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Method for evaluating effectiveness of measure for inhibiting alkali-silica active reaction of concrete aggregate

A concrete aggregate and active reaction technology, which is applied in the field of evaluating the effectiveness of concrete aggregate alkali-silicic acid active reaction inhibition measures, can solve problems such as imperfect inhibition efficiency, difficult time to meet, active aggregate activity, etc.

Active Publication Date: 2009-08-26
POWERCHINA ZHONGNAN ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] (2) In actual engineering, different types of active aggregates have different activity levels, and the ratio of raw materials for mortar or concrete is different. The amount of inhibitory materials required to achieve safe and effective inhibitory effects cannot be exactly the same, and 25% is used It is also incomplete to evaluate its inhibitory performance by the amount of admixture. Some concrete does not allow 25% of the admixture. How to evaluate its inhibitory performance?
This is difficult to meet in terms of time for general engineering

Method used

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  • Method for evaluating effectiveness of measure for inhibiting alkali-silica active reaction of concrete aggregate
  • Method for evaluating effectiveness of measure for inhibiting alkali-silica active reaction of concrete aggregate
  • Method for evaluating effectiveness of measure for inhibiting alkali-silica active reaction of concrete aggregate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Example 1: Refer to the current DL / T5151-2001 "Hydraulic concrete sand and gravel aggregate test procedures" in the mortar bar rapid method (400g cementitious material, five grades of sand, 1:2.25 lime sand Ratio, 0.47 water-cement ratio), using the Sanbanxi Hydropower Station sandstone artificial sand and low-alkali cement (effective alkali Na2O content ≤ 0.60%) to form a mortar rod rapid method test piece, the test piece is placed in 80 ℃ water soaked for 24 hours to determine the base length Then, the specimen was immersed in a NaOH solution with a temperature of 80°C and the same alkali concentration as the mortar specimen hole solution (NaOH concentration ≤0.41mol / L) for curing, and the expansion rate of the specimen was measured according to different ages.

[0021] At the same time, refer to the current DL / T5151-2001 "Hydraulic concrete sand and gravel aggregate test procedures" in the mortar bar rapid method (400g cementitious material, five grades of sand, 1:2.25 l...

Embodiment 2

[0028] Example 2: Refer to the current DL / T5151-2001 "Hydraulic concrete sand and gravel aggregate test procedures" in the mortar bar rapid method (400g cementitious material, five grades of sand, 1:2.25 lime sand Ratio, 0.47 water-cement ratio), using the Wuqiangxi Hydropower Station sandstone artificial sand and low-alkali cement (effective alkali Na2O content ≤ 0.60%) forming mortar rod rapid method test specimens, the specimens are placed in 80 ℃ water soaked for 24 hours to determine the base Then, the specimen is immersed in a NaOH solution with a temperature of 80°C and the same alkali concentration as the mortar specimen hole solution (NaOH concentration ≤0.41mol / L) for curing, and the expansion rate of the specimen is measured according to different ages. .

[0029] At the same time, refer to the current DL / T5151-2001 "Hydraulic concrete sand and gravel aggregate test procedures" in the mortar bar rapid method (400g cementitious material, five grades of sand, 1:2.25 lime-s...

Embodiment 3

[0036] Example 3: Use Wuqiangxi sandstone mixed with 5% high-activity glassy aggregate to configure artificial active aggregate. Refer to the current DL / T5151-2001 "Test Procedure for Hydraulic Concrete Sand and Stone Aggregate" for the alkali activity of aggregate The tested mortar bar rapid method (400g cementitious material, five grades of sand, 1:2.25 ash-sand ratio, 0.47 water-cement ratio), used the artificial active aggregate and low-alkali cement (effective alkali Na2O content ≤ 0.60%) to shape The mortar rod rapid method test piece, the test piece is placed in 80 ℃ water for 24 hours to determine the base length, and then the test piece is immersed in the temperature of 80 ℃ and the alkali concentration of the mortar test piece hole solution (NaOH concentration ≤ 0.41mol / L ) Soak and cure in the same NaOH solution, and measure the expansion rate of the specimens according to different ages.

[0037] At the same time, refer to the current DL / T5151-2001 "Hydraulic concrete ...

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Abstract

A method for evaluating effectiveness of a measure for inhibiting alkali-silica active reaction of concrete aggregate comprises the following steps: using active aggregate used in actual works and low-alkali cement with available alkali Na2O content less than or equal to 0.60% or high-alkali cement with available alkali Na2O content of 0.90%+ / -0.1% to form mortar test pieces by mixing fly ash, and determining an inhibition measure effective where low-alkali cement mortar test pieces are formed and expansion rate of the mortar test pieces in 14 days is equal to or less than 0.040%, and determining the inhibition measure effective where high-alkali cement mortar test pieces mixed with the fly ash are formed and expansion rate of the mortar test pieces in 14 days is equal to or less than 0.050%. Thus, the method can help quickly determine the expansion rate of the mortar test pieces formed with the active aggregate used in actual works, and verify and evaluate the effectiveness of the measure for inhibiting the reaction of the concrete aggregate to meet engineering construction need.

Description

Technical field [0001] The invention relates to a measure for inhibiting the alkali-silicic acid activity reaction of concrete aggregates, and particularly relates to a method for evaluating the effectiveness of the measures for inhibiting the alkali-silicic acid activity reaction of concrete aggregates. Background technique [0002] At present, a number of hydropower projects in my country including Xiangjiaba Hydropower Station, Sanbanxi Hydropower Station, Jinping Hydropower Station have successively carried out experimental research work to prevent concrete alkali-aggregate reaction. The experimental research results show that: the use of low-alkali cement (effective alkali Na 2 O content ≤ 0.60%), mixing concrete with admixtures that can consume the effective alkali in concrete and other measures to control the total alkali content of concrete can significantly inhibit the aggregate alkali-silicic acid activity reaction. [0003] The effect of concrete aggregate alkali-silic...

Claims

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Application Information

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IPC IPC(8): G01N33/38
Inventor 李双艳李蓓涂传林刘伯平唐爽
Owner POWERCHINA ZHONGNAN ENG
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