Low Temperature Cracking Evaluation of Asphalt Rubber Mixtures Using Semi-Circular Bending Test

2011 ◽  
Vol 243-249 ◽  
pp. 4201-4206 ◽  
Author(s):  
Jing Hui Liu
Keyword(s):  
Low Temperature ◽  
Asphalt Concrete ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Asphalt Pavements ◽  
Dry Process ◽  
Wet Process ◽  
Asphalt Rubber ◽  
Scb Test ◽  
Low Temperature Cracking

Low temperature cracking is the main distress in asphalt pavements in winter. As asphalt rubber course is increasing, there is no standard method to characterize the resistance to cracking of asphalt rubber mixtures. This paper investigates the use of a Semi Circular Bend (SCB) test as a candidate for a low-temperature cracking specification. Based on the SCB test, this paper presents the findings of a laboratory study that aimed to evaluate the effects of recycled tire rubber on the Low temperature cracking properties of asphalt mixtures. Three mix types, a conventional hot-mix asphalt concrete, a dry process rubber modified asphalt concrete, and a wet process asphalt-rubber asphalt concrete, were included in the investigation. It is found that the asphalt mixtures produced by the wet process showed much better low temperature crack resistance, the binder effect modified by rubber was significant.

Fatigue Life Evaluation of Asphalt Rubber Mixtures Using Semi-Circular Bending Test

2011 ◽  
Vol 255-260 ◽  
pp. 3444-3449 ◽  
Author(s):  
Jing Hui Liu
Keyword(s):  
Asphalt Concrete ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Fatigue Properties ◽  
Beam Test ◽  
Dry Process ◽  
Wet Process ◽  
Asphalt Rubber ◽  
Scb Test ◽  
Fatigue Life Evaluation

The Semi-Circular Bending (SCB) test, which is chosen as the best inspecting method for pavement cores, is of great significance. Based on the SCB test and flexure beam test, this paper presents the findings of a laboratory study that aimed to evaluate the effects of recycled tire rubber on the fatigue properties of asphalt mixtures. Three mix types, a conventional hot-mix asphalt concrete, a dry process rubber modified asphalt concrete, and a wet process asphalt-rubber concrete, were included in the investigation. It is found that the asphalt mixtures produced by the wet and dry process showed better fatigue performance, which is the same conclusion from the SCB test and flexure beam test. The SCB test can be an effective evaluation means for the pavement service performance of asphalt rubber mixtures.

Thermal Cracking Models for AC and Modified AC Mixes in Alaska

1998 ◽  
Vol 1629 (1) ◽  
pp. 117-126 ◽  
Author(s):  
Lutfi Raad ◽  
Stephan Saboundjian ◽  
Peter Sebaaly ◽  
Jon Epps
Keyword(s):  
Low Temperature ◽  
Extreme Temperature ◽  
Thermal Cracking ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Cracking Resistance ◽  
Dry Process ◽  
Wet Process ◽  
Low Temperature Cracking ◽  
Styrene Butadiene

Low-temperature cracking is a major distress mode in Alaskan pavements because of the extreme temperature conditions—which range, in some instances, from about −50°C in winter to more than 40°C in summer. The use of asphalt modifiers in Alaskan pavements occurred over the past 15 years. These modifiers include Styrene-Butadiene-Styrene polymers, Styrene-Butadiene-Rubber polymers, ULTRAPAVE, and CRM [both the dry process (PlusRide) and the wet process]. Field observations and laboratory studies in Alaska and elsewhere indicate that the use of these modifiers would improve the low-temperature cracking resistance of pavements. The degree to which these modifiers provide beneficial effects for Alaskan pavements needs to be evaluated. The objectives of this research were (1) To characterize asphalt and polymer modified asphalt from a number of selected sites using Superpave PG grading system and to conduct thermal stress restrained specimen tests (TSRST) and Superpave IDT laboratory tests on field specimens; (2) To compare low-temperature cracking performance using field surveys; (3) To verify the applicability of the Superpave thermal cracking model (TCMODEL) and other available models for predicting low temperature cracking; and (4) To recommend guidelines for predicting minimum pavement temperatures in Alaska. Results of this study indicate, in general, significant improvement in low-temperature cracking resistance when polymer modifiers are used. Comparisons between predicted and observed low-temperature cracking using available crack propagation models, including Superpave TCMODEL, were poor. An improved regression model was developed using minimum air temperature, TSRST fracture temperature and strength, and pavement age to fit the observed field data for both conventional and polymer modified sections.

