Cement self-levelling mortar has been used in the building decoration industry for a long time. It is mainly used for leveling the base layer of decorative floors such as wood flooring, PVC plastic flooring, and floor paint. In the long-term application process, many insurmountable problems appear:
1. Problems such as cracking, ashing, and sanding of the drum are prone to occur;
2. It is difficult to level one-time for the ground with large height difference. It is necessary to level the concrete or cement floor mortar first and then level it with cement self-leveling, which increases the construction process and labor and management costs.
3. Shrinkage and cracking often occur when the construction thickness exceeds 5mm. Traditional materials such as fine stone concrete and cement mortar are required for floor leveling and floor heating backfill leveling. The construction efficiency is low and the leveling accuracy is low. Cement self-leveling secondary leveling is required. Increase construction costs.
Gypsum-based self-leveling mortar is bound to gradually replace cement self-leveling screed and traditional concrete and cement mortar backfill screeding process due to its excellent performance. The main reasons are as follows:
01 does not crack
Cement self-leveling is due to the shrinkage properties of the cementitious material cement. Therefore, under different technical conditions of various manufacturers, the quality of cement self-leveling products on the market is uneven, and it is difficult to ensure that the self-leveling ground does not crack. The gypsum-based self-leveling mortar has good volume stability and shrinkage rate is much lower than the cement self-leveling because of its micro-expansion property. At the same time, the construction thickness is not limited, and 3mm-100mm can be freely selected according to the height difference and strength of the ground. The backfill leveling can be completed in one time, and the drum will not crack.
02High construction efficiency
Ordinary cement self-leveling can be used in 24 hours, hardening in winter is slower, and the construction interval is not allowed in low temperature environment; while the hardening time of gypsum-based self-leveling mortar is short, it can be used for walking in 3-4 hours, and the strength can reach 90 times the design strength % Or more, decorative surface construction can be carried out in 1-2 days, regardless of the season, and mechanized pumping and automatic pouring can be used. The construction area of a single machine can reach 2000m² / day, improving the construction efficiency by more than 10 times, and greatly shortening the construction cycle. Is the best ground material for the construction period.
03 cost savings
When it comes to saving costs, I have to talk about it in detail. After consulting the price of gypsum-based self-leveling, some people say that it is more expensive than cement self-leveling. How can it save money! Cement self-leveling has poor fluidity and poor flatness, and secondary leveling is required for subsequent decoration. The gypsum-based self-levelling mortar can be leveled at one time regardless of the height difference of the ground. No maintenance is required, no secondary leveling is required. The decoration can be directly laid on the wooden floor, PVC plastic floor, floor paint, various tiles, marble, and various types. Carpets and other decorative finishes. The dry density of gypsum-based self-levelling is only about 1100kg / m3, which can effectively reduce the building load, improve the seismic level of the building, and reduce the design cost of the building. Therefore, the comprehensive cost of gypsum-based self-leveling is less than that of cement self-leveling.
04 "Floor heating" leveling overlay
Gypsum self-leveling is especially suitable for "floor heating" screed covering, which can be used for one-time construction to meet the floor heating pipe coverage and ground leveling. Compared with the effect of cement mortar floor heating backfill and secondary leveling of cement self-leveling, the advantages are outstanding. The gypsum-based self-leveling mortar does not crack, its volume expands slightly during the setting and hardening process, no shrinkage cracks are generated, and its thermal stability is good; while the cement-based self-leveling mortar is easily cracked due to thermal expansion, cold shrinkage, and dry shrinkage. In the case of long-term dynamic stress, the leveling layer will be damaged, which will affect the service life of floor heating pipes and other pipelines and surface decoration materials. This has been fully verified in developed countries. The building is basically all self-leveling gypsum mortar;
The gypsum-based self-leveling originated in Europe. The gypsum-based self-leveling mortar was used as early as the 1960s. By the 1980s, the gypsum-based self-leveling mortars in Europe and the United States were very standardized and mature. China's gypsum-based self-leveling began in the early 1990s. Due to the limitations of gypsum calcination technology and production costs, the scale has not grown. In recent years, relevant companies have used industrial by-product gypsum such as desulfurized gypsum instead of natural gypsum to develop gypsum self-leveling mortar, which has greatly reduced production costs. The gypsum calcination technology is becoming more and more mature, and the product quality is becoming more and more stable.
With the popularization of residential finished products, the floor heating is backfilled, and the application of ground elevation is huge. The gypsum-based self-leveling can achieve two-in-one elevation and screed. Subsequent construction can be directly carried out with thin floor tiles, wooden floor assembly, and elastic flooring. Paving, which can not only greatly shorten the construction period, but also has a good leveling effect and low comprehensive cost, which is the only choice for the construction industry to raise and level the ground. Gypsum-based self-leveling will gradually change the construction method of the building ground elevation and leveling project in China, leading the development of China's high-end fine residential industry.
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