Laboratory Investigation of the Performance Evaluation of Fiber-Modified Asphalt Mixes in Cold Regions

2020 ◽  
Vol 2674 (7) ◽  
pp. 323-335
Author(s):  
Luis Alberto Perca Callomamani ◽  
Leila Hashemian ◽  
Katrina Sha
Keyword(s):  
Low Temperatures ◽  
Polymer Fibers ◽  
Cost Comparison ◽  
Moisture Susceptibility ◽  
Traffic Loading ◽  
Asphalt Mixes ◽  
Modified Asphalt ◽  
Reliable Source ◽  
Asphalt Mix ◽  
Source Of Information

Thermal cracking of pavement is caused by contraction of the asphalt layer at low temperatures, when tensile stresses build up to a critical point at which a crack is formed. The cracks formed then propagate under traffic loading conditions. Freeze-thaw cycles accelerate crack propagation and deterioration of the asphalt layer, and can also lead to the formation of more severe distresses such as potholes. Fibers have attracted increasing attention in the asphalt industry for use as asphalt concrete modifiers. The addition of fibers to hot mix asphalt (HMA) results in a composite material that has a higher tensile strength, along with the ability to absorb greater energy during the fracture process. The fibers within the material also act as a barrier preventing the formation and propagation of cracks in the asphalt mix. This research evaluates the effectiveness of adding polymer fibers to HMA to increase both its resistance to cracking at intermediate and low temperatures, and its rutting resistance and moisture susceptibility at high temperatures. For this purpose, three different types of polymer fibers: aramids, polyethylene terephthalate (PET), and polyacrylonitrile (PAN), were added to conventional HMA mixes. The resulting samples were compacted, and their mechanical properties were compared with conventional HMA in the laboratory. At the end of the paper, a material cost comparison is provided as a reliable source of information when selecting materials to fulfill minimum industry specifications.

scholarly journals Laboratory performance and modelling behaviour of hot-mix asphalt with recycled crushed glass

2020 ◽  
Vol 62 (3) ◽  
Author(s):  
T B George ◽  
J K Anochie-Boateng ◽  
K J Jenkins
Keyword(s):  
Permanent Deformation ◽  
Constitutive Models ◽  
Hydrated Lime ◽  
Moisture Damage ◽  
Fine Aggregate ◽  
Moisture Susceptibility ◽  
Asphalt Mixes ◽  
Laboratory Performance ◽  
Deformation Properties ◽  
Asphalt Mix

In South Africa research is currently under way to determine the suitability of using locally available recycled crushed glass as a partial fine aggregate substitute in the production of asphalt mixes. This paper characterises the laboratory performance of a dense-graded asphalt wearing course mix consisting of 15% recycled crushed glass. The influence of selected antistripping additives on moisture susceptibility was specifically assessed as a variable in the performance evaluation of the glass-asphalt mix as follows: (a) the effect of 1% hydrated lime, (b) the effect of 0.5% liquid antistripping additive, and (c) the effect without the addition of antistripping additive. The effect of these variables on the moisture susceptibility of the glass-asphalt mix was evaluated using the tensile strength ratio parameter supported with a microscopic imaging analysis. Additionally, the stiffness and permanent deformation properties of the glass-asphalt mix that demonstrated optimum resistance to moisture damage was compared to the same mix without crushed glass. The performance properties were evaluated using the Huet-Sayegh model and a polynomial model respectively, which were used particularly to develop performance characterisation models for the glass-asphalt mix. The findings of this study revealed that an anti-stripping additive is essential to meet moisture susceptibility criteria and alleviate moisture damage in dense-graded glass-asphalt mixes. In particular, moisture susceptibility was improved using hydrated lime rather than the liquid antistripping additive. Furthermore, the selected constitutive models were able to effectively characterise the laboratory performance of both mixes, with the glass-asphalt mix demonstrating improved resistance to permanent deformation when compared with the conventional asphalt mix.

