2013 Session: 597

• Mechanical Property Characterization of Warm-Mix Asphalt Prepared with Chemical Additives
  Abstract: This study experimentally characterized the mechanical properties of warm-mix asphalt (WMA) prepared with two chemical additives: EvothermTM 3G and Rediset® LQ-1106, using laboratory-mixed and laboratory-compacted (LMLC) specimens. A conventional stone matrix asphalt (SMA), widely used in expressway overlay projects in the Chicago area, was selected as the control mixture. Two warm SMA mixtures were prepared by adding 0.5% EvothermTM 3G and 0.5% Rediset® LQ-1106 by weight of binder, respectively. The performances of the control SMA, EvothermTM SMA, and Rediset® SMA were evaluated and compared through extensive laboratory testing, including complex modulus, loading wheel track, indirect tension, and semi-circular beam at various curing time periods after compaction. This study concluded that the two warm SMA mixtures performed comparably to the control SMA with regards to the complex modulus, potential rutting resistance, tensile strength, and potential fracture resistance. Both warm SMA mixtures provided slightly lower tensile strengths and complex moduli than the control SMA. The rutting and fracture resistance potential of the two warm SMA mixtures was relatively similar to that of the control SMA. The curing time effect on the performance of the two warm SMA mixtures varied depending on the material property measured as well as the additive type. However, a strong correlation between strength gaining and curing time for the two warm SMA mixtures could not be concluded.
  Authors: Leng, Zhen; Gamez, Angeli; Al-Qadi, Imad L.
  Authors: Leng, Zhen; Gamez, Angeli; Al-Qadi, Imad L.
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 597
  Paper Number: 13-0938
• Fracture Resistance of Warm-Mix Asphalt Concretes at Low Temperatures
  Abstract: The fracture resistance of WMA concrete was examined at low temperatures in co The fracture resistance of WMA concrete was examined at low temperatures in comparison with HMA. Three WMA additives (Evotherm, Pewo and Sasobit), two polymers (LVM and SBS), and one aggregate source were used to prepare 9 WMA mixtures and 3 HMA mixtures. The fracture toughness (KIC) was measured by a 3-point bending beam test at -5, -15, -20, -25 and -35¡É. All mixtures showed KIC increase by temperature decrease, making a peak at -15¡É or 20¡É, then decreased with further lowering temperatures due to differential thermal contraction. Most of WMA mixtures, showed higher KIC than HMA at severely low temperatures. It was found that the WMA mixtures were not more susceptible to brittle fractures than HMA at low temperatures, although they were produced at a relatively lower aggregate heating temperature.
  Authors: Lee, Sung-Jin; Park, Jiyong; Hong, Jun-Pyo; Kim, Kwang W.
  Authors: Lee, Sung-Jin; Park, Jiyong; Hong, Jun-Pyo; Kim, Kwang W.
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 597
  Paper Number: 13-1858
• Evaluation of Tensile Property of Warm-Mix Asphalt Concretes at Low Temperatures
  Abstract: The tensile strength (St) of WMA and HMA concretes were measured by indirect tensile strength test methods at 25, 5, -5, -15, -25 and- 35¡É. Fracture energy (FE) was calculated from each of the tensile strength test curves. Two WMA additives and two polymer modifiers were used to produce WMA mixtures at 135¡É in the laboratory. All asphalt concretes evaluated in this study showed St increase by temperature decreases, peaking at -15¡É or -25¡É, then decreasing with further lowering of temperatures. The St values of WMA mixtures were observed to be higher than those of HMA mixtures, and, in most cases, at all low temperatures evaluated in this study. After being subjected to differential thermal contraction damage at -15 and/or -20¡É, most of the WMA mixtures showed higher St than HMA mixes at severely low temperatures (-25 and -35¡É). Therefore, it was concluded that the WMA mixtures had stronger tensile strength than HMA mixtures at low temperatures when prepared with the same low-temperature PG binders, even though they were produced at a relatively lower aggregate-heating temperature.
  Authors: Kim, Sungun; Choi, Hyun Jun; Kim, Kwang W.
  Authors: Kim, Sungun; Choi, Hyun Jun; Kim, Kwang W.
