Concrete with ultrahigh content of mixed fly ash

Abstract

The invention discloses a concrete with an ultrahigh content of mixed fly ash, and relates to the field of construction materials. The concrete comprises the following components in parts by weight: 48 to 60 parts of cement, 240 to 272 parts of fly ash, 656 to 696 parts of sand, 1293 to 1333 parts of broken stone, 3.0 to 4.8 parts of water reducer, 0.18 to 0.26 part of air-entrainer, and 80 to 90 parts of water. The mechanical performance and deformation performance of the concrete meet the requirements of water resources and hydropower engineering C18040 concrete and lower grades; moreover, the hydration temperature rise is lower, the anti-cracking performance is stronger, thus the happening rate of cracks in concrete is reduced, and the cost of temperature control is reduced.

Description

technical field [0001] The invention relates to the field of building materials, in particular to an ultra-high fly ash-mixed concrete. Background technique [0002] Concrete technology in construction projects is developing in the direction of high strength and high fluidity. However, with the increase in the amount of cementitious materials, a series of problems such as high heat of hydration and large shrinkage of concrete have become more prominent. Crack control in concrete construction Difficulty also increases. For mass concrete, the heat of hydration generated by cement hydration during the setting and hardening of concrete is not easy to conduct to the outside world. These heat will cause the internal temperature of the concrete to rise continuously, and the temperature difference between the inside and outside will generate a large tensile stress on the surface of the concrete. When this part of the tensile stress When the tensile strength of concrete is exceeded,...

AI Technical Summary

Problems solved by technology

Since the 1980s, through a lot of research on fly ash, the use of large amounts of fly ash has been continuously promoted, and a large number of research results have been achieved, which has promoted the change of people's concept of fly ash, but people are using fly ash There are still many concerns. It is difficult to break through 70% of the fly ash content in the large-volume normal concrete of water conservancy and hydropower projects. There are few reports on the use of high fly ash concrete with a fly ash content of more than 70%.

[0004] The current design concept of concrete adheres to the principle of keeping the water-binder ratio consistent with the control group, ignoring the important parameters that affect the test results (such as the water-binder ratio and the influence of the internal temperature rise of the dam concrete on its strength development, etc.), which has become a limitation for large-scale mixing. The Bottleneck in the Development of Fly Ash Dam Concrete

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