Test on aggregate
Any Concrete work before must be Test on aggregate because of sure working quality of Concrete. Difference type of test no aggregates. as per below tests point out of aggregate tests
1. Sampling of Aggregate Tests
2. Aggregate Crushing Value
3. Impact Value of Coarse Aggregate
4. Sieve Analysis Test of Coarse Aggregates
5. Flakiness Index of Aggregate
6. Elongation Index of Aggregate
7. Compressive Strength Test for Concrete
Sampling of Aggregate Tests
Samples from stockpiles shall be taken equally from the top third, midpoint and bottom third of the height of stock.
The outer layer of the sampling point shall be removed, and the sample is taken from the material beneath.
The sample thus collected will be the gross sample. The quantity of the total sample depends on the aggregate size.
Reduction of Gross Sample will be made as per quartering method to required sample size for testing as per following;
Take the gross sample on the open platform. For Fine aggregate, use tray so that residual fines can be collected by brushing.
The aggregate shall be mixed and then scooped into a cone shape pile.
After the cone is formed, it shall be flattened by pressing the top.
Then it is divided into four quadrants diagonally.
The bulk of the sample is reduced by rejecting any two diagonally opposite Quarters
This method is repeated until the sample size is approximately achieved forgiven.
Aggregate Crushing Value
To calculate aggregate Crushing value by testing aggregate passing 12.5 mm sieve and retained on a 10 mm sieve.
This procedure covers all relative activity for the project site.
15cm dia. steel cylinder with plunger and base plate
Tamping rod 16 mm dia. and 600 mm long with one end rounded
Weighing balance of accuracy 1 g
Sieves 12.5 mm 10mm & 2.36 mm
Take a sample of aggregates by sieving through 12.5mm and retained on 10mm.
The aggregate shall be tested in dry surface conditions. If dried by heating, the period of drying shall not exceed 4 hours and temp shall be 100-110 deg C.
A sample shall be cooled down to room temperature before testing. Take approximately 6 kgs of a sample.
The quantity of the sample shall be such that the depth of material in the cylinder after tamping shall be 10cms.
The cylinder shall be filled up in 3 layers, and each layer shall be tamped 25 times with tamping rod and finally leveled off.
The weight of the material comprising the test sample shall be determin.
The plunger shall be placed in position, and the apparatus shall be then placed between the platens of CTM.
The load shall be applied at a uniform rate so that the load of 40T is reached in 10 minutes.
The load shall be removed from the cylinder, and the crushed sample shall be sieved through 2.36 mm sieve. The fraction passing sieve 2.36 mm shall be weighed to nearest 1gm.
Such two tests shall be taken for each lot.
Calculation & Records:
• Aggregate Crushing Value, % = (B / A) x100
• The mean of the two results shall be reported to the nearest whole