Self-leveling gypsum is the abbreviation of self-leveling ground leveling gypsum, also known as gypsum-based self-leveling mortar. It is a kind of special purpose made from gypsum materials, special aggregates and various construction chemical additives that are carefully configured and mixed uniformly in the factory. Dry powder mortar leveled on the ground.
1. Material: interface agent, gypsum-based self-leveling mortar
2. Construction tools
(1) Mechanical tools: electric mixers, buckets, buckets, scrubbers, vacuum cleaners, electric cutting machines.
(2) Testing tools: level gauge, fluidity tester.
(3) Auxiliary equipment: water pipe, wire and cable, bottom coating roller brush, soft brush, measuring cylinder, toothless scraper, special scraper for gypsum-based self-leveling mortar (fine tooth scraper), defoaming roller, spike shoes, trowel Knife, trowel, shovel, etc.
The configuration of construction personnel should be determined according to the construction area, and generally should include: mechanics (self-leveling mixing, ground polishing, vacuum cleaners, electric cutting machines, etc.), bricklayers (repair, leveling), workers (sweeping, handling, painting) Brush interface agent), management personnel (site management, quality control, etc.)
Trowel, spikes, defoaming roller, fine tooth scraper
1. Close the site
The site should be closed and cross-operation is strictly prohibited. During indoor construction, the self-leveling ground will crack due to indoor ventilation, so doors and windows should be closed to close the site. Construction requires the cleanliness of the base and the environment, without interference from other types of work, and no interruption or pause is allowed.
2. Grassroots inspection
Thoroughly check the surface of the base layer for defects such as sanding, hollowing, shelling, peeling, loosening, pitting, grease, dust, cracks, etc. The surface dryness and flatness should meet the requirements.
3. Grassroots cleanup and treatment
(1) Remove the grease, wax and other contaminants on the base layer with a cleaning agent. If necessary, use a scrubber to clean the ground. Dust, unsturdy concrete surface, grease, cement slurry or putty and may affect the bonding strength The impurities, etc. are cleaned up, so that the base is dense, and the surface is free of looseness and debris.
(2) The floating soil on the base surface must be cleaned with a vacuum cleaner.
(3) Use special repair mortar to repair the honeycomb and holes of the base layer. Large areas of hollow drums should be completely removed and re-constructed; local hollow drums should be treated with grouting or other methods.
4. Elevation control.
Use a spirit level to measure the level and thickness of the self-leveling mortar to be constructed, and use the level screw to mark the level of the base layer. Generally, the construction thickness of self-leveling mortar is not less than 4mm.
5. Brush the interface agent
(1) The purpose of applying the interface agent is to seal the base layer, to prevent premature loss of water from the self-leveling mortar; to strengthen the bonding strength between the ground base layer and the self-leveling mortar layer; to prevent the generation of air bubbles; to improve the fluidity of the self-leveling mortar.
(2) According to the requirements of the interface agent instructions, use a roller to apply the interface agent to the ground. The coating should be even, without omission, and it should not be allowed to form local effusion; it should be processed twice for dry, strong water-absorbing substrates , The second pass should be applied after the first pass of the interface agent.
(3) Generally, the drying time of the first interface agent is about 1~2 hours, and the second drying time of the interface agent is about 3~4 hours.
(4) Ensure that the interface agent is completely dry, and there is no accumulation before proceeding to the next step of construction.
6. Self-leveling mortar construction
(1) It should be partitioned in advance to ensure continuous pouring of the entire area at one time.
(2) Accurately weigh the right amount of clean water into a clean mixing bucket with a water tank, start the electric mixer, slowly add the entire package of self-leveling material, and continue to mix evenly for 3 to 5 minutes. Make it into a fluid slurry with uniform consistency and no caking, and check the fluidity of the slurry. The amount of water added must be strictly controlled according to the requirements of self-leveling materials.
(3) Tilt the agitated fluid self-leveling material to the base surface within the construction time, and let it flow like water. It should be tilted into strips, and ensure that the cast-in-place strip and the previous one can flow together.
(4) The cast strip self-leveling material should reach the design thickness. If the design thickness of self-leveling construction is less than or equal to 10mm, it is necessary to use a special scraper for self-leveling to batch scrape to assist leveling.
(5) Continuous casting should be performed. The interval between the two castings should be within 10 minutes to avoid difficult removal of the stubble.
(6) After spreading the slurry, spread the slurry with a toothed scraper and control the appropriate thickness. Let it stand for 3 to 5 minutes to let the bubbles inside be discharged, and then use the defoaming roller to deflate. To help the slurry flow and remove the bubbles generated, to achieve a good stubble effect.
(7) Before the initial leveling of the self-leveling, you must wear spiked shoes to walk into the self-leveling ground and quickly roll the cast self-leveling ground with a defoaming roller to discharge the air brought in during stirring to avoid bubbles, pits and strips. The height difference between the interfaces.
(8) Used tools and equipment should be cleaned with water in time.
After the construction is completed, the self-leveling ground should be maintained under the construction environment for more than 24h before it can be used. During the curing period, strong wind flow should be avoided, and the temperature should not be too high. When the temperature or other conditions are different from the normal construction environment conditions, the curing time needs to be adjusted according to the situation.
8. Finished product protection
After the construction is completed, the self-leveling ground shall be well protected. During the protection of finished products, garbage, debris, paint and construction machinery should not be piled on the self-leveling ground that has been prepared to avoid contamination; the surface layer of the self-leveling ground cannot be hit or scored with blunt objects, sharp objects, or Can’t walk on it.
Matters needing attention
1. Construction environment requirements: the temperature of the dry ground should not be lower than +10C, and the relative humidity of the ground should be kept below 90%; do not have excessive wind through the hall to avoid local premature drying.
2. The self-leveling ground has higher requirements for the base layer. The base layer must not have loose concrete, grease, debris, and dust; the floor drains, trenches, grid joints, etc. on the ground must be sealed with sponge strips; the original cushion place The remaining joints should be closed with the same material as the self-leveling mortar.
3. Before brushing the second interface agent and before self-leveling construction, the surface of the interface agent should be dried in order to obtain better connectivity. Care should be taken to maintain ventilation during construction.
4. The best water for construction is clean tap water, so as not to affect the appearance and quality of the surface.
5. The self-leveling ground must be constructed continuously without stopping in the middle; the use time after adding water is 20~30 minutes. After exceeding, the self-leveling mortar will gradually solidify, producing strength and losing fluidity. The pouring width can be determined according to the capacity of the pump and the thickness of the paving, usually not more than 10~12 meters; the too wide ground needs to be separated into small pieces with sponge strips for construction.