Testing Ivaylovgrad Gneiss for Construction Purposes

Rock construction materials’ testing is carried out to assist in the selection of suitable materials for every construction project. In addition, it ensures compliance with all regulatory standards.

качество на ивайловградския гнайс

Testing is carried out by specialized companies such as SGS Bulgaria and is  a highly sought – after service from Bulgarian and foreign clients, regarding their construction projects.

Testing of the rock building materials provides valuable data, regarding these materials, which can help at the initial stage of selection. Thus, the choice of materials for construction is done early enough and based on reliable data.

Furthermore, if the materials have already been chosen, testing at the initial phase can eventually lead to changes being made which can help you avoid problems in the future.

Testing of rock materials by SGS Bulgaria is performed in a number of Bulgarian laboratories, linked in a global network. Another convenience is the deployment of a mobile laboratory at the construction site, in order to provide continuous tests or tests on request. This will ensure the quality of the materials that will be tested.

While carrying tests of rock materials, we should check the rocks for the following qualities: density,

  • absorption
  • deformity
  • shear strength
  • concentrated load
  • pressure strength
  • tensile strength
  • water content and permeability
  • water storage capacity and water saturation
  • ratio of porosity
  • coefficient of Poisson
  • modulus of elasticity of rock materials (Yang module)

Testing of Gneiss from Ivaylovgrad, Supplied by the Company Valmarg Stone

Testing of the gneiss from Ivaylovgrad, in the form of slabs for external paving, were carried out during the period November 2011-January 2012 in the Construction Testing Center in Sofia.

Three tests were conducted to establish the conformity of this material in regards to the standards and norms of rock materials for building purposes.

Here is the exact protocol for the results from the tests: A certificate for testing of gneiss material from Valmarg Stone.

After conducting the first test, the following qualities of gneiss plates were verified:

  • resistance to frost;
  • bending strength under concentrated load;
  • water absorption at atmospheric pressure.

For testing purposes, 20 prismatic test fixtures, with dimensions of 50 x 50 x 300 mm and 6 cubes, with a length of 50 mm for each side, were used.

The test concluded that:

  • there were no variations in the properties of the gneiss plates;
  • no rounding of the edges of the plates, cracks, dents, breaking, fragmentations were observed

Further testing was conducted on the abrasion resistance of the material by the company “Valmarg Stone”.

Testing was carried out on plates with dimensions of 70 x 70 x 30 mm.

Furthermore, Böhm method and a wide grinding wheel were also used to check gneiss for abrasion resistance. Testing has shown that its resistance to abrasion corresponds to the standards.

Ivaylovgrad gneiss was subjected to another test, for which 15 kg stone pieces were used. Testing was performed with “Deval” type drums to determine the erosion of the material. The results indicated full compliance to the applicable standards.

All checked characteristics of the gneiss from Ivaylovgrad have excellent performance indicators; they have established gneiss as a highly sought- after material not only on our domestic market, but also abroad.

Gneissic tests, offered by the company Valmarg Stone, conducted in the Construction Testing Center – Sofia, are proof of the high quality of this material and ensure its excellent resistance to frost, its bending strength, its impermeability, its resistance to abrasion and erosion.

Those qualities make this kind of rock material extremely suitable for construction purposes.