Method for measuring pH value of carbonated concrete pore solution

A concrete and pore solution technology, applied in the direction of material inspection products, etc., can solve the problems that it is difficult to see the pH value of the carbonized concrete pore solution, the pH value of the press filter pore solution, and the difficulty of obtaining the press filter pore solution, etc., achieving low cost , the effect is good, and the effect of solving the difficulty of obtaining

Inactive Publication Date: 2013-07-03
HOHAI UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Due to the long-term concrete and low water ash (glue) than concrete, it is difficult to obtain the filter press solution; due to the continuity of the carbonization process, it is more difficult to obtain the pH value of the concrete filter press solution with a specified carbonation depth under different carbonation degrees; Therefore, it is difficult to see the study of the pH value of the carbonized concrete pore solution.

Method used

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  • Method for measuring pH value of carbonated concrete pore solution
  • Method for measuring pH value of carbonated concrete pore solution
  • Method for measuring pH value of carbonated concrete pore solution

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Concrete specimens are made, the size is 3×10×10mm, the cement is 42.5 grade ordinary Portland cement, and the sand is medium sand with a fineness modulus of 2.8. After the specimens were cured for 28 days under standard conditions, in CO 2 The accelerated carbonization test was carried out in an environment with a concentration of 5%, a temperature of 20°C, and a relative humidity of 40%. Concrete mix parameters: the amount of cement is 400kg / m 3 , water-binder ratio 0.5, fine aggregate dosage 650 kg / m 3 .

[0019] With the progress of carbonization, there is a fitting curve relationship between the pH value of the pore solution and the pH value of the suspension: , and the correlation coefficient is 0.98. At 3 days of carbonization, the measured pH values ​​of the pore solution and suspension were 12.01 and 12.22 respectively, and the calculated value of the pore solution was 11.84, with a difference of 1.3% between the measured value and the calculated value; at...

Embodiment 2

[0021] Concrete specimens are made, the size is 3×10×10mm, the cement is 42.5 grade ordinary Portland cement, and the sand is medium sand with a fineness modulus of 2.8. After the specimens were cured for 28 days under standard conditions, in CO 2 The accelerated carbonization test was carried out in an environment with a concentration of 5%, a temperature of 20°C, and a relative humidity of 40%. Concrete mix parameters: the amount of cement is 450kg / m 3 , water-cement ratio 0.5, fine aggregate consumption 650 kg / m 3 .

[0022] As the carbonization progresses, the pH value of the pore solution is related to the pH value of the suspension as follows: , and the correlation coefficient is 0.98. At 3 days of carbonization, the measured pH values ​​of the pore solution and suspension were 12.25 and 12.37 respectively, and the calculated value of the pore solution was 12.24, with a difference of 0.1% between the measured and calculated values; at 6 days of carbonization, the me...

Embodiment 3

[0024] Concrete specimens are made, the size is 3×10×10mm, the cement is 42.5 grade ordinary Portland cement, and the sand is medium sand with a fineness modulus of 2.8. After the specimens were cured for 28 days under standard conditions, in CO 2 The accelerated carbonization test was carried out in an environment with a concentration of 5%, a temperature of 20°C, and a relative humidity of 40%. Concrete mix parameters: the amount of cement is 500kg / m 3 , water-cement ratio 0.5, fine aggregate consumption 680 kg / m 3 .

[0025] As the carbonization progresses, the pH value of the pore solution is related to the pH value of the suspension as follows: , and the correlation coefficient is 0.98. At 3 days of carbonization, the measured pH values ​​of the pore solution and the suspension were 12.35 and 12.45 respectively, and the calculated value of the pore solution was 12.39, with a difference of 0.3% between the measured value and the calculated value; at 6 days of carboniz...

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Abstract

The invention relates to a method for measuring a pH value of carbonated concrete pore solution, belonging to the technical field of civil engineering materials. The method for measuring the pH value of the carbonated concrete pore solution provided by the invention comprises the following steps of: producing thin concrete test pieces, accelerating carbonation, filter pressing the concrete pore solution, preparing suspending liquid by concrete powder and the like. The pH value of the concrete pore solution is calculated by measuring the pH value of the concrete pore solution in different carbonation degrees and the pH value of the carbonated concrete powder suspending liquid, establishing the relationship between the pH value pH value of the concrete pore solution in different carbonationdegrees and the pH value of the suspending liquid, and measuring the pH value of the concrete suspending liquid. The method for measuring the pH value of the carbonated concrete pore solution provided by the invention is simple in equipment, low in cost, excellent in effect and the like; and the method is suitable for durability test research work such as concrete carbonation, pH measurement and the like.

Description

technical field [0001] The invention relates to a method for measuring the pH value of carbonized concrete pore solution, belonging to the technical field of civil engineering materials. Background technique [0002] Corrosion of steel bars is one of the most important reasons for the lack of durability of reinforced concrete structures and the failure of reinforced concrete structures. Carbonation itself does not cause deterioration of concrete, but changes the pH of the concrete pore solution. Uncarbonated concrete is alkaline, and steel bars are in a passivated state in an alkaline environment and will not rust. However, carbonation will cause acidification of concrete, destroy the passivation film of steel bars, and cause corrosion of steel bars. [0003] The pH value of the concrete pore solution is closely related to whether the steel bar will corrode. Based on this, some studies on concrete pore solutions have been carried out by methods such as on-site dissolution...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N33/38
Inventor 蒋林华濮琦蒋俣徐怡徐金霞
Owner HOHAI UNIV
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