scholarly journals Implementation of a laboratory batching procedure with a correction for fines and moisture

1969 ◽  
Vol 18 (32) ◽  
pp. 9
Author(s):  
Jose Corrales Azofeifa ◽  
Adrian Ricardo Archilla
Keyword(s):  
Design Method ◽  
Binder Content ◽  
Performance Characteristics ◽  
Mix Design ◽  
Aggregate Structure ◽  
Asphalt Content ◽  
Target Design ◽  
Selection Of

The selection of an appropriate aggregate structure is a key step during mix design since this directly affects mix performance and the amount of asphalt in the mix. During conventional batching procedures, the aggregates are dried and sieved into different sizes only to be recombined later into the appropriate proportions to reproduce the design gradation. This type of procedure can produce gradations with substantially larger percent passing the sieve No.200 relative to the target gradation. This paper explores the effects that fines adhered to larger particles have on the batch gradation, the resulting optimum binder content and dust proportion. An improved batching procedure that corrects for fines adhered to larger particles and trapped moisture is presented in detail and shown to replicate the target design gradation more closely. The optimum asphalt content was determined by means of the Superpave® design method for both, a gradation batched conventionally and a gradation batched with the suggested corrected procedure. The results show that the optimum asphalt content and volumetrics obtained in both cases are substantially different. The procedure developed for the fines correction is recommended for routine batching in order to minimize the inclusion of additional fines that can potentially affect the performance characteristics of the mix.

Evaluation and Selection of Aggregate Gradations for Asphalt Mixtures Using Superpave

1997 ◽  
Vol 1583 (1) ◽  
pp. 91-97 ◽  
Author(s):  
R. Michael Anderson ◽  
Hussain U. Bahia
Keyword(s):  
Design Process ◽  
Permanent Deformation ◽  
Asphalt Binder ◽  
Asphalt Mixtures ◽  
Mix Design ◽  
Second Phase ◽  
Aggregate Structure ◽  
Aggregate Gradation ◽  
Complex Process ◽  
Selection Of

The design of asphalt mixtures is a complex process that requires the proper proportioning of materials to satisfy mixture volumetric and mechanical properties. The majority of time spent in the mix design process is used in evaluating and selecting aggregate gradations to meet project requirements. The latest set of requirements for asphalt mixtures is the Superpave system, developed during the Strategic Highway Research Program. This system incorporates materials selection, evaluation of trial aggregate structures, selection of design asphalt binder content, moisture sensitivity, and, in some cases, determination of performance properties of the selected asphalt-aggregate blend. The selection of a design aggregate structure reduces to selecting an aggregate gradation that will meet minimum volumetric and densification criteria, and selecting an aggregate structure that will provide adequate resistance to permanent deformation, fatigue, and thermal cracking. In the Superpave volumetric mix design process, achieving voids in mineral aggregate (VMA) is the most difficult task facing the mix designer. One phase of this evaluation focuses on providing Guidelines to achieve VMA requirements with Superpave mix designs. This phase was accomplished by evaluating the existing database of information on Superpave mix designs at the Asphalt Institute. The second phase examines the relationship between properties determined during the Superpave volumetric mix design process, and material properties determined by mix analysis tests.

Effect of Mix Design Variables on Thermal Cracking Performance Parameters of Asphalt Mixtures

2018 ◽  
Vol 2672 (28) ◽  
pp. 471-480 ◽  
Author(s):  
Mirkat Oshone ◽  
Debaroti Ghosh ◽  
Eshan V. Dave ◽  
Jo Sias Daniel ◽  
Joseph M. Voels ◽  
...  
Keyword(s):  
Fracture Energy ◽  
Correlation Coefficients ◽  
Thermal Cracking ◽  
Binder Content ◽  
Asphalt Mixtures ◽  
Mix Design ◽  
Design Variables ◽  
Cracking Performance ◽  
Asphalt Content ◽  
Asphalt Film

