How to calculate the weight of asphalt
- About specific gravity. “Specific gravity” is a word indicating how heavy an object is with respect to the same volume of water.
- The calculation method for finding weight from volume. When calculating the weight of asphalt by calculation, you can use a method of multiplying the volume by specific gravity.
- Points to note when calculating. ...
What is the specific gravity of asphalt?
There is no specification for bulk specific gravity, but it is used to calculate other specified parameters such as air voids, VMA and VFA. Typical values for bulk specific gravity range from 2.200 to 2.500 depending upon the bulk specific gravity of the aggregate, the asphalt binder content, and the amount of compaction.
How do you calculate the weight of asphalt?
Multiply the weight density of the asphalt by the volume to arrive at the weight of the asphalt needed in pounds. Consult the asphalt manufacturers if you do not know the weight density of the asphalt.
How do you find the specific gravity of a sample?
The basic premise of the maximum specific gravity is to divide the mass of the sample by the volume of the sample excluding the air voids. The mass is determined by measuring the dry mass of the sample either at the beginning of the test or after it has been dried at the end of the test.
How is specific gravity calculated from compacted HMA samples?
A compacted HMA sample (usually a SGC compacted laboratory sample or a field-obtained HMA core) is weighed dry, saturated surface dry (SSD) and submerged (Figure 1). These weights are used to calculate specific gravity and the percentage of water absorbed by the sample. Each test takes approximately 7 minutes to conduct excluding preparation time.
What is the specific gravity for asphalt?
around 1.03Because the specific gravity of asphalt binders change with temperature, specific gravity tests are useful in making volume corrections based on temperature. The specific gravity at 15.6° C (60° F) is commonly used when buying/selling asphalt cements. A typical specific gravity for asphalt is around 1.03.
How do you test the specific gravity of asphalt?
The bottle is immersed till the neck in the water bath maintained at 27 ± 0.1 °C temperature for 30 minutes. The outer surface of the bottle is wiped with a dry cloth to clean it. The specific gravity bottle filled half with bitumen and half with distilled water is weighed. The weight is noted as d.
What is the specific density of asphalt?
Standard density for asphalt is 145 lb/ft3 (2322 kg/m3). Multiply the volume by the density (in the same units) to get the weight.
How do you calculate specific gravity of bitumen?
The principle is that it is the ratio of mass of a given volume of bitumen to the mass of an equal volume of water, both taken at a recorded/specified temperature. Take the sample (half the volume of the specific gravity bottles). i) Clean, dry and weigh the specific gravity bottle along with the stopper (Weight 'A').
Why is specific gravity important in asphalt?
In essence, the specific gravity measurements are conversion factors which allow conversion of mass percentages to volume proportions/percentages. The accuracy and reliability of the specific gravity measurements are therefore fundamental to the business of building quality hot-mix asphalt (HMA) pavements.
What is GMM and GMB in asphalt?
• Gmb= bulk specific gravity of the mixture. • Gmm= theoretical maximum specific gravity of the mixture.
What is the formula for asphalt?
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How do you calculate maximum specific gravity?
Theoretical maximum specific gravity is determined by taking a sample of loose HMA (i.e., not compacted), weighing it and then determining its volume by calculating the volume of water it displaces (Figure 1). Theoretical maximum specific gravity is then the sample weight divided by its volume.
What are the apparatus needed in determining the specific gravity and density of asphalt?
A Pycnometer or Filter Flask which meets ASTM and AASHTO specifications is required for specific gravity determinations.
Why specific gravity test is done?
A urine specific gravity test compares the density of urine to the density of water. This quick test can help determine how well your kidneys are diluting your urine. Urine that's too concentrated could mean that your kidneys aren't functioning properly or that you aren't drinking enough water.
What is the density of bitumen?
1.01-1.05 g/cm 3The density of bitumen is 1.01-1.05 g/cm 3 in the temperature range of 25°C to 85°C [63] .
What is the specific gravity of aggregate?
Specific Gravity is the ratio of the weight of a given volume of aggregate to the weight of an equal volume of water. Water, at a temperature of 73.4°F (23°C) has a specific gravity of 1. Specific Gravity is important for several reasons. Some deleterious particles are lighter than the good aggregates.
How to calculate the weight of asphalt?
Multiply the weight density of the asphalt by the volume to arrive at the weight of the asphalt needed in pounds. Consult the asphalt manufacturers if you do not know the weight density of the asphalt. In the example, use a typical weight density of 145 pounds per cubic foot.
What is apparent specific gravity?
Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water at its densest (4°C) for liquids; for gases it is air at room temperature (21°C).
Why does specific gravity have no unit?
The specific gravity has no unit because the units of the numerator and the denominator are the same.
What is the ratio of the density of a substance to that of a standard substance?
Specific gravity, also called relative density is the ratio of the density of a substance to that of a standard substance. In this case, the standard substance is pure water.
What is the density of liquid X?
The density of liquid X is 21g/ml while the density of pure water at 4°C is 1g/ml. Determine the specific gravity of liquid X.
How to calculate maximum specific gravity?
