JP3527441B2 - Prediction method of deterioration progress of concrete structure by alkali-silica reaction - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for predicting the progress of deterioration of a concrete structure deteriorated by an alkali silica reaction (hereinafter sometimes simply referred to as "ASR").

[0002]

2. Description of the Related Art Conventionally, much research has been conducted on ASR in concrete structures, and the results of those studies have made clear the factors that promote the mechanism and reaction of ASR. Above all, A
SR is a chemical reaction between a pore solution in concrete and a reactive substance in aggregate, cement, fine aggregate,
ASR due to admixture and alkali supplied from the external environment, temperature, humidity, or a combination of these factors
It is well known that is promoted.

It has also been pointed out that the state of damage to concrete caused by ASR and the degree of damage depend on environmental conditions. Furthermore, in concrete structures affected by seawater and snow melting agents, Na supplied from the outside
Although it is known that indoor experiments and outdoor exposure tests show that Cl accelerates ASR deterioration, it is not possible to use AS under natural conditions in actual concrete structures.
At present, there are very few studies that have examined the progress of R deterioration in detail.

On the other hand, the prediction of the future progress of deterioration of a concrete structure due to ASR deterioration is extremely important in the maintenance and management of the concrete structure, but the conventional method is to use 40 samples taken from the concrete structure. It is known that the degree of deterioration is judged to some extent from the residual expansion rate after 6 months in an environment of ° C and humidity of 95% or more. However, in this method, it takes time and the prediction of the deterioration degree is insufficient, and there is currently no rational prediction method.

Further, Japanese Patent No. 2535177 discloses that
A deterioration determination method for a reinforced concrete structure is disclosed by determining a corrosion area of a reinforcing bar by superimposing a self-potential distribution map and a specific resistance distribution map, and Japanese Patent Laid-Open No. 9-61421 discloses a concrete. A method for evaluating the soundness of concrete and a method for repairing deteriorated concrete are disclosed by determining the sulfuric acid component (presence or absence of sulfuric acid ion) of concrete taken from a structure, and Japanese Patent Laid-Open No. 10-90235 discloses a concrete. By measuring the occurrence status of acoustic emission (AE) that occurs when gradually increasing hysteresis load is applied to the structure,
A method for determining deterioration of a concrete structure is disclosed that determines deterioration of the concrete structure at any time. However, the deterioration determination methods for concrete structures and the like disclosed in these publications do not accurately predict the progress of deterioration of the concrete structure deteriorated by the alkali-silica reaction, and the technical idea of the present invention is the same. It is different.

[0006] As described above, conventional ASR-related technologies and the like are mainly based on indoor experimental research and the like, and at present, there is very little research or the like targeting actual concrete structures, and under the natural environment. At present, there is a strong demand for accurate prediction of deterioration progress of a concrete structure that has been placed in an ASR deteriorated concrete structure.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and it is an object of the present invention to solve the problems. ASR deteriorated concrete placed in a natural environment in a short period of time by a simple method. An object is to provide a method for predicting the progress of deterioration of a structure.

[0008]

As a result of intensive studies on the above-mentioned problems of the prior art, the present inventors have found that the expansion rate of concrete under a specific test taken from a concrete structure, and It was found that a method for predicting deterioration progress of the concrete structure by the alkali silica reaction can be obtained by combining it with the alkali hydroxide concentration in the pore solution extracted from the prepared concrete, and the present invention has been completed. It was. That is, the present invention resides in the following (1) to (3). (1) Deterioration of the concrete structure deteriorated by the alkali-silica reaction according to the correlation between the expansion coefficient of the concrete in the accelerated expansion test of the concrete sampled from the concrete structure and the alkali hydroxide concentration of the concrete sampled from the concrete structure. A method for predicting the progress of deterioration of a concrete structure due to an alkali-silica reaction, which is characterized by predicting the progress. (2) The expansion coefficient of the concrete is the expansion coefficient of the concrete measured by the NBRI test, and the alkali hydroxide concentration is the OH ⁻ ion concentration in the pore solution.
(1) A method for predicting the progress of deterioration of a concrete structure due to an alkali silica reaction. (3) The method for predicting the deterioration progress of a concrete structure due to an alkali silica reaction according to (1) or (2) above, which predicts the deterioration progress of a concrete structure in four stages.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. The method of predicting the deterioration progress of the concrete structure of the present invention due to the alkali-silica reaction, the expansion rate of the concrete in the accelerated expansion test of the concrete taken from the concrete structure, and the alkali hydroxide concentration of the concrete taken from the concrete structure According to the correlation, the deterioration progress of the concrete structure deteriorated by the alkali-silica reaction is predicted.

