Temperature control anti-cracking method for large-volume hydraulic concrete for super high arch dam

Abstract

The invention discloses a temperature control anti-cracking method for a large-volume hydraulic concrete for a super high arch dam. According to the method, the concrete out-of-mixer temperature and the concreting temperature are controlled by pre-cooling aggregate, and adding flake ice and cold water; low-heat cement and highly-doped grade I coal ash are taken as a cementing material; cooling water pipes are buried and water is introduced to reduce the maximum temperature of the hydraulic concrete; grade-4 aggregate and PVA (Polyvinyl Acetate) fibers are adopted to prevent cracks. The purposes of controlling the hydraulic concrete out-of-mixer temperature to be lower than or equal to 7 DEG C in summer and lower than or equal to 9 DEG C in winter, the concreting temperature to be lower than or equal to 12 DEG C, and the maximum temperature to be lower than or equal to 27 DEG C are achieved. By actual application of the temperature control anti-cracking method for the large-volume hydraulic concrete to the super high arch dam, the maximum temperature is remarkably reduced, and cracks are not found on site.

Description

technical field [0001] The invention relates to the field of building materials, in particular to a method for temperature control and anti-cracking of large-volume hydraulic concrete for extra-high arch dams in the field of water conservancy and hydropower. Background technique [0002] With the development of domestic hydropower and water conservancy projects, a large number of ultra-high arch dams will be built in the southwest of China and areas rich in hydropower resources in the world. Extra-high arch dams often have a high storage capacity. Once a dam breaks, it will cause loss of life and property downstream. loss, so safety is the first consideration. [0003] Super-high arch dams generally use mass concrete. According to the definition in the national standard GB50496-2009 "Construction Specifications for Mass Concrete": "The minimum geometric size of the concrete structure is not less than 1m. Concrete that develops detrimental cracks due to temperature changes a...

AI Technical Summary

Problems solved by technology

[0004] During the construction of extra-high arch dams, the minimum geometric size of a single pouring warehouse is generally 3m. Since extra-high arch dams generally require low-temperature arch sealing, low-temperature water cooling is required to reduce the temperature of the dam body to the arch sealing temperature in a short period of time. The cooling range is large and the speed is fast. In addition, the upper and lower layers are mutually restrained during the second cooling. It is more likely to cause excessive tensile stress and cracks.

Images