A Measurement Approach for Critical Voids in Mineral Aggregate Based on AC-20

2010 ◽  
Vol 108-111 ◽  
pp. 708-712
Author(s):  
Chen Ning ◽  
Ming Hui Wang
Keyword(s):  
Laboratory Data ◽  
Aggregate Size ◽  
Test System ◽  
Mix Design ◽  
Maximum Aggregate Size ◽  
New Paradigm ◽  
Aggregate Gradation ◽  
Mineral Aggregate ◽  
Superpave Gyratory Compactor ◽  
Object Of Study

The voids in the mineral aggregate (VMA) is considered to be the most important mix design parameter which affects the durability of the asphalt concrete mix. This has traditionally been addressed during mix design by meeting a minimum voids in the mineral aggregate (VMA) requirement, based solely upon the nominal maximum aggregate size without regard to other significant aggregate-related properties. The goal of this study is to determine the validity of the minimum VMA requirement versus nominal maximum aggregate size required in Marshall volumetric mix design. Specimens were compacted using the Superpave Gyratory Compactor (SGC), conventionally tested for bulk and maximum theoretical specific gravities and physically tested using the thiaxial creep test system under a repeated load confined configuration to identify the transition state from sound to unsound. AC-20 was classified in the light of fine, dense and coarse gradation. The AC-20C, AC-20D and AC-20F asphalt mixtures were tested as the object of study. The results clearly demonstrate that the volumetric conditions of an VMA mixture at the stable unstable threshold are influenced by a composite measure of the aggregate size gradation .The currently defined VMA criterion, while significant, is seen to be insufficient by itself to correctly differentiate sound from unsound mixtures. Under current specifications, many otherwise sound mixtures are subject to rejection solely on the basis of failing to meet the VMA requirement. Based on the laboratory data and analysis, a new paradigm to volumetric mix design is proposed that explicitly accounts for aggregate gradation factors.

Field Density Investigation of Asphalt Mixtures in Minnesota

2021 ◽  
pp. 036119812110095
Author(s):  
Tianhao Yan ◽  
Mihai Marasteanu ◽  
Chelsea Bennett ◽  
John Garrity
Keyword(s):  
Material Properties ◽  
Research Effort ◽  
Aggregate Size ◽  
Asphalt Mixtures ◽  
Mix Design ◽  
Maximum Aggregate Size ◽  
Density Level ◽  
Fine Aggregate ◽  
Aggregate Gradation ◽  
Field Density

In a current research effort, University of Minnesota and Minnesota Department of Transportation have been working on designing asphalt mixtures that can be constructed at 5% air voids, similar to the Superpave 5 mix design. High field density of asphalt mixtures is desired because it increases the durability and extends the service life of asphalt pavements. The paper investigates the current situation of field densities in Minnesota, to better understand how much improvement is needed from the current field density level to the desired level, and to identify possible changes to the current mix design to improve field compactability. Field densities and material properties of 15 recently constructed projects in Minnesota are investigated. First, a statistical analysis is performed to study the probability distribution of field densities. Then, a two-way analysis of variance is conducted to check if the nominal maximum aggregate size and traffic levels have any significant effect on field densities. A correlation analysis is then conducted to identify significant correlations between the compactability of mixtures and their material properties. The results show that the field density data approximately obey normal distribution, with an average field density of 93.4% of theoretical maximum specific gravity; there are significant differences in field density between mixtures with different traffic levels; compactability of mixtures is significantly correlated with fine aggregate angularity and fine aggregate gradation of the mixtures.

Experimental Research on Sound Absorption Performance of Low-Noise Pavement

2011 ◽  
Vol 374-377 ◽  
pp. 1400-1404 ◽  
Author(s):  
Ji Tan Guo ◽  
Rui Zhang ◽  
Rui Wang
Keyword(s):  
Sound Absorption ◽  
Traffic Noise ◽  
Aggregate Size ◽  
Low Noise ◽  
Maximum Aggregate Size ◽  
Aggregate Gradation ◽  
Absorption Performance ◽  
Standing Wave Tube ◽  
Air Void ◽  
Pavement Noise

OGFC can reduce traffic noise which has very high air-void contents to absorb tire-pavement noise. This paper proposes maximum aggregate size and aggregate gradation of OGFC with the objective void of 20%. Performance of modified asphalt and best asphalt-aggregate ratio are also proposed with four kinds of modifiers, including SBS, rubber, EVA and PVC. The absorption coefficients of the four kinds of OGFC and the dense-graded Marshall specimens were tested with standing wave tube. Then their sound absorption performances were compared.