Effect of Increasing Sasobit on Permanent Deformation and Moisture Damage of Asphalt Mixes

2018 ◽  
Vol 877 ◽  
pp. 241-247 ◽  
Author(s):  
Fazal Haq ◽  
Arshad Hussain ◽  
Kamran Mushtaq
Keyword(s):  
Transportation Network ◽  
Permanent Deformation ◽  
Road Construction ◽  
Cost Effective ◽  
Moisture Damage ◽  
Moisture Susceptibility ◽  
Asphalt Mixes ◽  
The Road ◽  
Asphalt Mix ◽  
The Impact

Transportation network plays a substantial role in the everyday life of social beings. The preservation of this vast infrastructure needs appropriate and cost-effective design techniques, which depends upon the selection and proportion of binder and aggregate. With the passage of time, as compared to HMA (Hot Mix Asphalt), WMA (Warm mix asphalt) has become extreme prevalent in the road construction industry, because WMA offers the opportunity of production asphalt mix at a reduced temperature than conventionally used for HMA, hence saving energy, cutting CO2 emission and improve environmental quality. This study aims to assess the impact of sasobit (an organic WMA additive) on permanent deformation and moisture susceptibility of asphalt mixes. Under the scope of this paper, the authors have added three percentages of sasobit that is 1%, 2% and 3% to check the effect of increasing sasobit percentage on rutting and moisture damage of asphalt mixes. In summary, rut depth of WMA as obtained from Hamburg Wheel Tracker Device (HWTD) slightly decreased from that of HMA, while rut depth at 1% and 2% was even less than that of 3% sasobit. A slight increase in moisture damage as compared to control mix was observed by adding sasobit, as illustrated by decreased Tensile Strength Ratios TSR.

scholarly journals Laboratory Study on the Performance of Asphalt Mixes Modified with a Novel Composite of Diatomite Powder and Lignin Fiber

2020 ◽  
Vol 10 (16) ◽  
pp. 5517 ◽  
Author(s):  
Moustafa Abdelsalam ◽  
Yanchao Yue ◽  
Ahmed Khater ◽  
Dong Luo ◽  
Josephine Musanyufu ◽  
...  
Keyword(s):  
Asphalt Pavement ◽  
Fiber Composite ◽  
Immersion Test ◽  
The Other ◽  
Bending Test ◽  
Asphalt Mixes ◽  
Modified Asphalt ◽  
Splitting Test ◽  
Cracking Performance ◽  
Asphalt Mix

The performance and the fundamental weaknesses of asphalt mix under environmental temperature and water effects have made researchers try to modify the asphalt mix properties by using the proper additives. For this reason, this paper aims to improve the anti-cracking performance and water stability of asphalt pavement by adding a novel composite of diatomite and lignin fiber in asphalt mixes. Four types of asphalt mixes, including control asphalt mix (CAM), diatomite modified asphalt mix (DMAM), lignin fiber modified asphalt mix (LFMAM), and diatomite-lignin fiber composite modified asphalt mix (DLFMAM) were prepared in the laboratory. Low-temperature bending test, Marshall Immersion test, and freeze-thaw splitting test were employed to evaluate the performance of the asphalt mixes. Results reveal that the use of the lignin fiber in reinforced asphalt mixes combined with diatomite led to an enhancement in the asphalt pavement performance more than the other three types of mixes. Diatomite has an important influence on the water damage resistance of asphalt mix more than lignin fiber. On the other hand, diatomite has a small effect on the anti-cracking performance; meanwhile, lignin fiber showed a significant improvement in the cracking resistance of asphalt mixes. DLFMAM has the best traveling performances among all asphalt mixes. Thus, this work provides a good reference for the design of composite asphalt mixes.

scholarly journals Properties of Waste Polyethylene Terephthalate (PET) Modified Asphalt Mixes: Dependence on PET Size, PET Content, and Mixing Process