Arkansas Experience with Crumb Rubber Modified Mixes Using Marshall and Strategic Highway Research Program Level I Design Methods

1996 ◽  
Vol 1530 (1) ◽  
pp. 25-33 ◽  
Author(s):  
Gary V. Gowda ◽  
Kevin D. Hall ◽  
Robert P. Elliott
Keyword(s):  
Asphalt Concrete ◽  
Hot Mix Asphalt ◽  
Heavy Traffic ◽  
Percent Level ◽  
Crumb Rubber ◽  
Aggregate Gradation ◽  
Dry Process ◽  
Wet Process ◽  
Asphalt Rubber ◽  
Level I

Unmodified and crumb rubber modified mixes conforming to the Arkansas State Highway and Transportation Department Type II surface course specifications were designed for heavy traffic conditions and environmental conditions typical to Arkansas by using the Marshall and Superpave Level I methods. Specimens prepared at appropriate design asphalt contents were evaluated for both volumetric and performance considerations. Three mix types, an unmodified hot-mix asphalt concrete, a dry process rubber modified asphalt, and a wet process asphalt rubber, were included in the investigation. For the asphalt cement, crumb rubber, aggregate type, and aggregate gradation used, the design asphalt content and the VMA were reduced for the SHRP Level I method relative to the Marshall method. Incorporation of crumb rubber into hot-mix asphalt concrete provided increased rutting resistance; however, the rubber modified mixes did not show enhanced resilient and tensile properties when tested at 25°C. Also, the performance-related properties of the SHRP Level I asphalt-rubber mixes (5, 10, and 15 percent A-R blends) evaluated did not differ significantly at 5 percent level of significance.

Performances Research of Hybrid Fiber Reinforced Asphalt Concrete

2009 ◽  
Vol 614 ◽  
pp. 283-288
Author(s):  
Shao Peng Wu ◽  
Hong Bo Yue ◽  
Qun Shan Ye ◽  
Ling Pang
Keyword(s):  
Low Temperature ◽  
Asphalt Concrete ◽  
Cellulose Fiber ◽  
Asphalt Mixtures ◽  
Temperature Deformation ◽  
Integrated Analysis ◽  
Price Ratio ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Low Temperature Cracking

A kind of hybrid fiber was added into asphalt mixtures with the purpose of gaining pavement material with higher performance-to-price ratio. The hybrid fiber was constitutive of cellulose fiber and polyester fiber in several different proportions. Superpave mix design procedure was used to prepare hybrid fiber reinforced asphalt mixtures. Different kinds of specimens were formed with optimum asphalt content. Prolonged rutting test was conducted for the investigation of pave pavement properties of asphalt concrete. Test results show that hybrid fiber reinforced asphalt mixtures have better high-temperature deformation resistance, when the proportion of cellulose fiber in hybrid fiber ranges from 20% to 60%. Three points blending test was used to evaluate the low-temperature cracking property. Data prove that hybrid fiber with property proportion is of benefit to low-temperature cracking resistance. Water sensitivity test and indirect tension fatigue test were also carried out. Asphalt concrete with fiber has much better water damage resistance than that without fiber. For asphalt mixtures containing hybrid fiber, the cycle numbers to failure increase with the proportion decreasing of cellulose fiber in hybrid fiber. Making integrated analysis, hybrid fiber reinforced asphalt concrete has high performance-to-price ratio, which is propitious to spread of fiber reinforced asphalt concrete.