In the present invention, the expansion coefficient of concrete is
Concrete (core) sampled from a concrete structure
The expansion rate of concrete in the accelerated expansion test of.
Examples of the accelerated expansion test include a 50 ° C. saturated sodium chloride solution dipping method and an accelerated test in an 80 ° C. 1N sodium hydroxide solution [NBRI test], and the NBRI test is preferable. The accelerated material age (number of days elapsed) in these accelerated expansion tests is appropriately set depending on the environmental conditions of the concrete structure, for example, the degree of solar radiation, changes in temperature and humidity, and environmental conditions such as the supply of water and salt. However, in view of accuracy and short-term prediction, it is within 120 days, preferably within 30 days, and more preferably within 10 to 21 days.

The presence of the reactive substance in the concrete is confirmed by measuring the expansion rate of the concrete in this accelerated expansion test, that is, when the concrete in the accelerated expansion test expands, the reactive substance in the concrete ( It will be understood that the component) still remains. In the present invention, the reference value (threshold value) that the expansion rate of concrete in the accelerated expansion test affects the deterioration progress of the concrete structure due to ARS depends on the type and elapsed days of the accelerated expansion test, and the environmental conditions of the concrete structure. The difference is set appropriately. For example, in the NBRI test, a coefficient of expansion of 0.1% on the 14th day is cited as a threshold value, and the reactivity in the concrete is limited to 0.1% (14 days). The degree of progress of deterioration of ARS differs depending on the amount of substance.

In the present invention, the alkali hydroxide concentration of concrete taken from the concrete structure is
In the case of ASR deterioration, it can be performed by evaluating the composition of the sample pore solution of the concrete [sodium hydroxide (NaOH) and potassium hydroxide (KOH) are the main components]. The alkali hydroxide concentration in the pore solution can be measured, for example, by using a high-pressure extraction device and measuring the OH ⁻ ion concentration by pore solution analysis. In the present invention, the reference value (threshold value) at which the alkali hydroxide concentration affects the progress of deterioration of the concrete structure due to ARS is different depending on the environmental conditions of the concrete structure and is appropriately set. For example, pore solution analysis As the threshold of OH ^- ion concentration by
OH ^- ion concentration of 250
With the mmol / l as the boundary, the degree of progress of deterioration of ARS varies depending on the difference in the amount of alkali components in the concrete.

