Test Method for Slump of Sealants

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The test method for slump of sealants covers a laboratory procedure for determining the degree of the slump of a sealant when used in a vertical joint in a structure.

This method of testing is as per the ASTM standards.

Significance and Use for Slump Test of Sealant

Excessive sealant slump or sag in a vertical joint may cause improper bead shape or inadequate sealant thickness in the completed joint. 

As described in this test method, slump measurements serve to evaluate only this application characteristic. However, they do not predict the performance capability of the sealant after installation.

Test Apparatus

1. Flow Test Jig
2. Gravity Convection Oven having a temperature-controlled at 50±2°C (122±3.6°F). 
3. Steel Spatula
4. Plastic scraper, an ordinary 114 by 114-mm (4 1⁄2by 4 1⁄2-in) plastic tile.

Test Reagent

Solvent- such as methyl ethyl ketone.

Conditioning

The condition for both the test jig and the sealant is required for at least 5h at 23±2°C (73.4±3.6°F).

Test Procedure

1. The test jig is cleaned thoroughly with the solvent, then placed on a level table with the front face upward, and the plunger is depressed to the limit of its travel.
2. The mixed, conditioned sealant is placed in the jig cavity, and the sealant is leveled flush with the surface of the block.
3. This is carried out by one gentle upward stroke of the plastic scraper held at a 45° angle. The formation of air pockets is avoided in the sealant, especially near the surface of the plunger.
4. The area around the cavity is cleaned with the plastic scraper and a cloth; then, a jig is placed immediately on its end, and the plunger is advanced gently to one-half its maximum travel, or 4.75 mm (3⁄16 in). 
5. This leaves a solid cylinder of caulking or sealant 38.1 mm (11⁄2 in) in diameter and 4.75 mm (3⁄16 in) thick, ready to flow down the face of the instrument.
6. The jig is placed immediately in a vertical position on a level shelf in the oven and conditioned for 30 min at 50±2°C (122±3.6°F), while taking care to avoid any movement or vibration of the oven during this period.
7. At the end of the 30 min period, take the reading to the nearest 0.2 mm (0.01 in) of the maximum point of flow of the compound.
8. Clean the jig and recondition it as specified above.
9. Repeat the steps from 1-7 with another specimen of sealant.

Test Report

The slump readings obtained in each of the two tests for each specimen and the average value are taken down. 

Test Precision 

The precision statements for this test method are obtained from two separate inter-laboratory tests. In one, five laboratories tested two (2) oil-based sealants in triplicate. The results of the lab tests are given in the table below. In the other, four laboratories tested four (4) solvent release sealants, each in duplicate.

1. Repeatability for Oil-Based Sealants- At 95% confidence, a variation of as much as 1.07 mm (0.042 in) can be expected between two test results obtained by the same operator on the same material. 
2. Reproducibility for Oil-Based Sealants- At 95% confidence, a variation of as much as 1.93 mm (0.076 in) can be expected between two test results obtained by different operators in different laboratories on the same material.

The data for oil-based sealants was generated by testing each sealant in triplicate, whereas the procedure in this test method specifies only duplicate testing. Duplicate testing may yield more variable results than indicated in the table above.

1. Repeatability for Solvent-Release Sealants- At 95% confidence, a variation of as much as 1.35 mm (0.053 in) can be expected between two test results obtained by the same operator on the same material.
2. Reproducibility for Solvent Release Sealants- At 95% confidence, a variation of as much as 1.88 mm (0.074 in) can be expected between two test results obtained by different operators in different laboratories on the same material.

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