5.

6.

2、 The significance of cement testing: 1.

The strength of cement mortar refers to the ability of the hardened specimen of cement mortar to withstand external force damage, which is an important physical property to reflect the quality of cement.

Controlling the loss on ignition in cement is actually limiting the amount of gypsum and admixture added to ensure cement quality.

1、 Cement testing items: The latest standard for cement quality inspection is carried out in accordance with GB175-2020 “General Portland Cement”.

8.

Soundness refers to the property of whether the volume change of cement is uniform during the hardening process.

Steel bar corrosion is one of the main forms of concrete damage, which can cause concrete structure cracking.

If the content of sulfur trioxide exceeds the national standard, it will seriously affect the stability of cement and cement products, which will have adverse consequences such as expansion and cracking on cement products.

Excessive magnesium oxide leads to warping, deformation, cracking, and decreased strength of cement products.

Any use of cement with unqualified soundness in engineering can cause varying degrees of quality problems.

However, if the cement is too fine, it can easily cause cracks.

The larger the specific surface area of cement, the finer the cement, and the better its strength.

If the final setting time is too long, it will affect the construction progress of concrete engineering.

If the initial setting time is too short, it will affect the transportation and pouring of concrete mixtures.

2.

The setting time is of great significance for the construction of cement concrete.

Chemical items: loss on ignition, magnesium oxide, sulfur trioxide, chloride ions.

4.

Chloride ions are a harmful component in cement, and cement is a very important material in concrete building structures.

7.

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If the soundness is not qualified, it will cause cracking, loosening, and collapse of hardened cement stones or concrete.

If the chloride ion content exceeds a certain level, it will rust the steel bars in concrete.

3.

Because the most important performance of cement is strength, whether it is concrete or mortar, we mainly use the strength of cement in construction.

Shim Pack

Taking ordinary Portland cement as an example, the testing items include: physical items: setting time, stability, cement mortar strength (3d, 28d), and specific surface area.