Asphalt Mix Design: Discussion on the Results Obtained from Empirical, Volumetric, and Performance-Based Methods

2022 ◽  
Author(s):  
Dinis Correia Gardete ◽  
Luís Picado-Santos ◽  
Silvino Capitão ◽  
Rosa Luzia
Keyword(s):  
Mix Design ◽  
Asphalt Mix ◽  
And Performance

scholarly journals Asphalt Mix Design and performance

1995 ◽  
Author(s):  
Shakor Badaruddin ◽  
Thomas White
Keyword(s):  
Mix Design ◽  
Asphalt Mix ◽  
And Performance

The Superpave Gradation Restricted Zone and Performance Testing With the Georgia Loaded Wheel Tester

1997 ◽  
Vol 1583 (1) ◽  
pp. 106-111 ◽  
Author(s):  
Donald E. Watson ◽  
Andrew Johnson ◽  
David Jared
Keyword(s):  
High Performance ◽  
Performance Testing ◽  
Mix Design ◽  
Design System ◽  
Department Of Transportation ◽  
Natural Sand ◽  
Aggregate Gradation ◽  
Actual Field ◽  
And Performance ◽  
Highway Research

Guidelines for the new hot-mix asphalt design system, Superpave, were developed under the Strategic Highway Research Program. One of the most controversial components of this system is the aggregate gradation restricted zone. This restricted zone was adopted as a gradation specification primarily to deter the use of high levels of natural sand in high-performance mixes. By designing mixes with gradations that avoid the restricted zone (i.e., limit natural sand), the internal strength provided by internal friction could be improved. Some agencies question the validity of the restricted zone. The specified gradations of many current mixes contain bands that enter the restricted zone, but the mixes have performed well for years in actual field conditions. The Georgia Department of Transportation (GDOT) currently specifies several standard mixes with gradations that enter the restricted zone and still perform well. These high-performance mixes contain good quality, 100 percent manufactured aggregates and no natural sand. GDOT recommends that the Georgia loaded wheel tester or some other proof tester be incorporated into the mix design process to screen mixes before rejecting them solely because their combined gradation enters the restricted zone. If mixes having combined gradations that enter the restricted zone are categorically rejected, mixes that are economical for the purpose intended may be rejected in the process.

Initial Approach to Performance (Balanced) Mix Design: The Virginia Experience

2019 ◽  
Vol 2673 (2) ◽  
pp. 335-345 ◽  
Author(s):  
Stacey D. Diefenderfer ◽  
Benjamin F. Bowers
Keyword(s):  
Performance Testing ◽  
Performance Criteria ◽  
Mix Design ◽  
Department Of Transportation ◽  
Innovative Methods ◽  
Asphalt Mix ◽  
Performance Additives ◽  
Virginia Department ◽  
Selection Of

Performance mix design (PMD) of asphalt mixtures, often referred to as balanced mix design, is a design methodology that incorporates performance testing into the mix design process. The Virginia Department of Transportation (DOT), like many owner agencies, is interested in ways to specify asphalt mix designs better in an effort to make its roadway network more sustainable, longer lasting, and more economical. By adding performance criteria through a PMD framework, that goal can be achieved. Further, a PMD framework should allow for the development of new, innovative methods to increase pavement recyclability, new performance additives, and other means to enhance pavement performance. This paper provides details and documentation of the approach being taken by the Virginia DOT in their efforts to develop a PMD specification. Aspects of development presented include PMD method options, selection of performance tests, and determination of acceptance criteria. A discussion about validating specifications with in-service performance data and addressing quality control and quality assurance is also provided. Although additional work is needed for full development and implementation, the methodology being applied has been found to provide useful outcomes for the Virginia DOT even in the initial stages of development.

The influence of porous asphalt mix design on raveling resistance

2019 ◽  
Author(s):  
Marijana Cuculić ◽  
Aleksandra Deluka Tibljaš ◽  
Fabian Vasić ◽  
Ivana Pranjić
Keyword(s):  
Mix Design ◽  
Porous Asphalt ◽  
Asphalt Mix

scholarly journals A Method to Quantify Reclaimed Asphalt Pavement Binder Availability (Effective RAP Binder) in Recycled Asphalt Mixes

