Binder Tests Research Articles

Performance research of high-viscosity asphalt mixture as deck-paving materials for steel bridges

This paper describes the performance tests for a high-viscosity asphalt mixture (HVAM) mixed with a newly developed high-viscosity asphalt (HVA) used for steel bridge deck pavement. Binder test results showed that the resistance to high-temperature rutting and low-temperature cracking of the HVA increased significantly compared to that of traditional asphalt binder and styrene-butadiene-styrene (SBS)-modified asphalt binder. Then stone mastic asphalt with this HVA was designed by Marshall Method and its engineering properties were investigated, and test results showed that HVAM has better fatigue performance and resistance against damage induced by temperature and moisture than that mixed with SBS-modified asphalt. Furthermore, dynamic modulus tests were performed on the HVAM and then master curves of the dynamic modulus and phase angle were constructed based on test results, which can be used for structure design of bridge deck paving. Application results proved the applicability of the HVAM as deck-paving materials for steel bridges.

Relating asphalt binder elastic recovery properties to HMA crack modeling and fatigue life prediction

Fatigue cracking is one of the major distresses occurring in hot-mix asphalt (HMA) pavements, which is a consequence of accumulation of damage under repeated load applications and changes in the environmental conditions. HMA is predominantly composed of aggregates and asphalt binder, where the latter plays a significant role in the HMA fatigue performance. The elastic recovery of asphalt binders is one of the characteristic properties that are hypothesized to play a significant role in the fatigue cracking resistance of HMA pavements. In this study, the relationships between the asphalt binder elastic recovery properties and the HMA fatigue performance were comparatively investigated. Two asphalt binder tests, namely the elastic recovery (ER) and multiple stress creep recovery (MSCR) tests were conducted to comparatively characterize the asphalt binder elastic recovery properties in the laboratory, and their results were then correlated to the predicted HMA fatigue life based on the TxME modeling software, which was subsequently validated with other laboratory test results and field performance data. Eleven typical Texas HMA mixes collected from different construction sites were used for the study. Overall, the results indicated that HMA mixes with high asphalt binder elastic recovery properties (⩾59%) exhibited better cracking resistance potential with long predicted fatigue life (>150months), which was also consistent with other studies and field performance observations. For mixes with low elastic recovery properties (<59%), there is no clear correlation with the predicted fatigue life.

Method for the Accelerated Testing of the Durability of a Construction Binder using the Arrhenius Approach

Abstract The single most reliable indicator of a material’s durability is its performance in long-term tests, which cannot always be carried out due to a limited time budget. The second option is to perform some kind of accelerated durability tests. The aim of the work described in this article was to develop a method for the accelerated durability testing of binders. It was decided that the Arrhenius equation approach and the theory of chemical reaction kinetics would be applied in this case. The degradation process has been simplified to a single quantifiable parameter, which became compressive strength. A model hydraulic binder based on fluidised bed combustion ash (FBC ash) was chosen as the test subject for the development of the method. The model binder and its hydration products were tested by high-temperature X-ray diffraction analysis. The main hydration product of this binder was ettringite. Due to the thermodynamic instability of this mineral, it was possible to verify the proposed method via long term testing. In order to accelerate the chemical reactions in the binder, four combinations of two temperatures (65 and 85°C) and two different relative humidities (14 and 100%) were used. The upper temperature limit was chosen because of the results of the high-temperature x-ray testing of the ettringite’s decomposition. The calculation formulae for the accelerated durability tests were derived on the basis of data regarding the decrease in compressive strength under the conditions imposed by the four above-mentioned combinations. The mineralogical composition of the binder after degradation was also described. The final degradation product was gypsum under dry conditions and monosulphate under wet conditions. The validity of the method and formula was subsequently verified by means of long-term testing. A very good correspondence between the calculated and real values was achieved. The deviation of these values did not exceed 5 %. The designed and verified method does not also consider the influence of other effects, for instance, chemical corrosion or corrosion caused by frost-thaw cycles. However, this method could be a supplementary tool applicable to the study of degradation processes and the estimation of a binder´s durability as well.

