The asphalt rice test was developed to help determine the percentage of air voids in an HMA sample, otherwise known as the theoretical maximum specific gravity of asphalt test. ASTM
ASTM International
ASTM International, formerly known as American Society for Testing and Materials, is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services. Some 12,575 ASTM volun…
American Association of State Highway and Transportation Officials
The American Association of State Highway and Transportation Officials is a standards setting body which publishes specifications, test protocols and guidelines which are used in highway design and construction throughout the United States. Despite its name, the association r…
Asphalt
Asphalt, also known as bitumen is a sticky, black and highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product; it is a substance classed as a pitch. Until the 20th century, the term asphaltum was also used. The word is derived fr…
What is rice test for specific gravity of asphalt?
The Rice Test for Specific Gravity of Asphalt is a common test that measures the Theoretical Maximum Specific Gravity (G mm) of asphalt specimens. The test is an integral part of quality assurance of asphalt mixtures. Free and entrapped air is removed from the asphalt sample to prepare for the test.
What is the specific gravity of Asphalt Test?
Specific Gravity of Asphalt Test: What Equipment Do I Need? Several AASHTO and ASTM standards govern the measurement of the specific gravity of asphalt, also known as theoretical maximum specific gravity, or simply the Rice Test.
What is an asphalt air quality test?
The test is an integral part of the quality assurance of asphalt mixtures. Free and entrapped air is removed from the asphalt sample to prepare for the test. The prepared sample is then weighed immersed in water.
What is rice test Shaker?
Rice Test Shaker for Specific Gravity & Asphalt Rice Test agitates the pycnometer in preparing asphalt samples for Rice Test to remove entrapped air. Meets several ASTM and AASHTO standards. Digital Residual Pressure Manometer for measuring vacuum that is applied to sample during deairing. It meets ASTM D2041 and AASHTO T 209 standards.
What is a rice number for asphalt?
This value is based on the asphalt mixture's maximum specific gravity – also known as the Rice value or G mm in Superpave. The maximum unit weight is determined by multiplying the Rice value by 62.4 pounds per cubic foot (PCF). For example, 2.500 is a typical Rice value. 2.500 X 62.4 = 156.0 PCF.
What is the asphalt test?
Asphalt materials testing includes roofing and viscosity grading and asphalt binder testing. Asphalt cargo inspection services are available on a global basis.
What is GMM and GMB in asphalt?
• Gmb= bulk specific gravity of the mixture. • Gmm= theoretical maximum specific gravity of the mixture.
What is specific gravity of asphalt?
Because 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.
Why is asphalt testing important?
However, pavement testing requires specialized training and experience to help prevent future problems that include premature cracking, rutting, and or pavement breakup due to poor subgrade/ base support, poor mix materials or design and/or construction issues.
How do you take asphalt samples?
The sample should be obtained by shoveling away the top material with a round-point shovel and removing the material from at least three places in the hopper, directly above the slat conveyors. Ensure that in each of the three sampled areas, a portion is placed in each of the buckets to obtain a representative sample.
What is TMD in asphalt?
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.
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 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.
What is the compaction rate of asphalt?
Remember, the compaction rate, as a general rule, is about 6 mm (1/4") per 25 mm (1") of screed laid thickness when a vibratory screed is used and about 5 mm (1/5") per 25 mm (1") when a tamping and vibrating screed is used. Always verify the compaction rate of the fresh layer when building a longitudinal joint.
What is viscosity of bitumen?
The standard penetration value of bitumen viscosity grade VG-20 is 60 mm at 25 °C. The absolute viscosity of VG-20 bitumen is 1600 to 2400 poise at 60 °C.
How is asphalt content calculated?
The asphalt content is calculated as the difference between the initial mass of the asphalt paving mixture and the mass of the residual aggregate, and the calibration factor. The asphalt content is expressed as mass percent.
What is the phone number for asphalt rice testing?
If you have questions or need help selecting equipment, please call us at 1.800.544.7220 or use our Ask Humboldt form.
Who developed the asphalt compaction test?
The test (originally developed by engineer James Rice) ultimately provides a compaction target for the asphalt laydown based on air void percentage.
Specific Gravity of Asphalt
Several AASHTO and ASTM standards govern the measurement of the specific gravity of asphalt, also known as theoretical maximum specific gravity, or simply the Rice Test.
