Test method for measuring plastic concrete permeability coefficient

A technology of plastic concrete and permeability coefficient, which is applied in the direction of permeability/surface area analysis, measuring device, suspension and porous material analysis, etc. It can solve the problems of instantaneous breakdown, low compressive strength and impermeability, and inability to obtain permeability coefficient, etc. problem, achieve the effect of reducing resistance and ensuring integrity

Active Publication Date: 2011-01-19
SINOHYDRO BUREAU 14 CO LTD
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method is mainly aimed at nearly rigid ordinary concrete, but for plastic concrete, there are obviously unreasonable places
Since the water-cement ratio of plastic concrete is generally large, the compressive strength and impermeability are low. When the "concrete impermeability test" in the hydraulic concrete test method is carried out, it is necessary to increase the water pressure by 0.1MPa. If the water pressure is 8 hours, the plastic concrete specimen will not be able to obtain the result of the impermeability grade due to the early permeation; and if the test is carried out according to the "concrete relative impermeability test", the water pressure specified in the test is 0.8MPa, and the water pressure will be too high. Causes instant breakdown or destruction of plastic concrete specimens and results of permeability coefficient cannot be obtained

Method used

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  • Test method for measuring plastic concrete permeability coefficient
  • Test method for measuring plastic concrete permeability coefficient
  • Test method for measuring plastic concrete permeability coefficient

Examples

Experimental program
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Effect test

Embodiment 1

[0028] Test method for determining the permeability coefficient of plastic concrete.

[0029] 1.1 Specifications / procedures used in experimental research

[0030] "General Portland Cement" GB175-2007

[0031] "Concrete Admixtures" GB8076-2008

[0032] "Hydraulic Concrete Test Regulations" DL / T5150-2001

[0033] DL / T5151-2001 "Test Regulations for Hydraulic Concrete Sand and Gravel Aggregate"

[0034] DL / T5199-2004 "Code for Construction of Concrete Cutoff Walls in Hydropower and Water Conservancy Regulations"

[0035] "Soil Engineering Test Regulations" SL237-1999

[0036] 1.2 Test materials

[0037] 1.2.1 Cement

[0038] The technical performance of ordinary Portland 42.5 cement produced for Huaxin Cement Factory is as follows:

[0039] Table 1 Huaxin Ordinary Portland 42.5 Cement Technical Performance

[0040]

[0041] 1.2.2 Clay and bentonite

[0042] The clay is local red clay in Ning'er County, Yunnan Province, which is dried in the sun and passed through a 2m...

Embodiment 2

[0069] Repeat Example 1 with the following differences: when the air temperature is less than 15° C., butter and fly ash are uniformly mixed in a weight ratio of 1:2 as a sealing material.

[0070] Concrete penetration test sealing material requirements are able to resist a certain water pressure without leakage, and have a certain degree of hydrophilicity. The greater the water pressure used, the higher the solid content in the sealing material. The weight ratio of traditional butter and fly ash is 1: ≥ 3, and the sealing material is relatively hard. When entering the mold, the load of ≮20kN will be tested. The piece is pressed into the test mold. The strength of plastic concrete is low, and the mold-in method of ordinary concrete cannot be used. Therefore, the proportion of solids in the sealing material must be reduced to ensure that the specimen can be molded in place with only a small pressure when it is molded, and can be used in the test. No water leakage under the con...

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Abstract

The invention discloses a test method for measuring plastic concrete permeability coefficient. Six test pieces are manufactured; butter is mixed with coal ash or cement at the mass ratio of 1:2-2.5 to prepare a sealing material for sealing the test pieces and a die trial. The water pressure of a permeameter is added to 0.2 MP once, constant pressure is kept for 6 hours, and the water seepage height is taken by ten moieties by splitting the test pieces. The relative permeability coefficient of the test piece is calculated according to the following formula: Kr=aDm2 / 2TH. The average value of the relative permeability coefficients of the six test pieces is the permeability coefficient of the plastic concrete. The invention fills the blank of the plastic concrete test method, and effectively overcomes the problem that the test result in the mix proportion design of the existing impermeable wall plastic concrete can not truly reflect the practical impermeable ability, thereby better matching the design index with reality.

Description

technical field [0001] The invention belongs to the technical field of water conservancy and hydropower construction, and in particular relates to a test method for measuring the permeability coefficient of plastic concrete in the construction of anti-seepage walls. Background technique [0002] Plastic concrete refers to the compressive strength ranging from 1 to 5 MPa, the elastic modulus of 300 to 2000 MPa, and the permeability coefficient of n×10 -6 ~n×10 -8 , and has a large fluidity of underwater concrete, which is mostly used in the cut-off wall structure of earth-rock dams. Because the amount of cement used in the mix ratio is less, more bentonite and clay are mixed, and water reducing agent and air-entraining agent are added to improve its impermeability, therefore, plastic concrete has low strength and certain impermeability. A special type of concrete with low elastic modulus and large strain. Compared with ordinary underwater concrete (the compressive strength...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N15/08
Inventor 涂志军陈文海袁梅和孙文赵家声熊伟李绍平卫红红张光梅沈早杨德梅王江卫秦明菊唐自琴李川
Owner SINOHYDRO BUREAU 14 CO LTD
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