Performance properties of polymer modified asphalt binders containing wax additives

The study presents an experimental evaluation of the rheological properties of control and polymer modified asphalt (PMA) binders containing wax additives and a comprehensive comparison between these two binder types. The control and PMA binders with the additives were produced using two of the available warm asphalt processes (i.e., LEADCAP and Sasobit) and then artificially short-term and long-term aged using the rolling thin film oven (RTFO) and pressure aging vessel (PAV) procedures. Superpave binder tests were carried out on the binders through the rotational viscometer (RV), the dynamic shear rheometer (DSR), and the bending beam rheometer (BBR). In general the results of this study indicated that (1) the addition of wax additives into the control and PMA binders decreases the viscosity, as expected; (2) the reduction rate of viscosity was quite similar for both the binders with wax additives; (3) the percentage increase of rutting resistance due to the additives was much higher for the control binder, compared to the PMA binder; (4) both the control and PMA binders showed the similar trends in terms of fatigue cracking and low temperature cracking behavior after the addition of wax additives.

Fractional Viscoelastic Modeling of Antirutting Response of Bituminous Binders

AbstractA three-parameter fractional model, composed by a springpot in series with a dapshpot, was employed to describe the rheological behaviour of a set of polymer-modified bituminous binders obtained by combining a single-base bitumen with different types of syrene-butadiene-styrene copolymers at different concentrations. Experimental strain-time curves gathered from creep-recovery shear tests carried out by means of a dynamic shear rheometer at various temperatures were found to be in good agreement with model predictions. The fractional approach leads to a synthetic yet exhaustive description of the viscoelastic behavior of all materials. Variation of model parameters, each of which with a precise physical meaning, appears to be coherent with different binder compositions and testing conditions, reflecting the variations in terms of polymer concentration and temperature.

Determining Optimum Sulfur Content as Alternative Binder Additive in Asphaltic Concrete Pavements

AbstractAlthough bitumen, the binder most commonly used in asphaltic concrete pavements, constitutes only 3 to 5% of the total mixture, it has a significant impact on the total cost of the pavement. Because of this cost factor, this paper investigates the optimal use of the very abundant sulfur as a replacement for the more expensive bitumen. In this study, bitumen-sulfur blends were prepared, using an increasing amount of sulfur as replacement, up to 50% by weight. A group of samples were then short-term and long-term aged by using the rolling thin film oven test and a pressure aging vessel. Aged and virgin samples were then further tested with Superpave binder test methods. The promising results demonstrate that the addition of sulfur not only lowers total costs, but also increases the performance of the binder.

Performance of a Highly Polymer-Modified Asphalt Binder Test Section at the National Center for Asphalt Technology Pavement Test Track

Polymer modification of asphalt binders is commonly used to improve either the rutting or the cracking performance of asphalt mixtures. In most cases, 2% to 3% polymer is added to the binder; however, highly polymer-modified (HPM) mixtures can use 7% to 8% polymer to create a more integrated polymer chain network, which improves rutting and fatigue performance. In 2009, an HPM mixture test section was built at the National Center for Asphalt Technology Pavement Test Track; the test section was approximately 5.75 in. thick. A control test section was simultaneously built at 7 in. thick with the use of conventional paving materials. The objective of this study was to assess the long-term field performance of the HPM mixture and control sections placed at the test track. These sections were evaluated in regard to field performance and structural capacity. Falling weight deflectometer testing was conducted to determine in-place modulus over time, and weekly strain and pressure responses were collected to determine how the test sections behaved mechanistically under live trafficking. The performance of the test sections was monitored with the use of inertial profilers to measure rutting and ride quality, and visual inspection was used to quantify cracking. After 20 million equivalent single-axle loads of trafficking, the HPM mixture test section had less cracking and rutting than the control section and the ride quality had not diminished over time. These findings support the use of HPM mixes in agency paving programs where appropriate.

Evaluating Diffusion and Aging Mechanisms in Blending of New and Age-Hardened Binders During Mixing and Paving

As virgin pavement material sources become scarcer and costlier, the use of higher quantities of reclaimed asphalt pavement (RAP) in the production of new asphalt mixes becomes desirable. A major concern associated with the use of high percentages of RAP in new mixes is the interaction between age-hardened and new binders because the performance of the mix can be highly influenced by the properties of the composite binder. The objective of this study was to use asphalt binder testing and diffusion and aging theory to investigate the evolution of blending of virgin and RAP binders during asphalt mix production, storage, and placement. The rheological properties of a two-layer asphalt binder sample composed of virgin and simulated RAP binder and conditioned over time at different temperatures were measured with a dynamic shear rheometer. The conditioning process simulated the hot-mix asphalt (HMA) and warm-mix asphalt (WMA) time–temperature paths during mixing, storage, and placement. The diffusion and aging coefficients for the composite binder were estimated by comparing measured shear stiffness values with those predicted with a diffusion model and considering asphalt binder aging over time. The diffusion model was solved numerically with the finite control volume approach. On the basis of the preliminary laboratory test results, full blending of the age-hardened binder and the new binder was observed during HMA mixing and construction, while only partial blending was achieved during WMA production and construction. The blending of age-hardened and new binders could potentially be improved with the aid of warm-mix admixtures, rejuvenating agents, or both.

