quality is directly related. The use of high-quality cement is the basis for producing high-quality micro-cement. The main inspection indicators of the national standard GB175-2020 Portland cement: strength (flexural and compressive), stability, setting time, standard consistency, water consumption, and fineness , chloride ion content, loss on ignition, insoluble matter, sulfur trioxide, magnesium oxide and other indicators can directly reflect the quality of cement.  
      Cement should be strictly protected from moisture during transportation and storage, and should not be mixed with sundries. Even so, it will absorb air during storage The moisture and carbon dioxide in the steel make the surface slowly hydrated and reduce the strength. The strength, stability, setting time, water consumption of standard consistency, etc. of the main inspection indicators of Portland cement are tested. It can be found that the strength of cement is generally reduced by 10-20% after three months of storage; after six months, it is reduced to about 30%; about 80% after one year.
     The powder of microcement contains a considerable proportion of cement and special additives and aggregates, and the mixed material is more Easily absorb moisture and carbon dioxide in the air. Thereby reducing the activity and strength of cement. Under the same circumstances, the shorter the storage time of micro-cement, the less its performance will be lost. Generally, the storage of micro-cement can maintain the original performance indicators within three months. After the storage period exceeds three months, various performance indicators begin to decline. The quality of micro-cement stored for half a year may not be guaranteed.
     So designers need to fully consider the time limit of microcement from production to final use when choosing microcement products. Abandon those suppliers with particularly long transportation distances and long transportation periods, do not use products with slow turnover and a storage period of more than 6, and use caution when using products that have degraded product performance due to long storage periods, and use products with a delivery date of less than 3 months It is better to use the products of enterprises with large production volume and fast turnover of raw materials. Do not blindly trust imported products, especially those from small foreign factories. These areas have a small consumer population, slow product turnover, long shipping time, and many import and export links will affect the performance indicators of microcement products. Impairs the performance of microcement products.