A low temperature rise, low shrinkage, high crack resistance, high durability roller compacted concrete and its preparation method

A technology of roller compacted concrete and low shrinkage, which is applied in the field of high-durability roller compacted concrete and its preparation, low shrinkage, high crack resistance, and low temperature rise. Concrete temperature difference is obvious and other problems, to achieve the effect of simplifying temperature control measures, improving crack resistance, and slowing the heat release of hydration

Active Publication Date: 2022-03-11
CHINA THREE GORGES CORPORATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, traditional roller compacted concrete uses medium-heat Portland cement. During the construction process, thin-layer paving and uninterrupted rolling are used to raise layers, resulting in obvious temperature differences between the interior and exterior of the concrete, and temperature cracks are prone to occur.
The main reasons are as follows: on the one hand, the heat of hydration of the cement used is relatively high, which can easily lead to the accumulation of heat of hydration inside; The temperature is higher than the ambient temperature, and the heat dissipation effect of the layer is not good. The construction of small and medium-sized roller compacted concrete dams in China is usually forced to choose low-temperature season construction to solve the problem, and cannot give full play to the technical advantages of rapid construction of roller compacted concrete
[0003] Low-heat Portland cement has the unique characteristics of low heat of hydration, but because of its difficult production technology, low early strength, and insufficient construction experience, in recent years, after repeated tests, local trial applications, and multi-party demonstrations, it is only used in Application in normal concrete, there is no precedent for successful application in roller compacted concrete

Method used

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  • A low temperature rise, low shrinkage, high crack resistance, high durability roller compacted concrete and its preparation method
  • A low temperature rise, low shrinkage, high crack resistance, high durability roller compacted concrete and its preparation method
  • A low temperature rise, low shrinkage, high crack resistance, high durability roller compacted concrete and its preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] A low temperature rise, low shrinkage, high crack resistance, high durability roller compacted concrete has the following components by weight: 60 parts of low heat Portland cement, 89 parts of fly ash, 740 parts of sand, 1514 parts of stone, and water reducer 0.89 parts, 0.045 parts of air-entraining agent, 0.75 parts of shrinkage reducing agent, 82 parts of water, each part is 1kg, as shown in Table 1.

[0031] The specific surface area of ​​the low-heat Portland cement is 332m 2 / kg, MgO content 4.7%, 3d, 7d heat of hydration are 194kJ / kg, 234kJ / kg respectively;

[0032] The alkali content of the fly ash is 0.9%; the sand is processed from limestone aggregate, and the fineness modulus is 2.71;

[0033] The particle content of d≤0.16mm in the stone is 19%, wherein the particle content of d≤0.08mm is 8%,

[0034] The stones are in three grades, big stones (40mm-80mm), medium stones (20mm-40mm), small stones (5mm-20mm), and the volume ratio is 30:40:30.

[0035] The ...

Embodiment 2

[0044] The difference is that medium-heat Portland cement is used instead of low-heat Portland cement, and the others are the same as in Example 1. The specific surface area of ​​medium heat Portland cement is 338m 2 / kg, MgO content 4.2%, 3d, 7d heat of hydration were 239kJ / kg, 280kJ / kg.

[0045] Table 3C 90 Mix ratio of 15F100W8 three-stage medium-heat Portland cement roller compacted concrete

[0046] cement fly ash sand gravel Superplasticizer air entraining agent Shrinkage reducer water 63 94 734 1501 0.94 0.047 0.75 86

[0047] Test results of thermal Portland cement RCC properties in Table 4

[0048]

[0049] It can be seen from Table 1 and Table 3 that when the site construction requirements are met, compared with the traditional medium-heat Portland cement RCC under the same conditions, the water consumption of low-heat Portland cement is reduced by 4kg / m 3 , the total amount of cementitious materials is reduced by 8kg / m 3...

Embodiment 3

[0052] The difference is that no water reducer is included, and the others are the same as in Example 1.

[0053] Field tests show that without adding water reducing agent, the mixing performance of RCC is extremely poor, it is not easy to shape, and cannot meet the construction requirements.

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Abstract

The invention relates to a low-rise, low-shrinkage, high-crack-resistance, high-durability roller compacted concrete and a preparation method thereof. All components of the roller compacted concrete are as follows in parts by weight: 60-80 parts of low heat portland cement, 89-114 parts of fly ash, 740-771 parts of sand, 1486-1514 parts of stone, 0.89-1.18 parts of water reducer share. Compared with traditional medium-heat Portland cement roller compacted concrete, the present invention has good working performance, mechanical performance and durability, and at the same time, the concrete has lower adiabatic temperature rise, smaller autogenous volume deformation and shrinkage, and even exhibits micro-expansion characteristics, and temperature control and anti-cracking capabilities Significant improvement can further simplify temperature control measures and reduce engineering costs. At the same time, it can realize construction in high temperature seasons and gradually cancel cooling water pipes in low temperature seasons. The technical and economic benefits are remarkable.

Description

technical field [0001] The invention relates to the application field of new technology in concrete engineering, in particular to a low-temperature-rise, low-shrinkage, high-crack-resistant, high-durability roller compacted concrete and a preparation method thereof. Background technique [0002] Roller compacted concrete dam building technology began in the 1980s and has undergone a lot of exploration, research and engineering practice so far. Because of its fast construction, short construction period and low cost, it has always been favored by the hydropower dam industry. However, medium-heat Portland cement is used in traditional RCC. During the construction process, thin layers of paving and uninterrupted rolling are used to raise layers, resulting in obvious temperature differences between the interior and exterior of the concrete, and temperature cracks are prone to occur. The main reasons are as follows: on the one hand, the heat of hydration of the cement used is rel...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B28/04C04B111/34C04B111/20
CPCC04B28/04C04B2111/343C04B2111/20C04B18/08C04B14/06C04B14/02C04B2103/302C04B2103/304
Inventor 李文伟陆超
Owner CHINA THREE GORGES CORPORATION
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