There are different types of cement. The main varieties of portland cement are PI42.5, PI52.5 and PI62.5, the main varieties of ordinary portland cement are PO32.5, PO42.5 and PO52.5, the main models of slag portland cement are PS32.5, PS42.5 and PS52.5, the main types of pozzolanic portland cement are PP32.5, PP42.5 and PP52.5, and the main types of fly ash portland cement are PF32.5 and PS 52.5.

First, the date of production. The performance of cement beyond the 30-day validity period will decrease, and the cement strength will decrease after three months of storage 10%~20%. High-quality cement can set over 6 hours, while cement that cannot set over 12 hours is of poor quality.

Buying cement depends on whether the paper bag packaging is intact and whether the logo is complete.

Observe whether the color of cement is dark gray or dark green, and the strength of cement along the yellow and white lines is relatively low.

Twist the cement powder with your fingers, and it feels a little fine sand powder, indicating that the fineness of cement is normal.

Generally, 32.5R composite portland cement is used for home decoration, and "fresh" cement produced within three months is selected as far as possible.