1.1 This test method covers the determination of the competence and aesthetic effects of Freeze/thaw cycles on natural stones by Rapid Freezing and Thawing by two different procedures: Procedure A, Rapid Freezing and thawing in fresh water and Procedure B, Rapid Freezing and Thawing in salt (saline) solutions. Both procedures are intended for use in determining the quantitative and qualitative resistance of natural stone to the freezing-and-thawing cycles specified in this procedure.
thawing cycle; TPS specimen; grading chart; defect weighted value matrix; freeze-thaw grade; weighted value; freeze-thaw grade value; bedding separation; filtrate particulates; temperature probe specimen
Rational for an ASTM Freeze-Thaw Standard for Stone
1. ASTM C 18 has not formally adopted any ASTM Committee’s Test Method for conducting environmental testing of Dimensional Stone for Freeze-Thaw cycling.
2. The “industry accepted ASTM C666” Freeze-Thaw cycling test does not allow for a natural material to be used in many thermal environments due to it’s “Pass/Fail” perception.
3. ASTM C666 is used to determine adjustments to Concrete mixtures to ensure resistance to environmental conditions of Freeze-Thaw cycling. Whereas Natural Dimensional Stone cannot be adjusted, this makes the use of C666 inappropriate. Therefore, we a new standard appropriate to the stone industry.
4. The use of this proposed standard introduces the industry norm of ‘Grading’ that is used with other construction materials (Ceramic Tile, Glass, Carpeting, Flooring, Wood, etc.) to determine the appropriate use of the stone. The Pass/Fail of ASTM C666 is detrimental to promoting the widest and/or most appropriate use of Natural Dimensional stone.
5. This proposed Standard enhances the Dimensional Stone industry and enables all users to evaluate the tested material equally regardless of geological classification.
Per the charter of the C18 Committee, the Committee’s Scope is to promote knowledge to stimulate research, and to develop specifications, methods of test, definitions and nomenclature, and recommended practices relating to dimension stone.
The resistance of Stone to Freeze-thaw conditions is a significant area of testing not currently addressed by the C18 Methods of Test Standards. To overcome this lack of direction, the Stone Industry has adopted an informal and nonuniform solution by using the ASTM C666 (Concrete) Standard from the ASTM C09 Committee, ASTM C67 (Bricks) from the C15 committee and ASTM D5312 (Soil Erosion) from the D18 committee.
The most commonly used procedure has been the C666 test method which was written for concrete specimens to allow for addressing the freeze-thaw concerns of various concrete mixtures with changes in aggregate and admixture factors, none of which are relevant to the testing of stone.
While this is a common test procedure for Dimensional Stone, it does not appear that an official adoption of the C666 standard for use in stone freeze-thaw testing has been conducted with proper vetting and supporting documentation and or guidance from the C18 committee on how to adapt it to the testing of stone.
The use of concrete standards for stone fails to address the unique needs of the Dimension Stone industry. The C666 standard is designed to test the concrete parameters of admixtures, curing time of the material, the effect of coarse aggregates on freeze resistance, air-void entrainment, field vs. lab prepared specimens, etc. This testing and evaluations allow for the adjustment of the concrete mixture to design a freeze-thaw resistant concrete mixture for use is a specific application. None of which really relates to the testing of stone. Whereas concrete mixtures compositions can be adjusted, natural stone components cannot.
On the other hand, the parameters important to the dimension stone industry are aesthetic appearance, change in competence of the stone in relatively thin specimens compared to massive concrete pours, effect of de-icing salts on paving, bedding plane orientation, installation orientation, etc.
And just as the Committed determined that using concrete’s ASTM C 295 for petrographic procedures did not address all the aspects of Dimensional stone, for which ASTM C1721 was developed, this proposed new Standard addresses the unique needs of the Dimension Stone industry. It allows for testing the stone in a rigorous method revealing the stone’s various vulnerabilities. This Standard allows enough data to be collected to apply a system for grading of the stone tested. The grading gives the specifiers and users of dimensional stone a method to determine appropriate use of a stone type in specific applications and enables complete building envelope design. It also allows quarries to understand appropriate use for the materials found in their quarry with a grading system that helps direct the sale of their stone materials to the correct markets.
Additionally, by using ASTM C1721 Petrographic support, a Dimensional stone can be investigated at the microscopic level to actually examine the affects of the thermal freeze thaw cycles on the samples.
The results of this testing procedure and grading system give enough data points that all involved can now make an informed decision if the stone fits the unique job site conditions of climate, application/installation of the stone, tolerance of the customer to potential defects, and the nature of the defects. By defining the nature of the defects, it also allows adjusting installation to protect the stone. By grading the stone, it gives a way for both architects and quarries to adapt the stone in question to the best use and avoids the simplistic pass/fail as the only option.
The two different exposure procedures, using fresh water and saline solutions, of this procedure also eliminates the informal use of non-stone standards from other ASTM committees to perform saline testing on dimension stone.
The title and scope are in draft form and are under development within this ASTM Committee.
Date Initiated: 03-11-2022
Technical Contact: Frank Strickland