2018 ◽  
Author(s):  
Rajan Choudhary ◽  
Abhinay Kumar ◽  
Kishori Murkute
Keyword(s):  
Experimental Design ◽  
Polyethylene Terephthalate ◽  
Volumetric Properties ◽  
Mixing Process ◽  
Moisture Susceptibility ◽  
Asphalt Mixes ◽  
Dry Process ◽  
Modified Asphalt ◽  
Pet Bottles ◽  
Waste Polyethylene

Management and disposal of waste polyethylene terephthalate (PET) bottles is an ever-growing challenge. The present study investigated the effect of incorporation of shredded waste PET bottles on properties of asphalt mixes in terms of: (i) process of PET addition, (ii) PET content, and (iii) PET size. Experimental design included three variables: two processes (dry process, and modified dry process), three PET contents (2.5%, 5.0%, and 7.5% by weight of binder), and two PET sizes (2.36–1.18 mm, and 0.30–0.15 mm). Volumetric properties, Marshall parameters, and moisture susceptibility characteristics of PET modified mixes were evaluated and compared with control mix (without PET). Analysis of variance (ANOVA) was performed to evaluate main and interaction effects of the variables. Results indicated that all the three variables had significant influence on the measured properties. Further, mixes prepared using modified dry process outperformed other mixes and showed highest resistance towards moisture induced damage.

Prawne regulacje pobierania i transplantacji narządów oraz tkanek w ujęciu europejskiej konwencji bioetycznej

2016 ◽  
pp. 52-65
Author(s):  
Patryk Kołodyński ◽  
Paulina Drab
Keyword(s):  
Ex Vivo ◽  
Legal Aspects ◽  
European Convention ◽  
The Public ◽  
Additional Protocol ◽  
The Past ◽  
Reliable Source ◽  
International Legal Order ◽  
Definition Of ◽  
Source Of Information

Over the past several years, transplantology has become one of the fastest developing areas of medicine. The reason is, first and foremost, a significant improvement of the results of successful transplants. However, much controversy arouse among the public, on both medical and ethical grounds. The article presents the most important concepts and regulations relating to the collection and transplantation of organs and tissues in the context of the European Convention on Bioethics. It analyses the convention and its additional protocol. The article provides the definition of transplantation and distinguishes its types, taking into account the medical criteria for organ transplants. Moreover, authors explained the issue of organ donation ex vivo and ex mortuo. The European Convention on Human Rights and Biomedicine clearly regulates the legal aspects concerning the transplantation and related basic concepts, and therefore provides a reliable source of information about organ transplantation and tissue. This act is a part of the international legal order, which includes the established codification of bioethical standards.

Multiple object positions and how to diagnose them

2017 ◽  
Author(s):  
Lieven Danckaert
Keyword(s):  
Structure Analysis ◽  
Phrase Structure ◽  
Final Part ◽  
Multiple Object ◽  
Reliable Source ◽  
Extended Projection ◽  
Modal Verb ◽  
Source Of Information

This chapter addresses the question of which syntactic environment constitutes the most reliable source of information on variable object placement in Latin. The relevance of this question is illustrated by showing that very different results are obtained when one compares the rate of VO in two different syntactic contexts, namely clauses with a single synthetic verb and clauses with a modal verb and a dependent infinitive. It is argued that the OV/VO alternation is best studied to clauses with more than one verb, as in such clauses, more object positions can be unambiguously identified. The final part of the chapter is devoted to the phrase structure analysis of clauses with the modals possum ‘be able’ and debeo ‘have to’. These structures are argued to constitute monoclausal domains, in which the modals are raising predicates that originate in functional heads in the extended projection of lexical verbs.

scholarly journals Material Properties and Environmental Benefits of Hot-Mix Asphalt Mixes Including Local Crumb Rubber Obtained from Scrap Tires

Environments ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 47
Author(s):  
Lim Min Khiong ◽  
Md. Safiuddin ◽  
Mohammad Abdul Mannan ◽  
Resdiansyah
Keyword(s):  
Asphalt Binder ◽  
Crumb Rubber ◽  
Environmental Benefits ◽  
Asphalt Binders ◽  
Rubber Content ◽  
Scrap Tires ◽  
Asphalt Mixes ◽  
Temperature Resistance ◽  
Modified Asphalt ◽  
Marshall Stability

