rubber modified asphalt. In this study, CRMA was prepared by mixing Karamay 70 penetration grade base asphalt at 15%, 20% and 25% crumb rubber proportions by weight of asphalt. TOR, a typical reactive modifier, was added to CRMA at two percentages of 0% and 4.5%, respectively. Several conventional laboratory rheological tests were carried out to evaluate the performance of CRMA with and without TOR additive at different temperatures. Furthermore, in order to investigate the interaction mechanism of TOR and CRMA, a series of advanced tools, including the scanning electron microscopy (SEM) test, differential scanning calorimeter (DSC) test, Fourier transform infrared spectroscopy (FTIR) test were conducted. From the experimental results obtained, it may be concluded that CRMA with adding TOR not only improves the engineering properties of the rubber modified asphalt, but also improves the performance of asphalt rubber. From the microscopic tests, it is concluded that there is a complex chemical reaction between TOR and CRMA, which changes the rheological properties of CRAM and contributes to the storage stability of asphalt binder.

Physical properties and storage stability of asphalt binder modified with nanoclay and warm asphalt additives

Nowadays, researchers are interested in using the material at nanoscales as one of asphalt binder modifier. In this paper, Malaysian asphalt binder was modified with nanoclay and warm asphalt additives (WAA) and tested to determine the physical properties and storage stability. The results of the investigation indicated that the modified asphalt binders were stable in term of storage and they also have potential to improve physical properties of asphalts such as increasing softening point and decreasing the penetration. In addition, there was a significant reduction of temperature for mixing and compaction of asphalt mixtures.

Storage stability of modified binders using the newly developed LAST procedure

ABSTRACT The Laboratory Asphalt Stability Test (LAST) was introduced as part of the NCHRP 9–10 project to evaluate storage stability of asphalt binders. The unique design allows varying the temperature, time of storage, and level of agitation during storage and allows sampling of the material continuously throughout the test. The test design is based on scaling down one of the commonly used storage tanks used for modified asphalts in the field. The test results can be used to guide the production of the modified binders and determine the performance of these binders during the construction process. This paper discusses the design and introduces the details of the testing protocol proposed to evaluate thermal stability of binders. The protocol follows a systematic procedure for detailed evaluation of effects of phase separation and possible degradation during storage. A set of parameters is proposed for use as indices to reflect the potential of binders for phase separation and/or thermal degradation. A large number of binders have been tested with the LAST and the results are summarized and discussed in this paper. The results indicate that binders can vary significantly in their thermal stability characteristics and thus their stability characteristics need to be measured and considered in selection of binders for different applications. The LAST results indicate that some binders are very stable for extended times, others can be kept homogeneous only with minor agitation while others require more rigorous agitation. Time for separation is an important factor that should be considered. The results also indicate that agitation can result in degradation of modifier and/or significant additive hardening. The rheological measurements conducted indicate that phase separation and/or degradation appear to have influences on rheological type of binders, such that frequency dependency of temperature dependency changes with storage.

Evaluation of Stability, Nature of Modifier, and Short-Term Aging of Modified Binders Using New Tests: LAST, PAT, and Modified RTFO

In a recent survey of users and producers of modified asphalts, stability and short-term aging were two of the main concerns regarding the use of modified asphalts. In an NCHRP project, a concentrated effort was put into development of revised or new testing procedures to better characterize the nature of modified asphalt and to solve some of the difficulties with using existing aging procedures developed for neat asphalts and modified asphalts. Three main procedures have been proposed to complement the existing Superpave procedures: the laboratory asphalt stability test, for measuring the storage stability of asphalt binders; the particulate additive test, for separation of particulate additives; and the modified rolling thin film oven test for short-term aging. The background behind the development of these test methods is explained, and typical data collected for a number of modified asphalts are presented. The results indicate that these tests show high promise in covering characteristics not covered by the current Superpave binder specifications and in solving some of the problems with the existing aging methods. The results also indicate that the behavior of modified binder can be very complex and that the method of data interpretation is very critical.