STANDARD
- BS: 812 (Part 3)1990.
DEFINITION
- Ten percent fines value is defined as the load taken by the soaked sample at ten percent of fines.
APPARATUS
- Standard Compression Testing Machine.
- A cylindrical metal measure having an internal diameter of 57 ± 1 mm and an internal depth of 90 ± 1mm
- Steel cylinder open ended with plunger and base plate with a normal internal diameter of 75mm
- Straight steel rod of circular cross section 8mm diameter and 300mm long, one end shall be rounded.
- Balance of capacity 15Kg and sensitivity 1 gram.
- 14mm, 10mm and 2.36mm IS test sieves.
- Thermostatically controlled oven with capacity up to 250 °C.
PROCEDURE
- Take approximately 15kg of sample passing through 14mm and retained on 10 mm sieves.
- Place the test specimen in the wire basket and immerse it in the water with a cover of at least 50 mm of water above the top of basket.
- Immediately after immersion remove the entrapped air from the sample by lifting the basket 25mm above the base of container and allowing it to drop 25 times at the rate of one drop per second.
- Keep the basket and aggregates completely immersed in water for a subsequent period of 24 ± 1/2 hours and the temperature of water maintained at 20 ± 5 °C.
- Remove the specimen of aggregates from the basket after the specified period of soaking and blot the free water from the surface of the material with the absorbent cloths.
- Immediately place the test specimen in to the cylinder in three layers each layer being subjected to 25 blows from the tamping rod distributed evenly over the surface of the layer and dropped from a height of 50mm above the surface of aggregates.
- Carefully level the surface of the aggregates and insert the plunger so that it rests horizontally on the surface.
- Place the apparatus with the test specimen and plunger in position between the platens of the Compression Testing machine.
- Apply load at a uniform rate to cause a total penetration 15 mm (for rounded aggregate) & 20 mm(For Normal crushed aggreagete) of the plunger in 10 min+/-30 sec.
- Replace the load and remove the crushed material by holding the cylinder over a clean tray.
- Dry it in the oven at a temperature of 105 ± 5 °C either to constant mass or for a period of 24 ± 1/2 hours.
- After specified period of time remove the aggregates from the oven and allow the material to cool, weigh and record the mass of the aggregates (m1).
- Sieve the whole of the specimen in the tray on the 2.36mm sieve until no further significant amount passes during a further period of l min.
- Weigh and record the masses of the fraction passing ( m2) and retained ( m3) on the sieve to the nearest gram.
- The total mass ( m2+m3 ) should not differ from the initial mass (m1) by more than 10 grams other wise discard the test and start a fresh test.
- Repeat the complete test procedure for another three or more samples with the same of the aggregates at different loads that gives a percentage fines value within the range of 7.50% to 12.50%.
CALCULATIONS
- Percentage of material passing, P = ( m2 / m1 ) x 100
REPORT
- Plot the graph representing load on Y-axis and percentage of fines on X-axis.
- Draw an average line through the plotted points.
- Record the load at ten percent fines from the graph.
PRECAUTION
- Care shall be taken to ensure that the plunger does not jam in cylinder while applying load.
DETERMINATION OF 10% FINES VALUE
BS: 812 (Part 3)1990
Location : Date of testing :
Sample No : Type of material :
| Description | Test I | Test 2 | Test 3 | Test 4 | Test 5 | Average |
| Wt. of oven dried sample after applying load (m1) | . | |||||
| Wt. of material passing 2.36mm sieve (m2) | ||||||
| Wt. of material retained on 2.36mm sieve (m3) | . | |||||
| % fines= (m2 / m1) x 100 | ||||||
| Total wt. of material passing and retained on 2.36mm sieve (m2+m3) | ||||||
| Load applied in KN | ||||||
| Load required for 10% fines = | ||||||
| Remarks: | ||||||