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 597
  Paper Number: 13-2747
• Influence Of Aggregate Source On The Properties Of Wma Mixtures In South Dakota
  Abstract: This study evaluated the impact of three aggregate sources (Limestone, Quartzite and Natural Gravel) and three different WMA processes (advera, evotherm, and plant foaming) on the properties of asphalt mixtures from South Dakota (SD). Moreover, the WMA mix design as proposed by NCHRP 9-43 was implemented. The aggregate source and warm-mix process were found to have impact on the mixing and compaction temperatures of the WMA mixture. The performance of the WMA mixtures was evaluated in terms of moisture damage, rutting, thermal; cracking, and fatigue cracking resistance. Aggregate source, WMA additive type, and the interaction between the two were shown to have moderate to significant effects on the performance of the asphalt mixtures for certain tests, while having no effect for other tests. Statistical differences were found when comparing indirect tensile strength and tensile strength ratio values, Flow Number, Asphalt Pavement Analyzer rut depth, and fatigue cracking test results for the various mixtures. None of the WMA mixtures performed as well as the HMA, except in the beam fatigue test. This was mainly related to the difference between the HMA and WMA short-term aging procedures. However, WMA mixtures exhibited similar or higher moisture damage, rutting, and fatigue cracking resistance than the HMA mixtures produced at the WMA temperatures or with two hours short-term conditioning instead of the recommended four hours by Superpave. Dynamic modulus results showed that, on average, WMA mixtures had significantly lower dynamic modulus values than the HMA mixtures, but similar values to HMA mixtures produced at the WMA temperature and short-term conditioning. The Thermal Stress Restrained Specimen Test (TSRST) showed that the reduction of production temperatures and short-term aging lowered the fracture temperature while it did not impact the fracture stress. The impact of WMA additives on thermal cracking and fatigue characteristics depended on the type of aggregate.
  Authors: Ahmed, Taha; Hajj, Elie Y; Sebaaly, Peter E.; Majerus, Nate
  Authors: Ahmed, Taha; Hajj, Elie Y; Sebaaly, Peter E.; Majerus, Nate
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 597
  Paper Number: 13-3501
• Comprehensive Evaluation of Polymer-Modified SMA Mixture Produced with New Polyethylene Wax-Based WMA Additive with Adhesion Promoter
  Abstract: The use of polymer-modified stone mastic asphalt (PSMA) is increased in highway and expressway because it provides high rutting resistance, a good skid resistance and noise reduction for heavily trafficked roads. However, PSMA mixture requires high mixing and compacting temperatures to create a suitable coating between polymer-modified asphalt and large size of aggregate. Warm-mix asphalt (WMA) technology is being used in polymer-modified asphalt (PMA) mixture to reduce mixing and compacting temperatures. A new polyethylene wax-based WMA additive with adhesion promoter was selected to use in PSMA mixtures at significantly lower temperature than a conventional PSMA mixture. In this study, the performance characteristics of PSMA mixture using new polyethylene wax-based WMA additive (PSMA-WMA) are evaluated against a conventional PSAM mixture without additive (PSMA-HMA) in terms of the moisture susceptibility, viscoelastic properties, rutting resistance at high temperature, fatigue resistance and crack resistance at low temperature. The mix design is carried out in the laboratory for the conventional PSMA-HMA mixture and a similar composition was adopted for the PSMA-WMA mixture (with the incorporation of 1.5% WMA additive in the bitumen) in order to evaluate the influence of polyethylene wax-based additive on the performance characteristics of the resulting mixture. Drain-Down and Cnatabro test results of PSMA-WMA mixture meets the requirement of criterion. Based upon the comprehensive evaluation of PSMA-WMA mixture against PSMA-HMA mixture, it is concluded that the performance characteristics of the PSMA-WMA mixture are better than those of the PSMA-HMA mixture in the moisture susceptibility, rutting resistance at high temperature, fatigue resistance at intermediate temperature and crack resistance at low temperature. Thus, new polyethylene wax-based WMA additive is effective on reducing the production temperature without compromising the performance of PSMA-WMA mixture.
