Knowledge of self-leveling plaster

Gypsum self-leveling gypsum is also called self-leveling gypsum short for ground leveling gypsum, also known as gypsum base self-leveling mortar, is made of gypsum materials, special aggregate and a variety of building chemical additives in the factory carefully arranged, mixed evenly and made of a special ground leveling dry mortar. Currently, the corresponding product standard has been set up in our country is JC/T 1023-2007 "gypsum base self-leveling mortar"According to the raw material, the self-leveling gypsum is divided into α-semi-hydrous gypsum type and Ⅱ type anhydrous gypsum type (obtained from the two hydrous gypsum calcined at 650℃ ~ 750℃), which is to add a certain proportion of retarding agent (α-semi-hydrous gypsum type) or activator (Ⅱ type anhydrous gypsum type) in the corresponding raw material, and then add cement, water reducing agent, water retaining agent, fine aggregate (quartz sand), defoaming agent, etc. Mix well to make it. Due to the addition proportion of the above additives is very small, are below 1%, and are commonly used chemical products, therefore, the essence of the self-leveling gypsum production technology is the production technology of α-hemihydrous gypsum or type II anhydrite.At present, due to the low yield and relatively high production cost of high-quality natural gypsum, α-hemihydrous gypsum in China is basically used in ceramic molds. The production and sales volume of self-leveling gypsum are extremely small, and the quality supervision is still blank. Because the physical and mechanical indexes formulated in JC/T 1023-2007 adopt the lowest value of the corresponding foreign standards, some manufacturers use building gypsum to produce self-leveling gypsum, relying on increasing the proportion of chemical additives, so that the quality of self-leveling gypsum is close to the physical and mechanical properties of JC/T 1023-2007. It has caused the high price of self-leveling gypsum, which is difficult to popularize and apply.Advantages of self leveling plaster (1) The ground of self-leveling gypsum construction, accurate size, high levelness, no empty drum, no cracking; Easy and convenient operation, high efficiency; And can use pumping construction, day shop ground up to 800 ~ 1000m². (2) Used as "floor heating" leveling covering layer (floor heating compared with other heating methods, energy saving range is about 20%, such as the use of partition temperature control device, energy saving range can reach 40%), not like cement mortar layer, due to thermal expansion cold contraction cracking, drum phenomenon. (3) When self-leveling gypsum and cement mortar are used in the screed layer of the building floor, the final cost of the two materials is similar. If cement mortar is replaced by self-leveling gypsum, the reduction in the amount of cement in the total cement output is small, less than one percent; Basically will not affect the interests of cement production enterprises. Therefore, there is little resistance and great prospect in the application of self-leveling gypsum in our country's building materials market. (4) Foreign applications are very common, has been decades, there are mature construction technology and supporting construction tools