This paper presents the results of a laboratory-based experimental investigation on the properties of asphalt binder and hot-mix asphalt (HMA) mixes modified by locally available crumb rubber, which was used as a partial replacement of asphalt by weight. In this study, fine crumb rubber with a particle size in the range of 0.3–0.6 mm, obtained from scrap tires, was added to the asphalt binder through the wet process. Crumb rubber contents of 5%, 10%, 15%, and 19% by weight of asphalt were added to the virgin binder in order to prepare the modified asphalt binder samples, while the unmodified asphalt binder was used as the control sample. The crumb rubber modified binder samples were examined for measuring viscosity indirectly using the penetration test, and temperature resistance using the softening point test. Later, both the modified and unmodified asphalt binders were used to produce HMA mixes. Two categories of HMA mix commonly used in Malaysia—namely, AC 14 (dense-graded) and SMA 14 (gap-graded)—were produced using the modified asphalt binders containing 5%, 10%, 15%, and 19% crumb rubber. Two AC 14 and SMA 14 control mixes were also produced, incorporating the unmodified asphalt binder (0% crumb rubber). All of the AC 14 and SMA 14 asphalt mixes were examined in order to determine their volumetric properties, such as bulk density, voids in total mix (VTM), voids in mineral aggregate (VMA), and voids filled with asphalt (VFA). In addition, the Marshall stability, Marshall flow, and stiffness of all of the AC 14 and SMA 14 mixes were determined. Test results indicated that the modified asphalt binders possessed higher viscosity and temperature resistance than the unmodified asphalt binder. The viscosity and temperature resistance of the asphalt binders increased with the increase in their crumb rubber content. The increased crumb rubber content also led to improvements in the volumetric properties (bulk density, VTM, VMA, and VFA) of the AC 14 and SMA 14 mixes. In addition, the performance characteristics of the AC 14 and SMA 14 mixes—such as Marshall stability, Marshall flow, and stiffness—increased with the increase in crumb rubber content. However, the AC 14 mixes performed much better than the SMA 14 mixes. The overall research findings suggest that crumb rubber can be used to produce durable and sustainable HMA mixes, with manifold environmental benefits, for use in flexible pavements carrying the heavy traffic load of highways.

scholarly journals Mechanical Characteristics of Graphene Nanoplatelets-Modified Asphalt Mixes: A Comparison with Polymer- and Not-Modified Asphalt Mixes

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2434
Author(s):  
Laura Moretti ◽  
Nico Fabrizi ◽  
Nicola Fiore ◽  
Antonio D’Andrea
Keyword(s):  
Fatigue Resistance ◽  
Graphene Nanoplatelets ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Asphalt Mixes ◽  
Modified Asphalt ◽  
Bituminous Mixtures ◽  
Water Sensitivity ◽  
Polymer Modified Asphalt ◽  
Mechanical Performances

In recent years, nanotechnology has sparked an interest in nanomodification of bituminous materials to increase the viscosity of asphalt binders and improves the rutting and fatigue resistance of asphalt mixtures. This paper presents the experimental results of laboratory tests on bituminous mixtures laid on a 1052 m-long test section built in Rome, Italy. Four asphalt mixtures for wearing and binder layer were considered: two polymer modified asphalt concretes (the former modified with the additive Superplast and the latter modified with styrene–butadiene–styrene), a “hard” graphene nanoplatelets (GNPs) modified asphalt concrete and a not-modified mixture. The indirect tensile strength, water sensitivity, stiffness modulus, and fatigue resistance of the mixtures were tested and compared. A statistical analysis based on the results has shown that the mixtures with GNPs have higher mechanical performances than the others: GNP could significantly improve the tested mechanical performances; further studies will be carried out to investigate its effect on rutting and skid resistance.

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