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A model to predict creep compliance of asphalt mixtures containing recycled materials
... Therefore, only E is considered viscoelastic and time-dependent. Creep compliance (D(t)) value is defined by Equation 1 (Huang, 2004;Safi, Hossain, Wu, Al-Qadi, & Ozer, 2018). ...
... Test methods used to measure the creep behavior of HMA can be listed as, uniaxial, triaxial, and indirect tensile tests. Uniaxial testing is more preferred because it is simple and reflects the in-situ behavior of flexible pavements.The triaxial test also reflects the in-situ conditions well due to the horizontal confinement, but this method cannot be widely used because of the complexity of equipment setting up (Safi et al., 2018). ...
... Indirect tensile test (IDT) that is preferred by the Strategic Highway Research Program (SHRP) characterizes the thermal cracking performance of HMA at low temperatures (Marasteanu et al., 2012;Richardson & Lusher, 2008;Safi et al., 2018). In this experiment, creep compliances of different asphalt concrete mixtures are obtained according to the standard AASHTO T 322-07 method (Christensen & Bonaquist, 2004;Jeong, 2005;Richardson & Lusher, 2008;Safi et al., 2018). ...
In the design of layered flexible pavements with the mechanistic-empirical (M-A) method, the material characterization of layers is critical for the correct calculation of mechanical responses. The surface layers of flexible pavements produced as hot mix asphalt (HMA) behave as a visco-elastic material under real field conditions. In this study, in which the HMA surface layer was defined viscoelastic by creep-compliance method, functional grading was applied to the surface layer at the same time to increase the fatigue strength of the pavement. Functional grading application was performed in the form of 3, 5, 7, and 9 sub-layers with linear and exponential functions. The pavement life values due to the mechanical responses that occurred in the pavement were determined by the Asphalt Institute and Shell methods. The study results show that the fatigue strength of the viscoelastic surface layer increases significantly as a result of functional grading. Especially in sections with exponential grading, an improvement of more than 10% was achieved even when a small number of sub-layers used. These results show that functional grading can also be successfully applied in field studies, and even with three sub-layers, significant improvements can be provided
... Therefore, only E is considered viscoelastic and time-dependent. Creep compliance (D(t)) value is defined by Equation 1 (Huang, 2004;Safi, Hossain, Wu, Al-Qadi, & Ozer, 2018). ...
... Test methods used to measure the creep behavior of HMA can be listed as, uniaxial, triaxial, and indirect tensile tests. Uniaxial testing is more preferred because it is simple and reflects the in-situ behavior of flexible pavements.The triaxial test also reflects the in-situ conditions well due to the horizontal confinement, but this method cannot be widely used because of the complexity of equipment setting up (Safi et al., 2018). ...
... Indirect tensile test (IDT) that is preferred by the Strategic Highway Research Program (SHRP) characterizes the thermal cracking performance of HMA at low temperatures (Marasteanu et al., 2012;Richardson & Lusher, 2008;Safi et al., 2018). In this experiment, creep compliances of different asphalt concrete mixtures are obtained according to the standard AASHTO T 322-07 method (Christensen & Bonaquist, 2004;Jeong, 2005;Richardson & Lusher, 2008;Safi et al., 2018). ...
In the design of layered flexible pavements with the mechanistic-empirical (M-E) method, the material characterization of layers is critical for the correct calculation of mechanical responses. The surface layers of flexible pavements produced as hot mix asphalt (HMA) behave as a viscoelastic material under real field conditions. In this study, in which the HMA surface layer was defined viscoelastic by creep-compliance method, functional grading was applied to the surface layer at the same time to increase the fatigue strength of the pavement. Functional grading application was performed in the form of 3, 5, 7, and 9 sub-layers with linear and exponential functions. The pavement life values due to the mechanical responses that occurred in the pavement were determined by the Asphalt Institute and Shell methods. The study results show that the fatigue strength of the viscoelastic surface layer increases significantly as a result of functional grading. Especially in sections with exponential grading, an improvement of more than 10% was achieved even when a small number of sub-layers used. These results show that functional grading can also be successfully applied in field studies, and even with three sub-layers, significant improvements can be provided.
