scholarly journals High-Performance Sustainable Asphalt Mixtures for High-Volume Traffic Roads in Severe Climates

2020 ◽  
Vol 12 (21) ◽  
pp. 8765
Author(s):  
Fernando Moreno-Navarro ◽  
Francisco Javier Sierra ◽  
Miguel Sol-Sánchez ◽  
M. Carmen Rubio-Gámez ◽  
Manuel Castillo ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
High Performance ◽  
High Volume ◽  
Crumb Rubber ◽  
Asphalt Mixtures ◽  
Asphalt Pavements ◽  
Mechanical Resistance ◽  
Heavy Vehicles ◽  
Bituminous Materials ◽  
Traffic Volumes

This paper summarizes the work carried out in a research project whose main objective was to develop high-performance sustainable bituminous materials (using crumb rubber and additives to reduce their manufacturing temperature) to be used in roads that support high traffic volumes and/or severe environmental conditions. For this purpose, various studies were conducted both in a laboratory and in a real asphalt plant (at binder and mixture level). Later, these materials were used to construct a trial section in a highway at a mountain pass (at more than 1400 m above sea level) supporting more than 2600 heavy vehicles each day under severe environmental conditions (snow during winter, and high temperatures and many hours of solar radiation during the summer). The results indicate the viability of using these materials, since they provide a number of advantages such as improved workability at lower temperatures and an increase in the mechanical resistance against the main sources of distress that affect asphalt pavements.

scholarly journals Functional and environmental performance of plant-produced crumb rubber asphalt mixtures using the dry process

2021 ◽  
Vol 54 (5) ◽  
Author(s):  
M. Bueno ◽  
R. Haag ◽  
N. Heeb ◽  
P. Mikhailenko ◽  
L. Boesiger ◽  
...  
Keyword(s):  
Environmental Performance ◽  
High Performance ◽  
Large Scale ◽  
Fatigue Behavior ◽  
Permanent Deformation ◽  
Asphalt Mixture ◽  
Crumb Rubber ◽  
Asphalt Mixtures ◽  
Gaseous Emissions ◽  
Dry Process

AbstractIncorporating crumb rubber (CR) using the dry process, directly in the asphalt mixture rather than into the bituminous binder requires no plant retrofitting, and therefore is the most practical industrial method for CR incorporation into asphalt mixtures. Nevertheless, very few large scale studies have been conducted. This work uses a holistic approach and reports on the functional and environmental performance of asphalt mixtures with different concentrations of CR fabricated employing the dry process in asphalt plants. Gaseous emissions were monitored during the production and laboratory leaching tests simulating the release of pollutants during rain, was conducted to evaluate the toxicology of both the CR material alone and the modified asphalt mixtures. In addition, laboratory compacted samples were tested to assess their fatigue behavior. Furthermore, noise relevant surface properties of large roller compacted slabs were evaluated before and after being subjected to a load simulator (MMLS3) to evaluate their resistance to permanent deformation. The results confirm that comparable performance can be achieved with the incorporation of CR using the dry process for high performance surfaces such as semi-dense asphalt, which usually require the use of polymer modified binders. Environmental performance improvement can be achieved by a washing step of the CR material that could remove polar CR additives which have commonly been used as vulcanization accelerator during rubber production.

scholarly journals Effect of Aging and Moisture Damage on Fatigue Cracking Properties in Asphalt Mixtures

2021 ◽  
Vol 11 (22) ◽  
pp. 10543
Author(s):  
Sung Lin Yang ◽  
Cheolmin Baek ◽  
Hee Beom Park
Keyword(s):  
Service Life ◽  
South Korea ◽  
Material Properties ◽  
Fatigue Cracking ◽  
Moisture Damage ◽  
Asphalt Mixtures ◽  
Asphalt Pavements ◽  
Heavy Vehicles ◽  
Road Pavement ◽  
Damage And Fracture

Recently, damage to asphalt pavements in South Korea has increased because of direct and indirect factors caused by abnormal climatic changes, such as torrential rains, prolonged heatwaves in summer, and heavy snowfall in winter. Additionally, the use of medium and heavy vehicles is also a contributing factor. Therefore, an experimental procedure to study the moisture damage and fracture properties of asphalt pavements considering the recent changes in precipitation properties, deterioration of road pavement, and traffic conditions in South Korea was developed in this study. Additionally, changes in material properties according to the indoor aging process and fatigue crack resistance were evaluated for hot mix and warm mix asphalt mixtures of the same grade and different initial production and construction temperatures. To evaluate the effect of aging and moisture damage on fatigue cracking, the experimental coefficient values of the predictive model were calculated for each condition. It was observed that the material properties of hot mix asphalt mixtures changed with an increase in aging and moisture damage. The service life of the pavement was reduced by approximately 40–80% owing to moisture damage, whereas aging had a greater effect on fatigue life as the service life increased.

