The latest gypsum-based self-leveling standard JC Y1023-2021 important instructions include the following aspects:
1.Definition and classification: gypsum-based self-leveling mortar refers to the ground plastering material with gypsum as the main cementitious material, which can be divided into ordinary type and quick-drying type according to its technical properties and application methods.
2.Raw material requirements: The raw materials of gypsum-based self-leveling mortar should meet the requirements of relevant standards and regulations, of which gypsum should comply with the provisions of GB T 176, cement should comply with the provisions of GB T 175, and aggregate should comply with the provisions of GB T 14685.
3.Technical requirements: The technical requirements of gypsum-based self-leveling mortar include compressive strength, flexural strength, bonding strength, wear resistance, shrinkage and other indicators, and the specific indicators should comply with the provisions of JC T 2177.
4.Test method: The test method of gypsum-based self-leveling mortar includes compressive strength test, flexural strength test, bond strength test, wear resistance test, shrinkage test, etc., and the specific test method should comply with the provisions of JC T 2177.
5.Inspection rules: The inspection rules of gypsum-based self-leveling mortar include factory inspection and type inspection, the factory inspection shall comply with the provisions of GB T 25181, and the type inspection shall comply with the provisions of JC T 2177.
6.Packaging, transportation and storage: The packaging, transportation and storage of gypsum-based self-leveling mortar should meet the requirements of relevant standards and regulations, among which the packaging should be made of moisture-proof and waterproof materials, and moisture and freezing should be avoided during transportation and storage.
The national standards for gypsum-based self-leveling mortar mainly include the following aspects:
1.Surface flatness: The surface should be flat and smooth, without unevenness, wave groove marks and other defects, and there should be no obvious height difference. The flatness error shall not exceed 2mm m, the pothole concave and convex error shall not be greater than 2mm, and the local hollow drum degree shall not be greater than 1mm.
2.Strength: The self-leveling layer should have sufficient strength to withstand normal pressure and load, and there should be no obvious cracking or falling off.
3.Compactness: The self-leveling layer should reach a certain degree of compactness, and there should be no obvious porosity, hollowing and other phenomena.
4.No obvious color difference: The self-leveling layer should maintain a uniform and consistent color, and there should be no obvious color difference.
5.Drying time: After the self-leveling layer is completed, it should reach a certain drying time to ensure that it can be covered by other decorative materials or flooring.
6.Raw material requirements: The raw materials of gypsum-based self-leveling mortar mainly include gypsum, cement, filling materials, additives, etc. These raw materials should meet the requirements of national standards or industry standards. The moisture content of gypsum should be less than 5%, and the cement should meet the requirements of cement standards.
7.Technical requirements: gypsum-based self-leveling mortar should have good self-leveling performance and be able to self-flatten on the ground to form a flat surface. Its thickness is generally adjustable between 3mm and 30mm. After pouring, there should be sufficient initial and final setting time. The maximum initial setting time requirement is 60 minutes.
8.Slump: Slump refers to the change in specific volume over a certain period of time.
9.Initial setting time and final setting time: The initial setting time refers to the time when a certain state of the concrete mixture begins to show signs of hardening, and the final setting time refers to the time when most of the moisture in the concrete mixture reacts with the cement to form hardening substances.