106.3.2.90, Determination of Chemical Components in Asphalt and Non-Asphalt Rejuvenators

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106.3.2.90.1 Determination of Chemical Components in Asphalt Rejuvenators

Scope

This test method (referenced from ASTM D 2006-70) determines chemical components of asphalt rejuvenators. The chemical components of asphalt rejuvenators are classified as asphaltenes, polar compounds, first acidaffins, second acidaffins and saturates.

Summary of Method

Asphaltenes are determined (by difference) by measuring the percentage of material soluble in n-heptane. Polar compounds are determined (by difference) by measuring the percentage of material that does not react with 85% sulfuric acid. First acidaffins are determined (by difference) by measuring the percentage of material that does not react with concentrated sulfuric acid. Second acidaffins are determined (by difference) by measuring the percentage of material not adsorbed on silica gel. Saturates are determined (directly) by measuring the percentage of material not adsorbed on silica gel.

Equipment and Reagents

1. Heptane, HPLC Grade
2. Sulfuric acid (H2SO4), certified ACS grade
3. Erlenmeyer flasks, 250 ml
4. Glass beaker, 100 ml
5. Evaporating dish, porcelain, 100 ml capacity
6. Graduated cylinder, 100 ml
7. Glass chromatographic column: 1000 mm long, 31 mm inside diameter, having a 2 mm stopcock with vernier adjustment
8. Silica gel, high purity grade, Grade 12 28-200 mesh, Grade 62 60-200 mesh, Grade 643 200-425 mesh
9. Concave filter pad cut from a 33/80 extraction thimble
10. Funnel, graduated 125 ml with 24/40 standard taper joints
11. Utilities- steam bath, aspiration suction system, hot plate
12. Filter flask, 500 ml
13. Rinse squeeze bottle, 500 ml capacity
14. Filter paper, rapid filtering, 110 mm
15. Filter funnel
16. Sodium hydroxide (NaOH), certified ACS grade
17. Gooch crucible, 44 mm top, 36 mm bottom, depth of 24 mm to 28 mm
18. Glass fiber pad, 32 mm

Determination of Asphaltenes

1. Weigh 1 g +/- 0.1 g of residue into a tared 250 ml Erlenmeyer flask, record weight and cool to room temperature.
2. Gently warm flask on a hot plate to distribute the residue evenly over the bottom of the flask and cool.
3. Add 50 ml of heptane and swirl occasionally until the sample is dispersed.
4. Allow to stand for a minimum of 15 hours at room temperature.
5. Filter through a #41 filter into pre-weighed evaporating dish and rinse three times using 10-20 ml of heptane.
6. Rinse the filter with heptane until the filter paper shows no oily ring.
7. Evaporate on a steam bath until all solvent has been volatilized, cool and record the weight.
8. The residue is the heptane – soluble portion of the specimen.
Q_1 = \frac{weight\,of\,heptane\,-\,soluble\,portion}{weight\,of\,residue} \times\,100

Determination of Polar Compounds

1. Weigh a 1 g +/- 0.1 g of residue into a tared 250 ml Erlenmeyer flask, record weight and cool.
2. Gently warm flask on a hot plate to distribute residue evenly over the bottom of the flask and cool.
3. Dissolve the residue in 5 ml of heptane.
4. Add 2.5 ml 85% H2SO4, stopper the flask and shake for 3 minutes.
5. Release the pressure by carefully loosening the stopper after each minute.
6. Settle the acid sludge from the heptane solution for a minimum of 2 hours.
7. Decant the heptane solution into a clean, dry 250 ml Erlenmeyer flask.
8. Rinse the flask three times with heptane and decant into the flask.
9. Discard the acid sludge
10. Add 20 grams of NaOH pellets to the flask, swirl and allow to stand a minimum of 20 minutes.
11. Filter through a #41 filter into a pre-weighed evaporating dish and rinse 3 times with heptane.
12. Evaporate on a steam bath until all solvent has been volatilized, cool and record weight.
13. The residue is the fraction not reacting with 85% H2SO4.
Q_2 = \frac{weight\,of\,fraction\,not\,reacting\,with\,85%\,H_2SO_4}{weight\,of\,residue} \times\,100

