Polymer Modified Asphalt Binders Research Articles

INVESTIGATION OF THE MECHANICAL PERFORMANCE OF STONE MASTIC ASPHALT MIXTURES MODIFIED BY RECYCLED WASTE POLYMERS

The usage of polymer-modified asphalt binders has increased as a result of the significant increase in the number of conventional cars operating on Iraqi roads in recent years. This has resulted in increased strains being placed on pavement structures and materials. Global exploration has focused on the development of stabilizing Stone Mastic Asphalt mixtures for improved pavement behavior. Numerous effective efforts were made to stabilize stone mastic asphalt mixes with polymers and fibers. Iraq produces a considerable amount of waste polymer materials each year. Usually, they are sent to landfills for disposal. These wastes are dumped, occupying a sizable portion of landfill space and creating various serious environmental issues. The study focuses on how waste polymer additions, such as recycled plastic bottles, shopping boxes, and tire crumb rubber, affect the mechanical performance and durability of stone mastic asphalt mixtures. The mechanical performance attributes were assessed. It is evident from the findings that the drain-down amounts were within the permissible requirement range. The findings also showed that the indirect tensile strength, Marshall Stability, moisture damage resistance, and resistance for permanent deformation of stone mastic asphalt mixtures have all increased as a result of the use of waste polymer components. The recycled polymer-modified mixes are the combinations that are most resistant to rutting, according to the results of the repeated load axial creep tests. Iraq may have new options to employ the significant volumes of recycled polymers that are becoming accessible as a result of recycling waste polymers.

Experimental Investigation of LDPE and EVA on Asphalt Binder

Abstract: This research study aims to investigate the impact of incorporating Ethylene Vinyl Acetate (EVA) and Low-Density Polyethylene (LDPE) on the properties of asphalt binder. The use of polymer-modified asphalt binders has gained significant attention in recent years due to their potential to improve the performance and durability of asphalt pavements. EVA and LDPE are two commonly used polymers that have shown promise in enhancing the rheological and mechanical properties of asphalt binders. The experimental investigation involved the preparation of asphalt binder samples with varying percentages of EVA and LDPE, ranging from 0% to 8% by weight. A series of laboratory tests were conducted to evaluate the effects of polymer modification on the fundamental properties of asphalt binder. These tests included penetration, softening point, ductility, viscosity, and dynamic shear rheometer (DSR) tests.The results of the study indicated that the addition of EVA and LDPE led to notable improvements in the rheological and mechanical properties of asphalt binder. Increased polymer content resulted in reduced penetration values, higher softening points, and improved resistance to rutting and deformation. Additionally, the modified binders exhibited enhanced viscosity and elastic behavior, as indicated by the DSR tests. The study also investigated the compatibility between EVA/LDPE and asphalt binder through microscopy and chemical analysis techniques. The findings of this experimental investigation contribute to the understanding of the effects of EVA and LDPE on asphalt binder performance. The results highlight the potential of these polymers in enhancing the resistance to rutting and deformation of asphalt pavements. This research can serve as a basis for further studies on polymer modification of asphalt binders and aid in the development of improved asphalt pavement materials with enhanced durability and longevity.

Rheological analyses of binders modified with triple combinations of Crumb-Rubber, Sasobit and Styrene-Butadiene-Styrene

The development of polymer-modified asphalt (PMA) has been a widely used technique by many researchers. Moreover, further modification of PMA binders has generated interest due to possible improvements in performance and cost. In this regard, Sasobit wax has been an alternative to reduce costs in Crumb-Rubber (CR) and Styrene-Butadiene-Styrene Copolymer (SBS) binders. However, there is little detail on the rheological behaviour of CR-SBS-Sasobit triple-modified samples for failure and damage resistance properties. Therefore, this study shows various properties of binders with triple modification of CR-SBS-Sasobit at different dosages. For this purpose, the development of single, double and triple modifications has been proposed to be tested by Multiple Stress Creep Recovery (MSCR) for permanent deformation. In the case of radial cracking and thermal cracking, it is evaluated by linear amplitude sweep test (LAS) and binder creep energy test (BYET). The results indicate that a CR-SBS combination in single or double addition achieves good thermal stability and behaviour. However, a higher elasticity is achieved in the case of a triple modification with CR-SBS-Sasobit. Specifically, Sasobit achieves 67% and 28% reduction in the cumulative deformation of MSCR for a variation of 40–80 °C, respectively. Concerning fatigue life (Nf), it is shown that CR-SBS modifications do not always acquire higher Nf than single modifications. However, adding Sasobit in triple modifications increases these values, generating bitumen with higher strength. It is also shown that adding Sasobit is a viable modifier in yield, even increasing the yield energy (Er) for samples with equal CR-SBS and reducing the percentage of SBS in the sample.