In the present invention, attention is paid to the fact that ASR is a chemical reaction between the reactive substance in the aggregate and the pore solution in the concrete. It is possible to predict the future progress of deterioration of concrete in a relatively short period of time by combining the presence or absence of residual reactive components and the concentration of alkali hydroxide in the pore solution of concrete, for example, the OH-ion concentration. It will be possible. That is, in the present invention, the expansion rate of concrete in the accelerated expansion test of the concrete extracted from the concrete structure [for example, the expansion rate by the NBRI test [(14 days) (threshold) 0.1%] and the expansion rate of the concrete extracted from the concrete structure] Concentration of alkali hydroxide in pore solution of cured concrete [eg, OH ^- ion concentration (threshold value) 2
50 mmol / l], the progress of deterioration of the concrete structure deteriorated by the alkali-silica reaction can be predicted, for example, as shown in FIG. 1 (deterioration degree is 4 steps). This will be described in detail in the test examples described later). Here, the criteria A to D are as follows. Judgment A is O
H ^- ion concentration (threshold value) of 250 mmol / l or more, NB
The expansion rate (14 days) by the RI test is in the range of 0.1% or more. In this range, there are many residual reactive components in the aggregate and alkali hydroxide in the pore solution, and there is a possibility that deterioration will progress in the future. large. Judgment B was within the range of the standard value (threshold value) of OH ^- ion concentration of less than 250 mmol / l and the expansion coefficient (14 days) of 0.1% or more by the NBRI test. In this range, residual reactive components in the aggregate were However, since the alkali hydroxide concentration is low, it is unlikely that deterioration will progress in the future. However, if there is a possibility of alkali supply from the outside in the future, the possibility of deterioration progressing in the future increases. Judgment C is a reference value (threshold value) of OH ⁻ ion concentration
It is in the range of 250 mmol / l or more and less than 0.1% of the expansion coefficient (14 days) by the NBRI test.
Although the alkali hydroxide concentration is high, there is little residual reactive component in the aggregate, so there is little possibility of future deterioration. Judgment D is a standard value (threshold value) of OH ⁻ ion concentration of 250 mmo.
Less than 1 / l, expansion coefficient by NBRI test (14 days) 0.
It is in the range of less than 1%. In this range, the residual reactive component in the aggregate is small, and the alkali hydroxide concentration in the pore solution is low, so that there is almost no progress of deterioration in the future.

According to the present invention having such a structure, according to the correlation between the expansion coefficient of concrete in the accelerated expansion test of the concrete sampled from the concrete structure and the alkali hydroxide concentration of the concrete sampled from the concrete structure, As it is possible to predict the progress of deterioration of concrete structures deteriorated by silica reaction, it can be used for the evaluation of deterioration of concrete structures deteriorated by alkali silica reaction and the determination of the repair time and degree, and it is effective for concrete structures. In addition to being able to carry out repairs, deterioration can be predicted easily in a relatively short time. In the present invention, the concrete structure to be predicted is not particularly limited, for example, a building made of a concrete structure, a dam,
Useful for predicting deterioration of concrete structures such as chimneys, tunnels, viaducts such as railways and roads, bridges, breakwaters, etc., where safety is particularly required, such as buildings, tunnels, railways and roads viaducts. You can

The present invention is constructed as described above, but is not limited to the above-mentioned embodiment, and can be appropriately changed depending on the environmental conditions of the concrete structure and the like. For example, in the above-described embodiment, the threshold value of the OH ⁻ ion concentration is 250 mmol / l and the threshold value of the expansion coefficient is 0.1% (14 days). However, depending on the environmental conditions of the concrete structure, for example, The threshold of the OH ⁻ ion concentration may be 250 mmol / l, the threshold of the expansion coefficient may be 0.1%, and the number of elapsed days may be 14 days.

[0016]

EXAMPLES Next, the present invention will be described in more detail with reference to test examples, but the present invention is not limited to the following test examples.

The concrete structure used in this test, the measurement of the expansion coefficient of the core (concrete) under accelerated conditions, the pore solution extraction test, etc. will be described in detail below. [Concrete structure subject to test] The concrete structure subject to this test (Location: Oshiudani, Shirakawa-mura, Ono-gun, Gifu Prefecture) is a rubber-flooded undulating weir (hereinafter referred to as "rubber") constructed as a verification test facility. Figure 2 attached to the "weir")
The sample obtained from the concrete retaining wall shown in was used. This rubber weir was built in 1982 and is 10m high, 14m wide and has a slope of 1: 0.5 on the left and right banks.
A wear resistant rubber weir is fixed to the concrete retaining wall, and it is designed to automatically detect the water level and to fall when the water depth becomes 5.3 m due to the air expansion type and to rise up to 0.2 m. Has been done. A concrete wall was placed behind the concrete retaining wall on the right bank, and most of the rear surface of the concrete retaining wall on the left bank was backfilled with earth and sand. The structure as of 1996 was 14 years old after construction and had already undergone significant deterioration mainly due to ASR.