scholarly journals Preliminary Studies to Use Textile Fibers Obtained from Recycled Tires to Reinforce Asphalt Mixtures

2018 ◽  
Vol 7 (2) ◽  
pp. 14-30
Author(s):  
Jorge C. Pais ◽  
António Ferreira ◽  
Caio Santos ◽  
Paulo Pereira ◽  
Davide Lo Presti
Keyword(s):  
Asphalt Mixture ◽  
Tensile Tests ◽  
Crumb Rubber ◽  
Asphalt Mixtures ◽  
Asphalt Pavements ◽  
Valuable Resource ◽  
Scrap Tires ◽  
Textile Fibers ◽  
Asphalt Rubber ◽  
Indirect Tensile

Abstract The use of crumb rubber in the modification of asphalt has occurred because of the problems related to disposal of scrap tires. However, the use of scrap tires in asphalt pavements, known as asphalt rubber pavements, can minimize environmental impacts and maximize conservation of natural resources. The textile fibers from recycled tires are typically disposed of in landfills or used in energetic valorization, but similar to other fibers, they can be used as a valuable resource in the reinforcement of engineering materials such as asphalt mixtures. Thus, this work aims at studying the use of textile fibers recycled from ground tires in the reinforcement of conventional asphalt mixtures. The application of textile fibers from ground tires was evaluated through laboratory tests on specimens extracted from slabs produced in the laboratory. Indirect tensile tests were performed on a series of nine asphalt mixtures with different fiber and asphalt contents and compared with a conventional mixture. The results obtained from a 50/70 pen asphalt were used to define three asphalt mixture configurations to be used with 35/50 pen asphalt. The results indicate that the textile fibers recycled from used tires can be a valuable resource in the reinforcement of asphalt mixtures.

scholarly journals The Impact of Heavy Vehicle Traffic Trends on the Overdesign of Flexible Asphalt Pavements

2020 ◽  
Vol 12 (7) ◽  
pp. 2688
Author(s):  
Paolo Intini ◽  
Nicola Berloco ◽  
Pasquale Colonna ◽  
Vittorio Ranieri
Keyword(s):  
Cost Benefit ◽  
Design Methods ◽  
Pavement Design ◽  
Asphalt Pavements ◽  
Heavy Vehicle ◽  
Traffic Data ◽  
Heavy Vehicles ◽  
Vehicle Traffic ◽  
Traffic Volumes ◽  
The Impact

Given their environmental impact, the careful design of asphalt pavements is crucial. Previous research has highlighted the influence of several parameters on the outputs of different pavement design methods. In this study, the focus is on heavy vehicle trends, considering both the percentage of heavy vehicles in the average traffic flow and its evolution over time, which is usually included as a growth factor in the design inputs. Since these factors are very often assumed to be based on old estimates, the first aim of this study was to update them by exploring a recent series of continuous data collected on the Italian motorway network and showing how to infer estimates from historical traffic data. Subsequently, the variability of these input factors is introduced in standard pavement design methods to assess their influence on the design process and to quantify the risk of overdesign. While the analysis of historical heavy vehicle traffic data may reveal an overall zero-growth traffic tendency, different scenarios should be considered and assessed in cost-benefit analyses given the not negligible influence of growth factors on pavement thicknesses. This influence is shown here in different simulated design conditions, with different initial traffic volumes, share of heavy vehicles, and resilient moduli.

