Testing apparatus for gas permeability in concrete and testing method therefor

Patent metadata

Field	Value
Publication number	US-10488319-B2
Application number	US-201715803767-A
Country	US
Kind code	B2
Filing date	Nov 4, 2017
Priority date	May 4, 2015
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

An apparatus and method for testing gas permeability in concrete are provided. The apparatus is used for testing gas permeability of a concrete test sample, and includes a gas supply apparatus, an instrument body and a gas flow meter. The instrument body includes a frame body. A gas inlet ring, a gas outlet ring and a connection plate are successively arranged on the frame body from inside to outside. An input end of the gas inlet ring is connected with the gas supply apparatus, and an output end is connected with an input end of the gas outlet ring through the concrete test sample. An output end of the gas outlet ring is connected with the gas flow meter. The connection plate is connected with the concrete test sample.

First claim

We claim:

1. An apparatus for testing gas permeability in concrete, which is used for testing gas permeability of a concrete test sample ( 1 ), comprising: a gas supply apparatus ( 2 ), an instrument body ( 3 ), and a gas flow meter ( 4 ), wherein the instrument body ( 3 ) comprises a frame body ( 36 ); a gas inlet ring ( 31 ), a gas outlet ( 32 ) and a connection plate ( 33 ) are successively arranged on the frame body ( 36 ) from inside to outside; an input end of the gas inlet ring ( 31 ) is connected with the gas supply apparatus ( 2 ); an output end is connected with an input end of the gas outlet ring ( 32 ) through the concrete test sample ( 1 ); the output end of the gas outlet ring ( 32 ) is connected with the gas flow meter ( 4 ); and the connection plate ( 33 ) is connected with the concrete test sample ( 1 ); and
the gas supply apparatus ( 2 ) supplies test gas of constant gas pressure to the instrument body ( 3 ); the test gas flows to the gas flow meter ( 4 ) from the gas inlet ring ( 31 ) successively via the concrete test sample ( 1 ) and the gas outlet ring ( 31 ); and then a gas permeability coefficient of the concrete is calculated according to a gas flow.

2. The apparatus for testing gas permeability in concrete according to claim 1 , wherein a bottom surface of the gas inlet ring ( 31 ) is circular; a bottom surface of the gas outlet ring ( 32 ) has a shape of a circular ring; and a bottom area of the gas inlet ring ( 31 ) is the same as the bottom area of the gas outlet ring ( 32 ).

3. The apparatus for testing gas permeability in concrete according to claim 1 , wherein an inner sealing ring ( 34 ) is arranged between the gas inlet ring ( 31 ) and the gas outlet ring ( 32 ), and an outer sealing ring ( 35 ) is arranged between the gas outlet ring ( 32 ) and the connection plate ( 33 ).

4. The apparatus for testing gas permeability in concrete according to claim 3 , wherein the gas supply apparatus ( 2 ) comprises a gas source ( 21 ), and a first gas transport channel ( 22 ), a second gas transport channel ( 23 ) and a third gas transport channel ( 24 ) with input ends being respectively connected with the gas source ( 21 ); an output end of the first gas transport channel ( 22 ) is connected with the input end of the gas inlet ring ( 31 ); an output end of the second gas transport channel ( 23 ) is connected with the input end of the inner sealing ring ( 34 ); and the output end of the third gas transport channel ( 24 ) is connected with the input end of the outer sealing ring ( 35 ).

5. The apparatus for testing gas permeability in concrete according to claim 4 , wherein a test gas dehumidification apparatus ( 221 ) is arranged on the first gas transport pipe ( 22 ).

6. The apparatus for testing gas permeability in concrete according to claim 4 , wherein the gas source ( 21 ) comprises a relief valve ( 211 ), and a precision relief valve ( 222 ) is arranged on the first gas transport pipe ( 22 ).

7. The apparatus for testing gas permeability in concrete according to claim wherein the instrument body ( 3 ) further comprises a plurality of fixing screw rods ( 37 ), and the connection plate ( 33 ) is connected with the concrete test sample ( 1 ) through the fixing screw rods ( 37 ).

8. A test method of the apparatus for testing gas permeability in concrete according to claim 1 , comprising the steps:
A, fixing an instrument body ( 3 ) to a structural concrete test sample ( 1 ) reaching maturity, and inflating an inner sealing ring ( 34 ) and an outer sealing ring ( 35 ) until the internal pressure reaches 6 to 7 atmospheric pressures;
B, introducing test gas with the gas pressure constant at the test gas pressure into the gas inlet ring ( 31 ), recording a gas flow permeating the concrete test sample ( 1 ) after the gas flow is stabilized, and calculating a permeability coefficient:

D
=

2
⁢

⁢
QL
⁢

⁢
μ
⁢

⁢
Pa

A
⁡

(

P
2

-

Pa
2

)

wherein is the permeability coefficient, L is an effective permeation thickness, Q is gas flow, u is gas viscosity, Pa is local atmospheric pressure, A is permeable area, and P is the test gas pressure; and
C, changing the test gas pressure, repeating the step B for three to five times, and calculating an average value of multiple measured permeability coefficients as a test value of the concrete test sample ( 1 ).

9. The test method according to claim 8 , wherein an effective permeation thickness L is:

L
=

2

2

⁢

R
3
2

+

R
2
2

-

2

2

⁢

R
1

wherein R 7 is a radius of a bottom surface of the gas inlet ring, R 2 is a radius of an inner circle of a bottom surface of the gas outlet ring, and R 3 is a radius of an outer circle of the bottom surface of the gas outlet ring.

Assignees

• Univ Tongji

Inventors

• Wang Zhongping
• Ni Xiaoxu
• Sun Ronglong
• Zhou Long
• Cheng Fei

Classifications

• G01N7/10

  by allowing diffusion of components through a porous wall and measuring a pressure or volume difference · CPC title

• G01N15/0826 Primary

  and measuring fluid flow rate, i.e. permeation rate or pressure change · CPC title

• G01N33/383

  Concrete or cement · CPC title