[Measurement of expansion coefficient of concrete (core)]
The residual expansion coefficient was measured using cores (diameter 96 mm) collected from each location of the retaining wall shown in Table 1 below. The core test piece was cut into a length of about 130 to 250 mm, stored in a closed container having a temperature of 40 ° C. and a humidity of 95% or more, and the length was measured for 6 months. The test results are shown in FIG. 3 and Table 1 below.

[0019]

[Table 1]

As is clear from the results of the test shown in Table 1 and FIG. 3, the expansion coefficient of the core taken from any part is about 0.02% or less, and it is judged that the ASR expansion is almost converged. It was In addition, the rubber weir fixing part was considered to have been mitigated by the effects of solar radiation and changes in humidity, but the average expansion coefficient of the core sampled from this part was 0.015%, similar to other parts of concrete. It is considered that the ASR has almost converged.

Next, to determine the ASR reactivity of the aggregate, the coarse aggregate and the fine aggregate were taken out from the concrete of the rubber dam retaining wall, and after the visual classification, thin pieces were prepared to identify the rock species. . The rock type composition of coarse aggregate (about 13 kg) is shown in Table 2 below.

[0022]

[Table 2]

Among them, the ones in which the reaction ring was confirmed by observing the thin piece with a polarization microscope were andesite, rhyolite and hornfels. In addition, as a result of carrying out a chemical method [JIS A 5308-1993 (ready-mixed concrete)] in order to know the alkali reactivity of these aggregates, all were harmless except that the fine aggregates were determined to be harmless. . In addition, the mortar bar method [JIS A 5308-1993]
(Lady-mixed concrete)], the expansion rate of all samples was around 0.03% (6 months),
Both coarse aggregate was judged to be harmless. However, it is possible that the amount of reactive components is significantly reduced in the aggregate taken out of the concrete in which ASR has already progressed to a considerable extent. In addition, in the mortar bar method, alkali hydroxide may leak from the specimen, which may result in a judgment on the dangerous side. Therefore, the core (diameter 4
Using 8 × 100 mm), a 50 ° C. saturated sodium chloride solution immersion method (Denmark method) and an accelerated test (NBRI method) at 80 ° C. 1N sodium hydroxide solution were carried out. As shown in FIG. 4, in any accelerated test,
It was confirmed that the core expanded rapidly, and even after 14 years had passed since the construction, the reactive component still remained in the aggregate of the concrete containing the rubber dam retaining wall.

(Analysis of pore solution of cement paste and mortar) In the analysis of pore solution, there is no report of data on the composition of pore solution in cement paste or mortar with various water-cement ratios. In this test, the pore solution analysis of cement paste and mortar was conducted first, and the effect of the water-cement ratio on the composition of the pore solution was clarified. After that, the pore solution was extracted from the concrete core taken from the concrete structure and analyzed. The pore solution is obtained by setting the pore solution extraction high-pressure device in a 200t universal testing machine and repeating loading and unloading stepwise up to a maximum load of about 600 kN / mm ² . Immediately dilute the sampled pore solution 100 to 200 times with pure water to obtain Na ⁺ , K ⁺ , C
The a ²⁺ ion concentration was measured by the ICP solution analysis method, and the OH ⁻ ion concentration was measured by the hydrochloric acid titration method using phenolphthalein as a reagent.

In order to investigate the composition change of the pore solution when the water-cement ratio is different, the water-cement ratio of 30, 40, 50,
Extraction of pore solutions and their analysis (Na ⁺ , K ⁺ , Ca ²⁺ , OH ⁻ ) using 5 types of 60, 70% cement paste and mortar (cement: sand = 1: 2) samples.
Ion concentration). The material used was ordinary portland cement manufactured by Taiheiyo Cement Co. (total alkali content 0.61).
%), ISO sand. The sample has a diameter of 50 mm and a height of 1
After driving into a 00 mm cylindrical formwork, the mold was removed the next day and the material was aged 7
Up to the day, curing was carried out in a closed container at 20 ° C., and the solution was inserted into the above high pressure device to extract the pore solution. The analysis results are shown in FIG. 5 and Table 3 below.