Investigation of Aging in Hydrated Lime and Portland Cement Modified Asphalt Concrete at Multiple Length Scales

AbstractThe properties of asphalt concrete are the result of many interdependent physical and chemical mechanisms occurring across multiple length scales. Admixtures such as hydrated lime (HL) and portland cement (PC) are known to affect the behaviors of asphalt concrete at the macroscale, but their contribution at other scales and influences on overall performance of the material are not well understood. This paper presents the findings of a study that evaluates the potential for HL and PC for mitigating the effects of asphalt concrete aging with respect to modulus and fatigue resistance. The properties of interest were evaluated at multiple scales, which involved binder, mastic, and mixture testing. Rheological analyses of aged and non-aged control, HL modified, and PC modified mastics indicate that HL possesses greater potential to mitigate aging than PC. In mixture testing, the modulus results showed trends similar to that of mastics, in which the HL-modified samples were the stiffest and showed great...

Laboratory performance of warm mix asphalt binder containing polyphosphoric acid

In this study, the objective was to conduct a laboratory investigation of rheological and morphological properties of warm mix asphalt containing polyphosphoric acid (WMA-PPA). The Superpave binder tests (i.e., rotational viscosity test, dynamic shear rheometer (DSR) test and bending beam rheometer (BBR) test) as well as microscopic tests (i.e., Fluorescence microscopy, Fourier transform infrared spectroscopy (FT-IR) and Differential Scanning Calorimetry and Thermogravimetry (DSC/TG) test) were performed to determine the influences of polyphosphoric acid (PPA) on warm mix asphalt binders. The experimental design included six binders and four different polyphosphoric acid dosages (by weigh of neat asphalt). The test results indicated that, the addition of PPA into warm mix asphalt binders exhibited an increase in the viscosity at different test temperatures, giving clear indication of the modification effects of PPA on the warm mix asphalt binders’ high-temperature performances. Temperature and frequency sweep tests show that the WMA-PPA binders demonstrate lower value of phase angle and higher value of complex modulus compared with the WMA binder regardless of aging state, the WMA-PPA asphalt containing more PPA has higher values of complex modulus (lower values of phase angle) than the WMA-PPA asphalt with less PPA in original state and after RTFO aging state. Bending beam rheometer (BBR) test illustrates that the addition of PPA making the low temperature rheological properties of the WMA binder worse. Furthermore, the amount of PPA has a great effect on the microstructures and hot storage stability of WMA-PPA asphalts, and the modification effect of PPA on WMA asphalt is a chemistry process. The 1.5% of PPA was found to be the optimum content between the studied percentages due to the warm mix asphalt binder containing 1.5% PPA achieved comparative good intermediate and high temperature rheological properties and at the same time is considered economical.

EFFECT OF BIO-OIL FROM EMPTY FRUIT BUNCH ON PENETRATION INDEX OF ASPHALT BINDER

Bio-oil which is derived from pyrolysis palm empty fruit bunch (EFB) is expected to be a potential alternative modifier for asphalt. This study focused on the effect of bio-oil on the penetration index (PI) asphalt. Bio-oil is blended between 2%-10% by weight of virgin asphalt penetration grade 80/100. Physical properties are measured and compared with virgin asphalt by the conventional physical binder test – softening point and penetration. The penetration index (PI) values is calculated to identify the typical values of asphalt type. Based on the findings, it was found that increased bio-oil content can effectively soften the asphalt at the same time maintain the temperature susceptibility. Modification asphalt is still within the grade 80/100 PEN with the addition of 10% maximum of bio oil. The stiffness of modified asphalt need to be further improved by addition polymer for better asphalt binder properties.

A novel micromechanical–analogical model for low temperature creep properties of asphalt binder and mixture

The ENTPE (Ecole Nationale des Travaux Publics de l’Etat) transformation is commonly used to predict the low temperature properties of asphalt binders from the corresponding mixtures experimental d...

