The calculation of toluene insoluble matter content in coal pitch samples is based on the difference in solubility of coal pitch in toluene. In the experiment, the soluble part was removed by extraction, and the remaining residue was insoluble. After drying and weighing, the ratio of the residue to the mass of the initial specimen is calculated to obtain the percentage content of toluene insoluble. The results were averaged over two parallel trials to ensure that the difference did not exceed 1.0%.
The purpose of this method is to determine the content of toluene insoluble matter in road coal asphalt materials.
Fat extractor – 250 mL capacity.
Weighing flasks – 35 mm diameter, 70 mm high.
Oven – fitted with temperature controller.
Analytical balance – sensibility not more than 0.1 mg.
Toluene – chemically pure.
Standard sieves – square bore sieves (0.3 mm, 0.6 mm, 1.18 mm).
Dosing filter paper – 150 mm and 140 mm diameter, or finished filter cartridges.
Fine sand - the particle size is between 0.3~1.18 mm.
Others – sand baths, dryers, fine aggregates (sand), iron supports, etc.
Preparation
1. Soak the fine sand in water, float away the floating ash, dry it and sieve it, take the part with a particle size of 0.3~1.18 mm, and soak it in toluene for more than 24 hours; Take it out and let it dry, then place it in the oven (105°C±5°C) and dry it for later use.
2. Fold the two layers of 150 mm and 140 mm filter paper into a filter paper cylinder with a diameter of about 25 mm, soak it in toluene for 24 hours, dry it and place it in an oven for drying.
3. Heat the coal asphalt specimen to no more than 50°C of its softening point.
4. Wash the weighing flask and dry it in the oven.
Test procedure
1. Weigh about 10 g of fine sand in the filter paper tube, put it in a weighing flask, and bake it in the oven until it reaches a constant weight.
2. Weigh the heated coal asphalt sample, add it to the filter paper cylinder and sand, and stir it well with a glass rod.
3. Add 120 mL of toluene to the flask of the fat extractor, place the cartridge containing the tar sands into the extractor, and rinse the glass rods in fractions with 30 mL of toluene.
4. After the condenser tube is installed, fix the fat extractor and heat it in a sand bath to control the reflux rate until the reflux liquid is close to colorless and transparent, and there is no obvious yellow color on the filter paper in the extraction cylinder.
5. After the heating is stopped, take out the filter paper tube, wait for the toluene to volatilize, and then put it in the oven to bake to constant weight, and weigh its quality after cooling to room temperature.
The content of toluene insoluble matter in the coal pitch sample is calculated according to the formula, and the result is expressed as a percentage by mass.
At least two parallel tests are carried out on the same sample, and when the difference in the results does not exceed 1.0%, the average value is taken as the test result. The permissible error for repeatability tests is 1.0%.
This method is suitable for determining the residual asphalt content of various types of emulsified asphalt after heating and dehydration.
Specimen container - a metal dish with a capacity of 1500 mL and a wall thickness of 0.5~1 mm, can also be replaced by a small aluminum pot or porcelain evaporation dish.
Balance – Inductance not more than 1 g.
Oven – fitted with temperature controller.
Electric or gas stoves – with asbestos mats.
Others – thermometers, solvents, lotions, etc.
1. Clean the specimen container and glass rod, and weigh the total mass after drying.
2. Weigh 300 g of emulsified asphalt in the sample container, and weigh the total mass of the container and the emulsion.
3. Place the container containing the specimen with the glass rod on an electric or gas stove and heat it slowly to confirm that the water has completely evaporated, and then heat it at 163°C±3.0°C for 1 minute.
4. Remove the sample container, cool it to room temperature, and weigh the total mass of the container, glass rod and asphalt.
The evaporation residue content of emulsified bitumen is calculated according to the formula and expressed as an integer.
At least two parallel tests of the same sample, and the difference between the results is not more than 0.4%, the average value is taken as the test result. The allowable error is 0.4% for the repeatability test and 0.8% for the reproducibility test.
This test procedure provides systematic technical requirements and method steps for the testing of coal asphalt and emulsified asphalt to ensure the accuracy and reliability of the test results. Through the standardized experimental procedures, the relevant indexes of asphalt materials can be effectively determined, so as to provide a basis for road engineering and related applications.