Minimum Voids in Mineral Aggregate in Hot-Mix Asphalt Based on Gradation and Volumetric Properties

1996 ◽  
Vol 1545 (1) ◽  
pp. 75-79 ◽  
Author(s):  
John A. Hinrichsen ◽  
John Heggen
Keyword(s):  
Hot Mix Asphalt ◽  
Heavy Traffic ◽  
Field Application ◽  
Mix Design ◽  
Volumetric Properties ◽  
Aggregate Gradation ◽  
Mineral Aggregate ◽  
Traffic Loads ◽  
Recent Developments ◽  
Asphalt Mix

The use of voids in mineral aggregate (VMA) criteria for proper mix design of hot-mix asphalt is a time-honored and fairly successful tool. Recent developments in the field of asphalt mix design have encouraged the use of mixtures with a coarse aggregate structure to resist the effect of heavy traffic loads. By using the equations presented, which account for both aggregate gradation and the volumetric properties of the materials, the mix designer is able to judge the proper VMA requirement for each unique blend of materials. By applying the new equations, the most economical mix may be selected without great risk of reduced durability. Supporting data from field application are presented to illustrate the use of the equations.

Effect of Single Face Compaction on Stability and Flow of Asphalt Specimen

2014 ◽  
Vol 69 (3) ◽  
Author(s):  
Fung-Lung Chang ◽  
Haryati Yaacob ◽  
Mohd. Rosli Hainin
Keyword(s):  
Design Method ◽  
Aggregate Size ◽  
Maximum Aggregate Size ◽  
Specimen Preparation ◽  
Aggregate Gradation ◽  
Single Face ◽  
Stone Mastic Asphalt ◽  
Local Specifications ◽  
The Stability

Recent research on the performance of bond strength between pavement layers results in the preparation of double layered specimen becomes inevitable. Double layered specimen may be in field scale or laboratory scale. Marshall mixture design method is normally adopted to prepare double layered specimen in laboratory, incorporating the compaction of binder course at both faces and followed by a single face compaction of wearing course. Due to that, compaction at single face only will raised potential scepticism over the quality of the compacted mixture. This paper focused on the performance of stability and flow for single face compacted wearing course specimen prepared using Marshall procedure at a thickness of 50mm for Asphaltic Concrete mixture of nominal maximum aggregate size 10 mm (AC10) and Stone Mastic Asphalt of nominal maximum aggregate size 14 mm (SMA14). The stability and flow was investigated with the increasing compacting effort. The stability and flow at optimum compacting effort was also checked. From the research, it was noticed that stability increased with compacting effort while flow shows a decreasing trend. A stability and flow value of 12.8 kN and 2.27 mm as well as 10.4 kN and 2.61 mm was recorded for AC10 and SMA14 respectively at optimum compacting effort. Such observation may be accounted to the aggregate gradation in the mixture besides the binder properties of two different binders used. Despite the adoption of single face compaction in specimen preparation, at optimum compacting effort, the stability and flow values was also found to be within the range as specified by local specifications.