Nanoindentation investigation of asphalt binder and mastic cohesion

A nanoindentation technique for determining the cohesive properties of neat, modified, and aged asphalt binders and mastics with varying filler volumetric concentrations is developed, tested, and verified. Cohesive properties of binder and mastic are critically important to the fracture resistance of asphalt concrete. A new approach to calculate and interpret important cohesive properties from nanoindentation data through low-load sphero-conical (blunt) nanoindentation is presented. Work of effective cohesion values are determined as the average response over multiple possible microstructures for three asphalt binders and 30 different mastics of varying filler volumetric concentrations. Results point to evidence of a critical filler volume fraction beyond which further addition of filler does not affect work of effective cohesion. This plateau in work of effective cohesion values is speculated to be related to the combined effects of volume-filling, particle interactions, and physicochemical interactions. The critical filler volumetric concentrations corresponding to the plateau in work of effective cohesion range between 0.20 and 0.30, which is within the range from literature of 0.15–0.30. Testing of binder and mastic through nanoindentation is an important step toward in situ testing of mastic within asphalt concrete, which is inaccessible using conventional macroscopic experimental methods.

Investigation of Isosorbide Distillation Bottoms as a Bio-Based Warm-Mix Additive

AbstractBiorefineries are increasing in number and size and include products based on food, energy, and chemicals. Depending on size and targeted products, biorefineries produce distillation bottoms with surfactant characteristics in sufficient quantities that can be used as a warm-mix asphalt (WMA) technology. Isosorbide distillation bottoms (IDB), having amphiphilic properties much like a classical ionic surfactant, are derived as coproducts of bio-based chemical production and show potential for reducing mixing and compaction temperatures as well as having low-temperature performance grade (PG) benefits. The objective of this paper is to evaluate the performance and potential of IDB as an asphalt additive through asphalt binder testing and mixture testing. Binder gradations were conducted for multiple binders at several dosage rates to verify compatibility with various petroleum crude sources and determine the optimum dosage level. Testing indicates promising results and shows an optimal dosage rate at...

Fatigue resistance of asphalt binders: Assessment of the analysis methods in strain-controlled tests

Fatigue testing of binders is an important subject in asphalt research and in recent decades several test procedures and analysis methods have been proposed. This paper discusses the application of several analysis methods to two different strain-controlled tests, implemented with the DSR.The fatigue laws obtained from the time sweep (TST) and the linear amplitude sweep (LAS) tests with the traditional failure limits, based on a fixed stiffness reduction value, are quite different. Using LAS, with maximum shear stress as failure criterion, gives rise to better results that can be further improved when changing the failure criterion to one based on the dissipated pseudo strain energy evolution.

Unified failure criterion for asphalt binder under cyclic fatigue loading

Defining failure and developing a unified failure criterion for the fatigue testing of asphalt materials remain a challenge. This study seeks to develop a failure criterion for the fatigue testing of asphalt binders under cyclic loading in the dynamic shear rheometer. Newly developed pseudo-strain energy (PSE)-based failure analysis is introduced for both the time sweep fatigue test and the accelerated linear amplitude sweep (LAS) test (AASHTO TP101). The presented methodology builds upon recent advances in the simplified viscoelastic continuum damage (S-VECD) modelling of asphalt mixtures. Trends in stored PSE have been proven to be effective in defining failure for the LAS tests of asphalt binders. This new proposed failure definition is material-dependent and, thus, is effective in capturing the benefits of asphalt modification for binder fatigue resistance. In addition, it is found that a unique relationship that is independent of loading history exists between the PSE release rate and fatigue life. The fatigue life predictions using this relationship and the S-VECD model are in reasonable agreement with the laboratory-measured fatigue life data and also generally relate well with the field fatigue performance measured in the FHWA-ALF (Federal Highway Administration – Accelerated Loading Facility) pooled fund study.

Use of the MSCR test to characterize the asphalt binder properties relative to HMA rutting performance – A laboratory study