  Authors: Kim, Yongjoo; Lim, Jaekyu; Lee, Munsup; Kwon, Soo-Ahn; Hwang, Sungdo; Wei, Liu
  Authors: Kim, Yongjoo; Lim, Jaekyu; Lee, Munsup; Kwon, Soo-Ahn; Hwang, Sungdo; Wei, Liu
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 597
  Paper Number: 13-3530
• Laboratory Evaluation of Asphalt Mixtures Containing Bio-Binder Technologies
  Abstract: The use of bio-binder as a replacement to petroleum-based asphalt binders has received considerable attention in recent years. The objective of this study was to conduct a comprehensive laboratory evaluation of asphalt mixtures containing bio-binder technology at a content of 20, 25.5, 30, and 50%. To achieve this objective, Superpave Performance Grade (PG) of the modified blends was compared to the unmodified binder. In addition, a suite of laboratory tests was conducted to capture the mechanistic behavior of the mixtures against major distresses. Laboratory testing evaluated the rutting performance, moisture resistance, and fracture resistance of the produced mixtures using the Hamburg loaded-wheel tester, the modified Lottman test, the semi-circular bending (SCB) test, and the thermal stress restrained specimen (TSRST) test. Results of the experimental program showed that the use of bio-binder did not influence the final PG of the binder with the exception of one blend, which dropped one grade at low temperature. Mixtures modified with bio-binder had similar or improved rutting performance when compared to the conventional mixes. With respect to moisture susceptibility, all mixtures, except the mixes prepared with PG 67-22, exceeded the 80% tensile strength ratio. However, when an anti-stripping agent was added, the tensile strength ratio of the mix with 50% bio-binder exceeded 80%. With respect to fracture resistance at intermediate temperatures, the mixes containing bio-binder exhibited reduced fracture resistance as compared to conventional mixes. With respect to low temperature fracture performance, bio-binder modification improved the low temperature fracture performance of the mixtures when compared to conventional mixtures of similar performance grade.
  Authors: Mohammad, Louay N.; Elseifi, Mostafa A.; Cooper, Samuel; Challa, Harshavardhan; Naidoo, Prem
  Authors: Mohammad, Louay N.; Elseifi, Mostafa A.; Cooper, Samuel; Challa, Harshavardhan; Naidoo, Prem
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 597
  Paper Number: 13-3784
• Development of a Simple Test to Determine Workability and Field Compaction Temperatures of Asphalt Concrete
  Abstract: A simple and easy-to-use test method to determine workability of asphalt mixtures was developed. This new method, called ‘Dongre Workability Test’ (DWT – pronounced DWIGHT), uses the Superpave Gyratory Compactor (SGC) to measure workability. DWT is conducted under displacement control at the rate of 0.05 mm/s in the gyratory compactor using 4224 g of asphalt loose mix. No gyrations are used in the DWT. Workability of asphalt concrete, expressed in kPa units, is defined as the slope of the non-linear stress (kPa) versus volumetric strain (%) curve calculated at 600 kPa stress level. DWT is able to resolve differences in workability due to aggregate gradation, asphalt binder grade, warm mix additives and polymer modification.A chart was also developed as a part of this study to establish field compaction temperatures using the workability values (on-mat and off-mat rolling temperatures for field compaction). Using this chart and the DWT workability values at two test temperatures (200oF and 300oF), field compaction temperatures were successfully predicted for various warm-mix, hot-mix and polymer modified asphalt mixtures. DWT may also be used to calculate the temperature reduction by the use of warm-mix additives.