Identification of undisclosed modifiers and their effects on chemical, thermal, and microstructural properties of unaged and aged industrial high polymer-modified asphalt binders

This study employs thermo-chemical and microstructural analyses to identify undisclosed crystalline modifiers (UMs) in industrial high polymer-modified binders (HiPMBs) and evaluate their effects on aging phenomena. Chemical, thermal, and microstructural properties of several industrial HiPMBs were evaluated via Fourier-transformed infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), fluorescence microscopy (FM), and atomic force microscopy (AFM). Results indicate that crystalline UMs, contained in most binders, can be readily identified by calorimetric analysis. In contrast to styrene–butadienestyrene (SBS) thermoplastic elastomers, UMs drastically alter the surface microstructure of all binders. Typical bee-like structures disappear, and undefined topographies emerge due to the interactions between UMs and bituminous waxes. No significant effects were noticed concerning the homogeneity of the binders’ amorphous phases. Aging processes affect the characteristics of base bitumen, SBS, and UMs. Oxidation of bitumen and degradation of SBS can be evaluated by semi-quantitative analysis of FT-IR absorption bands and glass transition temperature (Tg) values. At the same time, variations of DSC endotherms reflect the influence on the crystallinity of UMs.

Properties of polymer modified asphalt by polyphosphoric acid through molecular dynamics simulation and experimental analysis

Polyphosphoric acid (PPA) plays an important role in improving the performance of polymer modified asphalt binders. This study aims to understand the modification mechanism of PPA in styrene-butadiene rubber (SBR) modified asphalt and investigate the rheological and chemical properties after modification based on molecular dynamics (MD) simulation and experimental analysis. Unaged and aged SBR asphalt binders with six PPA contents (0, 0.3%, 0.6%, 0.9%, 1.2%, and 1.5%) were prepared and tested. Four modified asphalt system models in different modifying and aging states were constructed in the molecular dynamics process. The calculated molecular dynamics parameters were used to observe intermolecular behaviors and system phenomena. Dynamic shear rheometry (DSR) and Fourier transform infrared (FTIR) spectroscopy were used to characterize rheological and chemical properties respectively. The results showed that the addition of PPA increased the complex modulus (G*) to promote elasticity and stiffness, and then enhanced the rutting resistance of the SBR asphalt binder. Multiple stress creep recovery (MSCR) results revealed that PPA/SBR asphalt had a better high-temperature performance than SBR asphalt due to its excellent creep recovery capability. Besides, the interaction between PPA and asphalt introduced phosphorus-containing functional groups into asphalt. In addition, analysis of the free volume and mean square displacement (MSD) displayed larger and higher molecular weight in PPA/SBR asphalt hindered the diffusion and mobility of the system. The radial distribution function (RDF) and radius of gyration (Rg) were calculated to observe that PPA provided a more ordered and more stable molecular structure. The electron density and potential were estimated to explore the adsorption mechanism of PPA to asphalt or SBR molecules and explain the source of stability and orderliness of the unaged and aged PPA/SBR/asphalt system.

Evaluating Self-Healing Behaviour of Asphalt Binders Modified with Phase-Change Materials, Polymers and Recycled Glass Powder.

