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Method for evaluating workability of large-flow-state ultra-high-performance concrete mixture and application

An ultra-high performance, evaluation method technology, applied in the direction of DC flow characteristics measurement, instruments, analysis materials, etc., can solve the gap in the workability evaluation of mixtures, affecting the quality of ultra-high performance concrete, and the large difference in steel fiber density and other problems, to achieve the effect of less manpower and mixture, ensuring service performance and simple operation

Pending Publication Date: 2022-06-28
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

And considering that there are steel fibers in ultra-high performance concrete, the density of steel fibers is quite different from that of the slurry, and the rheological properties of the mixture have an important influence on the distribution of fibers in the mixture, especially in the slurry Large fluidity or uneven fiber distribution may occur during vibrating construction, which will significantly affect the quality of ultra-high performance concrete
[0004] Therefore, the distribution uniformity of fibers in the mixture has a very important impact on ultra-high performance concrete. At present, there are only a few evaluation methods for the fiber distribution of hardened paste [6], and the related workability of the mixture The evaluation is still blank, it is difficult to quickly guide the mix ratio correction during construction, and reduce quality fluctuations

Method used

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  • Method for evaluating workability of large-flow-state ultra-high-performance concrete mixture and application
  • Method for evaluating workability of large-flow-state ultra-high-performance concrete mixture and application
  • Method for evaluating workability of large-flow-state ultra-high-performance concrete mixture and application

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] see attached figure 1 , 2 , a method for testing the workability of a large fluid state ultra-high performance concrete mixture, comprising the following steps:

[0052] Step 1. Put the transparent test box on the vibrating platform, and the test box is formed with an L-shaped flow channel of equal cross-section; wherein, the L-shaped flow channel is composed of a vertical flow channel and a horizontal flow channel. There is a movable gate at the junction of the channel; the length and width of the vertical flow channel and the horizontal flow channel are both 150mm, the height of the vertical flow channel is 400mm, the length of the horizontal flow channel is 1000mm, and the end face of the horizontal flow channel away from the vertical flow channel is closed. The vertical flow channel and the horizontal flow channel are made of plexiglass; the length direction of the horizontal flow channel is provided with a length scale; the vibration frequency of the vibration pla...

Embodiment 2

[0075]The ultra-high performance concrete in this example is prepared according to the mixing ratio in Table 1. All dry materials are put into the mixer and dry mixed until the materials are uniform, then slowly add water and water reducing agent, and continue to stir until a uniform mixture is formed. After cleaning, put the workability test box on the flat vibration table, close the movable gate 3 of the upright cylinder 1, so that the connection between the upright cylinder 1 and the horizontal cylinder 2 is not connected, and wet the test box with a damp cloth to ensure that there is no The ultra-high performance concrete mixture to be tested is continuously and evenly loaded into the upright cylinder 1, so that the surface of the mixture is level with the upper mouth of the upright cylinder.

[0076] Table 1 embodiment ultra-high performance concrete mix ratio (kg / m 3 )

[0077]

[0078]

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Abstract

The invention relates to a workability evaluation method and application of a large-flow-state ultra-high-performance concrete mixture, and the evaluation method comprises the following steps: putting a to-be-tested concrete mixture into a test box, and measuring the average flow velocity v of the mixture in a horizontal flow channel 300 mm before flowing and the total horizontal flow distance L when the flow is completed; after the flowing is finished, respectively taking the mixture in the vertical flow channel and the horizontal flow channel, and measuring the mass percentages MC and MF of steel fibers in the mixture; and evaluating the workability of the mixture according to the measured flow distance L, the average flow velocity v, the calculated settlement degree C and the calculated separation degree F. The application of the method is to compare and analyze workability evaluation indexes of mixtures with different components and guide the design of the components of the ultra-high performance concrete mixture. According to the method, evaluation indexes are provided for the workability of the high-content steel fiber large-flow-state ultra-high-performance concrete mixture for the first time, the workability of the mixture can be objectively and accurately evaluated, and design and construction quality control of components of the large-flow-state ultra-high-performance concrete mixture can be guided.

Description

technical field [0001] The invention relates to the technical field of performance testing and evaluation of concrete mixtures, in particular to a workability evaluation method and application of large-fluid ultra-high-performance concrete mixtures. Background technique [0002] Ultra-high-performance concrete (UHPC) originated from the reactive powder concrete developed by the French, and has many advantages: the compressive strength of ultra-high-performance concrete is generally higher than 150MPa, which is about three times that of traditional concrete [1-3]. The incorporation of fibers makes the ultra-high performance concrete have excellent toughness and fracture energy. Compared with high-performance concrete, the toughness of ultra-high-performance concrete is increased by more than 300 times, which is comparable to some metals, which makes the concrete structure under overload environment or earthquake. It has more excellent structural reliability [1, 4-5]. [0003...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N11/06G01N33/38C04B28/02
CPCG01N11/06G01N33/383C04B28/02C04B18/08C04B18/146C04B14/06C04B14/48C04B2103/302
Inventor 龙广成谢友均孙成名曾晓辉董荣珍马昆林唐卓
Owner CENT SOUTH UNIV