EN 13364 Natural Stone Test Methods - Determination of Breaking Load in Dowel Hole

A European standard, “EN 13364 Natural stone test methods - Determination of the breaking load in the dowel hole”, describes a test method for determining the breaking load in the dowel hole of natural stones used as coating or lining in structures. This test, in principle, consists of applying a force perpendicular to the surface of the sample by means of a dowel previously placed in a hole drilled on one side of the sample and measuring the breaking load of the sample.

The main equipment used in these tests includes:

• A balance that can weigh samples to an accuracy of 0,01 percent of their mass.
• A ventilated oven that can maintain a temperature of 70 degrees plus/minus 5 degrees.
• A linear measuring device with an accuracy of 0,05 mm.
• A rotary drilling machine equipped with a diamond or tungsten carbide tipped bit.
• A testing machine that is calibrated and has the force required by the standard “EN 12390-4 Testing of hardened concrete - Part 4: Compressive strength - Specification for testing machines”.
• A clamping device consisting of two metal plates having the shape and dimensions shown in the figure given in the standard.
• A device for applying loads perpendicular to the axis of a dowel.
• A room or compartment in which the air temperature can be kept at 20 degrees plus/minus 5 degrees.

Sampling is not the responsibility of the testing laboratory unless specifically requested. The location of any bedding or anisotropy should be shown by at least two parallel lines on each sample.

Tests can be performed as a diagnostic test or a technological test:

• Identification tests are tests performed when the use of the stone according to the location of the anisotropy planes and the thickness and surface quality of the elements in the coating are unknown.
• Technological tests are tests performed when the use of the stone according to the location of the anisotropy planes and the thickness and surface quality of the elements in the coating are known. In this case, the main surfaces of the samples must have the same orientation as the surface to be loaded during use.

The minimum number of test specimens depends on the presence of planes of anisotropy. If the stone does not show planes of anisotropy, 10 Type 0 tests should be performed on three specimens. If the stone shows planes of anisotropy:

• Ten Type I tests should be performed on three specimens cut parallel to the planes of anisotropy;
• Ten Type IIa tests and 10 Type IIb tests should be performed on five specimens cut perpendicular to the planes of anisotropy.

In this standard, the surface quality of the samples is determined as follows:

• Identification test: The surface quality on the faces and sides of the samples should be sawn, ground or polished.
• Technological test: The surface quality of the faces and sides of the samples must be carried out according to the application (e.g. sawn, roughened, polished, sanded, rubbed, flamed, bush hammered, split).

The dimensions of the samples are determined in this standard as follows:

• Identification test: The samples are square sheets with a surface of 200 mm plus/minus 1 mm and a thickness of 30 mm plus/minus 3 mm. The maximum permissible deviation in squareness is 2 mm.
• Technological test: Samples are square plates with the following dimensions:
  • 20mm x 65mm for thickness from 200mm to 200mm
  • 65mm x 80mm for thickness from 300mm to 300mm

The dowel hole breaking load value is considered an important design parameter in the installation of natural stones, which are preferred as cladding materials in high-rise buildings, on building facades due to reasons such as their aesthetic appearance, ease of production and assembly, and resistance to external climatic conditions. When the basic mechanical strength values ​​of natural stones to be used as cladding in buildings are known, the dowel hole breaking load values ​​can be determined quickly and reliably using a few equations.

Briefly, samples are tested using a calibrated loading apparatus in accordance with the method described in standard EN 13364, although the test can also be performed in a saturated condition.

Our organization has a strong staff that closely follows the developments in the world in the field of science and technology and constantly improves itself. Among the numerous test, measurement, analysis and evaluation studies provided for businesses in various sectors, there are also test services in accordance with the standard "EN 13364 Natural stone test methods - Determination of breaking load in dowel holes".