Tile Testing Basics

ASTM C370: Moisture Expansion
Changes in physical dimensions of tile due to exposure to water and water vapor are determined by this method. Such dimensional changes may influence the integrity and stability of an installation. Tile specimens are tested for elongation of size due to rehydration by autoclaving.

Three (3) test pieces of size 1" × 4", cut from the center of whole tiles, are required for one test. The test pieces are measured with a micrometer and subjected to steam under pressure in an autoclave for five hours. After autoclaving, the test pieces are dried to a constant mass and measured again with a micrometer to determine expansion due to moisture exposure.

ASTM C373: Water Absorption
In this test method, water absorption of tile specimens is calculated based on a five hour boiling water method. This test is used to determine the degree of maturation of the ceramic tile body or for evaluating structural properties that may be required during installation.

Five (5) test pieces, weighing at least 50 grams and cut from the center of whole tiles are required for one test. Test pieces are dried to a constant mass, weighed and placed in boiling water for five hours then soaked in room temperature water for 24 hours. Wet weights are determined after soaking for 24 hours. The difference in weights of test pieces before and after boiling is used to calculate percent water absorption.

ASTM C424: Crazing Resistance
This method evaluates resistance of tile specimens to crazing. Test specimens are subjected to heat and steam under pressure and evaluated for crazing failure. Test pieces are observed visually with the aid of oblique lighting and inks or dyes to identify crazing failures.

Ten (10) whole tiles having facial dimensions of 6" × 6" or 6" × 8" or less are required for one test. For larger tiles, five (5) whole tiles are required which are cut and tested.

ASTM C482: Bond Strength
In this test method, the bond strength between tile specimens and a mortar bed when bonded with portland cement paste is determined. The test method may be used to evaluate glazed ceramic wall tile, ceramic mosaic tile, quarry tile, pressed floor tile, and porcelain tile. This method also includes both face-mounted and back-mounted tile.

Five (5) whole tiles are required for a single test. The test specimens are bonded to a mortar bed and cured for seven days to create the test assembly. Once cured, the bond strength is assessed by applying a shear load force until bond failure. The results are reported in pounds per square inch (psi) units and the nature of failure is also included in the test report.

ASTM C484: Thermal Shock Resistance
Resistance of tile specimens to thermal shock under normal conditions of use is determined. The test pieces are subjected to alternating low and high temperatures and visually observed for defects with the aid of inks or dyes.

Ten (10) whole tiles are required for a single test. The test pieces are subjected to ten cycles of alternating temperatures of 15 ± 5˚C and 145 ± 5˚C. Depending on the water absorption value of the test pieces, the test method includes two procedures, with or without immersion in water. The test pieces are inspected for damage as a result of temperature cycling.

ASTM C485, ASTM C499, ASTM C502: Warpage, Facial & Thickness Dimensions, and Wedging
In these test methods, diagonal and edge warpage (flatness), wedging (squareness), facial dimensions and thickness of ceramic tiles are determined. The diagonal warpage, edge warpage, and wedging are all reported as a percentage. Facial and thickness dimensions are reported in inches.

ASTM C609: Measurement of Light Reflectance Value & Small Color Differences
Light Reflectance Value (LRV) and small color differences between pieces of ceramic tiles are determined. This method may be applied to glazed or unglazed ceramic tiles. LRV may be measured for either solid colored tile or tile having multicolored, speckled, or textured surfaces. LRV and color difference of tile specimens are measured using a spectrophotometer with specific requirements.

ASTM C648: Breaking Strength
In this test method, breaking strength of glazed ceramic wall tile, ceramic mosaic tile, quarry tile, pressed floor tile, and porcelain tile is determined. The tile specimens are evaluated for meeting requirements which may appear in tile specifications.

ASTM C650**: Chemical Resistance
In this test method, changes due to prolonged exposure of ceramic tiles to chemicals are determined. Chemical substances in common household cleaning products, swimming pool chemicals, as well as other severe chemicals are used to determine resistance to damage by a chemical.

ASTM C674: Modulus of Rupture
Modulus of rupture of tile specimens is determined by this test method. The test method is applicable to both glazed and unglazed tiles.

ASTM C1026: Freeze-Thaw (up to 300 cycles)
In this test method, resistance of tile specimens to repeated cycles of freezing and thawing is evaluated. The test functions as a guide for selection of tiles for exterior installations and suitability to environmental conditions where freezing and thawing may occur.

ASTM C1027: Surface Abrasion
In this test method, resistance of tile surfaces to visible surface abrasion is measured.

ASTM C1028: Static Coefficient of Friction
In this test method, ceramic tile are measured for static coefficient of friction under both wet and dry conditions. A horizontal dynamometer pull meter and Neolite heel assemblies are used to determine the static coefficient of friction (SCOF).

ASTM C1243: Deep Abrasion
Unglazed ceramic tiles used for floor coverings are evaluated for resistance to deep abrasion using this test method. Abrasion is achieved applying a rotating disc and a continuous flow of abrasive grit to the tile surface.

ASTM C1243: Deep Abrasion
Unglazed ceramic tiles used for floor coverings are evaluated for resistance to deep abrasion using this test method. Abrasion is achieved applying a rotating disc and a continuous flow of abrasive grit to the tile surface.

ASTM C1378: Staining Resistance
In this test method, resistance of ceramic tile surfaces to staining is determined. Staining is achieved by prolonged exposure of the tile surface to test solutions and dry staining agents. Tiles are visually evaluated after the staining agent has been cleaned off using a combination of cleaning procedures.

ISO 10545-8: Linear Thermal Expansion
Coefficient of linear thermal expansion of ceramic tile is determined using this test method. Linear thermal expansion coefficient is determined for a temperature range from ambient temperature to 100˚C.

ISO 10545-9: Thermal Shock Resistance
In this test method, resistance to thermal shock of any type ceramic tiles is determined under normal conditions of use. Thermal shock is achieved by subjecting whole tiles to ten cycles between the temperatures of 15˚C and 145˚C.

ISO 10545-10: Moisture Expansion
In this test method, moisture expansion of ceramic tiles is determined. Moisture expansion is achieved by heating tiles in boiling water and measuring the proportional change in length.

Mohs: Scratch hardness
In this test method, the resistance to scratching of ceramic tile is evaluated using the Mohs scale of mineral hardness. The ceramic tile surface is scratched using the mineral from each hardness class.

ISO 10545-14: Stain Resistance
In this test method, surfaces of ceramic tiles are tested for resistance to stains. Resistance is assessed after the staining agents are in contact with the tile surface for 24 hours.

ISO 10545-13: Chemical Resistance
In this test method, chemical resistance of ceramic tiles at room temperature is determined. Tile specimens are subjected to various chemicals representative of normal exposure conditions and visually assessed after a specified period of time.

ISO 10545-11: Crazing Resistance
In this test method, resistance of the tile specimens against crazing failure is determined by subjecting whole tiles to steam under pressure in an autoclave.