... The Prony series constituted the input data for viscoelastic models, which are included by pairs of shear relaxation moduli and its associated characteristic time. The Poisson's ratio (ν) for the bituminous mixture was considered to be 0.35 in both numerical simulations (elastic and linear viscoelastic), in accordance with literature values (Huang, 2004;Nilsson et al., 2002), even though previous researches have shown that it is highly dependent on strain, frequency and temperature levels (Nilsson et al., 2002;Perraton et al., 2016;Safi et al., 2018). Table 4 contains the final number and type of elements of each component, as well as the moduli and Poisson's ratio adopted. ...
The use of bituminous subballast (BS) in railways has gained importance due to structural and geometrical enhancing properties of these infrastructures. Oftentimes, during renovations the paving quality control of bituminous mixtures is compromised due to reduced time span. To verify the effects of significant air voids content variation on the mechanical response of railway tracks, this paper performed a 3-D numerical modelling of a Brazilian railway renovated with BS. First, the BS was characterised in laboratory for model inputs. Then, 3-D numerical models were developed assuming two constitutive behaviour for the BS: linear elastic and linear viscoelastic. An all granular track was also simulated for comparisons. Numerical results were compared with actual instrumented test section. As expected, displacements on foot-of-rail and stresses on the subgrade were reduced when using BS. Moreover, the different air voids content of the bituminous mixture evaluated herein caused low variation in the overall track response.
... Where D ′ is viscoelastic compliance component at any time, D (t) is total compliance at any time, D 0 is instantaneous compliance, t is loading time and a and m are material regression coefficients. According to previous studies, Iskakbayev et al. (2016) and Safi et al. (2018), creep compliance parameters have been successfully used to characterise the potential of asphalt concrete mixtures for permanent deformation. The resulting parameters for the high and low compacted specimens are summarised in Tables 7 and 8, respectively. ...
This research investigates the effect of adding three different modifiers to laboratory-prepared Superpave asphalt concrete mixtures to evaluate their ability to strengthen and reinforce asphalt concrete mixtures and improve their rutting resistance. The three used modifiers were Crumb Tire Rubber (CTR), Microcrystalline Synthetic Wax (MSW), and Nano Silica (NS). The CTR, MSW, and NS modifiers were added at their optimum contents determined previously which were 12%, 2%, and 5% by weight of asphalt binder, respectively. Asphalt concrete mixtures were tested at two temperature levels; 40°C and 55°C, and were compacted at two compactive efforts to simulate high and low levels of traffic with Ndes = 119 and 82, respectively. Static creep test was used to evaluate the effect of changing modifier type, temperature, and compactive effort on creep properties and rutting potential of modified mixtures through studying five creep parameters. These parameters were accumulated axial micro-strain, creep stiffness, steady state creep slope, creep compliance, and creep compliance parameters. Results revealed that all the used modifiers had improved mixture performance. It was found that CTR modified mixtures had the best performance at high temperature level, while NS modified mixtures showed the best performance at medium temperatures. Moreover, it was found that lower temperatures and higher compactive efforts increase mixture stiffness and decrease deformation and their rutting potential. Statistical analysis was carried out and regression models were developed for the prediction of stiffness modulus, accumulated axial micro-strain, and steady state creep slope as a function of modifier type (MT), testing temperature (Temp) and compactive effort (CE). Models yielded relatively high coefficients of determination (R²) and adjusted R², indicating their ability in explaining much of the variability in the response variables.
... For instance, when the aging level or recycled material content increases, the magnitude of the asphalt layer modulus increases, and the relaxation ability and fracture resistance decrease. Consequently, the asphalt pavements with long-term aging or containing a large amount of recycled materials are more susceptible to thermal cracking [9,10]. Moreover, temperature variation in asphalt pavements is another prominent environmental effect on the thermal cracking behavior. ...
