AS 2341.30:2021 – Methods of testing bitumen and related roadmaking products Method 30: Recovery of residue from bituminous emulsion.
indicates a recommendation
S Reagent
A 2:1 by volume mixture of methylated spirits and water,
NOTE Domestic grade methybted spirits has been found to be suitable.
6 Apparatus
The following apparatus is required:
(a) Balance, with a minimum capacity of 250 g. readable to at least 0.1 g, with a limit of performance not exceeding 0.3 g.
(b) Inert gas delivery system consisting of a carbon dioxide gas bottle (food grade) with pressure regulator, connected by flexible tubing through a 500 mL glass gas washing bottle to a nozzle of glass tubing having an Internal diameter of about 6 mm. The gas nozzle shall have the delivery end bent through approximately 1800 so that it may be hooked over the side of the metal container and extended down the inside about 50mm.
NOTE 1 The purpose olthls apparatus Is to direct the flow of gas down the Inside of the container to form a non.oxidizing atmosphere without hindering the escape of volatile matter
NOTE 2 Another inert gas. e.g. nitrogen (food grade), maybe used.
c) Hot plate, with variable temperature control.
(d) Wire gauze (optional).
(e) Container, metal with an open top, up to 1 L capacity.
NOTE 3 A food can having a diameter of appropriately 75 mm and a depth of appropriately 105 mm has been Found to be suitable.
(f) Shallow dish, to hold cooling water.
(g) Tongs or thermally insulated gloves, to hold the metal container.
(h) Stirrer, suitable for the containers used, such as a metal spatula or glass rod.
(i) Digital infrared thermometer, which is readable to at least I °C and accurate to at least ± 5 °C, and able to measure temperatures in the range between 20 and 200 °C.
7 Procedure
The procedure shall be as follows:
(a) Prepare the bituminous emulsion sample for testing in accordance with AS/NZS 2341.21.
(b) Place the stirrer into the container and weigh the container and stirrer on the balance (A).
Tare the balance with the container and stirrer and add about 60 g of the bituminous emulsion
sample. Record the mass of bituminous emulsion added to the container (M).
NOTE 1 Where subsequent testing require5 larger quantities of residue, a larger mass of emulsion may be used.
(d) Add approximately 25 mL of the reagent and place the container on the hotplate.
(c) Connect the inert gas delivery system to the container, adjust the rate of flow of gas at about 2 bubbles per second (when passed through the gas washing bottle), and commence the evaporation process.
(f) Adjust the temperature of the hotplate and, in order to control boiling, rock the container from side to side using the tongs or thermally insulated gloves, while stirring the sample with the stirrer.
NOTE 2 Ii may be advantageous to place a piece of wire gauze over the hotplate as an additional means of regulating the rate of heating.
(g) When frothing of the sample subsides, monitor the temperature of the sample using the digital infrared thermometer. Remove the container from the hotplate when the temperature of the sample Is about 130 °C.
(h) Place the container in a shallow dish of water while maintaining the gas flow into the container. Monitor the temperature of the sample using the digital infrared thermometer. Allow the sample to cool to about 50 C.
(i) Remove gas nozzle, dry the outside ni the container, and weigh the container, stirrer and residue on the balance.
(I) Repeat the evaporation with further additions of reagent until the loss in mass between successive evaporations is less than 0.2 g. Take the final mass recorded to be the mass of container, stirrer and residue after evaporation (B).
NOTE 3 Some hydrocarbon solvents may not be completely removed even alter repeated evaporations. This may affect the test results obtained for the residue.
8 Calculation of residue from evaporation (if required)
If it is required to calculate the residue from evaporation of the bituminous emulsion, the following equation shall be used.