To address asphalt pavement thermal cracking, researchers have developed performance-based evaluation tools for asphalt mixtures. A minimum fracture energy obtained from a disc-shaped compact tension test and Black space parameters determined by the stiffness and relaxation properties of asphalt mixtures are two such methods to ensure good thermal cracking resistance. Mix specifiers and producers strive to meet the requirements set by these performance-based criteria by adjusting their mix designs. However, there is a lack of information and consensus on the effect of mix design variables (such as binder grade and mix volumetrics) on thermal cracking performance of mixtures as it relates to fracture energy and Black space location. This study strives to fill this gap by quantifying the effect of: (1) recycled asphalt content, (2) effective binder content, (3) air voids, (4) asphalt film thickness, (5) voids in mineral aggregates, and (6) PG low and high temperature grades on thermal cracking resistance. A large dataset, 90 mixtures from the Minnesota Department of Transportation and 81 mixtures from University of New Hampshire database, was used for the study. The results indicate a strong correlation between binder related properties (binder content, asphalt film thickness, PG spread) and fracture energy. The correlation coefficients obtained from this study for PG spread, effective binder content, and air void can be confidently employed to achieve targeted fracture energy thresholds. The same can be achieved for the Glower-Rowe parameter at 15ºC by employing the correlation coefficients obtained for PG low temperature, virgin asphalt content, and voids in the mineral aggregate.

A Balanced Mix Design Method for Selecting the Optimum Binder Content of Cold In-Place Recycling Asphalt Mixtures

2019 ◽  
Vol 2673 (3) ◽  
pp. 526-539 ◽  
Author(s):  
Ahmed Saidi ◽  
Ayman Ali ◽  
Wade Lein ◽  
Yusuf Mehta
Keyword(s):  
Complex Modulus ◽  
Cement Content ◽  
Design Method ◽  
Binder Content ◽  
Asphalt Mixtures ◽  
Mix Design ◽  
Air Voids ◽  
Foamed Asphalt ◽  
Indirect Tensile ◽  
Emulsified Asphalt

The objective of this paper is to present a procedure for designing cold in-place recycling (CIR) mixtures through balancing rutting and cracking for these mixtures. Four CIR mixtures were prepared using two recycling agents (foamed and emulsified asphalts), and compacted at two gyration levels (30 and 70 gyrations). The CIR mixtures were prepared at a constant water content of 3% and a constant cement content of 1% while curing of the compacted samples was conducted by placing them in an oven for three days at 140°F (dry curing). The CoreLok device was used for measuring air voids in compacted samples. The rutting susceptibility of these mixtures was then evaluated using the asphalt pavement analyzer (APA) and dynamic complex modulus (|E*|) while resistance to cracking was assessed using the indirect tensile strength (ITS) test and fracture energy as determined using the semi-circular bend (SCB-FE) test. A demonstration of how these tests were utilized to select a performance balanced optimum binder content for each of the four CIR mixes was also presented. The developed balanced mix design approach was used successfully for designing four CIR mixtures and selecting the optimum binder content for each mix. The results also showed that using a higher compaction level leads to increasing both foamed and emulsified asphalt CIR mixtures’ ability to resist rutting. In terms of cracking, SCB-FE results showed that foamed asphalt mixtures were better at resisting cracking than emulsified asphalt CIR mixtures.

Research on Proportioning Design of Tourmaline Modified Asphalt Mixture

2013 ◽  
Vol 405-408 ◽  
pp. 1928-1931 ◽  
Author(s):  
Xin Qi Wang ◽  
Biao Dong ◽  
Chao Hui Wang ◽  
Xiao Hua Wang
Keyword(s):  
Design Method ◽  
Asphalt Mixture ◽  
Mixture Design ◽  
Mix Design ◽  
Surface Theory ◽  
Modified Asphalt ◽  
Marshall Test ◽  
Asphalt Content

In order to study the effect of tourmaline on asphalt mixture design indexes, the optimal asphalt content of modified asphalt mixture with different contents of tourmaline were determined through Marshall Test, and the variation of optimal asphalt content caused by tourmaline was analyzed. The effect of tourmaline on density, porosity, VMA, VFA, stability, flow value were studied. Under the guidance of surface theory and mortar theory respectively, the Marshall Volume indicators of tourmaline modified asphalt mixture were analyzed comparatively. A mix design method for asphalt mixture modified inorganic powder is recommended.

scholarly journals Sensitivity of the Superpave mix design method to different methods for determining the maximum specific gravity