Thermal cracking is a non-load associated distress mode of asphalt pavements. Finite element models (FEM) were first introduced in this study to determine the thermally induced J-integral at the tip of thermal crack. After extensive runs of the FEM, artificial neural network models were constructed to predict the J-integral, which was used in the Paris’ law to calculate the cumulative thermal crack growth over time and thermal cracking fatigue life. Additionally, Long-term pavement performance data was collected to characterize the thermal cracking in different climatic zones. The calculated fatigue life was well correlated with the observed transverse cracking field performance.
... The m-value is slightly reduced with field aging, as would be expected, except for 185N07. Figure 4 shows the master curves of the PMLC and PMFC specimens, showing that the TRA mixes were relatively less compliant and all mixes behaved very similarly at low temperature (29). The 138P70 and 338N67 mixes demonstrated stiff behavior; the first contained a high percentage of steel slag and the latter had a high absorption rate (1.7%) and high ABR content. ...
The use of recycled materials in asphalt concrete (AC) pavement has increased significantly for economic and sustainable benefits. However, the use of recycled materials can pose risks to the performance of asphalt pavements. The Illinois Department of Transportation (IDOT) has developed five distinct total recycled asphalt (TRA) mixes, containing up to 60% asphalt binder replacement (ABR) obtained from reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS); whereas 100% recycled aggregates are acquired from RAP, steel slag, and recycled concrete aggregate (RCA). According to the laboratory testing, all mixes offered excellent rutting resistance as it contains high ABR. TRA is relatively less compliant and not very sensitive to field aging, whereas indirect tensile strength tests showed indistinguishable results. The TRAs become stiffer at higher temperatures, and likewise, all mixes have comparable a complex modulus (E*) and phase angle ( ) at low temperatures. Plant-mixed lab-compacted (PMLC) mixes have a relatively lower flexibility index (FI), from the Illinois Flexibility Index test (I-FIT), with time compared to the first field cores. The FI values for field cores decreased with aging and increased recycled materials. Furthermore, the field results confirm an excellent rutting performance. An exponential increase in transverse cracking was observed and a good correlation between FI and transverse cracking was observed. This allows the use of FI as a parameter with rut depth in constructing 2-D and 3-D balanced mix design charts and performance evaluation tools that can be used by practitioners.
The low-temperature creep compliances (D(t)) of asphalt mixture is one of the necessary parameters to predict the depth and amount of low-temperature cracks. Level 3 analysis in Mechanistic-Empirical Pavement Design Guide (MEPDG) software uses asphalt binder properties parameters and mixture volumetric properties to predict D(t) when the real laboratorial data is not available. However, some parameters in the model may not be routinely measured in Superpave system, which restricts the use of the prediction model. In addition, new additives and recycling materials such as reclaimed asphalt pavement (RAP) have been extensively used in recent years and shown to have significant effect on the low-temperature cracking resistance of asphalt mixture. However, the effects have not been considered in the existing D(t) prediction models. Hence, the objective of this study is to develop models with significantly high accuracy to predict the D(t) of asphalt mixtures containing RAP. A total of 1890 sets of data points were collected from three different research projects. A Pearson correlation analysis was carried out to select the input parameters which are most influential to D(t). Two prediction models (i.e., multiple linear regression and artificial neural network (ANN) models) were proposed. A comprehensive analysis on the prediction accuracy and reasonability of the proposed models was conducted. The results showed that the proposed models had much better prediction performance with high accuracy than the existing models. The comparisons between the proposed models with the existing models confirmed that it is necessary to take the new additives and recycling materials into account in developing D(t) prediction models.
A shared goal of the Federal Highway Administration (FHWA) and the National Asphalt Pavement Association (NAPA) is to support and promote sustainable practices, such as the use of recycled materials and warm-mix asphalt (WMA). The use of recycled materials, primarily reclaimed asphalt pavement (RAP) and reclaimed asphalt shingles (RAS), in asphalt pavements conserves raw materials and reduces overall asphalt mixture costs, as well as reduces the stream of material going into landfills.
WMA technologies have been introduced to reduce production and compaction temperatures for asphalt mixtures, which reduces the energy needed and emissions associated with mixture production. Additional benefits include improved low-temperature compaction of asphalt mixtures leading to improved pavement performance, as well as a longer paving season. WMA was chosen for accelerated deployment in federal-aid highway, state department of transportation, and local road projects as part of FHWA’s 2010 Every Day Counts initiative.
