Fracture toughness of polymer-modified asphalt concrete at low temperatures

2003 ◽  
Vol 30 (2) ◽  
pp. 406-413 ◽  
Author(s):  
Kwang W Kim ◽  
Seung Jun Kweon ◽  
Young S Doh ◽  
Tae-Soon Park

The fracture toughness of asphalt concrete increases at low temperature and then decreases at temperatures below a certain level. Some polymers are known to have the property of improving the temperature susceptibility of asphalt binder at low temperatures. Therefore, this study evaluated the fracture toughness (KIC) of some polymer-modified asphalt concretes. Low-density polyethylene (LDPE), styrene–butadiene–styrene (SBS), and a mixed polymer of LDPE and SBS were used in this study. The fracture toughness KIC of normal asphalt concrete was compared with that of polymer-modified asphalt (PMA) concrete, and the effectiveness of polymer modification against falling values of KIC was evaluated at low temperatures. The results showed that PMA concretes, in general, showed better KIC than normal asphalt concretes, and the temperature at which the highest KIC was obtained was lower than that in the case of normal asphalt concrete. Therefore, the PMA concretes evaluated in this study had better fracture resistance than normal asphalt at low temperatures.Key words: asphalt concrete, polymer-modified asphalt, PMA, fracture toughness, differential thermal contraction, low-temperature damage.

Author(s):  
Alekh S. Bhurke ◽  
E. Eugene Shin ◽  
Lawrence T. Drzal

Pavement distress occurs through a variety of mechanisms, but it is always controlled by the adhesive and cohesive performance of the asphalt binder. Although the causes of pavement failures are known, the precise mechanisms by which they occur remain to be understood. Observation of the fracture morphology of asphalt concrete can provide some information in this respect. The fracture morphology of asphalt concrete is dependent on the morphology of the binder. A network structure was observed in thin asphalt binder films and the fracture morphology and engineering properties of asphalt concrete were found to be dependent on the network morphology of the asphalt binder. Addition of polymers to asphalt binders causes changes in the nature of the network structure, and its effect can be qualitatively determined by characterizing the fracture morphology. Styrene butadiene styrene (SBS), styrene ethylene butylene styrene (SEBS), styrene butadiene rubber (SBR) latex and an epoxy-terminated reacting polyolefin (Elvaloy AM) were used in this study. A quantitative method to determine the effect of polymer modification on the fracture properties of asphalt concrete is the J-contour integral fracture toughness measurement. An experimental protocol to measure the critical J-integral fracture toughness ( J1 c) was developed and the low temperature (-10°C) J1 c values were determined for SEBS and Elvaloy AM-modified asphalt concrete at three different concentrations.


2021 ◽  
Vol 13 (18) ◽  
pp. 10271
Author(s):  
Yuchen Guo ◽  
Xuancang Wang ◽  
Guanyu Ji ◽  
Yi Zhang ◽  
Hao Su ◽  
...  

The deteriorating ecological environment and the concept of sustainable development have highlighted the importance of waste reuse. This article investigates the performance changes resulting from the incorporation of shellac into asphalt binders. Seashell powder-modified asphalt was prepared with 5%, 10%, and 15% admixture using the high-speed shear method. The microstructure of the seashell powder was observed by scanning electron microscope test (SEM); the physical-phase analysis of the seashell powder was carried out using an X-ray diffraction (XRD) test; the surface characteristics and pore structure of shellac were analyzed by the specific surface area Brunauer-Emmett-Teller (BET) test; and Fourier infrared spectroscopy (FTIR) qualitatively analyzed the composition and changes of functional groups of seashell powder-modified asphalt. The conventional performance index of seashell powder asphalt was analyzed by penetration, softening point, and ductility (5 °C) tests; the effect of seashell powder on asphalt binder was studied using a dynamic shear rheometer (DSR) and bending beam rheometer (BBR) at high and low temperatures, respectively. The results indicate the following: seashell powder is a coarse, porous, and angular CaCO3 bio-material; seashell powder and the asphalt binder represent a stable physical mixture of modified properties; seashell powder improves the consistency, hardness, and high-temperature performance of the asphalt binder but weakens the low-temperature performance of it; seashell powder enhances the elasticity, recovery performance, and permanent deformation resistance of asphalt binders and improves high-temperature rheological properties; finally, seashell powder has a minimal effect on the crack resistance of asphalt binders at very low temperatures. In summary, the use of waste seashells for recycling as bio-modifiers for asphalt binders is a practical approach.


