Mixture for preparing C55 high-intensity ultra-high-pumping concrete

An ultra-high pumping and mixture technology, which is applied in the field of preparing C55 high-strength ultra-high pumping concrete mixture, can solve the problems of concrete workability and difficult control of pumpability, and achieve good pumpability and slump The effect of small loss and meeting the requirements of the intermittent time limit

Active Publication Date: 2012-02-15
THE FOURTH ENG CO LTD OF CHINA RAILWAYNO 20 BUREAU GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the western mountainous provinces such as Guizhou and Chongqing lack river sand, and the workability and pumpability of ordinary high-strength ultra-high pumpable concrete above C55 are difficult to control

Method used

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  • Mixture for preparing C55 high-intensity ultra-high-pumping concrete
  • Mixture for preparing C55 high-intensity ultra-high-pumping concrete

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0131] Embodiment 1 is used to prepare the mixing ratio design of each component in the mixture of C50 high-strength ultra-high pumping concrete

[0132] 1) The design of concrete mix ratio should comply with the "Design Regulations for Ordinary Concrete Mix Ratio" (JTJ55-2000).

[0133] 2) The concrete preparation strength is calculated according to the following formula: fcu.o≥fcu.k+1.645σ,

[0134] Where fcu.o-concrete preparation strength (MPa),

[0135] fcu.k - standard value of concrete cube compressive strength (MPa),

[0136] σ-Standard deviation of concrete strength (MPa), should be based on no less than 30 sets of statistical data of standard specimens with the same mix ratio; if there is no accurate statistical standard deviation, the value is 6MPa according to the specification.

[0137] 3) The concrete sand rate is controlled between 38% and 45%, and the water-cement ratio is between 0.34 and 0.38.

[0138] 4) Concrete slump is controlled between 180mm and 220m...

Embodiment 2

[0143] The mixing of embodiment 2 concrete

[0144] 1. The concrete prepared in Example 1 is mixed using an electronic automatic metering mixing station for centralized mixing. The mixing measurement is based on mass, and its deviation should meet the requirements of Table 1.

[0145] Table 1 Concrete mixing measurement allowable deviation

[0146]

[0147] 2. Measuring equipment should have a valid qualification certificate issued by the legal metrology department. Before formal weighing, the measuring equipment should be checked at zero point.

[0148] 3. The concrete mixing time is 120s~150s.

[0149] 4. Concrete every 30m 3 Take a sample once to check the slump of the concrete. When the measured slump and the set slump exceed ±30mm, the reason should be found out, and the stirring production can only be continued after the solution is resolved. When testing slump, the cohesion and water retention of concrete should also be observed.

[0150] 5. When the measured mo...

Embodiment 3

[0151] Example 3 Concrete Transportation

[0152]1. The concrete prepared in Example 1 is transported using a concrete transport vehicle and a delivery pump.

[0153] 2. After the concrete is transported to the pouring site, there will be no segregation, no stratification, no change in composition, and the slump necessary for construction can be guaranteed. If segregation or stratification occurs in the concrete mixture, the concrete mixture should be mixed again.

[0154] 3. During the transportation of the concrete mixer truck, the mixing drum is constantly stirred at a speed of 1 to 3 rpm. The mixing drum should be stirred for 1 to 2 minutes before being transported to the site for unloading.

[0155] 4. When the concrete is transported to the designated unloading site, its slump should be tested, and the measured slump value meets the construction requirements.

[0156] 5. When pumping concrete is used, the continuous operation of the concrete pump should be ensured. The...

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Abstract

The invention discloses a mixture for preparing C55 high-intensity ultra-high-pumping concrete, which comprises cement, river sand, mechanism sand, broken stone, water and additional additives. The slump of the concrete prepared from the mixture is 180 to 220mm, the expansion degree is greater than 500, and the air content is 2 percent to 4 percent. The work performance such as water preserving performance, cohesiveness, flowability and the like of the mixture of C55 high-intensity ultra-high-pumping concrete is good. The slump loss of the prepared concrete is small, the machine outlet slump is controlled to be 180 to 220mm, the expansion degree is greater than 500mm, the slump after 1h is not less than 180mm, and the expansion degree is also not smaller than 500mm. The air is properly led through the additional additives, so the air content of the concrete is controlled to be 2 percent to 4 percent, the pumpability of the concrete is good, and the pumping requirement is met. The initial setting time of the concrete is about 7 hours, and the concrete construction casting interruption time limit requirement can be perfectly met.

Description

technical field [0001] The invention relates to a material for preparing concrete, in particular to a mixture for preparing C55 high-strength ultra-high pumping concrete. Background technique [0002] With the development of my country's infrastructure and the advancement of science and technology, the strength and performance requirements of concrete are getting higher and higher. High-strength and ultra-high pumping concrete above C55 is more and more used in high-pier long-span bridges and high-rise buildings. In construction, the traditional preparation of such high-strength ultra-high pumping concrete is made of river sand. However, the western mountainous provinces such as Guizhou and Chongqing lack river sand, and the workability and pumpability of ordinary high-strength ultra-high pumpable concrete above C55 are difficult to control. [0003] In order to overcome the above-mentioned defects brought by the use of river sand to prepare concrete in the prior art, the in...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B28/00
Inventor 周玉兵肖红武黄小军
Owner THE FOURTH ENG CO LTD OF CHINA RAILWAYNO 20 BUREAU GRP
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