Mining engineering knowledge point: pneumatic material
Building gypsum is a kind of air hardening inorganic gelling material, has good fire resistance and decorative plaster, but with strong hygroscopicity, easilycausing adhesion strength decreased significantly; weakened, poor water resistance and frost resistance of gypsum. Therefore, the building plaster is not suitable for wet and low temperature environment; gypsum is not suitable for use in high temperature environment.
The lime used in the construction project is divided into three varieties: Construction lime, construction lime powder and construction lime powder. The preparation of building mortar with quicklime can significantly improve the workability of the mortar. Lime should not be used in a long humid environment or in a water environment. In the process of hardening lime, the volume will shrink significantly and the shrinkage cracks appear. In the process of storage and transportation, lime should be prevented from dampness and should not be stored for a long time. Not mixed with flammable and explosive liquids and transport, and to take waterproof measures, Caution.
(three) water glass
Water glass is also called paohuajian, is an alkali metal silicate, general hardening in the air.
Paohuajian has good adhesion and strong acid corrosion; paohuajian hardening can clog pores material, prevent moisture penetration effect. In addition, paohuajian also has good heat resistance, high temperature decomposition, reduce the strength (or even more).
The use of sodium silicate includes architectural coatings or directly painted brick, concrete products, to improve its compactness and durability; the special configuration (such as waterproof, acid resistant and heat-resistant mortar or concrete), or as a quick setting admixture, configuration of grouting fluid used for water shutoff and reinforcement.