The objective of this survey, first conducted for the 2009 and 2010 construction seasons, is to quantify recycled materials used and WMA produced annually by the asphalt pavement industry to document the deployment of these technologies to understand where they are being used and where they are underutilized. Results show significant growth in the use of RAP, RAS, and WMA technologies since 2009, although the rate of year-over-year growth has generally slowed since 2013.
The asphalt industry remains the country’s most diligent recycler with more than 99 percent of reclaimed asphalt pavement being put back to use. The average percentage of RAP used in asphalt mixtures has increased from 15.6 percent in 2009 to 20.5 percent in 2016. In 2016, the estimated RAP tonnage used in asphalt mixtures was 76.9 million tons. This represents more than 3.8 million tons (21.5 million barrels) of asphalt binder conserved, along with the replacement of some 73 million tons of virgin aggregate.
Similarly, the use of RAS in asphalt pavement mixtures has increased from 701,000 tons in 2009 to an estimated 1.39 million tons in 2016; however, the use of RAS declined significantly (27.9 percent) from 2015 to 2016.
The combined savings of asphalt binder and aggregate from using RAP and RAS in asphalt mixtures is estimated at more than $2.1 billion.
More than 768,000 tons of other recycled materials were reported as being incorporated into nearly 6.5 million tons of asphalt pavement mixtures during the 2016 construction season, including ground tire rubber, blast furnace slag, steel slag, and cellulose fibers.
The estimated total production of WMA for the 2016 construction season was 116.8 million tons. This was a decline of 2.5 percent from the estimated 119.8 million tons of WMA in 2015, due largely to a 10.2 million ton decrease in DOT tonnage for the year, but is still a greater than 595 percent increase from the estimated 16.8 million tons in the 2009 construction season. WMA made up 31.2 percent of the total estimated asphalt mixture market in 2016. Production Plant foaming, representing nearly 77 percent of the market, is the most commonly used warm-mix technology; chemical additive technologies accounted for a little more than 21 percent of the market.
Creep compliance and indirect tensile (IDT) strength of hot-mix asphalt (HMA) are the two primary inputs to the low-temperature or thermal cracking module in the new Mechanistic-Empirical Pavement Design Guide (M-E PDG) software. Creep compliance is defined as time-dependent strain per unit stress, while IDT strength is best defined as HMA strength when subjected to tension. AASHTO T 322 test protocol was used as reference for this work. However in preparation for the laboratory work performed at the Missouri University of Science and Technology many experts were consulted as to how IDT creep/strength testing and calculations are actually being performed. Using MoDOT supplied test specimens, six different plant-produced wearing (surface) course mixes were tested. Four mixes were tested at three levels of percent air voids: 4, 6.5, and 9% and two mixes were tested only at 6.5% air voids. Per requirements of the M-E PDG, creep testing was performed at 0, -10, and -20 degrees Centigrade (°C) and IDT strength testing was performed at -10°C. Additional IDT strength testing was performed at 4.4 and 21°C (40 and 70 °F) per MoDOT’s requirements. Poisson’s ratio was determined from the creep testing while tensile failure strain was determined from the IDT strength testing. Trends such as increasing creep compliance and decreasing tensile strength with increasing % air voids and/or temperature were confirmed. The presence of recycled asphalt pavement (RAP) in a mix tended to decrease the creep compliance (increase the stiffness) and increase the tensile strength compared to similar mixes without RAP.