Evaluation of Ability of Superpave Shear Tester To Differentiate Between Mixtures with Different Aggregate Sizes

1998 ◽  
Vol 1630 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Pedro Romero ◽  
Walaa S. Mogawer
Keyword(s):  
Aggregate Size ◽  
Complete Analysis ◽  
Maximum Aggregate Size ◽  
Air Voids ◽  
Asphalt Cement ◽  
Testing Sequence ◽  
Superpave Gyratory Compactor ◽  
Constant Height ◽  
Direct Measurements ◽  
Shear Tester

A study was conducted to determine whether the results from the Superpave shear tester (SST) could measure the effect of nominal maximum aggregate size on rutting susceptibility of asphalt mixtures without the need of a model. Four mixtures were analyzed using direct measurements from the SST. Two of the mixtures were prepared with AC-5 asphalt cement and nominal maximum aggregate sizes of 19.0 mm and 37.5 mm. The other two were prepared with AC-20 asphalt cement and the same two gradations. The results were analyzed statistically and compared with the performance of the respective mixtures tested by the FHWA Accelerated Loading Facility (ALF). The specimens were compacted to a target air voids of 7 percent using the Superpave gyratory compactor. The testing sequence consisted of performing the simple shear at constant height (SSCH) test followed by the frequency sweep at constant height (FSCH) test at 40°C and 58°C. These temperatures were chosen because they represent, respectively, the highest temperature used in Superpave complete analysis and the target pavement temperature at 20 mm depth used in the ALF tests. After the SSCH and FSCH tests, the repeated shear at constant height (RSCH) test was performed on all samples at 40°C. The ALF provided a significant decrease in rutting susceptibility with increase in aggregate size; however, the SST was unable to separate mixtures with the same binders and the two different nominal maximum aggregate sizes.

scholarly journals Meta-Analysis of Steel Fiber-Reinforced Concrete Mixtures Leads to Practical Mix Design Methodology

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3900
Author(s):  
Emilio Garcia-Taengua ◽  
Mehdi Bakhshi ◽  
Liberato Ferrara
Keyword(s):  
Design Methodology ◽  
Aggregate Size ◽  
Cementitious Materials ◽  
Fiber Reinforced Concrete ◽  
Supplementary Cementitious Materials ◽  
Mix Design ◽  
Data Driven ◽  
Validation Dataset ◽  
Maximum Aggregate Size ◽  
Steel Fiber Reinforced Concrete

The analysis of hundreds of SFRC mixtures compiled from papers published over the last 20 years is reported. This paper is focused on the relationships between the size and dosage of steel fibers and the relative amounts of the constituents of SFRC mixtures. Multiple linear regression is applied to the statistical modeling of such relationships, leading to four equations that show considerable accuracy and robustness in estimating SFRC mixture proportions as a function of fiber content and dimensions, maximum aggregate size, and water-to-cement ratio. The main trends described by these equations are discussed in detail. The importance of the interactions between aggregates, supplementary cementitious materials, and fibers in proportioning SFRC mixtures, as well as implications for workability and stability, are emphasized. The simplicity of these data-driven equations makes them a valuable tool to guide the proportioning of SFRC mixtures. Their predictive performance when used together as a data-driven mix design methodology is confirmed using a validation dataset.

Critical Review of Voids in Mineral Aggregate Requirements in Superpave

1998 ◽  
Vol 1609 (1) ◽  
pp. 21-27 ◽  
Author(s):  
Prithvi S. Kandhal ◽  
Kee Y. Foo ◽  
Rajib B. Mallick
Keyword(s):  
Film Thickness ◽  
Mix Design ◽  
Rational Approach ◽  
Asphalt Mixes ◽  
Mineral Aggregate ◽  
Superpave Gyratory Compactor ◽  
Asphalt Mix ◽  
Compactive Effort ◽  
Asphalt Content ◽  
Asphalt Film

Reports of increased difficulties in meeting the minimum voids in mineral aggregate (VMA) requirements have surfaced with the recent use of Superpave volumetric mix design. The low VMA of Superpave mixes generally can be contributed to the increased compactive effort by the Superpave gyratory compactor. This has led to the increased use of coarser asphalt mixes (gradations near the lower control points). However, the minimum VMA requirements in Superpave volumetric mix design for these coarse mixes are the same as those developed for the dense mixes designed by the Marshall method. Literature review has indicated that the rationale behind the minimum VMA requirement was to incorporate at least a minimum permissible asphalt content into the mix to ensure its durability. Studies have shown that asphalt mix durability is directly related to asphalt film thickness. Therefore, the minimum VMA should be based on the minimum desirable asphalt film thickness instead of on a minimum asphalt content because the latter will be different for mixes with different gradations. Mixes with coarse gradation (and, therefore, a low surface area) have difficulty meeting the minimum VMA requirement based on minimum asphalt content despite thick asphalt films. A rational approach based on a minimum asphalt film thickness has been proposed and validated. The film thickness approach represents a more direct, equitable, and appropriate method of ensuring asphalt mix durability, and it encompasses various mix gradations.