2007 ◽  
Vol 34 (5) ◽  
pp. 589-597 ◽  
Author(s):  
K Kandil ◽  
A O Abd El Halim ◽  
Y Hassan ◽  
A Mostafa

The extreme environmental conditions in Canada require the use of asphalt cement that can provide a high resistance to low-temperature cracking during the winter season and a high resistance to rutting due to the elevated temperatures in the summer. Earlier studies showed that such desired improvements in the quality of asphalt cement could be achieved using polymer-modified asphalt (PMA) cement. This paper presents a three-phase experimental program that was carried out to evaluate the expected performance of asphalt concrete mixtures with PMA compared to asphalt concrete mixtures with conventional and air-oxidized asphalt binders. The results of this study show that PMA in asphalt concrete mixes would significantly improve the resistance to cracking (loading and low-temperature). Key words: asphalt mixtures, polymer-modified asphalt, conventional asphalt cement, air-oxidized asphalt, testing.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2888
Author(s):  
Sylwia Dziadosz ◽  
Mieczysław Słowik ◽  
Filip Niwczyk ◽  
Marcin Bilski

The paper presents the results of laboratory investigation on asphalt binders relaxation at low temperature, carried out in a ductilometer using the tensile test with continuous force measurement. Polymer modified asphalt binder samples consisting of a 50/70 penetration grade bitumen mixed with a concentrate of styrene-butadiene-styrene (SBS) modified bitumen—a 160/220 penetration grade bitumen modified with a SBS copolymer in the amount of 9%—were tested. Therefore, polymer modified binders containing 3%, 4.5%, 6% and 7.5% SBS, respectively, were obtained and investigated. Tensile tests were performed at −16 °C on samples before aging and subjected to short-term aging (RTFOT). Test results in the form of relaxation curves have been mathematically described using a modified generalized Maxwell model. Based on the acquired results, it was shown that the increase of the SBS copolymer content in asphalt binder precipitates the relaxation process, while aging slows down this phenomenon. It has also been proven that with increased content of SBS elastomer in asphalt binder, the effect of short-term aging on binder’s stress relaxation ability at low temperatures is reduced.


2017 ◽  
Vol 5 (12) ◽  
pp. 7797-7801 ◽  
Author(s):  
Safaa Moubark ◽  
Farag Khodary ◽  
Ayman Othman

It is noticeable that the increase of road traffic during the last two decades in addition to the insufficient degree of maintenance caused an accelerated deterioration of road structure. These roads show early signs of distress such as rutting, cracking, low temperature cracking, ageing and stripping. Heavier loads and higher traffic volume demand higher performance of pavement.  Excellent performance of pavement requires bitumen that is less susceptible to high temperature, rutting or low temperature cracking. Several additives are used to increase the performance of bitumen and the quality of the produced mixtures. Polymers are considered the most widely used additives in asphalt modification that give better performance. The performance of the Polymer-modified asphalt depends on the type and the level of modification the used polymer. The choice of modification level and t modification type depends on the physical properties of the polymer, and its compatibility with bitumen. The polymer can be loosely classified into two categories, Plastomers and Elastomers. The results indicated that, the addition of polypropylene generally improved the mechanical properties of the mixture regardless of the percentage of polymers that added and (PP) content of 5%. it can be noticed that  the performance of PP-modified asphalt mixtures is better  compared with unmodified asphalt concrete mixtures  modifier because it has the highest Marshall Stiffness, indirect tensile strength and unconfined compressive strength


Author(s):  
M. Zh. Zhurinov ◽  
◽  
B. B. Teltayev ◽  
Ye. D. Amirbayev ◽  
A. O. Elschibayev ◽  
...  