For current recycled mix designs, the Illinois Department of Transportation (IDOT) assumes 100% contribution of working binder from Recycled Asphalt Pavement (RAP) materials when added to Hot Mix Asphalt (HMA). However, it is unclear if this assumption is correct and whether some binder may potentially be acting as “black rock,” and not participating in the blending process with the new binder. Furthermore, it is also unclear whether binder modifications should be considered in the mix design for recycled HMA. The goal of this research was to determine if the current IDOT mix design practice required modification with respect to the use of RAP. A set of mixtures was prepared using RAP in accordance with current practice. Additional sets were prepared using recovered binder and recovered aggregate to simulate the effect of RAP binder blending with virgin binder. Mixes containing 0, 20, and 40%RAP were prepared and the dynamic modulus testing results of these mixtures were compared to illustrate the effect of RAP on HMA. Tests on recovered, virgin, and blended binders were also conducted using the Dynamic Shear rheometer (DSR). This study found that up to 20% RAP in HMA does not require a change in binder grade. However, at 40% RAP in HMA, a binder grade bump at high temperature and possibly at low temperature is needed; more tests are required to verify the need for low temperature binder grade bumping. In addition, this study recommends RAP fractionation in the preparation of laboratory specimens. ICT-R27-11 published or submitted for publication is peer reviewed
Thermal cracking is a major distress type observed in flexible pavements, especially in regions with cold climates (e.g., northern United States and Canada). The Pavement ME Design Guide software developed under NCHRP Project 1-37A is the pavement analysis and design tool most widely used by state highway agencies for pavement designs. For thermal cracking predictions in flexible pavements, the most important material properties are the creep compliance and indirect tensile strength of an asphalt mixture in Level 1 and Level 2 analyses. Level 3 analyses use material properties and mixture volumetrics to predict creep compliance and indirect tensile strength. This study was part of a comprehensive research effort to characterize asphalt mixtures commonly used in the state of Michigan for implementation of the Pavement ME Design software. The main objective of the study presented in this paper was the investigation of methods of obtaining asphalt mixture creep compliance [D(t)] for use in flexible pavement analysis and design using the Pavement ME Design software. In this study, numerical interconversion between dynamic modulus (vertical bar E*vertical bar) and the creep compliance of asphalt mixtures with the Prony series method was investigated and validated. Then, the creep compliance of numerous asphalt mixtures was computed from the measured vertical bar E*vertical bar data. With these data, the creep compliance predictive equation used in Pavement ME Design software was evaluated and locally calibrated. In addition, an analytical model as well as an artificial neural network-based model was developed for improved prediction of D(t) from the mixture volumetrics.
The potential concerns associated with recycling of PMACs were addressed. A styrene-butadiene-styrene PMAC was selected and characterized using typical asphalt binder qualification techniques. Procedures were developed to separate the PMAC into its asphalt resin and polymer additive components as well as to characterize the relative concentrations of each component. Infrared and thermogravimetric spectrographic techniques were used to identify the changes in the components as a result of aging. The impact of the extraction and recovery process on binder properties was ascertained and found to be minimal. An eight year old polymer modified asphalt binder was recovered from a wearing course mixture located on route US61 in Livingston Parish, Louisiana. The field aged binder was characterized with respect to its composition and rheological properties. Blends of virgin PMAC and US61 recovered binder were prepared and analyzed.
The use of recycled asphalt pavements (RAP) and recycled asphalt shingles (RAS) as components of new asphalt mixes is expected to reduce construction costs, protect the environment, and conserve dwindling natural resources. However, the use of high percentages of RAP and RAS requires mix adjustments to accommodate the stiffer binder, which in turn requires quantification of the effect of the RAP and RAS binder on the fresh binder used in the mixture. Current methods for such estimates are performed on the basis of either chemical extraction and recovery of the binder or backcalculation from gyratory compacted samples. The former is not desirable because of the unknown effects of the chemical solvents on the binder, and the latter requires extensive laboratory work and resources. This paper modifies the analysis procedure for estimating the low-temperature properties of RAP binder by means of testing mortars and binders in the recently developed bending beam rheometer. The modified testing procedure was verified by testing artificial RAP materials, and found capable of estimating low-temperature grade of aged binder within 1 degrees C of the known grade. Furthermore, the application of the procedure to RAS allowed for the introduction of the basis for the development of RAP and RAS blending charts to estimate the final grade of blended binder in mixtures. The feasibility of extending the procedure to study the effect of RAP and RAS on binder fracture properties is also presented in this paper.
