Sampling from laid and compacted material by coring

5 Sampling from laid and compacted material by coring 

Sampling by coring has the advantage that there is certainty of the location of the material been sampled. However, it requires a core-cutting machine, it affects the pavement surface in case of insufficient restoration and cutting operation affects to some extent the aggregate grading (particularly of coarse mixtures). 

For the determination of the aggregate gradation, the diameter of the cores is usually 150 mm or greater, in contrast to the diameter of the cores for determination of layer thickness, air voids and density, which can be 100 mm. The number of cores required in both cases is at least two, spaced usually approximately 10 cm apart. 

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