A water-resistant machine-sprayed gypsum-based material and its preparation method

Abstract

The invention belongs to the technical field of building materials and in particular relates to a water-resisting machine-sprayed gypsum-based material and a preparation method thereof. A mixed waterrepellent is used and silicone acrylic emulsion forms a firm cross-linked net film on a gypsum hole wall; the film is attached on surfaces of an inner hole and a pore of a gypsum hardened body, so that surface properties of the hole and the pore are changed and the hydrophilic property is changed into the hydrophobic property; even if the contact angle theta of the surface of the inner hole and the pore of the gypsum hardened body is greater than 90 degrees and water cannot automatically seep into capillary pores, so that the waterproof performance of a phosphorus gypsum building block is improved, the growth of a crystal can be changed; the growth of the crystal in the direction of a long axis is inhibited; the growth of the crystal in the direction of a short axis is enhanced and the crystal becomes short and flat; the porosity between the crystals is reduced and the density is increased, so that the water-proof and water-resisting effects of gypsum are improved.

Description

technical field [0001] The invention belongs to the technical field of building materials, and in particular relates to a water-resistant machine-sprayed gypsum-based material and a preparation method thereof. Background technique [0002] At present, gypsum products are widely used in construction projects, such as indoor partition boards, decorative panels, etc. The water absorption rate is generally 10.0-11.0%, and the first-class product is 8.0-9.0%. After being damp, the strength is greatly reduced, and it is easy to warp and deform. , Seriously affect the decorative effect. Especially in the rainy season in the hot and humid southern regions, the ambient humidity is above 80%. If ordinary decorative gypsum board ceilings are used, the deflection value will be above 15mm after being damp, which will not only affect the decorative effect, but also be unsafe to use. [0003] The traditional plastering mortar for cement exterior walls has been widely used due to its high ...

AI Technical Summary

Problems solved by technology

But there are also the following defects: 1. The curing shrinkage value is large. Within 40 days after the construction of cement mortar, the curing shrinkage increases rapidly, and the shrinkage is proportional to the time. In 40 days to one year, the curing shrinkage has been occurring; 2. The dry shrinkage value is large, and the dry shrinkage value of cement mortar is generally 0.8-1.0mm / m, which is 4-5 times that of gypsum mortar; 3. The thermal expansion and contraction value of cement mortar is similar to that of gypsum mortar, about 10×10- 6

② Due to the moisture absorption on the inner surface of the micro-cracks of the gypsum body, the water film produces a wedging effect, so the micro-units of each crystal structure are separated and their strength is reduced

However, the water resistance is weak, and it is easy to encounter rainwater washing outdoors, causing the paint layer to be damaged

Images