The basic premise of the maximum specific gravity is to divide the mass of the sample by the volume of the sample excluding the air voids . The mass is determined by measuring the dry mass of the sample either at the beginning of the test or after it has been dried at the end of the test. The volume is calculated by weighing the mass of the water displaced by the sample and dividing by the unit weight of water.
How to determine if asphalt has seepage?
In highly absorptive aggregate, water may seep in between the absorbed asphalt and the aggregate particle resulting in an erroneous dry weight measurement.To determine whether significant seepage has occurred, decant the sample through a towel (so that the fines are retained) held over the top of the container. Take several of the larger pieces of aggregate and break them. Examine the broken faces for wetness. Wetness indicates seepage. If seepage is detected, a supplemental procedure needs to be run on the sample at the end of the test. Generally, if the aggregate has a water absorption of less than 1.5 percent the supplemental procedure is not needed.
What is the purpose of the theoretical maximum specific gravity test?
The theoretical maximum specific gravity test is integral to Superpave mix design as well as field quality assurance. Theoretical maximum specific gravity is used along with bulk specific gravity values from field cores and laboratory compacted specimens to calculate air voids and the in-place air voids of a HMA pavement. It is also used to calculate the amount of asphalt absorbed in a HMA mixture (Vba) , which is then used in determining the effective asphalt content (Pbe).
What is the maximum specific gravity of HMA?
The theoretical maximum specific gravity (Gmm) of a HMA mixture is the specific gravity excluding air voids. Thus, theoretically, if all the air voids were eliminated from an HMA sample, the combined specific gravity of the remaining aggregate and asphalt binder would be the theoretical maximum specific gravity. Theoretical maximum specific gravity can be multiplied by the density of water (62.4 lb/ft3 or 1000 g/L) to obtain a theoretical maximum density (TMD) or “Rice” density (named after James Rice, who developed the test procedure).
Why is theoretical maximum specific gravity critical?
Theoretical maximum specific gravity is a critical HMA characteristic because it is used to calculate percent air voids in compacted HMA. This calculation is used both in Superpave mix design and determination of in-place air voids in the field.
How to determine the volume of a loose sample of HMA?
A loose sample of either laboratory or plant produced HMA is weighed while dry (to determine its dry mass) and then a short procedure is used to determine the sample’s volume. The theoretical maximum specific gravity is then the sample’s mass divided by its volume.
How small should a test sample be?
The mixture should be loose and broken up so that the fine aggregate is separated into particles smaller than 0.25 inches (6.25 mm) taking care not to fracture aggregate (Figure 4).
What size test specimens should be used for HMA pavement?
Test specimens may be either laboratory-molded or from HMA pavement. For specimens it is recommended that the diameter be equal to four times the maximum size of the aggregate and the thickness be at least one and one half times the maximum size.
What is the capacity of a 5 kg scale?
Balance or scale: 5 kg capacity, readable to 0.1 g, and fitted with a suitable suspension apparatus and holder to permit weighing the specimen while suspended in water, conforming
How to determine specific gravity of HMA?
The bulk specific gravity test is used to determine the specific gravity of a compacted HMA sample by determining the ratio of its weight to the weight of an equal volume of water.
What is the specific gravity of water?
Specific gravity is a measure of a material’s density (mass per unit volume) as compared to the density of water at 73.4°F (23°C). Therefore, by definition, water at 73.4°F (23°C) has a specific gravity of 1.
Why is HMA bulk specific gravity needed?
HMA bulk specific gravity is needed to determine weight-volume relationships and to calculate various volume-related quantities such as air voids and voids in mineral aggregate (VMA).
How to calculate SSD?
The most common method (and the one described in the Test Description section), calculates the specimen volume by subtracting the mass of the specimen in water (Figure 2) from the mass of a SSD specimen. SSD is defined as the specimen condition when the internal air voids are filled with water and the surface (including air voids connected to the surface) is dry. This SSD condition allows for internal air voids to be counted as part of the specimen volume and is achieved by soaking the specimen in a water bath for 4 minutes then removing it and quickly blotting it dry with a damp towel.
How to calculate volume of specimen?
These methods, based on Archimedes Principle, calculate specimen volume by weighing the specimen (1) in a water bath and (2) out of the water bath. The difference in weights can then be used to calculate the weight of water displaced, which can be converted to a volume using the specific gravity of water.
Why is SSD calculation inaccurate?
Although it avoids problems associated with the SSD condition, it is often inaccurate because it assumes a perfectly smooth surface, thereby ignoring surface irregularities (i.e., the rough surface texture of a typical specimen).
What is superpave mix?
Superpave mix design is a volumetric process; key properties are expressed in terms of volume. However, direct volume measurements are difficult, therefore weight measurements are usually made and then converted to a volume based on material specific gravities. Bulk specific gravity is involved in most key mix design calculations including air voids, VMA and, indirectly, VFA. Correct and accurate bulk specific gravity determinations are vital to proper mix design. An incorrect bulk specific gravity value will result in incorrectly calculated air voids, VMA, VFA and ultimately result in an incorrect mix design.