DYNA ◽  
2019 ◽  
Vol 86 (211) ◽  
pp. 184-191
Author(s):  
Heraldo Nunes Pitanga HERALDO PITANGA ◽  
Tamyres Karla da Silva ◽  
T.O Silva ◽  
Geraldo Luciano De Oliveira Marques
Keyword(s):  
Particle Size ◽  
Specific Gravity ◽  
Design Method ◽  
Asphalt Binder ◽  
Binder Content ◽  
Asphalt Mixtures ◽  
Point Of View ◽  
Mix Design ◽  
Practical Point

This study aimed to analyze the influence of different methodologies to determine the maximum specific gravity on the Superpave mix design method. The comparative analysis focused on the volumetric parameters, on the choice of the design particle size and, consequently, on the respective design asphalt binder contents of the studied asphalt mixtures. Regarding the particularities of the research, there were no significant differences in the design binder contents obtained using the two adopted methodologies for determining the maximum specific gravity. From a practical point of view, the adoption of any of the methods interfered little with the results of the application of the Superpave mix design method. This fact demonstrates a quality of this method since similar researches based on the Marshall design method evidences the sensitivity of the protocol for determining the asphalt binder content in relation to the used type of maximum specific gravity.

Influence of Production Considerations on Balanced Mixture Designs

2018 ◽  
Vol 2672 (28) ◽  
pp. 426-437 ◽  
Author(s):  
Alexander J. Austerman ◽  
Walaa S. Mogawer ◽  
Kevin D. Stuart
Keyword(s):  
Design Method ◽  
Asphalt Binder ◽  
Mixture Design ◽  
Performance Tests ◽  
Moisture Susceptibility ◽  
Asphalt Content ◽  
Mixture Designs ◽  
Performance Results ◽  
Transportation Agencies ◽  
Selection Of

Measuring or predicting mixture performance prior to placement has become essential for many state transportation agencies due to incorporation of more recycled materials into mixtures, utilization of binders formulated with various modifiers, and utilization of new and unproven technologies. Mixtures designed incorporating these elements in accordance with the current Superpave mixture design method have unknown performance as Superpave was never designed to compensate for them. Thus, agencies have interest in implementing the balanced mixture concept that requires testing for acceptable mixture performance during the design phase. The effect of production considerations on a balanced mixture design is not known. It is unknown if a mixture remains performance balanced during production due to factors like asphalt content, gradation and binder source variations. This study was undertaken to understand the influence of these production considerations on a balanced mixture design. Two Superpave mixtures, a 9.5 mm and 12.5 mm, were developed using the balanced mixture design approach using volumetric properties, one rutting test and one cracking test. These mixtures were then modified to represent production variations in asphalt binder content, gradation passing the No. 200 sieve, and asphalt binder source. All mixtures remained performance balanced when examining the production considerations in terms of rutting and cracking using the selected tests. Examination of other performance results, like moisture susceptibility, suggest it is possible to effectively unbalance the mixture design during production. This underscores the importance of proper selection of performance tests to address the performance needs of the agency.

scholarly journals Structural sensitivity of an asphalt pavement to asphalt binder content and mix design method

TRANSPORTES ◽  
2021 ◽  
Vol 29 (4) ◽  
pp. 2456
Author(s):  
Cássio Alberto Teoro Do Carmo ◽  
Géssica Soares Pereira ◽  
Geraldo Luciano de Oliveira Marques ◽  
Paulo Roberto Borges
Keyword(s):  
Mechanical Properties ◽  
Resilient Modulus ◽  
Design Method ◽  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Binder Content ◽  
Asphalt Mixtures ◽  
Mix Design ◽  
Structural Sensitivity ◽  
Structural Responses

The goal of this study was to analyze the structural sensitivity of a flexible pavement, whose asphalt layers underwent variations in its mechanical properties due to the asphalt binder content and the mix design method Marshall and Superpave. A variation of ±0.5% within the optimum asphalt binder contents was used (service tolerance) considering possible permissible variations in the asphalt binder content during the asphalt mixture manufacturing process. The values of resilient modulus and indirect tensile strength (Brazilian test) of the resulting asphalt mixtures were applied to the reference pavement structure analyzed by the me-PADS software. The results show that the variations in the asphalt binder content and the asphalt mixtures design method influence the mechanical properties and corresponding structural responses of the pavement investigated: the asphalt layers designed by the Marshall method presented greater sensitivity to the variation in asphalt binder content, which may constitute a technical differential of asphalt mixtures designed by the Superpave method.

