Method To Ensure Stone-on-Stone Contact in Stone Matrix Asphalt Paving Mixtures

1997 ◽  
Vol 1583 (1) ◽  
pp. 11-18 ◽  
Author(s):  
E. R. Brown ◽  
John E. Haddock
Keyword(s):  
United States ◽  
Quantitative Method ◽  
Coarse Aggregate ◽  
Heavy Traffic ◽  
The United States ◽  
Stone Matrix Asphalt ◽  
Aggregate Breakdown ◽  
Superpave Gyratory Compactor ◽  
Asphalt Paving ◽  
Stone Matrix

The use of stone matrix asphalt (SMA) has continued to rise in the United States because of its ability to withstand heavy traffic without rutting. This ability is derived from a stone-on-stone coarse aggregate skeleton. While this coarse aggregate skeleton is imperative for SMA to perform, no quantitative method exists to measure it. A method for determining when stone-on-stone contact exists is presented. The proposed method first determines the voids in the coarse aggregate (VCA) for the coarse aggregate–only fraction of the SMA mixture. Second, the VCA is determined for the entire SMA mixture. When the two VCA values are compared, the VCA of the SMA mixture should be less than or equal to the VCA of the coarse aggregate–only fraction to ensure that stone-on-stone contact exists in the mixture. Five different methods for determining the VCA of the coarse aggregate–only fraction were used to see which performed best and was the most practical. The aggregate degradation produced by each of the five methods was also determined and compared with the coarse aggregate breakdown produced in an SMA mixture compacted with 50 blows of a Marshall hammer. The results indicate that the Superpave gyratory compactor and dry-rodded methods produced the best results. Both methods are recommended for further testing.

Investigation of Stone Matrix Asphalt Mortars

1996 ◽  
Vol 1530 (1) ◽  
pp. 95-102 ◽  
Author(s):  
E. Ray Brown ◽  
John E. Haddock ◽  
Campbell Crawford
Keyword(s):  
Resilient Modulus ◽  
Heavy Traffic ◽  
The United States ◽  
Asphalt Pavements ◽  
Fine Aggregate ◽  
Asphalt Cement ◽  
Stone Matrix Asphalt ◽  
Initial Application ◽  
Indirect Tensile ◽  
Stone Matrix

The use of stone matrix asphalt (SMA) has continued to increase in the United States since its initial application in 1991. This preference for SMA has been linked to its ability to withstand heavy traffic without rutting. The antirutting capability of SMA is normally accredited to the presence of a stone-on-stone aggregate skeleton in the mixture. However, the mortar in an SMA mixture is also important. The mortar is composed of fine aggregate, filler, asphalt cement, and a stabilizing additive. Work to characterize SMA mortars is detailed. For testing purposes, the mortar was broken into separate phases, total mortar and fine mortar. The fine mortar was tested using the Superior Performing Asphalt Pavements system (Superpave) binder tests. The total mortar was tested using the bending beam rheometer, resilient modulus, indirect tensile test, and Brookfield vis-cometer. The results indicate that the fine and total mortars are closely related. In addition, it was determined that at least some of the Superpave tests can be used to characterize SMA mortars. It is recommended that further testing be completed and specification criteria be established for the mortar.

Évaluation de la résistance à la fatigue des enrobés bitumineux fondée sur l'évolution de l'endommagement du matériau en cours d'essai : aspects fondamentaux et application à l'enrobé à matrice de pierre

2003 ◽  
Vol 30 (5) ◽  
pp. 902-913 ◽  
Author(s):  
Daniel Perraton ◽  
Hassan Baaj ◽  
Hervé Di Benedetto ◽  
Michel Paradis
Keyword(s):  
United States ◽  
Mechanical Properties ◽  
Standardized Tests ◽  
Fatigue Damage ◽  
The United States ◽  
New Approach ◽  
Stone Matrix Asphalt ◽  
Damage Rate ◽  
Stone Matrix

Fatigue of bituminous asphalts is one of the main types of pavement destruction. This phenomenon was studied extensively in Europe (RILEM) and in the United States (SHRP). There are no standardized tests in Quebec to assess asphalt fatigue resistance. In France, a new approach based on the determination of damage rates due to fatigue has been developed for a tension–compression test on asphalt core samples to study their fatigue strength. This paper presents a summary of the knowledge on asphalt fatigue. Damage rate analyses, developed by the DGCB (Département de Génie Civil et du Bâtiment) of the ENTPE at Lyon, is detailed and applied to stone matrix asphalt (SMA). Results show the validity of the approach by damage and the good fatigue damage strength of the SMA.Key words: bituminous asphalts, fatigue, complex module, damage, stone matrix asphalts (SMA), viscoelasticity, mechanical properties of bituminous asphalts.[Journal Translation]

