Anti-permeable admixtures are added to concrete to make waterproof concrete.
As long as it is a concrete structure that has direct contact with water, such as basements, pools, retaining walls, etc., impermeable agents will be added to the concrete. The impermeability of concrete is expressed by the impermeability grade (P) or permeability coefficient. Our country's standards adopt the impermeability grade. The impermeability grade is determined based on the maximum water pressure that a 28-day-old standard specimen can withstand when tested according to standard test methods.
GB50164-2011 "Concrete Quality Control Standard" According to the maximum water pressure that the concrete specimen can withstand during the impermeability test, the impermeability grade of concrete is divided into P4, P6, P8, P10, P12, etc. Five levels.
The symbol in GB50164-92 is "S", and GB50164-2011 is changed to "P" (P, formerly represented by the letter S, has the same meaning) indicates the impermeability level of concrete.
Extended information:
Waterproof concrete grades: P4, P6, P8, P10 and P12. The mix ratio should comply with the following regulations:
1. The cement dosage shall not be less than 300kg/m3; when mixed with active admixtures, the cement dosage shall not be less than 280kg/m3;
2 , The water-cement ratio should not be greater than 0.55
3. The sand rate should be 35%--45%, and the gray-sand ratio should be 1:2 or 1:2.5
4. It should be continuous When pouring, it is advisable to leave as few construction joints as possible
5. The waterproof concrete should be cured immediately after final setting, and the curing time should be no less than 14D
Reference: Baidu Encyclopedia-Impermeability Agent
p>Reference: Baidu Encyclopedia-Waterproof Concrete