[0026]

[Table 3]

From the results shown in Table 3 and FIG.
Mortar Na ⁺, K⁺, Ca²⁺, O
H^-Ion concentration is slightly lower than that of cement paste
Sai. In addition, N is almost proportional to the increase in the water cement ratio.
a⁺, K⁺, OH^-Each ion concentration of²⁺
On the contrary, the ion concentration increases. Furthermore, water cement ratio 70%
Also in OH^-Ion concentration is about 300 mmol / l
And OH that generates ASR^-Ion concentration threshold
Since it exceeds 250 mmol / l, past research
Judging from the results, this concentration is not enough to cause ASR.
It can be said that the concentration is sufficient.

(Diagnosis Progress Diagnosis and Evaluation by Analysis of Pore Solution) In order to predict the future progress of deterioration of the structure deteriorated by ASR, the pore solution analysis of the concrete sampled from the concrete structure was performed. The core samples used were the cores taken from the rubber weir retaining wall (see Table 1), substation retaining wall concrete (B), avalanche protection fence concrete (C), and water tank retaining wall concrete in the same area. The one collected from (D) is also included. Of these, the substation retaining wall is a concrete retaining wall with a height of 12 m and a wall thickness of 0.5 to 1.2 m 38 to 40 years after construction, and avalanche protection fence concrete (length 1.3 m × width 12. 4m x height 1.
8m) and located on the eastern slope, the sunshine conditions are not as good as on the right bank of the rubber weir retaining wall. In addition, the aquarium retaining wall has a height of 3.5 m and a wall thickness of 0.
It is a concrete retaining wall of 5 to 1.4 m and is located on the west slope, so the sunshine conditions are very good, but the mountain side is shaded and the sunshine duration is shorter than the valley side. The environmental conditions of these structures are shown in Table 4 below, and the concrete composition is shown in Table 5 below.

[0029]

[Table 4]

[0030]

[Table 5]

Although the composition of the substation retaining wall concrete (B) and the avalanche protection fence concrete (C) is unknown, it is estimated from the composition of the rubber dam retaining wall (A) and the water tank retaining wall (D). It is estimated that the water cement ratio was about 50 to 60%. The amount of alkali in the cement at the time of construction is unknown, but if the equivalent amount of Na ₂ O in the cement used was about 0.6%, it is estimated from the results in Table 3 above that of the pore solution OH ^-
It is estimated that the ion concentration had a value of about 350 to 450 mmol / l. Further, the core sample (96 mm in diameter) collected on site was immediately sealed in a vinyl bag so as to prevent water from entering and exiting until the time of extracting the pore solution in order to prevent alkali elution. Then, in the test room, the diameter is 46 mm from the center of the core and the length is 60 to 100.
mm core samples were cut out, and after 30 minutes to 1 hour, 2-3 ml of the pore solution was extracted from each core sample. The test results are shown in Tables 6 to 8 below.

[0032]

[Table 6]

[0033]

[Table 7]

[0034]

[Table 8]

From the results of the analysis of the pore solutions shown in Tables 6 to 8 above, the following was found. It can be seen that the balance between the cation concentration and the anion concentration in the pore solution is good. As is clear from FIG. 6 showing the relationship between the core sampling position and the (Na ⁺ + K ⁺ ) ion concentration in the pore solution, the standard deviation of the ion concentration is 44.3 mmol / l at the surface, Is 28.1 mmol / l, and the fluctuation range of the alkali ion concentration on the surface portion is large depending on the sampling position of the core. This result is considered to be due to the presence of more cracks on the surface of the concrete body than on the inside. In other words, carbonation due to invasion of carbon dioxide through many cracks existing near the surface and fixation of alkali due to drying proceed particularly actively around the crack, so that the concentration of alkali ions varies greatly depending on the sampling position of the core. It seems that it has become.

