Aggregate Test

It is essential that aggregates used in construction purposes are strong and durable. Think of bricks, blocks, concrete, coated materials – the largest single component in all of these construction materials is aggregate. It would be disastrous to construct houses or bridges or roads with building materials made with weak rock.

This is why quarrymen need to test the rocks that they quarry – they need to know if the rock is strong and suitable for the end-use it is to be put to. They need to know if there are any weak strata (rock layers) in the quarry that would be detrimental to the quality of the stone.

For instance, where basalt lavas are being quarried, the quarryman needs to take care to exclude any soft red rock that is often found between lava flows. He also needs to avoid any basalt that has weathered, or that contains excessive amounts of vesicles (gas cavities formed during the emplacement of the flow), or amygdales (cavities filled with soft white minerals called zeolites). In greywacke quarries, bands of soft shale have to be excluded from aggregate production.