Percent Air Voids in Asphalt
The test results also allow calculation of bitumen absorption by mineral aggregates. If the percent air voids are too low, rutting and shoving of the pavement can happen.
What is the Asphalt Rice Test?
The Asphalt Rice Test is a routine test performed by asphalt producers, state departments of transportation, and testing labs. Reliable results from this test method depend on competent personnel, and the selection of quality equipment can have a direct impact on test results.
How Does the Asphalt Rice Test Work?
The Rice Test compares the mass of the sample to its volume, excluding the air voids, by measuring the dry mass of the loose HMA sample either at the beginning of the test or at the end of the test, after it has been dried. The volume is calculated by dividing the mass of the water displaced by the sample by the unit weight of water.
What Equipment is Needed and What Does It Do?
There are different products available to get the job done in accordance with ASTM, AASHTO, and any applicable state DOT standards. Some will be more time and labor-intensive, but more economical, while those that are automated can be significantly more time and labor-efficient.
What is the most repeatable asphalt test?
Gmm is one of the most repeatable asphalt mix tests, with a multi-laboratory precision of 0.024, which equates to a difference in lab-molded density in the range of 1.0 percent. Gmb can be quite a bit more problematic to match from one lab to another, with a SGC maximum allowable difference of 1.7 percent.
What is asphalt mix?
Asphalt mix specimens are compacted in the lab using some type of equipment, most often a Superpave Gyratory Compactor (SGC) or a Marshall Hammer. The bulk specific gravity of these specimens, Gmb, is determined, and also the theoretical maximum specific gravity, Gmm. A simple calculation using these two values gives the percent lab-molded air voids, Pa:
Why does my asphalt mix bleed?
A binder content out of tolerance on the high side can lead to flushing or bleeding in the pavement because too little air is available to absorb binder movement. This can also cause the mix to experience plastic movement, exhibited by rutting and shoving of the asphalt.
Can a mix fail on aggregate size?
It is possible, but very rare, for a mix to fail on the maximum aggregate size. If it does, the reviewer should verify that the correct mix was sampled. » If the results are based on percent passing (most are), the magnitude of each sieve must decrease as the sieve sizes get smaller.
Which states require asphalt testing?
Only Delaware , Maine , Massachusetts and New Mexico DOTs are the exception. A majority of the testing requirements are to evaluate the moisture-damage susceptibility of the asphalt mixture.
What is AMPT test?
The AMPT has been researched very extensively in recent years and is continuing to gain acceptance from researchers and agencies. The test has great potential in predicting pavement-rutting performance and also has good potential in predicting fatigue cracking by means of computational models.
Is the thrust on the standard specifications and not the provisional specifications?
The thrust was on the standard specifications and not the provisional specifications. However, if other literature indicated that provisional specifications are requiring performance testing then those were reviewed; and. Testing requirements were focused on plant-produced asphalt concrete.
Is there a correlation between asphalt performance and mechanical test results?
A significant number of mechanical tests have been proposed as asphalt-performance tests, and a relatively low number have actually shown good correlation between the test results and field performance . This is especially true for pavement-cracking distresses;
Is a simulative test a proof test?
Simulative tests may be viable options for use in developing performance-based specifications and to serve as proof tests. A mature and simple simulative test for low-temperature cracking is not available. Furthermore, use of simulative tests will require a local calibration and validation process.
Basic Premise
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.
In-place Density Measurement
As previously discussed, theoretical maximum specific gravity is needed to calculate air void content; therefore, it is involved in in-place air void determination during HMA pavement construction. In-place air void measurements are used as a measure of compaction (Figure 2). This is because compaction reduces the volume of air in HMA.
Test Description
The following description is a brief summary of the test. It is not a complete procedure and should not be used to perform the test. The complete test procedure can be found in:
Summary
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.
Approximate Test Time
45 minutes per test after samples are prepared (2 samples per test typically).
Basic Procedure
Test samples may be representative of a mixture prepared in the laboratory or in a HMA plant. 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).
Specifications
There is no specification for theoretical maximum specific gravity, but it is used to calculate other specified parameters such as air voids (Va) in laboratory compacted mixtures and in-place density in the field.