Determination of First Acidaffins

1. Tare out 250 ml Erlenmeyer flask, weigh approximately 1 gram of residue and record.
2. Gently warm flask on hot plate to distribute residue evenly over the bottom of the flask and cool.
3. Dissolve the residue in 20 ml heptane.
4. Add 2.5 ml of concentrated H2SO4, stopper and shake for 3 minutes.
5. Release the pressure by carefully loosening the stopper after each minute.
6. Settle the acid sludge from the heptane solution for a minimum of 2 hours.
7. Decant the heptane solution into a clean, dry 250 ml Erlenmeyer flask.
8. Rinse the flask three times with heptane and decant into the flask.
9. Discard the acid sludge.
10. Add 20 grams of NaOH pellets to the flask, swirl and allow to stand at least 20 minutes.
11. Filter through a #41 filter into a pre-weighed evaporating dish and rinse 3 times with heptane.
12. Evaporate on a steam bath until all solvent is volatilized, cool and record weight.
13. The residue is the fraction not reacting with concentrated H2SO4.
Q_3 = \frac{weight\,of\,fraction\,not\,reacting\,with\,concentrated\,H_2SO_4}{weight\,of\,residue} \times\,100
First Acidaffin = Q2 - Q3

Second Acidaffins

1. Tare out 100 ml beaker and weigh approximately 1 gram of residue and record.
2. Gently warm flask on hot plate to distribute residue evenly over the bottom of the flask and cool.
3. Dissolve in 20 ml of heptane and let set overnight, if needed, to settle out asphaltenes.
4. Filter asphaltenes, discard and retain soluble portion for testing.
5. Set up column by tapping a cotton plug at the bottom of the column before adding silica gel.
6. Add 43 grams (Grade 12), 15 grams (Grade 62) and 3-4 grams (Grade 643) of silica gel to column.
7. Pre-wet column with 50 ml heptane.
8. As the last of heptane passes into the silica gel, add heptane-soluble portion of the residue.
9. Rinse beaker twice with heptane each time.
10. As the last of the solution passes into the silica gel, rinse the top with heptane.
11. Follow with 20 ml heptane and add sufficient heptane to maintain heptane level above silica gel.
12. Collect 100 ml of the effluent into a pre-weighed evaporating dish.
13. Evaporate on a steam bath until all solvent is volatilized, cool and record weight.
Q_4 = \frac{weight\,of\,fraction\,not\,adsorbed\,on\,the\,silica\,gel}{weight\,of\,residue} \times\,100
Second Acidaffin = Q3 - Q4

Calculations

Asphaltenes, percent by weight = 100 - Q1
Polar compounds, percent by weight = Q1 - Q2
First acidaffins, percent by weight = Q2 - Q3
Second acidaffins, percent by weight = Q3 - Q4
Saturates: Q4

106.3.2.90.2 Determination of Chemical Components in Non-Asphalt Rejuvenators

Scope

This test method (referenced from ASTM D 2006-70) determines the chemical components of non-asphalt rejuvenators. The chemical components of non-asphalt rejuvenators are classified as polar compounds, total acidaffins and paraffins since they are substantially free of asphaltenes.

Summary of Method

Total acidaffins and paraffins are determined using an adsorption column. Polar compounds (Q2) are determined the same as the asphalt rejuvenator procedure. Total acidaffins are determined (by difference) by measuring the percentage of the material not adsorbed on the silica gel. Paraffins are determined (directly) by measuring the percentage of material not adsorbed on the silica gel.

Equipment and Reagents

Refer to the Equipment and Reagents listing used for the determination of chemical components in asphalt rejuvenators.

Determination of Total Acidaffins and Paraffins

1. Weigh a 1 g +/- 0.1 g of residue and record.
2. Dissolve with 20 ml of heptane in a 150 ml beaker.
3. If the sample contains precipitates or flocculates, filter and transfer filtrate back to 150 ml beaker.
4. Prepare adsorption column.
5. Tamp the cut-out bottom of an extraction thimble to the bottom of the column.
6. Add 43 grams of Grade 12 silica gel and tap the column to settle.
7. Add 3-4 grams of Grade 643 silica gel and tap the column to settle.
8. Note: Grade 62 gel can be omitted from the column when asphaltenes are <1% in sample.
9. Pre-wet the column with 50 ml heptane.
10. As the last of the heptane passes into the silica gel, add heptane solution to the column.
11. Rinse the beaker twice and quantitatively transfer the remaining solution into the column.
12. Follow with 20 ml heptane and then add sufficient heptane to maintain level above silica gel.
13. Collect 100 ml of effluent into a pre-weighed evaporating dish.
14. Evaporate over steam bath until all solvent is volatilized, cool and record weight.
Q_4 = \frac{weight\,not\,adsorbed\,on\,the\,silica\,gel}{weight\,of\,sample} \times\,100

Calculations

Polar compounds, weight percent = 100 - Q2
Total acidaffins, weight percent = Q2 - Q4
Paraffins: Q4