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

A technology for concrete aggregates and active reaction, which is applied in the field of evaluating the effectiveness of measures for inhibiting the alkali-silicic acid active reaction of concrete aggregates, and can solve the problems of imperfect inhibition efficiency, high and low activity of active aggregates, and difficulty in meeting time.

Active Publication Date: 2012-07-04
POWERCHINA ZHONGNAN ENG
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  • Description
  • Claims
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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
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Effect test

Embodiment 1

[0020] Embodiment 1: With reference to the mortar rod rapid method of aggregate alkali activity test in the current DL / T5151-2001 "Hydraulic Concrete Sand and Stone Aggregate Test Regulations" (400g cementitious material, five-grade sand, 1: 2.25 lime sand Ratio, 0.47 water-cement ratio), use sandstone artificial sand of Sanbanxi Hydropower Station and low-alkali cement (effective alkali Na2O content ≤ 0.60%) to form a mortar rod rapid method test piece, place the test piece in 80 ° C water for 24 hours to measure the base length , and then soak the specimen in NaOH solution at a temperature of 80°C and the same alkali concentration as the mortar specimen pore solution (NaOH concentration ≤ 0.41mol / L), and measure the expansion rate of the specimen according to different ages.

[0021] At the same time, referring to the current DL / T5151-2001 "Hydraulic Concrete Sand and Stone Aggregate Test Regulations", the mortar rod rapid method of the aggregate alkali activity test (400g ce...

Embodiment 2

[0028] Embodiment 2: With reference to the mortar rod rapid method of aggregate alkali activity test (400g cementitious material, five grades of sand, 1: 2.25 lime-sand Ratio, 0.47 water-cement ratio), use sandstone artificial sand of Wuqiangxi Hydropower Station and low-alkali cement (effective alkali Na2O content ≤ 0.60%) to form a mortar rod rapid method test piece, place the test piece in 80 ° C water for 24 hours to measure the base Then soak the specimen in the NaOH solution with the temperature of 80°C and the same alkali concentration as the mortar specimen pore solution (NaOH concentration ≤ 0.41mol / L), and measure the expansion rate of the specimen according to different ages.

[0029]At the same time, referring to the current DL / T5151-2001 "Hydraulic Concrete Sand and Stone Aggregate Test Regulations", the mortar rod rapid method of the aggregate alkali activity test (400g cementitious material, five-grade sand, 1:2.25 gray-sand ratio, 0.47 water-cement ratio), with...

Embodiment 3

[0036] Example 3: Use Wuqiangxi sandstone mixed with 5% high-activity vitreous aggregates to configure artificial active aggregates, referring to the current DL / T5151-2001 "Test Regulations for Hydraulic Concrete Sandstone Aggregate" for alkali activity of aggregates The mortar rod rapid method of the test (400g cementitious material, five-grade sand, 1:2.25 lime-sand ratio, 0.47 water-cement ratio), using the artificial active aggregate and low-alkali cement (effective alkali Na2O content ≤ 0.60%) molding Mortar rod rapid method test piece, place the test piece in 80°C water for 24 hours to measure the base length, then soak the test piece in a temperature of 80°C and the alkali concentration of the pore solution of the mortar test piece (NaOH concentration≤0.41mol / L) Soak in the same NaOH solution for curing, and measure the expansion rate of the specimens according to different ages.

[0037] At the same time, referring to the current DL / T5151-2001 "Hydraulic Concrete Sand ...

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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 concrete aggregate alkali-silicic acid active reaction inhibition measures, in particular to a method for evaluating the effectiveness of concrete aggregate alkali-silicic acid active reaction inhibition measures. Background technique [0002] At present, many hydropower projects in my country, such as Xiangjiaba Hydropower Station, Sanbanxi Hydropower Station, and Jinping Hydropower Station, have successively carried out experimental research on the prevention of concrete alkali-aggregate reaction. Experimental research results show that: the use of low-alkali cement (effective alkali Na 2 O content ≤ 0.60%), adding admixtures that can consume the effective alkali in concrete and other measures to control the total alkali content of concrete can significantly inhibit the active reaction of aggregate alkali-silicic acid. [0003] The influence of concrete aggregate alkali-silicic acid active reaction on the durability of concr...

Claims

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Application Information

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Patent Type & Authority Patents(China)
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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