Effect of Addition of Dry Crumb Rubber on the Performance of Terminal Blend Crumb Rubber Modified Asphalt Mixtures

2017 ◽  
Vol 2633 (1) ◽  
pp. 90-97 ◽  
Author(s):  
Salih Kocak ◽  
M. Emin Kutay
Keyword(s):  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Crumb Rubber ◽  
Asphalt Mixtures ◽  
Fine Aggregate ◽  
Dry Process ◽  
Modified Asphalt ◽  
Wet Process ◽  
Low Temperature Cracking ◽  
Linear Viscoelastic

Three major methods are used to produce crumb rubber modified asphalt pavement: the dry process (CRDry), the terminal blend process (CRTB), and the wet process (CRWet). Although the CRDry process replaces the portion of fine aggregate in the asphalt mixture with crumb rubber (CR) particles, the CRWet process incorporates CR particles into hot liquid asphalt before it is mixed with aggregates. CRTB is known as a special type of CRWet process in which the CR is blended with asphalt binder at the asphalt terminal. In general, the CRWet process can integrate 15% to 22% CR by weight of the binder. This amount ranges from 10% to 12% in the CRTB process as a result of the limitations associated with transportation and pumping. This study investigated the feasibility of increasing the CR content of CRTB modified asphalt mixtures. The addition to the mixture of about 0.5% CR (by weight of the mix) through the CRDry process doubled the amount of rubber to be found in a conventional CRTB mix. The relative performances of the CRTB and the CRTB+CRDry processes [i.e., crumb rubber hybrid (CRHY)] were investigated with respect to their linear viscoelastic properties, rutting susceptibility, moisture damage, resistance to fatigue, and low temperature cracking. It was shown that it was possible to increase the amount of CR in the mixture through the use of the CRHY method proposed here, without adverse effect on the performance of the mixture.

scholarly journals Investigating the Effect of Aggregate Characteristics on the Macroscopic and Microscopic Fracture Mechanisms of Asphalt Concrete at Low-Temperature

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2675 ◽  
Author(s):  
Yinshan Xu ◽  
Yingjun Jiang ◽  
Jinshun Xue ◽  
Jiaolong Ren
Keyword(s):  
Low Temperature ◽  
Asphalt Concrete ◽  
Asphalt Pavements ◽  
Fracture Mechanisms ◽  
Discrete Element Modeling ◽  
Aggregate Distribution ◽  
Initiation Zone ◽  
Low Temperature Cracking ◽  
Different Temperatures ◽  
Temperature Crack

The low-temperature crack of asphalt concrete is considered to be one of the main deteriorations in asphalt pavements. However, there have been few studies on the composite effects of the aggregate characteristics and fracturing modes on the low-temperature cracking of asphalt concrete. Hence, the edge cracked semi-circular bend tests and the discrete element modeling approaches are combined to investigate the effect of the aggregate contents, aggregate morphological features and aggregate distributions on the fracture behavior of asphalt concrete in different fracturing modes at different temperatures. The results show that the fracture toughness and the crack extended time reduce with the increasing aggregate orientation and flatness and the decreased aggregate content. The effect of aggregate flatness is nonlinear and its reduction trend grows gradually with the increasing flatness. The total number of failed contacts is reduced with the increasing aggregate orientation and flatness, particularly at 10 °C. The number of failed contacts that occurred in the aggregate-mastic interface in quasi mode II fracturing is slightly higher than that in other fracturing modes. The aggregate distribution in the crack initiation zone greatly influenced the crack resistance, particularly at 10 °C. The research is beneficial to better understanding the fracture mechanisms of asphalt concrete at low-temperature.