Development of a Balanced Mix Design Method in Oregon to Improve Long-Term Pavement Performance

2021 ◽  
pp. 036119812110322
Author(s):  
Shashwath Sreedhar ◽  
Erdem Coleri ◽  
Ihsan Ali Obaid ◽  
Vikas Kumar
Keyword(s):  
New Technologies ◽  
Design Method ◽  
Complex Structure ◽  
Asphalt Mixture ◽  
Mixture Design ◽  
Design Methods ◽  
Binder Content ◽  
Asphalt Mixtures ◽  
Mix Design

Most state Departments of Transportation (DOTs) and asphalt contractors do not think that commonly used asphalt mixture properties, such as voids in mineral aggregate (VMA), voids filled with asphalt (VFA), and dust-to-binder ratio, reflect the long-term performance of asphalt mixtures. In addition, there are several new additives, polymers, rubbers, and high-quality binder types incorporated into asphalt mixtures today. Volumetric mixture design methods are not capable of capturing the benefits of using all these new technologies on asphalt mixture performance. Furthermore, the interaction of virgin binders with reclaimed asphalt pavement (RAP) mixtures with high binder replacement contents and the level of RAP binder blending into the asphalt mixture are still not well understood. Because of all these complications related to the more complex structure of asphalt mixtures, simple volumetric evaluations to determine the optimum binder content may not result in reliable asphalt mixture designs. Two volumetrically identical mixtures may provide completely different rutting and cracking performance according to laboratory tests. For all these reasons, in this study performance tests for rutting and cracking are incorporated into current asphalt mixture design methods to make it possible to validate or revise the optimum binder content determined by the volumetric mix design method (the only method currently used for asphalt mix design).

COMPARATIVE PERFORMANCE EVALUATION OF PMB and CRMB WITH PARTIAL REPLACEMENT OF BITUMEN (VG-30) USING MARSHALL MIX DESIGN METHOD-A REVIEW

2018 ◽  
Vol 5 (02) ◽  
Author(s):  
N. SATHEESHKANNA
Keyword(s):  
Performance Evaluation ◽  
Design Method ◽  
Mix Design ◽  
Partial Replacement ◽  
Comparative Performance

Waste generated from industries and from various places around us not only contains rubber or plastics but contains lot many harmful pollutants whichare hazardous if disposed continuously in open and leftto degrade in our environment.Our project aims to study properties of different materials which may help in utilising the waste as well as improve the quality of roads and make them efficient, stable, durable and long lasting. Some of the materials that we have studied and considered to be tested in the partial replacement of bitumen are PMB and CRMB.

Comparison of Superpave and Marshall Mixtures for Low-Volume Roads and Shoulders

1998 ◽  
Vol 1609 (1) ◽  
pp. 44-50 ◽  
Author(s):  
Affan Habib ◽  
Mustaque Hossain ◽  
Rajesh Kaldate ◽  
Glenn Fager
Keyword(s):  
Mix Design ◽  
River Sand ◽  
Low Volume Roads ◽  
Superpave Gyratory Compactor ◽  
Asphalt Content ◽  
Low Volume ◽  
Project Site ◽  
Axle Loads ◽  
Crushed Limestone ◽  
Asphalt Film

Superpave and Marshall mix designs using local aggregates were done to study the suitability of the Superpave mix design as compared with the Marshall mix design for low-volume roads, especially shoulders. The project site was Kansas Route 177 in northeast Kansas. Three locally available aggregates, crushed limestone and coarse and fine river sands, were used in this study. Five blends with varying proportions of coarse and fine river sands were selected. Mix samples were compacted in the Superpave gyratory compactor with the applicable number of gyrations and were compacted with the Marshall hammer by using 50 blows per face. Bulk densities of the compacted samples and maximum specific gravities of loose samples also were measured for each blend. The results show that the Superpave mix design for low-volume roads and shoulders results in lower estimated asphalt content than does the Marshall method. The required asphalt content increases as the proportion of coarse river sand increases in the mix. Superpave requirements for the voids filled with asphalt (VFA) for low-volume traffic, that is, less than 0.3 million equivalent single-axle loads, appeared to be too high. High asphalt film thicknesses were computed for the mixtures that did not meet the Superpave VFA requirements. Lowering the design number of gyrations (Ndes) for compaction of samples would result in increased asphalt requirement for the Superpave mixture with a given gradation.

Sign in / Sign up

Export Citation Format

Share Document