ABSTRACT
Frost resistance of concrete is characterized by the largest number of alternating freezing and thawing cycles maintained by 28-year-old samples when tested without reducing concrete strength by more than 15%. The number and zonal placement of different classes of concrete in the structure should be taken so that at each stage of the dam construction, no more than four classes of concrete are simultaneously laid; an increase in their number is allowed only with proper justification. Strength classes of concrete are determined by the stress state of the material of structures in specific sections, and the composition of concrete must meet the requirements for frost resistance, strength, and waterproofness by the time of dismantling of the concrete mass, if such requirement is indicated in the design. For the construction of dams, portland cement, sulfa-resistant portland cement with mineral additives, and pozzolanic portland cement should be used, and for underwater and internal zones, in addition, slag portland cement should be used.