Conceptualization of Three-Stage Fatigue Failure in Asphalt-Rubber Gap-Graded Mixtures using Dynamic Semi-Circular Bending Test

2020 ◽  
Vol 2674 (7) ◽  
pp. 44-55
Author(s):  
Veena Venudharan ◽  
Krishna Prapoorna Biligiri
Keyword(s):  
Failure Process ◽  
Mouth Opening ◽  
Fatigue Performance ◽  
Bending Test ◽  
Crack Mouth Opening Displacement ◽  
Fatigue Process ◽  
Structural Deterioration ◽  
Asphalt Rubber ◽  
Scb Test ◽  
Cracking Mechanism

The objective of this study was to qualitatively measure the cracking mechanism of asphalt-rubber gap-graded (AR-Gap) mixtures and compare the methodical approach proposed in this research with the conventional fatigue process. As part of experimentation plan, dynamic a semi-circular bending (SCB) test was conducted on 27 AR-Gap mixtures with varying mix parameters, including, binder type, binder content, and aggregate gradation. Fatigue life ( Nf) obtained from the dynamic SCB test was analyzed from a statistical viewpoint, and key relationships that potentially contribute to fatigue performance were identified. Later, crack mouth opening displacement (CMOD) was used to study the cracking mechanism of AR-Gap mixtures. CMOD data were analyzed using the Francken model that theorizes the accumulated damage as a three-stage failure. Further, fatigue tertiary life ( Nft) was determined on the premise of structural deterioration obtained from the three-stage failure process. The fatigue disparity factor (ξ), the ratio of Nf to Nft for each asphalt mix was estimated to compare fatigue performance indices. The score of ξ for all the mixtures exceeded 50%, which was indicative of longer crack initiation and crack propagation phase over the third stage of the fatigue cracking mechanism. Overall, the fatigue mechanism was explained through the conceptualization of the three-stage fatigue process through various intrinsic properties of AR-Gap mixtures.

scholarly journals Influence of Bitumen Type and Asphalt Mixture Composition on Low-Temperature Strength Properties According to Various Test Methods

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2118 ◽  
Author(s):  
Marek Pszczola ◽  
Cezary Szydlowski
Keyword(s):  
Tensile Strength ◽  
Low Temperature ◽  
Cooling Rate ◽  
Strength Properties ◽  
Test Methods ◽  
Asphalt Mixtures ◽  
Bending Test ◽  
Mixture Composition ◽  
Tension Stress ◽  
Strength Reserve

In regions with low-temperatures, action transverse cracks can appear in asphalt pavements as a result of thermal stresses that exceed the fracture strength of materials used in asphalt layers. To better understand thermal cracking phenomenon, strength properties of different asphalt mixtures were investigated. Four test methods were used to assess the influence of bitumen type and mixture composition on tensile strength properties of asphalt mixtures: tensile strength was measured using the thermal stress restrained specimen test (TSRST) and the uniaxial tension stress test (UTST), flexural strength was measured using the bending beam test (BBT), and fracture toughness was measured using the semi-circular bending test (SCB). The strength reserve behavior of tested asphalt mixtures was assessed as well. The influence of cooling rate on the strength reserve was investigated and correlations between results from different test methods were also analyzed and discussed. It was observed that the type of bitumen was a factor of crucial importance to low-temperature properties of the tested asphalt concretes. This conclusion was valid for all test methods that were used. It was also observed that the level of cooling rate influenced the strength reserve and, in consequence, resistance to low-temperature cracking. It was concluded that reasonably good correlations were observed between strength results for the UTST, BBT, and SCB test methods.

Low-Temperature Cracking of Recycled Asphalt Mixtures

2012 ◽  
pp. 1261-1270 ◽  
Author(s):  
N. Tapsoba ◽  
C. Sauzéat ◽  
H. Benedetto ◽  
H. Baaj ◽  
M. Ech
Keyword(s):  
Low Temperature ◽  
Asphalt Mixtures ◽  
Recycled Asphalt ◽  
Low Temperature Cracking
Sign in / Sign up

Export Citation Format

Share Document