How much cellulose is added to 100 pounds of cement?

How much cellulose is added to 100 pounds of cement?

Theoretical basis for the amount of cellulose added

The amount of cellulose ether added is usually expressed as a percentage of cement mass, with a common range of 0.05% -0.5%. The specific amount of addition depends on:

Mortar type: Plastering mortar, masonry mortar, or insulation mortar have different requirements for water retention and consistency.

• Cellulose type: The viscosity of HPMC (usually measured in mPa · s) affects the amount added. High viscosity HPMC (such as 100000 mPa · s) is used less, while low viscosity HPMC (such as 40000 mPa · s) is used slightly more.

Environmental conditions: In high temperature or dry environments, it is necessary to increase the amount of cellulose used to enhance water retention.

Performance objective: If it is necessary to improve crack resistance or bonding strength, the addition amount can be appropriately increased.

According to industry standards and research data (such as "Application of Cellulose Ether in Cementitious Materials"), the recommended addition amount of HPMC in ordinary plastering mortar is 0.1% -0.3% of the cement mass.

Calculation of cellulose addition for 100 pounds of cement

Assuming HPMC (viscosity 100000 mPa · s) is used as cellulose ether, the following are the calculation steps:

Cement quality: 100 pounds=50 kilograms.

• Addition ratio:

-Ordinary plastering mortar: 0.1% -0.2%, i.e. 50 × 0.001=0.05 kg (50 grams), up to 50 × 0.002=0.1 kg (100 grams).

-Insulation mortar or high water retention requirement: 0.2% -0.3%, i.e. 50 × 0.002=0.1 kg (100 grams), to 50 × 0.003=0.15 kg (150 grams).

-Special purpose (such as high bonding mortar): can reach 0.3% -0.5%, that is, 50 × 0.005=0.25 kilograms (250 grams).

Example:

• Plastering mortar: Add 50-100 grams of HPMC to 100 pounds of cement.

• Thermal insulation mortar: Add 100-150 grams of HPMC to 100 pounds of cement.

High bonding mortar: Add 150-250 grams of HPMC to 100 pounds of cement.

Adjustments in practical applications

Experimental verification: Due to differences in cement brand, aggregate particle size, and water cement ratio, it is recommended to conduct small-scale experiments in the laboratory or on-site to adjust the amount of cellulose used to achieve optimal water retention and construction performance.

Cost control: Cellulose ether has a high price (about 20-50 yuan/kg), and excessive addition will increase costs. Industry research shows that cellulose ether accounts for over 40% of the cost of dry mixed mortar materials, and a balance between performance and economy is needed.

• Upper limit of dosage: Studies have shown that when the amount of cellulose added exceeds 0.5%, the improvement in water retention is limited and may reduce the strength of the mortar. Therefore, excessive addition is not recommended.

Other types of cellulose

If carboxymethyl cellulose (CMC) or hydroxyethyl cellulose (HEC) is used, the amount added may vary slightly:

CMC: Low viscosity, the addition amount can be increased to 0.2% -0.4% (100-200 grams added to 100 pounds of cement).

HEC: Similar in performance to HPMC, typically added in an amount of 0.1% -0.3% (50-150 grams per 100 pounds of cement).

For 100 pounds of cement, the recommended dosage of HPMC is 50-150 grams (0.1% -0.3%), depending on the type of mortar and construction requirements. Suggest optimizing the dosage through experimentation.