scholarly journals Influence of Aggregate Gradation and Nominal Maximum Aggregate Size on the Performance Properties of OGFC Mixtures

2019 ◽  
Vol 2673 (1) ◽  
pp. 240-245 ◽  
Author(s):  
Haripriya Nekkanti ◽  
Bradley J. Putman ◽  
Behrooz Danish
Keyword(s):  
Shear Strength ◽  
Aggregate Size ◽  
Maximum Aggregate Size ◽  
Water Drainage ◽  
Aggregate Gradation ◽  
Performance Properties ◽  
Positive Effects ◽  
Current Specification ◽  
Permeability For Water ◽  
Indirect Tensile

The effect of aggregate gradation and nominal maximum aggregate size (NMAS) on the performance properties of open-graded friction courses (OGFC) mixtures was investigated in this research. Several tests which included porosity, surface texture, indirect tensile strength (ITS), shear strength, and Cantabro abrasion loss were used to compare eight different aggregate gradations having two NMAS (9.5 mm and 12.5 mm) all from one aggregate source. For each NMAS, the gradations varied by adjusting the percent passing the No. 4 (4.75 mm) sieve. The results indicated that aggregate gradation does influence the behavior of OGFC mixtures. An increase in percent passing the No. 4 sieve showed significant decreases in porosity, which were more pronounced for the 12.5 mm NMAS compared with the 9.5 mm NMAS. Conversely, the increase in the percent passing the No. 4 sieve generally resulted in increases in the mixture performance properties as measured by the ITS, Cantabro loss, and shear strength. The results of this study provide laboratory-based evidence that adjusting the OGFC gradation by increasing the allowable percent passing the No. 4 sieve toward the higher end of the current specification range (e.g., near 30% for 12.5 mm NMAS) could potentially have positive effects on mixture durability while also maintaining adequate permeability for water drainage.

scholarly journals Eksperimental Perbandingan Kekuatan Tekan Karakteristik Beton Self Compacting Menggunakan Agregat Kasar Alami Dan Agregat Kasar Daur Ulang

2020 ◽  
Vol 19 (1) ◽  
pp. 107-120
Author(s):  
Martinus Pramanata Sapeai ◽  
Johannes Adhijoso Tjondro
Keyword(s):  
Compressive Strength ◽  
Aggregate Size ◽  
Recycled Concrete ◽  
Mix Design ◽  
Sustainable Construction ◽  
Maximum Aggregate Size ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Coarse Aggregates ◽  
High Rise

Utilization of recycled concrete waste as an alternative to natural coarse aggregates in this experiment is in accordance with the concept of sustainable construction. Concrete is the main material of structural elements most commonly used in general construction and has properties that are difficult to recycle by themselves naturally. Nowdays concrete innovation with the concept of self compacting (SCC) is widely used especially in high rise building and buildings with special specification. SCC has high flowability properties so that it can flow and compact themselves, but in SCC with normal quality still need compactor. The concept of making test specimens is in accordance with real conditions in the field, where aggregates do not go through a cleaning process. There are four different mix design with the required specified compressive strength of 20 MPa. Mix design 1A (natural coarse) and 1B (recycled coarse aggregates) has a maximum aggregate size 12.50 mm, and mix design 2A (natural coarse) and 2B (recycled coarse aggregates) has a maximum aggregate size 19.00 mm. This experimental results in specified compressive strength concrete for mix design 1A, 1B, 2A, and 2B as follows: 30.93 MPa, 26.21 MPa, 30.82 MPa and 27.60 MPa. Therefore, recycled concrete aggregates can be alternative to natural coarse aggregates and can also be made into concrete with the SCC concept.

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