The objective of this paper is to evaluate the fatigue resistance and self-healing properties of asphalt binders modified with different types of additives (Styrene-Butadiene-Styrene (SBS), Glass Powder (GP) and Phase-Change Materials blended with Glass Powder (GPCM)). Two base binders were used in this study: a PG 58-28 straight-run asphalt binder and a PG 70-28 Polymer modified with 3%SBS. Moreover, the GP was added to the two base binders at two different percentages of 3.5% and 5% by binder weight. However, the GPCM was added with two different percentages of 5% and 7% by binder weight. In this paper, the fatigue resistance and self-healing properties were evaluated using Linear Amplitude Sweep (LAS) test. Two different procedures were adopted. In the first procedure, the load was applied continuously until failure (without a rest period), whereas, in the second procedure, rest periods of 5 and 30 min were introduced. The obtained results of the experimental campaign were ranked based on three different categories: Linear Amplitude Sweep (LAS), Pure Linear Amplitude Sweep (PLAS) and modified Pure Linear Amplitude Sweep (PLASH). The addition of GPCM appears to positively impact the fatigue performance of both straight-run and polymer-modified asphalt binders. Furthermore, when a short rest period of 5 min was introduced, the use of GPCM did not appear to improve the healing potential. However, a better healing capacity was observed when the 30 min rest period was applied. Moreover, the addition of GP alone to the base binder was not beneficial in improving fatigue performance based on LAS and PLAS methods. However, there was a slight reduction in the fatigue performance based on the PLAS method. Finally, unlike the PG 58-28, the healing capacity of the GP 70-28 was negatively affected by the addition of the GP.

Rheological, Spectroscopic, and Chemical Characterization of Asphalt Binders Modified with Phase Change Materials, Polymers, and Glass Powder

Recently, asphalt modifiers have increasingly gained attention for improving the mechanical and thermal characteristics of asphalt mixtures. As a result, innovative additives are being constantly developed to achieve this purpose. However, some modifiers can significantly impact the chemical and rheological properties of the asphalt binder. This paper investigates the rheological, spectroscopic, and chemical properties of asphalt binders modified with a bio-based phase change material (PCM) and phase change material mixed with glass powder (GPCM). Two binders were investigated, PG 58-28 and PG 70-28 polymer modified asphalt binder with 3% SBS. Two different percentages of GPCM (5% and 7%) were added to PG 58-28 and PG 70-28, and 5% PCM was added to PG 58-28. The results indicated that the PCMs effectively reduced the viscosity values of the asphalt binder. Moreover, testing the modified binders using differential scanning calorimetry (DSC) showed that the PCMs released the stored heat when the melting/freezing temperature was reached. However, adding glass powder with the PCMs negatively affected the thermal properties of PCMs in the asphalt mix. In addition, considerable changes in the stiffness of the binders modified with GPCM at an intermediate temperature were obtained when tested using DSR. Finally, the TGA results revealed that this specific type of PCM would not be suitable as a hot mix asphalt (HMA) modifier as its evaporation temperature is lower than the mixing temperature HMA. However, the use of PCM in warm mix asphalt (WMA) would be a more viable option. The results showed that the evaporation temperature for the PCMs was low; therefore, the PCMs cannot be used in HMA. In addition, modified binders with PCMs and GPCM showed lower viscosity compared to the control binder. The DSR rheological analysis showed that the control binder and 5%PCM, 5%GPCM, 7%GPCM, 5%GPCM, and 7%GPCM binders had similar overall properties. However, the addition of GPCM significantly decreases the stiffness at intermediate temperatures.

Review on laboratory preparation processes of polymer modified asphalt binder

Review on laboratory preparation processes of polymer modified asphalt binder

Short-Term Performance Characterization and Fatigue Damage Prediction of Asphalt Mixtures Containing Polymer-Modified Binders and Recycled Plastics

This study evaluated the short-term performance properties and predicted cracking performance of asphalt mixtures containing polymer-modified asphalt (PMA) binders and recycled polyethylene (RPE). To that end, binder rheological testing, mixture performance testing, and FlexPAVE simulations were conducted. Furthermore, three PMA mixtures were selected for field evaluation on the National Center for Asphalt Technology Test Track and rapid performance testing during production. The PMA binders modified with styrene-butadiene-styrene (SBS), reactive elastomeric terpolymer (RET), and RET-compatibilized RPE had significantly improved elasticity and rutting resistance compared with the unmodified binder. The PMA binders also exhibited good storage stability with minimal separation tendency. Both polymer modification of the asphalt binder and adding RPE via the dry process improved the rutting resistance of the mixture. Although the unmodified and PMA mixtures exhibited notably different load-versus-displacement curves from the Indirect Tensile Asphalt Cracking Test (IDEAL-CT), they had similar cracking tolerance index ( CTindex) results. The Gf-versus- l75 /m75 interaction diagram allowed a more robust understanding of the IDEAL-CT results by considering mixture toughness and brittleness, and their interactions with CTindex. In all cases, polymer modification increased the stiffness and fatigue damage resistance of asphalt mixtures, while adding RPE via the dry process embrittled the mixtures, making them more susceptible to fatigue damage. The PMA mixtures had significantly better predicted cracking performance in FlexPAVE simulations than the unmodified mixture. This improvement was mainly caused by polymer modification of the asphalt binder. Finally, adding dry RPE pellets improved the rutting resistance but reduced the intermediate-temperature cracking resistance of the plant-produced PMA mixture containing an SBS-modified binder.