Bartók's Last Years

Tempo ◽  
1955 ◽  
pp. 12-16
Author(s):  
Erno Balogh
Keyword(s):  
United States ◽  
New York ◽  
Heavy Traffic ◽  
The United States ◽  
Tidal Waves ◽  
The City

From his third visit to the United States Bartók never returned to Budapest. His remains, in a triple coffin, are buried in a cemetery on the outskirts of the City of New York. This New York represented much of what he sought to avoid all his life; noise, rush, many people and buildings, heavy traffic on the street with its accompanying gasoline, commerce and commercialism, tidal waves of opportunities for the practical-minded in any field, an Eldorado for the opportunist. He knew this New York, this America, from his earlier visits. The dictatorships which surrounded him in Europe, and which he hated—no matter from which side they blew their poisonous pollutions—compelled him to find refuge here.

Comparative study of performance of natural fibres and crumb rubber modified stone matrix asphalt mixtures

2006 ◽  
Vol 33 (2) ◽  
pp. 134-139 ◽  
Author(s):  
Vikas Sharma ◽  
Shweta Goyal
Keyword(s):  
Coarse Aggregate ◽  
Crumb Rubber ◽  
Natural Fibres ◽  
High Concentration ◽  
Modified Bitumen ◽  
Moisture Susceptibility ◽  
Stone Matrix Asphalt ◽  
Indirect Tensile ◽  
Stone Matrix ◽  
Asphalt Film

Stone matrix asphalt (SMA) is a gap-graded mix that contains a high concentration of coarse aggregate, thereby maximizing stone-to-stone contact in the mixture and providing an efficient network for load distribution. Coarse aggregate particles are held together by a rich matrix of mineral filler and stabilizer in the thick asphalt film. This paper presents details on the laboratory studies carried out on stone matrix asphalt (SMA) mixtures with natural fibres and crumb rubber modified bitumen (CRMB). Indirect tensile strength, retained stability, resistance to moisture susceptibility, resistance to rutting, resistance to creep, and resistance to permeability and aging were found to improve with SMA mixtures with CRMB when compared with SMA mixtures with fibres as stabilizers.Key words: natural fibres, CRMB, SMA mixtures, draindown, moisture damage, creep, rutting, permeability, aging.

Refinement of New-Generation Open-Graded Friction Course Mix Design

2003 ◽  
Vol 1832 (1) ◽  
pp. 78-85 ◽  
Author(s):  
Donald E. Watson ◽  
Kathryn Ann Moore ◽  
Kevin Williams ◽  
L. Allen Cooley
Keyword(s):  
United States ◽  
Design Procedure ◽  
The United States ◽  
Mix Design ◽  
Superpave Gyratory Compactor ◽  
Open Graded Friction Course ◽  
Compactive Effort ◽  
And Performance ◽  
New Generation ◽  
Air Void

Open-graded friction course (OGFC) has been used in the United States for more than 50 years. In 2000, National Center for Asphalt Technology (NCAT) research led to a recommended mix design procedure for a new-generation OGFC, but the work involved only one aggregate source. Therefore, NCAT is in the process of refining this design procedure to ensure that it is applicable to other aggregate types used in surface mixes throughout the United States. The objectives of NCAT's current research are to refine and field validate the new-generation OGFC mix design procedure. This work has led to several experiments. Several objectives have been identified that need to be addressed. Superpave® technology and use of the Superpave gyratory compactor (SGC) need to be incorporated into the mix design procedure. The Cantabro test for durability and resistance to stone loss needs to be adapted to SGC-prepared specimens and performance parameters established. The asphalt draindown test (AASHTO T 305-97), which was developed for stone-matrix asphalt mixtures, also needs to be evaluated for applicability to OGFC mixtures. In addition, a method for effectively evaluating air void criteria needs to be investigated. On the basis of the research conducted in this study, 50 gyrations of the SGC was selected as the design compactive effort during mix design. Also, the use of SGC-prepared samples during the Cantabro test appears to be a reasonable alternative to use of Marshall-compacted samples.

Updated Review of Stone Matrix Asphalt and Superpave® Projects

2003 ◽  
Vol 1832 (1) ◽  
pp. 217-223 ◽  
Author(s):  
Donald E. Watson
Keyword(s):  
Material Properties ◽  
The United States ◽  
Mix Design ◽  
Stone Matrix Asphalt ◽  
High Traffic Volume ◽  
Long Term Performance ◽  
Term Performance ◽  
Stone Matrix

Stone matrix asphalt (SMA) and Superpave® represent relatively new mix design technologies in the United States. Therefore, a condition survey was conducted of mixes that had been in service for several years to evaluate the long-term performance of SMA and Superpave projects. This study is a follow-up to a 1995 review of SMA projects and a 1998 review of Superpave projects. Both SMA and Superpave are acknowledged to be rut-resistant mixes, and this resistance was shown to be the case during this project review. However, a significant amount of cracking occurred early in the life of some of these mixtures. Overall, the SMA mixtures appeared to be more durable than the Superpave mixtures evaluated. The SMA mixtures have been in place about 2½ years longer than the Superpave mixtures, but the overall condition is about the same. Some of the primary conclusions from the survey are as follows: both SMA and Superpave mixtures were shown to be rut-resistant even when placed on facilities with high traffic volume; much of the observed cracking, especially load cracking, appeared to be more related to problems other than mix design or material properties; and SMA mixtures can be expected to last longer than Superpave mixtures before reaching the same condition level.