This paper provides an overview of the asphalt rubber interlayer benefits on reflective crack retardation in overlays over rigid pavements. These interlayers are known in California as asphalt rubber absorbing membrane interlayers (SAMI-R) or as asphalt rubber aggregate membrane interlayers (ARAM-I) chip seals. The paper focuses on the performance in terms of field project reviews, laboratory performance tests and finite element analysis. SAMI-R has been given a reflective cracking equivalent thickness of 15 mm of asphalt rubber hot mix overlays or 30 mm of dense graded hot mix overlays. The finite element analysis confirms the quantified reflective cracking benefits of SAMI-R and provides optimum design alternatives to conventional dense grades asphalt concrete overlays. The paper concludes that SAMI-R is effective in minimizing reflective cracking distress and in extending pavement life.
This research project evaluates the low-temperature performance of energy-efficient and environmentally friendly hot-mix asphalt (HMA) paving materials. Innovative materials gaining interest in the asphalt pavement industry includes warm mix asphalt (WMA), recycled asphalt shingle (RAS), reclaimed asphalt pavement (RAP), and bioasphalt. The materials are used as modifiers in typical HMA to enhance low-temperature field performances. Sasobit compounds at 0.5, 1.0, and 1.5%, by weight of performance grade (PG) 52-34 asphalt binder, are used to design the WMA. Five and 10% of RAS were also added to a PG 52-34 asphalt binder. 50% of RAP combined with 50% of the base PG 58-28 binder, and 100% RAP extracted from the PG 58-28 HMA, were prepared and tested. Bioasphalt was produced from swine waste and used to modify PG 64-22 asphalt binder. By using the Superpave bending beam rheometer (BBR) and the new asphalt binder cracking device (ABCD) method, the thermal cracking performance of the samples were tested. The results showed that (1) the ABCD method can be used alongside or as a confirmation test for the BBR in evaluating the low-temperature cracking resistance behavior of asphalt binders; (2) adding WMA beyond a certain percentage could potentially reduce the low-temperature cracking performance of asphalt binders; and (3) swine waste bioasphalt can enhance low-temperature asphalt binder performance. DOI: 10.1061/(ASCE)MT.1943-5533.0000295. (C) 2011 American Society of Civil Engineers.
This research evaluated the effect of reclaimed asphalt pavement (RAP) on the combined overall performance of stone matrix asphalt mixtures in Georgia. Four types of RAP were combined at four levels (0%, 10%, 20%, and 30%) with four aggregate sources, with the use of a one-fourth fraction factorial design. Granite materials common to Georgia were used exclusively in this study for both RAP and virgin aggregate. Testing was performed to evaluate the binder effect on resistance to moisture susceptibility, rutting potential, thermal cracking potential, and fatigue life of the recycled mixtures. The following main findings are applicable only to the RAP and virgin aggregates used in this study. Virgin aggregate had a greater effect on Los Angeles abrasion loss and percent flat and elongated particles than did the addition of RAP. Increasing RAP content resulted in higher tensile strengths (conditioned and unconditioned) for moisture susceptibility testing. Up to 20% RAP can he used without significantly affecting performance. Only fatigue life (at high strain levels) decreased significantly with the addition of 30% RAP. Fine-graded RAP reduced virgin binder requirements, which translates into increased economic benefits. However, mixes are stiffer because they have higher aged-to-virgin binder ratios and may be more susceptible to fatigue cracking. Adding up to 30% RAP had little effect on lowtemperature performance grade properties, which may indicate that the grade of virgin binder does not have to be adjusted to provide the desired low-temperature binder properties.
