Double punch test on mortar

The double punch test is carried out when a sufficient quantity of bedding mortar with adequate toughness can be extracted from a relatively flat horizontal joint, typically in solid brick masonry.
The mortar sample can either be already detached from the masonry units or obtained through core drilling orthogonal to the masonry plane, followed by precise mechanical separation of the joint.
If necessary, a capping layer of gypsum or fine mortar with similar strength to the sample is applied to ensure that the top and bottom surfaces are perfectly parallel. The test consists of applying a compressive force on two metal disks (40–50 mm in diameter), positioned above and below the sample, until failure due to crushing occurs.

Reference standard: DIN 18555-9:2019-04