A comparative analysis has been performed in this work for low temperature strength of 31 types of the conventional (non-modified) and modified road asphalt concretes. The neat bitumens of the grades BND 70/100, BND 100/130 and BND 130/200 have been produced by the Pavlodar petrochemical plant from the crude oil of the Western Siberia (Russia) by the method of direct oxidation and they satisfy the requirements of the standard ST RK 1373-2013. The polymers Elvaloy 4170, Elvaloy AM, Kraton, Calprene 501, Butonal NS, SBS (L 30-01 A), KUMHO KTP and crumb rubber have been used for the modification of the bitumens. The modification of the bitumens has been performed in the laboratory of Kazakhstan Highway Research Institute. The modified bitumens satisfy the requirements of the standard ST RK 2534-2015. The conventional and modified asphalt concretes satisfy the requirements of the standards ST RK 1225-2019, ST RK 1223-2019, ST RK 2028-2010, ST RK 2373-2019 and GOST 31015-2002. The strength of the asphalt concretes at uniaxial direct tension at a constant strain rate of 1 mm/min at the temperatures of -10 °С, -20 °С and -30 °С determined in the device TRAVIS under the standard EN 2697-46 has been accepted as a characteristic of their low temperature strength. It is found out that various modifiers affect the asphalt concrete strength in different ways: a degree of impact depends both on a type of an asphalt concrete and a modifier, as well as on a negative temperature value. Some modifiers increase, and some of them decrease the strength of the asphalt concretes at low temperatures compared with the original asphalt concretes. Among the modifiers the polymer Elvaloy AM has been found to be the most efficient at low temperatures. The asphalt concretes of type B with the bitumens of grades BND БНД 100/130 and BND 130/200 at modification by the polymer Elvaloy AM had the biggest strength at all the considered low temperatures: at -10 ºC – 6.79 MPa and 6.43 MPa; at -20 ºC – 7.57 MPa and 7.87 MPa; at -30 ºC – 7.35 MPa and 8.86 MPa. The stone mastic asphalt concretes 15 and 20 with the polymers and without them at all the considered low temperatures practically had the strength not higher than the basic asphalt concretes of type B with neat (original) bitumens of grades BND 100/130 and BND 130/200.


2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Hyun Hwan Kim ◽  
Mithil Mazumder ◽  
Moon-Sup Lee ◽  
Soon-Jae Lee

In this study, performance properties of polymer-modified asphalt (PMA) binders are evaluated depending on ground tire rubber (GTR) and styrene-isoprene-styrene (SIS). Styrene-butadiene-styrene- (SBS-) modified asphalt binder of PG 76-22 is used as a base binder to manufacture the rubberized PMA binder. The rubberized PMA binders are blended using SIS modifier. The binders were artificially short-term and long-term aged using rolling thin-film oven (RTFO) and pressure aging vessel (PAV) procedures. Superpave binder tests were conducted on the binders through rotational viscometer (RV), dynamic shear rheometer (DSR), and bending beam rheometer (BBR). Furthermore, multiple stress creep recovery (MSCR) test and atomic force microscopy (AFM) microstructural analysis were performed. The results of this study indicated that (1) the viscosity properties seem to be highly dependent on GTR and SIS contents, (2) the addition of SIS is observed to have a significant effect on improving the rutting performances of rubberized PMA binders, (3) the cracking properties are considered to be improved significantly through SIS modification, and (4) in general, the rubberized PMA binders with SIS showed the best performance for rutting and cracking among all the binders used in this study.


