Implementing ASTM C1735 into Conventional Methods for Assessing Durability of Sealants
Christopher C. White, Kelly Allore, Larry Carbary
The recent introduction of ASTM C1735 allows a durability assessment of a sealant joint assembly without incurring destruction. Conventional testing of sealant assemblies to ASTM C1135 or ISO 8339 for assessing durability is to fabricate sealant joint assemblies and then subject them to destructive testing after various exposures and durations. The stress strain curves are then compared to each other over time to draw conclusions on durability. This results in the fabrication of many assemblies when data points are the average of three or five assemblies. The ASTM C1735 method allows one to reuse the specimens to track changes in modulus with various exposures because it does not take the specimens to failure. The ASTM C1735 method takes the specimens to 25% maximum strain, typically well below the ultimate destructive strain of the assembly. One can then draw conclusions on the specimen durability performance based on tracking the data and determining modulus changes with time. This paper reports the data of sealant test assemblies built and tested to ASTM C1735 and subjected to static exposures of room temperature, UV florescent exposures according to ASTM C1442, room temperature water immersion, 50C water immersion, and 88C heat aging. The durability is assessed by visual inspection and change in modulus with exposure. The results show that ASTM C1735 is a viable method to assess durability and reduce the number of specimens fabricated for a specific study. A comparison is made between destructive testing and C1735 testing noting the advantages and disadvantages of each method.
Sixth Symposium on the Durability of Building and Construction Sealants and Adhesives