The main objective of this study is to assess the sensitivity of the predicted performance of recycled asphalt pavement (RAP) mixtures to the assumed binder grade. That is achieved with the Mechanistic-Empirical Pavement Design Guide (MEPDG) software to predict the performance of a specific flexible pavement structure with a RAP-modified hot-mix asphalt surface layer. Different design runs are conducted for which all the pavement properties and conditions are held constant except the properties of the surface layer. Specifically, a near-full factorial experiment is performed in which RAP content and effective binder PG grade are the main variables. Comparison of the predicted performance of the various runs reveals important findings on the extent and manner in which those two properties affect pavement distresses and performance. The influence of the assumed PG binder grade on the RAP mixtures, particularly the high-temperature grade, has a significant effect on the predicted amount of thermal cracking and rutting for the given structure. The predicted performance is especially sensitive to changes in assumed PG grade in the range in which the true effective PG grade is expected to fall; the difference from one PG grade to another can be the difference between a well-performing mixture and one that requires redesign. Results emphasize the importance of determining the effective binder grade of RAP mixtures. An added benefit of conducting the numerous MEPDG software runs is the identification of issues that need to be considered when incorporating RAP mixtures in pavement design using the software.
This report presents the results of an investigation of the performance of a variety of materials added to asphalt binders and mixtures to change their properties, particularly with respect to rutting and cracking. The approach included a field trial of seven polymer and particulate modifiers, supplemented by laboratory characterization of the materials used in the field. The modifiers evaluated included PAC, Novophalt, Multigrade asphalt cement, polyester fibers, Neoprene, SBR and asphalt rubber. The field trial showed that different modifiers do yield different performance. Modifiers are not essential to ensure that the pavement will not rut. None of the mixtures evaluated here exhibited appreciable rutting. Dramatic differences were noted in the cracking behavior, however. Newly developed laboratory tests were able to identify binders that would be more prone to cracking. All of the materials evaluated did change the properties of the binders or mixtures in some way. Some of the modifiers, however, were more effective at modifying the properties to provide improved field performance in a cost effective manner.
Illinois highway materials sustainability efforts of
- D L Lippert
- A K El-Khatib
- A Z Dahhan
- J S Trepanier
D.L. Lippert, A.K. El-khatib, A.Z. Dahhan, J.S. Trepanier, Illinois highway
materials sustainability efforts of 2013. No. 14, 2014.
Impact of High RAP Content on Structural and Performance Properties of Asphalt Mixtures
- I L Al-Qadi
- Q Aurangzeb
- S H Carpenter
- W J Pine
- J Trepanier
I.L. Al-Qadi, Q. Aurangzeb, S.H. Carpenter, W.J. Pine, J. Trepanier, Impact of High
RAP Content on Structural and Performance Properties of Asphalt Mixtures,
No. 12, 2012, p. 108.
Development and validation of performance prediction models and specifications for asphalt binders and paving mixes
- R L Lytton
- J Uzan
- E G F R Roque
- D Hiltunen
- Shelley M Stoffels
R.L. Lytton, J. Uzan, E.G.F.R. Roque, D. Hiltunen, Shelley M. Stoffels.
Development and validation of performance prediction models and specifications for asphalt binders and paving mixes, 357, Washington D.C, 1993.
Superpave asphalt mixture analysis: course notebook. Federal Highway Administration, Office of Technology Applications
- T A Institute
T.A. Institute, Superpave asphalt mixture analysis: course notebook. Federal
Highway Administration, Office of Technology Applications, Washington D.C,
1996.
Characterization of Wisconsin Mixture Low Temperature Properties for the AASHTO Mechanistic-Empirical Pavement Design Guide (No. WHRP 11-12)
- R Bonaquist
R. Bonaquist, Characterization of Wisconsin Mixture Low Temperature
Properties for the AASHTO Mechanistic-Empirical Pavement Design Guide
(No. WHRP 11-12), 2011.
Guide for Mechanistic-Empirical Design
- O New
O. NEW, Guide for Mechanistic-Empirical Design, Washington D.C, 2004.
- Y H Huang
Y.H. Huang, Pavement Anal. Des. (2004).
Testing Protocols to Ensure Mix Performance W/ High RAP and RAS
- I Al-Qadi
- H Ozer
- J Lambros
- D Lippert
- A El Khatib
- T Khan
- P Singh
- J J Rivera-Perez
I. Al-Qadi, H. Ozer, J. Lambros, D. Lippert, A. El Khatib, T. Khan, P. Singh, J.J.
Rivera-Perez. Testing Protocols to Ensure Mix Performance W/ High RAP and
RAS. Illinois Center for Transportation, No. 1, 2015, p. 209.