  Authors: Dongre, Raj N.; Morari, Eugene
  Authors: Dongre, Raj N.; Morari, Eugene
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 597
  Paper Number: 13-4542
• Mechanistic Structural Properties of Foamed Asphalt Stabilized Base Materials
  Abstract: Foamed asphalt stabilized base (FASB) combines reclaimed asphalt pavement (RAP) and/or recycled concrete (RC) with a foamed asphalt binder. The pavement structural properties of FASB fall somewhere between conventional graded aggregate base (GAB) and hot mix asphalt (HMA). When FASB is used in place of GAB, the required thickness of the pavement section can be reduced, resulting in cost savings in addition to recycling benefits. The objective of this study is to address the most important performance related parameters of FASB material: stiffness and permanent deformation resistance, particularly with regard to the new mechanistic-empirical pavement design guide (MEPDG). Triaxial dynamic modulus tests were performed on cores of a field compacted and cured FASB mixture consisting of 40% RAP+ 60% RC+ 2.8% foamed asphalt to assess the distinct behavior of FASB under triaxial dynamic loading. Evaluation of the effects of stress states (confining pressure, and deviator stress), loading rate, and temperature on DYNAMIC MODULUS found that loading rate and temperature were the most significant factors influencing FASB stiffness. Insights were also gained regarding the influence of construction and curing conditions in the field. Triaxial repeated load permanent deformation (RLPD) tests were also performed to assess the resistance of FASB material to rutting. The results suggest satisfactory resistance of FASB material to rutting.
  Authors: Khosravifar, Sadaf; Schwartz, Charles W.; Goulias, Dimitrios
  Authors: Khosravifar, Sadaf; Schwartz, Charles W.; Goulias, Dimitrios
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 597
  Paper Number: 13-2544
  Practice-Ready: Yes
• Moisture Damage Evaluation of Asphalt Mixes containing Mining By-products (Taconite Tailings) using Traditional and Fracture Energy Tests
  Abstract: The availability of mineral aggregates for pavement construction is continuously depleting. The aggregate manufacturing process requires significant amount of energy ranging from 10-30 MJ/ton. The process also produces 5 kg/ton of CO2 causing significant amounts of greenhouse gas emissions. With annual consumption of approximately 1.2 billion tons of aggregates in the United States, significant environmental impact is caused. Annually more than 125 million tons of fine grained crushed siliceous material is generated through iron ore mining in Northern Minnesota. This material is typically referred to as “taconite tailings” and usually ends up as landfills near mining operations.This paper describes moisture damage evaluation of asphalt mixes containing significant fraction of aggregate as taconite tailings. The evaluation is conducted using conventional AASHTO T-283 test procedure as well as fracture energy based approach. The paper presents comparative results for two mixes, one made with taconite tailings and other one using conventional granite aggregates. The results indicate that mix containing taconite has acceptable moisture damage resistance. The results also point out the limitations of AASHTO T-283 procedure, especially the process of moisture conditioning. The fracture energy results indicate that while mixes undergo reduced tensile strength, the overall capability of mix to strain without cracking significantly increased after AASHTO recommended moisture conditioning process. The study also included a set of samples that were field conditioned over the period of winter and spring months. The mechanical behavior of field conditioned samples was quite different as compared to those conditioned in lab using the AASHTO procedure.
  Authors: Dave, Eshan V.; Baker, Justin
  Authors: Dave, Eshan V.; Baker, Justin
  Year: 2013
  Document Type: Paper
  Subject: Materials
  Session: 597
  Paper Number: 13-4613
  Practice-Ready: Yes
• Evaluation of Tensile Property of Warm-Mix Asphalt Concretes at Low Temperatures
  Authors: Kim, Sungun
  Authors: Kim, Sungun
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Materials
  Session: 597
  Paper Number: 13-2747
• Evaluation of Tensile Property of Warm-Mix Asphalt Concretes at Low Temperatures
  Authors: Kim, Kwang
  Authors: Kim, Kwang
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Materials
  Session: 597
  Paper Number: 13-2747
• Influence Of Aggregate Source On The Properties Of Wma Mixtures In South Dakota
  Authors: Hajj, Elie
  Authors: Hajj, Elie
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Materials
  Session: 597
  Paper Number: 13-3501
• Fracture Resistance of Warm-Mix Asphalt Concretes at Low Temperatures
  Authors: Kim, Kwang
  Authors: Kim, Kwang
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Materials
  Session: 597
  Paper Number: 13-1858
• Development of a Simple Test to Determine Workability and Field Compaction Temperatures of Asphalt Concrete
  Authors: Dongre, Raj
  Authors: Dongre, Raj
  Year: 2013
  Document Type: Presentation; Poster
  Subject: Materials
  Session: 597
  Paper Number: 13-4542