Rock testing

Once opened, the sample is photographed, examined, and described to allow preliminary characterization.
During this phase, the following are determined:

• The sample’s lithology
• Particle size, assessed visually or with the aid of lenses and a microscope
• The presence of carbonates, using a 10% HCl solution

The procedure complies with the following standards:
UNI EN 932-3
UNI EN 932-1

Natural Water Content is one of the fundamental physical properties of great geotechnical interest. The test consists of determining the water content of a rock sample in its as-received condition.

The procedure complies with the following standards:
ISRM 1979, part 1

A physical property that defines the mass of rock per unit volume. It can be used as an index of the material’s density in natural conditions.

The procedure complies with the following standards:
ISRM 1979, part 1

This physical property can be defined as the average value of the unit weight of the solid component. Determining this property allows the calculation of various other parameters useful for the classification and geotechnical characterization of rocks.

The procedure complies with the following standards:
ISRM 1979, part 1

Porosity and void ratio are two important parameters for characterizing a material. Porosity expresses the percentage of empty space present within a given volume of material, while the void ratio is the ratio between the volume of voids and the volume of solids.

The procedure complies with the following standards:
ISRM 1979, part 1

This procedure clearly defines the methods to be followed by the Technicians listed in the Quality Manual for conducting the test.
The test allows for the determination of the uniaxial compressive strength of a cylindrical rock sample, and optionally the determination of compressibility parameters: tangent and secant modulus of deformation, and Poisson’s ratio.

Unlike the shear test, the uniaxial compression test is generally aimed at the classification of intact rocks.

The Brazilian test allows the indirect determination of the tensile strength of a rock. The validity of this method is based on the experimental fact that a rock subjected to a plane stress state breaks when one of the principal stresses is tensile, while the compressive stress does not exceed three times the tensile stress.

The testing method complies with the following standards:
ASTM D 3967-23
ISRM 1978

The test allows the determination of the peak and residual shear strength of a rock material as a function of the normal stress applied on the shear plane. The results are mainly used in limit equilibrium analyses for the stability assessment of rock slopes. Shear strength measurements are typically performed on planes of weakness within the rock mass, such as joints, fracture planes, or other discontinuities.

The testing method complies with the following standards:
ISRM – 1974
ASTM D5607 – 95

The test allows the determination of the uniaxial compressive strength of a cylindrical rock sample. Unlike the shear test, the uniaxial compression test is generally aimed at the classification of intact rocks.

The testing method complies with the following standards:
ISRM 1979
ASTM D7012 – 10

The test allows the determination of the uniaxial compressive strength of a cylindrical rock sample and the measurement of compressibility parameters:

• Tangent modulus of deformation
• Secant modulus of deformation
• Poisson’s ratio

The testing method complies with the following standards:
ISRM 1979
ASTM D7012 – 10

The test allows the determination of the triaxial compressive strength of a cylindrical rock sample. Unlike the shear test, the triaxial compression test is generally aimed at the classification of intact rocks.

The testing method complies with the following standards:
ASTM D2664 – 95
ISRM Recommendations – 1983

The test aims to determine the flexural strength (breaking load) of rock materials.

The testing method complies with the following standard:
UNI 9724:1990 Part 5a

Imbibition tests on rocks, or more precisely the determination of the imbibition coefficient, are laboratory tests that evaluate a rock’s ability to absorb water. The test calculates the ratio between the increase in weight of a rock sample after immersion in water and its original dry weight.

The testing method complies with the following standards:
Royal Decree No. 2234 dated 16/11/1939 – Article 7
CNR XXVI No. 137-1992

reeze–Thaw Resistance tests evaluate the durability of rock subjected to repeated cycles of freezing and thawing, simulating environmental conditions that can cause damage to rock materials.

The testing method complies with the following standards:
EN 1342:2000
Royal Decree No. 2234 dated 16/11/1939

The measurement of P-wave (Vp) and S-wave (Vs) velocities on rock samples is a fundamental method for characterizing the elastic properties of geological materials. The velocities of these waves depend on factors such as mineral composition, density, porosity, and fracturing of the sample.

The testing method complies with the following standards:
ISRM Recommendations – 1983

The preparation of cylindrical specimens, essential for performing mechanical tests, is a delicate and critically important phase. The reliability of test results (strength, compressibility, deformation parameters, etc.) depends on the correct preparation of specimens, which varies according to the type of material.

The testing method complies with the following standards:
ISRM 1979