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§ 06 · Quality and testing
What the sieve says
Every stockpile is sampled and sieved every week. These are the grading curves, against the band an engineer looks for. Example test data for this demo.
The shaded band is the target range. The line is the latest batch. Points show the percentage of the sample passing each sieve.
The lab
A small room that matters
Our lab is a converted container beside the weighbridge, with a nest of sieves, a shaker, an oven, a balance and a crushing value rig. It is not glamorous, but it is where every batch earns its ticket.
Each morning the lab assistant takes samples from the face of each stockpile, dries them, and shakes them through the sieves. The results go on the board at the pile and onto the batch sheet that travels with every delivery.
Once a month, a sample of each product goes to an independent materials lab in the city for crushing value, flakiness and silt tests. Example arrangement for this demo.
If a batch falls outside its band, the pile is closed until it is reworked through the screens. That has happened four times this year.
On every product
| Test | What it tells you | How often |
|---|---|---|
| Sieve analysis | The size spread of the stone | Every stockpile, weekly |
| Fines by washing | How much dust and clay is in the stone | Every stockpile, weekly |
| Flakiness index | How many flat, weak pieces there are | Monthly |
| Aggregate crushing value | How well the stone resists crushing | Monthly, independent lab |
| Moisture | How much water you are paying for | Daily in the rainy season |
“Engineers do not trust a quarry. They trust a test sheet with a batch number on it.”Engr. Musa, quality lead (example team member)
Sample
From the face of the pile, not the top.
Dry and weigh
Oven dried so moisture does not flatter the result.
Sieve
Through twelve sieves from 37.5 mm to 75 microns.
Publish
On the pile board and on your delivery ticket.
About quality
Can my engineer visit the lab?
Yes, any weekday. Call ahead and we will run a test while you watch.
Do you test for silt in sand?
Yes, every load of sharp sand from our partner pit is checked by washing before it is stockpiled.
Where are the certificates?
Monthly independent results are sent on request. Example arrangement for this demo.
What if my concrete fails a cube test?
Send us the batch number and the cube results. We will share our test data for that batch the same day.