Cement is a powdery hydraulic inorganic cementing material, which can harden in air or water after being mixed with water, and can firmly bond sand, stone and other materials together. The mixture of early lime and pozzolan is very similar to modern lime pozzolan cement.

Cement has a gelling effect in concrete. Concrete is mainly composed of cement, water, sand and stone. Sand plays a skeleton role and is called aggregate. Cement and water form cement slurry, which is wrapped on the surface of aggregate and fills its gaps. Cement slurry plays a lubricating role before hardening, which makes the mixture have certain workability and is convenient for construction. After the cement slurry hardens, the aggregate is cemented into a solid whole.

Cement purchase skills

1, you should choose to buy from a regular cement manufacturer, so that the product quality can be trusted, and the production date, shelf life, origin, license, number, weight and instructions for use will also be clearly marked on the cement bag; On the contrary, if it is inferior cement, the introduction on the outer packaging is definitely not sufficient, so it should be carefully identified.

2. When buying cement, the merchant shall be required to provide relevant certificates of cement products. After all, there are many cement producing areas now, and it is not excluded that there are black-hearted manufacturers. Cement quality can only be guaranteed by regular manufacturers, but not by informal manufacturers.

3. Look at the color of cement. Generally good cement, its color is gray. If the color is too dark, or other colors, it must be a mess.

4. You can also try to feel it. Good quality cement should have no hardening phenomenon, a lot of graininess and a very delicate feel; And inferior cement, its surface will harden, and it will be rough when twisted by hand. So everyone should choose carefully.

Method of identifying high-quality cement

Mainly to observe the packaging of cement. According to the national standard, the variety, label, factory name and factory number of cement in the cement packaging label are not all unqualified products. You can also look at the binding line and brand label of the package. There is the word "green product" above the paper bag, and the sealing edge of the seal is round and closed. If there are two single-sided paper edges, the package has been opened. The brand label behind the real cement bag is soft in color, and the word fixed point is written in small seal script, which is very different from the fake cement.

In addition, we have to check the production date of cement. Real cement bags will have a batch number on the side or back to indicate the production date, because cement is easy to get wet or agglomerate after being left for a long time, and generally the time from factory to purchase will not exceed one week. Fake because it is produced in a small workshop, there is generally no batch number and no expired packaging.