Cohesion of new concrete with old under winter conditions

Conclusions

• 1. Cohesion in the working joint of a monolithic structure when pouring concrete on a frozen foundation can be provided by using an addition of sodium nitrite to the concrete.

• 2. The magnitude of cohesion in the joint at negative temperatures is within approximately the same strength limits of a monolith as at positive temperatures and depends on the type of preparation of the foundation and methods of treating the joint.

• 3. The use of brushing of the surface of freshly-poured concrete during its setting period gives better results with respect to cohesion of concretes than the use of scoring.

• 4. Data from the laboratory experiments indicate the expediency of using the method of pouring concrete with sodium nitrite on a frozen concrete foundation at individual installations.