Study of phase behavior of epoxy asphalt binders using differential scanning calorimetry

Glass transition parameters can be used to study the miscibility, or lack of it, in polymer-modified asphalt binders. In this study, the contribution of thermodynamics of mixing to glass transition was quantitatively assessed in a differential scanning calorimeter for four asphalt binders partially and fully replaced by an epoxy system. The values of heat capacity (Cp) and, subsequently the glass transition temperature (Tg) of all binders were determined to quantify the miscibility based on the entropic changes. Emphasis was also given to examining the enthalpy of mixing as a function of epoxy system composition during curing to ensure that these binders were completely crosslinked for further analyses. In all cases, the positive deviations of the measured Tg of epoxy-modified asphalt binders (Tg,mix) obtained from the ideal mixing rule led to negative values of the entropy of mixing (ΔSmixc), dictating the presence of internal repulsive forces between the asphalt and epoxy components. Softer binders were associated with binders of low deviations of Tg,mix values from the ideal mixing rule. Lastly, the partial replacement of asphalt binders by the epoxy system increased the Tg and decreased the amount of ΔSmixc, and such performance imposes the formation of immiscible products.

Effect of polymer molecular weight on the rheology of SBS polymer-modified asphalt binder

Effect of polymer molecular weight on the rheology of SBS polymer-modified asphalt binder

Effects of Laboratory Ageing on the FTIR Measurements of Water-Foamed Bio-Fluxed Asphalt Binders.

The study investigated the effects of laboratory ageing on the fluxed and water-foamed asphalt binders in scope of Fourier transform infrared spectroscopic measurements of ageing indicators and changes in their chemical composition. The investigated binders included two paving grades, two polymer modified asphalt binders, and a highly modified asphalt binder. The bio-flux additive was produced from rapeseed methyl esters in an oxidation reaction in the presence of a metal catalyst and organic peroxide. The use of the bio-origin additive, in particular oil derivatives, was aimed at softening and better foaming of asphalt binders. This modification is possible due to the good mixability of vegetable oils with an asphalt binder, which gives a homogeneous product with reduced stiffness. The study involved the rolling thin film oven, short-term, and the pressure ageing vessel, long term, and ageing to induce oxidation on the evaluated asphalt binders. The addition of the bio-flux additive has significantly decreased the measured content of ketone compounds related to oxidation in both non-aged and aged asphalt binders, although this effect after ageing were far smaller in magnitude. Additionally, both ageing processes decreased significantly the absorbances in the ester spectral bands specific to the bio-flux additive. All mentioned effects were similar in magnitude in all tested asphalt binders.

Comparison and correlation between polymer modified asphalt binders and mastics in high- and intermediate-temperature rheological behaviors

Traditional evaluation parameters for multiple stress creep recovery (MSCR) test and linear amplitude sweep (LAS) test are difficult to deeply and theoretically characterize the high- and intermediate-temperature rheological behaviors of polymer modified asphalt (PMA) binders and mastics. In this paper, one neat asphalt and four types of PMA binders and mastics are selected (i.e., the rubber modified ones, SBS modified ones, thermoplastic elastomer modified ones and SBS/Rubber modified ones). Two new analysis methods, i.e. Burgers model and damage mechanics-based crack growth model, are applied in analyzing the high- and intermediate-temperature rheological behaviors of PMA materials respectively. The Burgers model results indicate adding filler decreases the viscous deformation, and leads to lower non-recoverable compliance in the MSCR test. The polymer modification transfers the delayed elastic deformation to elastic deformation, thus causing more excellent rutting resistance. The damage mechanics-based crack growth model analysis reveals that adding filler enhances the crack growth rate and crack length, thus sacrificing the fatigue resistance. By contrast, the polymer modification enhances the fatigue resistance regardless of polymer types. Notably, a two-stage pattern based on crack growth rate and energy release rate was further proposed to identify the crack initiation and propagation of PMA materials. Specifically, 30% rubber modified asphalt binders and mastics perform best in both rutting and fatigue resistance. Moreover, PMA binders and mastics have strong correlation based on the recovery percentage and delayed elastic deformation. The correlation of fatigue life between PMA binders and mastics is very significant, however there was no obvious correlation in terms of crack length.

