High-strength and low-water-absorption magnesium oxysulfate cement

Abstract

The invention discloses a high-strength and low-water-absorption magnesium oxysulfate cement, which comprises magnesium oxide powder, a magnesium sulfate solution, dried wood fiber, a medium alkali glass fiber cloth and a composite modifier, wherein the composite modifier comprises, by weight (calculated as the total weight of the magnesium oxysulfate cement), 0.2-0.8% of an organic acid and / or anorganic acid salt, 0.2-0.3% of polyvinyl alcohol, 0.2-1.0% of an organic silicon waterproofing agent, 0.2-1.0% of stearate, and 0.2-1.0% of an ethylene-vinyl acetate copolymer emulsion. According tothe present invention, the composite modifier is added on the basis of the original formula of the magnesium oxysulfate cement, such that the final set strength of the magnesium oxysulfate cement is increased by 90-110%, and the saturated water absorption rate is substantially reduced to 8% from 37%; and with the ethylene-vinyl acetate copolymer emulsion, the structure of the magnesium oxysulfatecement is subjected to weather-resistant film forming property protect, such that the strength retention rate of the modified magnesium oxysulfate cement is substantially improved.

Description

technical field [0001] The invention relates to a material for construction engineering, in particular to a magnesium oxysulfide cement with high strength and low water absorption, which belongs to the technical field of cement materials. Background technique [0002] Magnesium oxysulfide cement is a kind of magnesite cement, which was proposed by Belgian scholars in 1957. It consists of a certain amount of active magnesium oxide (MgO) and a certain amount of magnesium sulfate (MgSO) with a certain concentration. 4 ) solution composed of a MgO-MgSO 4 -H 2 O Ternary gelling system. The material with this ternary gel system solidifies quickly, is light, and has a fire rating as high as A1, and overcomes the defect of chloride ion antihalogenation in magnesium oxychloride cement proposed by French scholar Sorel, so it has been widely used in recent years. It should be used in the field of building materials such as indoor fireproof boards, fireproof door cores, fireproof flu...

AI Technical Summary

Problems solved by technology

However, magnesium oxysulfide cement has limited its application on exterior walls due to its high water absorption and special ternary structure.

In particular, its ternary gel system contains 5-7 crystal waters. In the case of humidity and hot weather, the above crystal water is prone to crystal water removal and moisture absorption and recondensation, which will seriously damage the cement structure and accelerate the wall panel. Aging will affect the strength of the wallboard, and in severe cases, problems such as cracking of the wallboard and peeling off of putty will occur

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