Permanent deformation (or rutting) is one of the common distresses occurring in hot-mix asphalt (HMA) pavements. HMA is predominantly composed of aggregates and asphalt binder; and the asphalt binder plays a significant role in the HMA performance including permanent deformation and rutting resistance. In order to characterize the properties of the asphalt binder related to HMA rutting, the Superpave performance grade system uses the high-temperature grade, which is determined based on the complex shear modulus (|G∗|) and phase angle (δ) parameter (G∗/sinδ) that is measured from the Dynamic Shear Rheometer (DSR) test. However, G∗/sinδ is not a performance-based parameter. Therefore, the Federal Highway Administration (FHWA) has developed a performance-based PG binder test, the Multiple Stress Creep and Recovery (MSCR) test, to supplement the conventional DSR high temperature test. The primary objective of this laboratory study was to compare the two asphalt binder tests (the MSCR and the DSR high-temperature grade) and two HMA rutting related performance tests (the Hamburg Wheel Tracking Test [HWTT] and the Repeated Loading Permanent Deformation [RLPD] Test) for characterizing the asphalt binder high temperature properties relative to HMA permanent deformation and rutting performance. For the asphalt binders and HMA evaluated, the MSCR showed a better correlation with the two rutting related performance tests (HWTT and RLPD) than the DSR high temperature grade. Thus, the MSCR test results shows promise to supplement or serve as a surrogate to the existing DSR test in characterizing the asphalt binder high temperature properties that are related to HMA rutting. However, more lab testing and field validation is still warranted to complement the results and findings reported herein.

Nanoclay application to asphalt concrete: Characterization of polymer and linear nanocomposite-modified asphalt binder and mixture

This paper presents and discusses benefits of nano engineering in asphalt binder and asphalt mixture; mainly the performances of polymer, nanoclay and nanocomposite-engineered asphalt mixtures were evaluated. A 58-10 performance grade conventional asphalt (CA), a base binder, was modified separately with a linear SBS polymer and nanoclay at different proportions. As a result, three modified binders: nano modified asphalt (NMA), polymer modified asphalt (PMA), and nanocomposite modified asphalt (NCMA) were made. These modified binders were used to prepare asphalt mixtures. A laboratory study included characterization of physical, mechanical, and rheological properties and behaviors of the modified binders and the asphalt mixtures were performed. Asphalt binder tests were used for the modified binders while performance tests such as tensile strength, resilient modulus and rutting tests were employed for the asphalt mixtures. Test results have shown that nanoclay can enhance physical and rheological properties of the PMA binder as well as its storage stability. With these enhanced binder characteristics, the asphalt concrete specimens showed an increase of tensile strength and resilient modulus and also improved rutting resistance over conventional asphalt concrete.

Micromechanical–analogical modelling of asphalt binder and asphalt mixture creep stiffness properties at low temperature

The Hirsch model and the ENTPE transformation are commonly used to predict low-temperature creep stiffness of asphalt binders from the corresponding asphalt mixture experimental data (forward problem) and vice versa (inverse problem). Nevertheless, the applicability of these models is affected by low accuracy and limited understanding of the model parameters, respectively. In addition, the transformation parameter, α, associated with the ENTPE equation, cannot be directly obtained without relying on both binder and mixture creep testing. This paper presents a comprehensive experimental and theoretical study to link model parameters and ENTPE transformation to the mixture microstructure. This is accomplished by three-point bending tests, performed on asphalt binders and mixtures, digital image processing and statistical evaluation of the mixture microstructure, together with a newly proposed micromechanical–analogical material model, called Moon Cannone Falchetto (MCF) model, used for deriving an explicit expression of the α parameter. The values of α obtained by fitting the Huet model to the asphalt binder and asphalt mixture laboratory results are compared with the values predicted by the newly proposed formulation based on microstructural and volumetric information. The results indicate that reasonable predictions of low-temperature creep stiffness of asphalt binder can be obtained from the corresponding mixture low-temperature creep properties when the new expression of α derived from the MCF model is used in the ENTPE transformation.

Performance evaluation of alternative polymer-modified asphalt binders

Styrene–butadiene–styrene (SBS) polymer-modified asphalt (PMA) binder is widely known to provide superior performance, particularly in terms of cracking, as compared to unmodified asphalt binder. In recent years, alternative PMA binders have been developed to meet PG 76-22 specifications and requirements from the multiple stress creep recovery (MSCR) test. However, existing tests/requirements may not be sufficient to ensure the quality of alternative PMA binders. This study evaluated seven types of alternative PMA binders using different tests, including existing Superpave PG binder tests, the MSCR test, and a newly developed binder fracture energy (BFE) test. Results showed that four alternative PMA binders can potentially have equivalent performance to SBS binder. Three deficient binders were identified in both the MCSR and the BFE tests. Superpave PG binder tests, however, distinguished only one as deficient. Compared to the MSCR test, which provides a qualitative assessment (pass/fail criterion), the BFE test brings the added advantage of providing a quantitative assessment of relative binder performance based on fracture energy density values. Findings appeared to indicate that the BFE test can be used as an effective tool for binder specification by state highway agencies.