This procedure describes the ways in which concrete samples are treated prior to its analysis of bubbles, air and aggregates counting. There are 9 steps to follow for the sample preparation.
Step 1: Polishing with Diamond grit platen
1. Set 100 diamond grit platen on the polishing machine so it does not move.
2. Set the water dropping bottle so it can drop water into the center of the diamond grit platen.
3. Then turn on the polishing machine and set the controller between 35~45.
4. Place the sample on the diamond grid platen and press the sample with using both hands to give even force on the area of sample. Ground the sample in only ONE DIRECTION. (Use lots of water)
5. Keep polishing sample until the saw marks on the sample disappears.
6. Clean with water and compressed air immediately after the sample is grounded flat.
8. Then clean the platen with water and air dry so not to get rusted. Also dry the platen holding part of the polishing machine not to get rusted.
Step 2: 12 minutes on Lapmaster 12
1. Do 12 minutes on “Labmaster 12.” (Check the link, Lapmaster U of T section in the Lab Procedures page.)
2. Clean with compressed air and water immediately after “Lap Master.”
3. Dry the sample in 45 °C oven about 30 minutes.
Step 3: Painting the sample
1. Paint the very thin 5:1 acetone and nail polish layer on the sample. (Less brush stains, easier to do the final polishing later)
2. Put in 45 °C oven about 10 minutes.
3. Clean the brush with acetone twice in 2 containers, then air dry.
Step 4: Final polishing
2. Set the platen on the polishing machine so it does not move.
3. Set the water dropping bottle so it can drop water into the center of the steel platen.
4. Then turn on the polishing machine and set the controller between 35~45.
5. Place the sample on the steel platen lightly, press the sample and also rotate the sample(different directions) to remove the brush stains. It might be hard to control the sample unlike the first step (diamond grit platen) so do not press too hard. (Use lots of water)
6. Keep polishing sample until the brush stains on the sample disappears.
7. Clean with water and compressed air immediately after brush stains are gone.
8. Air dry and put in 45 °C oven again about 10 minutes.
9. Air dry and put in 45 °C oven again about 10 minutes.
Step 5: Color scanning
1. Put stickers on the four edges of sample.
2. Scan with the color illustration.
-Setting for scanning: setting 1(color/24bit)
-The color illustration will allow comparing the colors of the sample image.
-The image will be used for checking the sample's aggregate percentage.
Step 6: Coloring black and powdering
1. Color the layers on the sample with the opegue permanent marker on one direction then wait until it dries completely.
-we choose the opegue permanent marker because it is more transparency so we are able to see the aggregate on the sample easily.
2. After it dries, color the another layers on the sample on different direction then wait a long time to let it dry.
3. Then remove the ink on the stickers.
- It is easier to use the isopropyl alcohol and q-tips.
4. Pour enough Calcium silicate(CaSiO3) powder, also called wollastonite, on the sample and press hard with using the card to fill all of air bubbles in sample.
5. Then sweep the powder with using the card and razor blade slightly.
6. Put very little amount of baby oil on fingers and sweep the sample slightly to remove the powder on the sample's surface. But be very careful not to sweep the powder inside the air bubbles.
Step 7: Coloring the aggregate
1. By the reflection from the sun light, try to color as much as air bubbles of aggregates possible to get rid of white powders.
2. Then use the microscope to color small air bubbles in aggregates to get rid of white powders.(Do your best)
-This will be helpful not to count the air bubbles in aggregates when we count the air content of the sample.
Step 8: Black and white scanning
1. Scan with the black and white illustration.
-Setting for scanning: Black and White color/ 8bit grey
-This will allow comparing the grey scale of sample image.
-The image will be used to figure out an air content of the sample.