What is VFA in asphalt?

Asked By: Kbir Sigle | Last Updated: 4th January, 2020
Category: science physics
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Percent Voids Filled with Asphalt (VFA)
The VFA is the percentage of voids in the compacted aggregate mass that are filled with asphalt cement. It is synonymous with the asphalt-void ratio.

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Similarly, you may ask, what is VMA in asphalt?

Let's look at VMA, which stands for “Voids in Mineral Aggregate.” VMA is the space between the rocks that can be filled with asphalt. The space filled with asphalt is known as VFA (Voids Filled with Asphalt). The remaining space is air voids.

Furthermore, how do you calculate air voids in asphalt? This volume is typically quantified as a percentage of air voids by volume and expressed as “percent air voids”. Percent air voids is calculated by comparing a test specimen's bulk specific gravity (Gmb) with its theoretical maximum specific gravity (Gmm) and assuming the difference is due to air.

Consequently, what is effective asphalt content?

Total asphalt content is the amount of asphalt that must be added to the mixture to produce the desired mix qualities. Effective asphalt content is the volume of asphalt not absorbed by the aggregate; the amount of asphalt that effectively forms a bonding film on the aggregate surfaces.

How do you calculate voids in mineral aggregate?

CALCULATION VMA = Voids in mineral aggregate, in percent of bulk volume, Gsb = Bulk specific gravity of the aggregate, Gmb = Bulk specific gravity of compacted mix, Ps = Aggregate, percent by total weight of mix. Where: P1 = Percent by weight of aggregate 1, etc., G1 = Bulk specific gravity of aggregate 1, etc.

34 Related Question Answers Found

What does VMA stand for in asphalt?

Voids in Mineral Aggregate

What are air voids in asphalt?

Air voids are the percentage of void spaces within the aggregate–binder matrix that are not filled with binder—sufficient voids should be provided to allow for a slight amount of additional compaction under traffic and a slight amount of asphalt expansion due to temperature increases, without flushing, bleeding, or

What is GMB asphalt?

ASPHALT CONTENT is a binding cement. Gmb is the determination of compaction level of HMA mix referring MAXIMUM THEORETICAL SPECIFIC GRAVITY (Gmm) at different ASPHALT CONTENTS to find suitable design for HMA.

What are the tests for asphalt?

Asphalt Tests
  • Kinematic Viscosity. The kinematic viscosity of a liquid is the absolute (or dynamic) viscosity divided by the density of the liquid
  • Superpave Shear Tester.
  • Absolute Viscosity.
  • HMA Performance Tests.
  • Mixture Characterization Tests.
  • Flash Point.
  • Asphalt Mixture Performance Test.
  • Binder Content.

What is GSB in asphalt?

Although high quality mixtures can be made with aggregates having a wide range in bulk specific gravity values, precisely determining the bulk specific gravity (Gsb) is critical to setting the optimum asphalt content of every mix design.

What is VFB in asphalt?

VFB is the voids in the mineral aggregate frame work filled with bitumen binder. This represents the volume of the effective bitumen content. It can also be described as the percent of the volume of the VMA that is filled with bitumen.

What is Marshall test on asphalt?

The Marshall Test is a popular and proven method to measure the load and flow rate of asphalt specimens, beginning with compaction into molds using manual or automated Marshall Compactors, and conditioned in a Water Bath at the specified temperature.

What is the use of Marshall stability test?

Marshall stability measures the maximum load sustained by the bituminous material at a loading rate of 50.8 mm/minute. The test load is increased until it reaches a maximum. Beyond that, when the load just starts to decrease, the loading is ended and the maximum load (i.e. Marshall stability) is recorded.

What is asphalt made of?

What is Asphalt Made of and Why Do the Quality of the Materials Matter So Much? Asphalt is a sustainable paving solution made from a mixture of aggregates, binder, and filler. Aggregates are processed mineral materials such as crushed rock, sand, gravel, slags, or various recycled materials.

What is the density of asphalt?

Concrete, Asphalt weighs 2.243 gram per cubic centimeter or 2 243 kilogram per cubic meter, i.e. density of concrete, Asphalt is equal to 2 243 kg/m³. In Imperial or US customary measurement system, the density is equal to 140 pound per cubic foot [lb/ft³], or 1.297 ounce per cubic inch [oz/inch³] .

What is asphalt mix design?

Mix design is a process to manipulate three variables: (1) aggregate, (2) asphalt binder content and (3) the ratio of aggregate to asphalt binder with the objective of obtaining an HMA that is deformation resistant, fatigue resistant, low temperature crack resistant, durable, moisture damage resistant, skid resistant

What is the optimum amount of air voids in asphalt?

The allowable percentage of air voids (in laboratory specimens) is between 2.0 percent and 4.0 percent for most surface course mixes or as required by the owner. The durability of an asphalt pavement is a function of the air-void content. This is because the lower the air-voids, the less permeable the mixture becomes.

What is Marshall mix design?

The Marshall Mix Design method was originally developed by Bruce Marshall of the Mississippi Highway Department in 1939. The main idea of the Marshall Mix Design method involves the selection of the asphalt binder content with a suitable density which satisfies minimum stability and range of flow values.

Why the stability values obtained have to be corrected?

Apply stability correction
It is possible while making the specimen the thickness slightly vary from the standard specification of 63.5 mm. Therefore, measured stability values need to be corrected to those which would have been obtained if the specimens had been exactly 63.5 mm.

How can I improve my Vmas?

Increase Manufactured Sand
If manufactured sand and natural sand are being used together in a mix design the manufactured sand portion can be increased to increase surface texture. Switching out 20% natural sand for a washed manufactured sand with good "bite" can increase VMA by 2%.

How do you find the volume of a void?

Void Volume Calculation
Multiply the voidage by the volume of the dry sand to find the volume of the void. With 1,000 ml of dry sand and a voidage of 0.4, you have a void volume of 400 ml.