In construction, sealants play a crucial role in maintaining structural integrity. One essential aspect is determining the slump of sealants when applied in vertical joints. This test, aligned with ASTM standards, aims to gauge the degree of slump and sag in these joints.
Excessive slump or sag in a vertical joint can lead to improper bead shape and inadequate sealant thickness. These issues may compromise the integrity of the joint. The slump measurements, as outlined in this method, specifically assess these application characteristics. However, it’s important to note that these measurements do not predict the long-term performance of the sealant after installation.
To conduct the slump test effectively, specific tools are needed. These include a Flow Test Jig, a Gravity Convection Oven with temperature control, a Steel Spatula, and a Plastic Scraper, akin to an ordinary 114 by 114-mm plastic tile.
| Test Apparatus | Description |
|---|---|
| Flow Test Jig | Ensures controlled testing conditions |
| Gravity Convection Oven | Maintains a stable temperature for accurate results |
| Steel Spatula | Facilitates precise application of sealant |
| Plastic Scraper | A common plastic tile used for leveling the sealant |
The use of a solvent, such as methyl ethyl ketone, is crucial for the testing process. It aids in cleaning and preparing the equipment for accurate readings.
Both the test jig and the sealant need to be conditioned for at least 5 hours at 23±2°C (73.4±3.6°F) to ensure stable and consistent testing conditions.
Record the slump readings from each test for every specimen and calculate the average value for accurate assessment.
Precision in this test method is derived from inter-laboratory tests. For oil-based sealants, both repeatability and reproducibility data are crucial.
| Precision Data | Variation at 95% Confidence |
|---|---|
| Repeatability for Oil-Based | 1.07 mm (0.042 in) between two test results |
| Sealants | by the same operator on the same material |
| Reproducibility for Oil-Based | 1.93 mm (0.076 in) between two test results |
| Sealants | by different operators in different labs |
It’s noteworthy that the data for oil-based sealants was generated through triplicate testing, whereas the test method specifies only duplicate testing. Duplicate testing might yield more variable results than indicated.
For solvent-release sealants, similar precision data applies:
| Precision Data | Variation at 95% Confidence |
|---|---|
| Repeatability for Solvent-Release | 1.35 mm (0.053 in) between two test results |
| Sealants | by the same operator on the same material |
| Reproducibility for Solvent-Release | 1.88 mm (0.074 in) between two test results |
| Sealants | by different operators in different labs |