EVALUATION OF RUTTING PERFORMANCE OF HOT MIX ASPHALT CONTAINING POLYMER ADDITIVES

2020 ◽  
Vol 2 (2) ◽  
pp. 127-132
Author(s):  
Ahmed Eltwati ◽  
Alaa A. A. Elkaseh
Keyword(s):  
Asphalt Mixtures ◽  
Asphalt Pavements ◽  
Structural Performance ◽  
Accelerated Pavement Testing ◽  
Modified Asphalt ◽  
Resistance To Deformation ◽  
Traffic Volumes ◽  
Pavement Testing ◽  
Polymer Modified Asphalt ◽  
Run Up

In recent decades, escalating traffic volumes initiate asphalt pavements revealed to larger stresses, which can create premature distresses. To enhance the resistance to distresses, modification of the asphalt mixtures has been studied extensively. The objective of this paper is to evaluate the performance of asphalt pavement made with various bitumen types and also different thicknesses. The bitumen types used were conventional asphalt (Ac 60-70) and polymer modified asphalt (PG 76-22). The thickness of asphalt samples tested was 70, 80, and 90 mm. In this study, Accelerated Pavement Testing (APT) was conducted to evaluate the rut depth in the surface of the pavement. The experiment was run up to 20,000 cycles. The results revealed polymer has a significant effect on pavement resistance to rutting. The resistance can be increased by up to 30%. In addition, the rutting occurred rapidly for the first 3,000 cycles. Beyond 3,000, the deformation is increased slowly.  On the other side, the results showed that as the HMA thickness increases as the resistance to deformation increases. We, therefore, can conclude that adding particles of polymer to HMA could improve the structural performance of pavement i.e. rutting resistance and reduce the thickness of the surface

scholarly journals Assessment of simultaneous incorporation of crumb rubber and asphaltite in asphalt binders

DYNA ◽  
2019 ◽  
Vol 86 (208) ◽  
pp. 257-263
Author(s):  
Javier Eduardo Mantilla Forero ◽  
Eduardo Alberto Castañeda Pinzón
Keyword(s):  
Service Use ◽  
Road Construction ◽  
Crumb Rubber ◽  
Asphalt Mixtures ◽  
Asphalt Binders ◽  
Asphalt Pavements ◽  
Cole Plot ◽  
Modified Asphalt ◽  
Different Temperatures ◽  
First Time

Every day, roads are submitted to greater stresses. Thereby, additives have been incorporated to asphalt mixtures to enhance pavements performance. The purpose of this experimental study is to characterize for the first time, to date, the viscoelastic properties of asphalt samples modified with recycled rubber —from used vehicles tires— and asphaltite in the same mixture, at different temperatures and frequencies. All with the aim of optimizing the material properties and coming up with a proposal to an environmental issue: discarded vehicles tires and their after-service use. The stiffness of briquettes was analyzed by axial compression test. The results were principally represented in Black Space and Cole-Cole plot and indicate a substantial increase in stiffness and elasticity of the modified asphalt throughout the whole temperature range. This shows that the simultaneous addition of these two ingredients to the bitumen is a favorable alternative in road construction using asphalt pavements.

scholarly journals Evaluation of Micro-Mechanism and High- and Low-Temperature Rheological Properties of Disintegrated High Volume Crumb Rubber Asphalt (DHVRA)

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1145
Author(s):  
Wei Li ◽  
Sen Han ◽  
Xiaokang Fu ◽  
Ke Huang
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Rheological Properties ◽  
Particle Diameter ◽  
Gel Permeation Chromatography ◽  
High Volume ◽  
Crumb Rubber ◽  
Test Method ◽  
Polar Component ◽  
Temperature Performance

The aims of this paper are to prepare disintegrated high volume crumb rubber asphalt (DHVRA) with low viscosity, good workability and low-temperature performance by adding disintegrating agent (DA) in the preparation process, and to further analyze the disintegrating mechanism and evaluated high-temperature and low-temperature rheological properties. To obtain DHVRA with excellent comprehensive performance, the optimum DA dosage was determined. Based on long-term disintegrating tests and the Fluorescence Microscopy (FM) method, the correlations between key indexes and crumb rubber (CR) particle diameter was analyzed, and the evaluation indicator and disintegrating stage division standard were put forward. Furthermore, Fourier transform infrared spectroscopy (FT-IR) and Gel Permeation Chromatography (GPC) was used to reveal the reaction mechanism, and the contact angle test method was adopted to evaluate the surface free energy (SFE). In addition, the high-temperature and low-temperature rheological properties were measured, and the optimum CR content was proposed. Results indicated that the optimum DA dosage was 7.5‰, and the addition of DA promoted the melt decomposition of CR, reduced the viscosity and improved the storage stability. The 135 °C rotational viscosity (RV) of DHVRA from mixing for 3 h could be reduced to 1.475 Pa·s, and the softening point difference was even less than 2 °C. The linear correlation between 135 °C RV and the diameter of CR particle in rubber asphalt system was as high as 0.968, and the viscosity decay rate (VDR) was used as the standard to divide the disintegrating process into a fast disintegrating stage, stable disintegrating stage and slight disintegrating stage. Compared to common rubber asphalt (CRA), DHVRA has an absorption peak at 960 cm−1 caused by trans olefin = C-H, and higher molecular weight and polar component of surface energy. Compared with CRA, although the high-temperature performance of DHVRA decreases slightly, the low-temperature relaxation ability can be greatly improved.