Stone Matrix Asphalt: The Wisconsin Experience

1998 ◽  
Vol 1616 (1) ◽  
pp. 34-41 ◽  
Author(s):  
Robert B. Schmiedlin
Keyword(s):  
Performance Measures ◽  
Asphalt Pavement ◽  
Research Effort ◽  
Aggregate Size ◽  
The State ◽  
Stone Matrix Asphalt ◽  
Wisconsin Department ◽  
Asphalt Paving ◽  
The Impact ◽  
Stone Matrix

In 1991, the Wisconsin Department of Transportation and the asphalt paving industry in the state decided to construct a trial installation of an asphalt paving technology that had piqued the interest of a group of professionals who had recently toured Europe. The success of that initial trial was the basis of the decision to conduct a thorough evaluation of stone matrix asphalt (SMA). Subsequently, six projects were constructed at various locations around the state. Each project contained six test sections utilizing various fiber and polymer-modified SMA mixes. Besides evaluating the various types of SMAs, this research effort also contained elements for evaluating the impact of aggregate size and aggregate hardness on the effectiveness of the SMA mixes. These projects were constructed over a period of 3 years; the last one was constructed in 1994. All the projects were evaluated from the standpoint of ease of construction and performance. Although the ease of construction was to be evaluated mostly on a subjective basis, the performance measures were established to be objective and measurable. The performance measures were amount of cracking, friction characteristics, overall pavement distress, amount of rutting, noise impacts, and ride. Although the data collected so far are limited because of the short time the pavements have been in place, they point to an asphalt pavement that resists cracking and rutting, while providing a good ride and excellent frictional qualities. The SMAs demonstrate promise of being a durable and long-lasting asphalt pavement.

Evaluation of Two Compaction Levels for Designing Stone Matrix Asphalt

2005 ◽  
Vol 1929 (1) ◽  
pp. 149-156 ◽  
Author(s):  
Hongbin Xie ◽  
Donald E. Watson ◽  
E. Ray Brown
Keyword(s):  
Asphalt Pavement ◽  
Design Guidelines ◽  
Mineral Aggregate ◽  
Rutting Resistance ◽  
Stone Matrix Asphalt ◽  
Aggregate Breakdown ◽  
Successful Design ◽  
Asphalt Content ◽  
Stone Matrix

Current stone matrix asphalt (SMA) design guidelines list two compaction options to design SMA, 50 blows Marshall or 100 gyrations with the Superpave® gyratory compactor (SGC). However, some states have found that 100 gyrations with the SGC is excessive for their materials. In this study a lower compaction level of 65 gyrations was used to compare with the standard 100 gyrations to design SMA mixtures. Results showed that mixtures designed by 65 gyrations had an average of 0.7% higher optimum asphalt content and 1.5% higher voids in mineral aggregate (VMA) than those designed by 100 gyrations. All mixtures designed by 65 gyrations met the minimum asphalt content and VMA requirements for SMA, whereas only eight of 15 mixtures designed by 100 gyrations met those two requirements. Compaction at 100 gyrations resulted in an additional 0.62% average aggregate breakdown at the critical sieve as compared with 65 gyrations. SMA mixtures designed by 65 gyrations and 100 gyrations had an average asphalt pavement analyzer rut depth of 3.9 mm and 3.1 mm, respectively. Thirteen of 15 mixtures designed by 65 gyrations performed well if 5.0 mm was set as the maximum allowed rut depth. On the basis of this study, 65 gyrations can be used to design a more durable SMA mixture, while still maintaining the good rutting resistance that SMA mixtures are noted for. The successful design by 65 gyrations for all five aggregates in this study indicates that a lower design compaction level may allow the use of more aggregate sources for SMA mixtures.

Effect of coarse aggregate morphology on the mechanical properties of stone matrix asphalt

2017 ◽  
Vol 152 ◽  
pp. 48-56 ◽  
Author(s):  
Yufeng Liu ◽  
Yucheng Huang ◽  
Wenjuan Sun ◽  
Harikrishnan Nair ◽  
D. Stephen Lane ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Coarse Aggregate ◽  
Stone Matrix Asphalt ◽  
Aggregate Morphology ◽  
Stone Matrix
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