Thermal cracking in cold regions’ asphalt mixtures prepared using high polymer modified binders and softening agents

ABSTRACT This study was conducted to assess high polymer modified asphalt binders including a corn oil-based softening agent (SA) and their impact on the cracking performance of mixtures in cold regions. Styrene–Butadiene-Styrene (SBS) polymer modifier, corn-oil-based softening agent, and Performance Grade 52–34 binder were proportioned at various dosages to prepare modified binders. The mixtures were aged according to three loose mix aging procedures (short-term, long-term, and extended long-term). It was found that the SBS and corn-oil combination improved both the high and low continuous grade along with percent recovery, and reduced fatigue cracking potentiality based on a reduced negative ΔTc at the binder level. In addition, at the mixture level, an increase in the Disc-shaped Compact Test (DCT) fracture energy was observed at low temperatures; also an increase in cracking temperature due to thermal stress from Thermal Stress Restrained Specimen Test (TSRST) was observed, indicating better cracking resistance. Regardless of aging, the flexural stress from the beam fatigue test also decreased, indicating higher resistance to fatigue cracking at intermediate temperatures. The study suggests that the balanced application of SBS and corn-oil can lead to the optimum improvement in low temperature cracking performance of the evaluated asphalt mixtures.

The Importance of Lower Truck Speeds (Longer Creep Times) on the Rutting Responses of Polymer-Modified Asphalt Binders

The Importance of Lower Truck Speeds (Longer Creep Times) on the Rutting Responses of Polymer-Modified Asphalt Binders

Sustainable Use of Polymer in Asphalt Mixture: A Review

Polymer modified asphalt (PMA) mixtures are commonly employed in flexible pavement and overlays with large traffic volumes. In contrast, a number of laboratory and field tests have been conducted to evaluate the performance of PMA with that of conventional hot mix asphalt (HMA) mixtures. This paper presents an overview of the various polymers utilised in asphalt mixtures and their effects on the rheological, morphological, physical, and mechanical properties of polymer-modified asphalt binders. According to a review of the relevant literature, a good modifier affects the failure characteristics of the binder, allowing it to withstand greater stresses and strains before failing. In asphalt pavement, adding polymers to asphalt binders to improve their qualities has a long history. Due to polymers' limited solubility, polymer-modified asphalt binders may have several disadvantages. In addition, a brief description of the general approach to mixing polymers is provided. A summary of the benefits and drawbacks of the most common polymers used to alter asphalt binders Styrene-butadiene-styrene (SBS), Styrene-butadiene–rubber (SBR), Polyethylene Terephthalate (PET), Polypropylene (PP), Polyvinyl Chloride(PVC) etc. are illusrated. The paper continues with a discussion of the lasting effects of PMAs on asphalt pavement. To evaluate the economic and environmental impacts, a life cycle assessment (LCA) is required.

Comprehensive performance evaluation of high polymer-modified asphalt binders beyond linear viscoelastic rheological surrogates

