The testing method of bitumen is a critical step in evaluating its physical properties and suitability. In construction, asphalt quality directly affects the service life and performance of the road. The following are several commonly used asphalt testing methods, combined with relevant standards and technical requirements, to introduce in detail the water mixing stability test of emulsified asphalt and the density test of compacted asphalt mixture.
Stability test of emulsified asphalt mixed with water
Purpose and Scope of Application
This test is mainly used to evaluate the stability of medium-cracked and slow-cracking emulsified asphalt after mixing with water, and is not suitable for fast-cracking emulsified asphalt. Through this test, the stability of emulsified asphalt in the dilution process can be evaluated, and the demulsification caused by improper dilution in the construction process can be prevented, which will affect the construction quality.
Instruments and materials
Filter sieve – 1.18mm mesh hole
Graduated cylinder - 200mL, minimum indexing 1mL
Beaker – 400 mL
Distilled or purified water
Balance - inductance not more than 0.1g
Others – glass rods, stopwatches, etc
Test procedure
1. The emulsified asphalt is filtered, and the filtered emulsified asphalt is used for the test.
2. Add 50mL of emulsified bitumen to a beaker and gradually add 150mL of distilled or purified water, stirring as you go.
3. Let the mixture stand at 25°C for 2 hours to see if the asphalt coalesces.
4. If there is no significant coalescence, it is recorded as "passed", otherwise it is "not passed".
Reporting requirements
At least two parallel tests were carried out on each specimen, and the water mixing stability of the emulsified asphalt was evaluated as "pass" or "fail" in the report.
Density test of compacted asphalt mixture (surface dry method)
Purpose and Scope of Application
The surface dry density test is suitable for asphalt mixtures with water absorption of less than 2%, including asphalt concrete, SMA, etc. The test can determine the gross volume density and gross volume relative density of asphalt mixture, and is used to calculate the porosity and mineral clearance ratio of the mixture.
Instruments and materials
Immersion balances or electronic balances
Basket
Overflow tank - 25°C±0.5°C constant temperature tank
Suspension device - hanging basket and specimen
Towels, stopwatches, electric fans or ovens
Test procedure
1. Prepare the specimen: The specimen can be molded in the laboratory or drilled in the field.
2. Weigh the aerial mass of the dried specimen, and then immerse it in water at 25°C for 3~5 minutes to weigh the mass of the specimen in water.
3. Dry the surface moisture of the specimen with a damp towel and weigh its surface dry mass.
4. Calculate the water absorption, gross volume density, gross volume relative density and other indicators of the specimen.
Calculation formula
The water absorption rate is calculated according to the formula, and the result is taken to one decimal place.
The relative density of gross volume, porosity and clearance ratio of ore were calculated by different formulas, and the results were taken to three decimal places.
summary
The stability test of emulsified asphalt mixing with water and the density test of compacted asphalt mixture are important testing methods to ensure the quality of asphalt materials. The former is used to evaluate the stability of emulsified asphalt during the dilution process, while the latter measures indicators such as the bulk density of the compacted asphalt mixture to ensure the quality of road construction.
