Punch test on mortar

When it is possible to extract enough bedding mortar from a sufficiently flat horizontal joint – generally taken from solid brick masonry, and this has sufficient toughness, the so-called “double punch test” can be carried out. This test corresponds to taking a sample of mortar already separated from the lower and upper blocks or obtained by core drilling orthogonal to the plane of the masonry, and separation of the joint using mechanical tools, taking care not to exert excessive force on it. Where necessary, a cap is applied to the sample using plaster or fine mortar of reduced thickness and similar resistance to the sample to be tested to make the lower and upper surfaces of the same perfectly parallel. At this point, a compressive force is applied on two metal disks with a diameter of 40-50 mm placed aligned below and above the sample, until the sample is crushed.
Technical standard: DIN 18555-9:2019-04