Author(s):  
Glen A. Crossley ◽  
Simon A. M. Hesp

Results from the low-temperature performance evaluation of a new class of reactive polymer modifiers designed to improve binder-aggregate adhesion in asphalt concrete are discussed. A living free radical polymerization process was used to prepare polyisoprene (PI) with short blocks of reactive silane-functional monomer at one end of the polymer chain. Performance was evaluated with the thermal stress restrained specimen test at a cooling rate of-10°C/h. The results obtained were compared with those for unmodified and styrene-butadiene (SB)-modified mixes. When added at 3 and 6 percent by weight of the binder, SB reduced the fracture temperature of the asphalt concrete by 6°C and 9°C, respectively. Similar results were obtained with the reactive polymers. However, although all the SB-modified samples failed in a catastrophic mode, none of the samples containing the silane-functional PI did. It is hypothesized that these polymers toughened the asphalt to an extent that cracks were only able to grow in a stable mode as opposed to an unstable mode or that localized yielding occurred. The method for obtaining the desired toughening effect is flexible; lower-cost monomers, such as butadiene, and more common polymerization methods, such as emulsion or anionic polymerization techniques, could be used equally well to produce polymers with similar or better performance characteristics. An added benefit is that the tested polymers were able to improve the stripping resistance of the mix significantly.


2019 ◽  
Vol 9 (9) ◽  
pp. 1949 ◽  
Author(s):  
Sen Han ◽  
Mengmei Liu ◽  
Weigong Shang ◽  
Xiang Qi ◽  
Zhuang Zhang ◽  
...  

Aiming to solve the contradiction between the workability and performance of pothole patching using cold mixtures, this paper proposed new patching materials based on the microcapsule technique and polymer reinforcement, namely cold mixtures with polymer modified asphalt and dense graded (DG) of aggregates (PADG) mixtures. Laboratory tests were conducted to compare the PADG mixtures with commonly used DG mixtures and open graded (OG) mixtures concerning workability, storability, cohesion, stability, and durability of each mixture. The results found that the PADG mixtures were satisfactory in their workability and storability and were as satisfactory as the OG mixtures. Meanwhile, stability and durability of the PADG mixtures was better than the DG mixtures and OG mixtures, i.e., the PADG mixtures showed stability in the conditions of the timeliness, low temperature, and immersion, as well as the freeze-thaw resistance and wear resistance in wet conditions. Therefore, it can be concluded that PADG mixtures are applicable in timely and durable pothole repairs in low temperatures and wet conditions.


Author(s):  
Jhony Habbouche ◽  
Ilker Boz ◽  
Brian K. Diefenderfer ◽  
Benjamin F. Bowers

The objective of this paper was to assess the viability of using high polymer (HP) modified asphalt concrete (AC) mixtures in Virginia as a reflective crack mitigation technique or when deemed appropriate as a tool for increased crack resistance on higher volume facilities. This was achieved by compiling and evaluating routine distress survey data against pre-paving distress survey data for relevant in-service HP pavements constructed between 2015 and 2018 and comparing them with several control in-service conventional polymer-modified asphalt (PMA) pavements. This is the first effort in North America to provide a detailed field performance of HP AC mixtures. In general, none of the evaluated mixtures (HP or PMA) was able to prevent reflective cracking completely. The HP sections showed the most promising performance 5 years after construction regardless of traffic level and the pre-existing pavement conditions. The pavement management system data for the reviewed sections indicated a potential controlling effect of the joint condition of the underlying jointed concrete pavement layer regardless of the asphalt mixture type employed (PMA or HP). Moreover, performance evaluations using the network-level pavement management data were conducted to estimate the life expectancy of HP AC overlays. Two different approaches and three levels of analysis were undertaken. Overall, PMA and HP AC overlays had an average predicted service life of 6.2 and 8.3 years, respectively, indicating a 34% extension of performance life of the AC overlays with high polymer modification.


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