2019 ◽  
Vol 2673 (1) ◽  
pp. 205-216 ◽  
Author(s):  
Fawaz Kaseer ◽  
Edith Arámbula-Mercado ◽  
Amy Epps Martin
Keyword(s):  
Asphalt Pavement ◽  
Economic Benefits ◽  
Binder Content ◽  
Mix Design ◽  
Void Content ◽  
Reclaimed Asphalt Pavement ◽  
Asphalt Mixes ◽  
Reclaimed Asphalt ◽  
State Highway ◽  
Asphalt Mix

State highway agencies recognize the environmental and economic benefits of utilizing reclaimed asphalt pavement (RAP) in asphalt mixes. Currently, most agencies assume all of the RAP binder content is available for mix design purposes. However, the percentage of available or effective RAP binder in the asphalt mix is usually less than 100% and not quantified, which could yield dry asphalt mix with a high air void content, potentially leading to premature distress. The term available or effective RAP binder refers to the binder that is released from the RAP, becomes fluid, and blends with virgin binder under typical mixing temperatures. This study proposes a method to estimate the RAP binder availability factor (BAF) which can be used to adjust the virgin binder content in RAP mixes to ensure that the mix design optimum binder content is achieved. In this method, asphalt mixes were prepared so that, after mixing and conditioning, the RAP material can be separated from the virgin aggregate, which allows for a thorough evaluation of the extent of RAP binder availability in the asphalt mix. This method was verified in a preliminary experiment and then used to estimate the BAF of RAP from different sources, and a correlation between RAP BAF and the high temperature performance grade (PG) of each RAP source was established. Finally, factors affecting the RAP BAF were also evaluated such as mixing temperature, conditioning period, the use of recycling agents (or rejuvenators), and the method of adding the recycling agent to the mix.

Laboratory Investigation of the Abrasive Wear Mechanism of Concrete Crosstie Rail Seat Deterioration (RSD)

2012 ◽  
Author(s):  
Amogh Arvind Shurpali ◽  
Emily Van Dam ◽  
J. Riley Edwards ◽  
David A. Lange ◽  
Christopher P. L. Barkan
Keyword(s):  
North America ◽  
Service Life ◽  
Abrasive Wear ◽  
Abrasion Resistance ◽  
High Speed ◽  
Mix Design ◽  
Concrete Mix ◽  
Rail Industry ◽  
And Performance ◽  
Performance Demands

Currently, there are divergent design and performance demands on railway infrastructure components due to increasing freight axle loads and cumulative gross tonnages, as well as increased investment in high-speed passenger rail development in North America. The divergence in loading and performance demands on shared infrastructure arises from the fact that while high-speed passenger trains exert lower loads at relatively high speeds, freight trains exert high loads at relatively low speeds. Improvements in infrastructure component designs are needed to achieve increased durability and tighter geometric tolerances. According to a rail industry survey administered by University of Illinois at Urbana-Champaign (UIUC) in 2008, Rail Seat Deterioration (RSD) is the principal performance problem limiting the service life of concrete crossties in North America. Rail infrastructure researchers and industry experts agree that abrasive wear may occur due to relative motion between the rail pad and concrete crosstie rail seat, potentially resulting in RSD. The complex tribological process of abrasion is further complicated and expected to be accelerated by the presence of abrasive fines and moisture, creating 3-body wear condition. Lack of understanding of the abrasion mechanism has resulted in a sub-optimal and iterative design of ties, causing reduced service life. This paper summarizes our efforts in understanding the effect of changing the mix design of concrete on the abrasion resistance of the rail seat which will eventually help us in modeling abrasive wear in RSD by constructing a mathematical relationship between the rail seat wear rate and input parameters including concrete mix design, mechanical/tribological properties of materials involved, normal load applied, presence of moisture, and abrasive fines. To simulate abrasive wear in RSD, a simple experiment is being carried out using a rotating wheel (lapping machine) capable of abrading concrete samples as a part of UIUC’s Small-Scale Abrasion Resistance Test (SSART). The objective of this research is to develop wear performance curves (e.g. wear depth versus load/time/cycles) for lab specimens developed from concrete crosstie mix designs that are currently being used in the industry, as well as for the evaluation of new mix designs. These data will help the rail industry in mechanistically designing concrete crossties by improving the understanding of materials used for concrete crosstie mix designs, with the objective of decreasing life cycle costs for the crosstie and fastening system. Preliminary SSART results are in agreement with relevant literature documenting the relationships between concrete mix designs and curing conditions and the resulting rate of abrasion.

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