Our newly refurbished Natural Stone Testing Laboratory has allowed us to expand our materials testing services as well as increase production and better improve on our turnaround of samples. Our Natural Stone Laboratory is equipped to test for a comprehensive range of geological, physical and mechanical properties on rock, natural stone and armour stone.
Natural Stone Tests by CTS
| Test | Method | What it shows |
| Abrasion Resistance | BS EN 14157 | This test simulates long term wear effects on natural stone products (e.g. pedestrian trafficked areas) using an abrasive flow medium and abrasion wheel. |
| Breaking Load and Dowel Hole | BS EN 13364 | This test gives a breaking load of a pin which is grout anchored into a natural stone specimen. Typically done on proposed cladding stone destined for interior and exterior fixings. |
| Flexural Strength under concentrated load | BS EN 12372 | This test gives a flexural strength from a single load point. Typically done on proposed cladding stone for ventilated facades. This test can also be done in conjunction with the frost resistance test to determine strength deterioration over a cyclic temperature pattern. |
| Flexural strength under constant moment | BS EN 13161 | This test gives a flexural strength from two load points. Typically done on proposed cladding stone for ventilated facades. This test can also be done in conjunction with the frost resistance test to determine strength deterioration over a cyclic temperature pattern. |
| Frost Resistance | BS EN 12371 | This test subjects natural stone specimens to a cyclic temperature pattern of freezing air and thawing in water. Specimens are either “Scored” visually during test or tested mechanically (Flexural strength or uniaxial compressive strength) to determine performance. |
| Petrographic Examination | BS EN 12407 | This test involves subjecting a specimen of the natural stone to visual and low power microscopy. The analysis gives information of constituents present in the stone in addition to any features of interest. This could include minerals which give rise to discolouration’s in the stone. |
| Point Load Strength Test (Rock) | IRSM | This test is used to classify the strength of rock materials on samples with little to no preparation. This test can also be used to predict strengths with correlated specimens (Uniaxial compressive strength). |
| Real and Apparent Density (total and open porosity) | BS EN 1936 | This test gives a density of stone and the porosity (Open voids ratio to volume). The density can be used to determine weight per volume for design purposes. The porosity can give an indication of the absorption properties. High porosity materials may also exhibit deterioration under frost cycling and salt crystallisation testing. |
| Resistance to Salt Crystallisation | BS EN 12370 | This test involves cycling specimens between an chemical solution, Air drying and then cooling. This cycle is run 15 times and then reported as a % Mass change. This test can be used in conjunction with the Frost Resistance test to determine durability over time in open weather conditions. |
| Slip Resistance by pendulum tester | BS EN 14231 | This test involves using a swing mounted rubber slider to determine the slip resistance of a surface. The higher the number, the less slippery the surface is. This can be done over different surface finishes (Polished, honed, sandblasted) to determine suitability for pedestrian areas. This test can also be conducted IN FIELD on natural stone products already laid. |
| Water absorption at atmospheric pressure | BS EN 13755 | This test gives a water absorption by weight (%) of natural stone. This can be used to calculate the saturated weight of the natural stone for use in the design phase in addition to indicating expected water addition for durability purposes (e.g. material alteration via mechanically or chemically). |
| Water absorption coefficient by capillarity | BS EN 1925 | This test gives a water absorption by unit area of natural stone in contact with water. This can be used in conjunction with other tests to determine suitability of the stone for the intended use (E.g. cladding, tiles etc). |
| Uniaxial compressive strength | BS EN 1926 | This test gives a compressive strength (MPa) of either cube or cylindrical specimens. This can be used in the design stage for structural or load bearing elements. This can also be used in addition to the frost resistance test to determine performance over time when exposed to cyclic freezing and thawing. |
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Frequently Asked Questions
Why is natural stone testing important?
Natural stone testing is crucial for understanding the geological, physical, and mechanical properties of stone materials planned for construction or found on existing sites. These tests enable informed decision-making in the design stage by assessing the stone’s potential durability and suitability for pavements, floors, steps, and other locations likely to experience foot traffic.
What is a petrographic examination?
In natural stone testing, petrographic examination uses microscopes to determine a sample’s mineralogical and chemical characteristics. Samples for petrographic examination can be extracted from cores or lump samples and are usually prepared with resin.
How do you test the water absorption of stone?
Water absorption analysis is a natural stone testing method used to identify the water absorption level by weight (%) or unit area of the natural stone in contact with water. For water absorption by weight, a stone sample is cut to a specified size, kiln-dried, and weighed before being immersed in water and weighed again.
What is the pendulum test for slip resistance?
The pendulum test for slip resistance is an established natural stone testing procedure that measures the dynamic friction of the surface of the stone. This test requires a slider to be mounted at the end of a pendulum arm, imitating the action of slipping.
The results are measured under a “Pendulum Test Value” (PTV) and can be used to determine the suitability of the material for pedestrian areas.