scholarly journals Exploring the Structure–Performance Relationship of Sulfonated Polysulfone Proton Exchange Membrane by a Combined Computational and Experimental Approach

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 959
Author(s):  
Cataldo Simari ◽  
Mario Prejanò ◽  
Ernestino Lufrano ◽  
Emilia Sicilia ◽  
Isabella Nicotera
Keyword(s):  
High Performance ◽  
Mechanical Stability ◽  
Structural Parameters ◽  
Hydration Number ◽  
Pem Fuel Cells ◽  
Proton Exchange ◽  
Water Dynamics ◽  
Mechanical Resistance ◽  
Theoretical Simulation ◽  
Sulfonated Polysulfone

Sulfonated Polysulfone (sPSU) is emerging as a concrete alternative to Nafion ionomer for the development of proton exchange electrolytic membranes for low cost, environmentally friendly and high-performance PEM fuel cells. This ionomer has recently gained great consideration since it can effectively combine large availability on the market, excellent film-forming ability and remarkable thermo-mechanical resistance with interesting proton conductive properties. Despite the great potential, however, the morphological architecture of hydrated sPSU is still unknown. In this study, computational and experimental advanced tools are combined to preliminary describe the relationship between the microstructure of highly sulfonated sPSU (DS = 80%) and its physico-chemical, mechanical and electrochemical features. Computer simulations allowed for describing the architecture and to estimate the structural parameters of the sPSU membrane. Molecular dynamics revealed an interconnected lamellar-like structure for hydrated sPSU, with ionic clusters of about 14–18 Å in diameter corresponding to the hydrophilic sulfonic-acid-containing phase. Water dynamics were investigated by 1H Pulsed Field Gradient (PFG) NMR spectroscopy in a wide temperature range (20–120 °C) and the self-diffusion coefficients data were analyzed by a “two-sites” model. It allows to estimate the hydration number in excellent agreement with the theoretical simulation (e.g., about 8 mol H2O/mol SO3− @ 80 °C). The PEM performance was assessed in terms of dimensional, thermo-mechanical and electrochemical properties by swelling tests, DMA and EIS, respectively. The peculiar microstructure of sPSU provides a wider thermo-mechanical stability in comparison to Nafion, but lower dimensional and conductive features. Nonetheless, the single H2/O2 fuel cell assembled with sPSU exhibited better features than any earlier published hydrocarbon ionomers, thus opening interesting perspectives toward the design and preparation of high-performing sPSU-based PEMs.

scholarly journals 2 + 1 Highways: Overview and Future Directions

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Manuel Romana ◽  
Marilo Martin-Gasulla ◽  
Ana T. Moreno
Keyword(s):  
Urban Areas ◽  
High Performance ◽  
White Paper ◽  
Future Directions ◽  
Research Directions ◽  
Traffic Volumes ◽  
Primary Means ◽  
The Common ◽  
Rural Access ◽  
Transportation Research

Most of the rural transportation system is composed of two-lane highways, and many of them serve as the primary means for rural access to urban areas and freeways. In some highways, traffic volumes can be not high enough to justify a four-lane highway but higher than can be served by isolated passing lanes, or can present high number of head-on collisions. In those conditions, 2 + 1 highways are potentially applicable. This type of highway is used to provide high-performance highways as intermediate solution between the common two-lane highway and the freeway. Successful experiences reported in Germany, Sweden, Finland, Poland, or Texas (US) may suggest that they are potentially applicable in other countries. The objective of this white paper is to provide an overview of the past practice in 2 + 1 highways and discuss the research directions and challenges in this field, specially focusing on, but not limited to, operational research in association with the activities of the Subcommittee on Two-Lane Highways (AHB40 2.2) of the Transportation Research Board. The significance of this paper is twofold: (1) it provides wider coverage of past 2 + 1 highways design and evaluation, and (2) it discusses future directions of this field.

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