GB/T 17669.3 - 1999 standard for the determination of building plaster mechanical properties. It specifies a detailed process for measuring the mechanical properties of building plasters such as compressive resistance and flexural strength. On the sample prepative, specify the mold specifications, slurry mixing and pouring methods. During testing, standardize the operating parameters and loading rate of presses and flexural testers. Through this standard, the mechanical properties of building plasters can be accurately quantified, providing a key basis for their rational application in construction engineering, and helping to optimize the mass control and performance of building plasters. It is widely used in building plaster production, architectural design and construction and other fields.