The ASTM standards define a laboratory procedure for assessing the degree of slump of a sealant when utilized in a vertical joint of a structure. This method of testing is specifically intended for the determination of a sealant’s ability to maintain its shape and consistency when applied in a vertical joint. The test is designed to ensure that the sealant will not sag or slump excessively after application, as this can compromise its ability to effectively seal the joint. The procedure is commonly referred to as the “slump test” and is widely used in the construction industry to evaluate the quality of sealants.
Significance and Use for Slump Test of Sealant
When applying sealant in a vertical joint, excessive slump or sag can lead to issues such as an improper bead shape or insufficient sealant thickness in the finished joint. To address this problem, a test method has been developed to measure the amount of slump present in the sealant during application. However, it is important to note that the results of this test method only evaluate this particular characteristic of the sealant’s application. They do not provide any information about the sealant’s performance or effectiveness after it has been installed. Therefore, it is necessary to take additional factors into account when assessing the overall quality of a sealant.
Test Apparatus
The equipment available for use in this task includes a Flow Test Jig, a Gravity Convection Oven that can be temperature-controlled to maintain a steady temperature of 50±2°C (122±3.6°F), a Steel Spatula, a Plastic Scraper, and an ordinary 114 by 114-mm (4 1⁄2by 4 1⁄2-in) plastic tile. These tools will be used in the execution of the assigned task.
The Flow Test Jig will be utilized in the testing process, while the Gravity Convection Oven will serve as a temperature-controlled environment to ensure consistency during the testing. A Steel Spatula will also be used to manipulate and handle samples, while a Plastic Scraper will be used for scraping and cleaning tasks. Lastly, an ordinary plastic tile with dimensions of 114 by 114-mm (4 1⁄2by 4 1⁄2-in) will be utilized as a standard platform for executing the task.
Test Reagent
A solvent, specifically methyl ethyl ketone, is a substance that has the ability to dissolve or disperse other substances, typically liquids or gases. It is commonly used in various industries, such as manufacturing, painting, and printing, due to its effectiveness in dissolving different types of materials. Methyl ethyl ketone, or MEK for short, is a colorless liquid with a sweet odor and a low boiling point. It is considered a highly volatile organic compound and can be hazardous if not handled properly. MEK is often used as a solvent for acrylic and vinyl resins, as well as adhesives, coatings, and rubber-based materials. It is also used as a cleaning agent for machinery and equipment.
Conditioning
Both the test jig and the sealant need to be subjected to a specific condition for a minimum of 5 hours. The condition required is maintaining a temperature of 23±2°C (73.4±3.6°F). It is crucial that both the test jig and the sealant are exposed to this temperature for the specified time frame to ensure optimal performance. Any deviation from this condition could potentially impact the results of the test and the effectiveness of the sealant. Therefore, it is essential to adhere to the specified temperature and time requirements to achieve reliable results.
Test Procedure
The process of preparing a test jig for sealant testing involves several steps. Firstly, the jig is thoroughly cleaned with a solvent and placed on a level table with the front face upwards. The plunger is then depressed to the limit of its travel.
Next, mixed and conditioned sealant is placed in the jig cavity and leveled flush with the surface of the block using a plastic scraper held at a 45° angle. Care must be taken to avoid the formation of air pockets, particularly near the surface of the plunger. Once the sealant has been leveled, the area around the cavity is cleaned with the plastic scraper and a cloth.
A jig is then placed immediately on its end, and the plunger is advanced gently to one-half of its maximum travel or 4.75 mm (3⁄16 in). This creates a solid cylinder of caulking or sealant that is 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.
The jig is then placed immediately in a vertical position on a level shelf in the oven and conditioned for 30 minutes at 50±2°C (122±3.6°F), taking care to avoid any movement or vibration of the oven during this period. After the 30-minute conditioning period, the reading is taken to the nearest 0.2 mm (0.01 in) of the maximum point of flow of the compound.
The jig is then cleaned and reconditioned as specified above, and the process is repeated with another specimen of sealant.
Test Report
In order to record data on the specimens, two tests are conducted for each of them. During these tests, readings are taken of the slump, which is a measure of the consistency and fluidity of the material being tested. The readings obtained from each test are recorded, and the average value of the two readings is also calculated and recorded. This process allows for a more accurate and reliable representation of the slump data for each specimen.
Test Precision
The precision statements for a particular test method were obtained from two separate inter-laboratory tests. In one test, five different laboratories tested two oil-based sealants in triplicate. The results of this test were recorded in a table. In the other test, four laboratories tested four solvent release sealants, each in duplicate.
The repeatability for oil-based sealants was determined to be a variation of up to 1.07 mm (0.042 in) at a 95% confidence interval. This variation refers to the amount of difference that can be expected between two test results obtained by the same operator on the same material. The reproducibility for oil-based sealants was also determined to be a variation of up to 1.93 mm (0.076 in) at a 95% confidence interval. This variation refers to the amount of difference that can be expected between two test results obtained by different operators in different laboratories on the same material.
It should be noted that the data for oil-based sealants was generated through triplicate testing, whereas the test method specifies only duplicate testing. As a result, duplicate testing may yield more variable results than what is indicated in the table above.
The repeatability for solvent-release sealants was found to be a variation of up to 1.35 mm (0.053 in) at a 95% confidence interval. This variation refers to the amount of difference that can be expected between two test results obtained by the same operator on the same material. The reproducibility for solvent-release sealants was also determined to be a variation of up to 1.88 mm (0.074 in) at a 95% confidence interval. This variation refers to the amount of difference that can be expected between two test results obtained by different operators in different laboratories on the same material.
FAQs
What is the objective of the slump test of sealant?
The purpose of the given laboratory procedure is to determine the slump of a sealant used in a vertical joint of a structure. This test method is specifically designed for measuring the extent to which the sealant material undergoes deformation or sinking when placed in a vertical joint. The procedure provides a standardized approach for evaluating the quality and performance of sealants used in construction applications. The test results can help determine the suitability of a sealant for a specific job, and assist in selecting the appropriate sealant for a particular application. Overall, this test method is an essential tool for ensuring the quality and reliability of sealants used in construction.
What are the significance and use of the slump test on sealant?
When a vertical joint experiences excessive sealant slump or sag, it can result in an inadequate sealant thickness or improper bead shape in the final joint. To address this issue, a test method has been developed that measures the extent of slump in the sealant. However, it is important to note that this test method only evaluates the application characteristic of the sealant and does not provide any indication of its performance capability after installation. Therefore, other factors must be considered when assessing the long-term effectiveness of the sealant in maintaining a secure joint.
Which is the test reagent used in the slump test of sealant?
Methyl ethyl ketone (MEK) is a common organic solvent that is widely used in the production of plastics, textiles, and other industrial materials. It is a colorless liquid with a sweet odor, and it is highly flammable. MEK is a powerful solvent that is capable of dissolving many different types of materials, including resins, adhesives, and coatings.
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