• High polymer-modified (HP) binders exhibit superior performance compared to PMA. • LVE surrogates fail to predict failure properties of complex and modified binders. • HP binders displayed higher strain tolerance in DENT compared to conventional PMA. • HP binders tend to have lower cracking temperature in ABCD compared to typical PMA. • FTIR I PTDB and I PVDB indices can be used to detect potential polymer degradation. Polymer modification of asphalt binders has progressively become more common over recent decades. Styrene-Butadiene-Styrene (SBS) is a well-recognized elastomer that has been commonly used in asphalt pavements. SBS polymer specifically exhibits a chemical morphology of hard polystyrene segment tethered by soft polybutadiene segment. Concerns related to binder pump clogging and reduced mixture workability have limited the SBS copolymer content in polymer-modified asphalt (PMA) to around 3 %. This motivated researchers to develop a new SBS polymer structure by modifying the midblock structure to have much higher vinyl content. High polymer-modified (HP) binder technology allowed the use of SBS at higher levels of 7–8 %. Although several studies have highlighted the positive impacts of HP on asphalt binders, they were mostly limited to the linear viscoelastic (LVE) domain. Therefore, there is still a need for a comprehensive evaluation of HP binders that considers failure properties, which constituted the main motivation of this research. In this study, Multiple Stress Creep Recovery (MSCR), Double Edge Notched Tension (DENT) and Asphalt Binder Cracking Device (ABCD) test results showed that HP binders exhibited superior performance compared to PMA in terms of higher strain recovery and lower non-recoverable creep compliance at high temperatures (52–70 °C), higher strain tolerance at intermediate temperature (25 °C), and lower (colder) cracking temperatures at sub-zero temperatures. Additionally, chemical analysis showed minimal HP degradation potential compared to PMA.

Polymer-modified asphalt binders’ properties deterioration under the action of chloride salt

ABSTRACT Asphalt pavement in a saline environment is subjected to the effect of salt. This paper aims to find out the influence of sodium chloride on polymer-modified asphalt binders by immersing specimens in the salt solution. The results analysis showed that asphalt binders’ properties deterioration in saline solution was mainly influenced by two factors: oxidation and polymerisation which accelerated the process of deterioration. Rheological test results showed that salt had a good effect on asphalt binders’ rutting resistance due to the change of the complex modulus but was harmful to fatigue cracking resistance. The properties of the HVA binder were less affected by salt solution compared to the PEN 40–60 binder and SBS binder based on the rate of influence. HVA binder indicated better rutting resistance and preferable fatigue resistance compared to other asphalt binders with respectively a rate of influence of 17.37% and 16.94%.

The laboratory performance of asphalt mixture with thermoplastic polyurethane (TPU) and amorphous poly alpha olefin (APAO) compound modified asphalt binder

• The effect of TPU/APAO on the asphalt mixture performance was explored. • APAO could enhance the rutting resistance of TPU modified asphalt mixture. • TPU has positive impact on the cracking resistance of asphalt mixture. • 2 % TPU + 6 % APAO modified asphalt mixture had superior road performance. The using of waste polymer modified asphalt binder in pavement construction is cost effective and beneficial to the environment. In this paper, the modified asphalt binders are prepared by adding thermoplastic polyurethane (TPU, 0 %, 2 %, 4 %, 6 %, by weight of asphalt binder) and amorphous poly alpha olefins (APAO, 0 %, 2 %, 4 %, 6 %). The conventional physical, rotational viscosity and dynamic shear rheometer (DSR) tests were conducted on the modified binders and the results indicated that the addition of APAO could improve the rutting resistance the TPU modified asphalt binder, and the modified asphalt binder with 2 % TPU and 6 % APAO showed the best rutting resistance among the studied binders. To assess the effect of APAO dosage on the performance of TPU modified asphalt mixture, mechanical performance tests including Marshall stability, dynamic stability, indirect tensile, immersion Marshall, freeze–thaw splitting and long-term aging tests were carried out on asphalt mixtures with various TPU/APAO content combinations. The test results proved that 2 % TPU + 6 % APAO modified asphalt mixture showed better resistance to rutting and moisture damage, the superior long-term aging damage resistance, and the excellent anti-freeze–thaw damage ability, when compared to the unmodified asphalt mixture. According to the indirect tensile test results at −10 °C, despite the indirect tensile strength ( ITS ) value of 2 % TPU modified asphalt mixture decreased after APAO added, the ITS value of asphalt mixture modified with 2 % TPU and 6 % APAO was still improved 5.8 % than base asphalt mixture. Based on the comprehensive analysis of the data, 2 % TPU + 6 % APAO modified asphalt mixture has superior road performance, and the performance characteristic of TPU/APAO compound modified asphalt mixture indicated that it could be applied for warmer regions.

The influence of long blending duration on physical and chemical properties of dual polymer modified asphalt binder with rejuvenator

The influence of long blending duration on physical and chemical properties of dual polymer modified asphalt binder with rejuvenator