Further, in FIG. 6, although the ion concentration of the sample surrounded by the dotted line is lower than the others, cracks existed in the vicinity of the concrete core at this portion, and the core was locally broken. From the observation at the time of core extraction, it is estimated that these cracks and fractures did not occur at the time of core extraction, so the cause of the concentration decrease is the elution of alkali in concrete due to the intrusion of rainwater through these cracks, Carbonation due to inflow of carbon dioxide gas through the cracks and fixation of alkali by drying near the cracks are considered.

Further, as indicated by * in Table 7, when the OH ^- ion concentration at the surface portion and the deeper portion at the same core sampling position are compared, the OH ^- ion concentration near the surface is lower than that at the deep portion. There is. The surface concrete is
This fact supports the result that the alkali ions in the pore solution near the concrete surface are fixed during drying, as they undergo repeated dry-wet cycles. Furthermore, although the alkali amount of the cement used in the production of this concrete is unknown, comparing with the results of the pore solution analysis of cement paste and mortar (see Table 3), Na ⁺ of the pore solution from the core, The K ⁺ and OH ⁻ ion concentrations are one order lower than the ion concentrations of cement paste and mortar at the initial age. The reason that the concentration of alkali ions in the concrete is low is presumed to be that alkali ions are consumed by ASR that has progressed over a long period of 14 years. Therefore, as described above, the residual expansion rate of the core is small despite the fact that the reactive component still remains in the aggregate.
OH ^- ion concentration threshold of pore solution (250 mmol /
l) It is presumed that it was decreased below.

The OH ^- ion concentration in the pore solution of the substation retaining wall and the avalanche fence is about 51 to 63 mmol / l, which is lower than that of the rubber dam retaining wall concrete. this is,
It is speculated that the concrete to be surveyed has passed 38 to 40 years after construction, and the progress of ASR and the degree of alkali elution due to rainwater etc. have progressed further. In addition, from Table 8, it is estimated that ASR was promoted by the influence of solar radiation on the aquarium retaining wall (38 mmol /
It can be seen that 1) has a smaller OH-ion concentration in the pore solution than the mountain side (92 mmol / l). Furthermore, 2
The OH ⁻ ion concentration in the saturated solution of calcium hydroxide at 0 ° C. was 42 mmol / l, and it was found that the OH ⁻ ion concentration of most of the cores obtained in this test was higher than this.

Considering the above test results, in FIG. 3 etc., the OH ⁻ ion concentration in the concrete decreased due to the progress of ASR even though the reactive component of the aggregate still remained. It was found that the residual expansion of the concrete core hardly occurred even under the accelerated condition at ℃ and 100% relative humidity. In addition, the threshold of the OH ⁻ ion concentration that causes ASR is 250 mmol /
However, the result of this test is consistent with the above threshold. Based on these test results, the presence or absence of residual reactive components in the aggregate was determined by the NBRI test (expansion test in high-concentration NaOH solution at high temperature), and the results and the analysis results of the pore solution (water It is shown that the future progress of deterioration of a structure deteriorated by ASR can be predicted by combining it with (alkali oxide concentration), and ASR deteriorated structures are targeted within the range obtained in this test. Therefore, the deterioration progress prediction can be performed based on the criteria as shown in FIG. 1 (the criteria for judging A to D are described above). For example, the judgment of the deterioration progress in the concrete structure is B, but the interpretation here is as follows.
That is, although the reactive components still remain in the aggregate in this concrete, it can be said that there is no possibility of future deterioration at present due to the decrease in the alkali concentration. However, if alkali is expected to be supplied from the outside in the future, the possibility of deterioration due to ASR increases.

[0040]

INDUSTRIAL APPLICABILITY According to the present invention, it can be used for the deterioration evaluation of the concrete structure deteriorated by the alkali silica reaction and the judgment of the repair time and degree, and the effective repair can be performed in a relatively short time. A method for predicting the progress of deterioration of a concrete structure due to an alkali-silica reaction is provided.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing an example of a prediction standard of deterioration progress of a concrete structure deteriorated by an alkali silica reaction in the present invention.

FIG. 2 (a) is a schematic plan view of Oshidani, Shirakawa-mura, Ono-gun, Gifu prefecture, which is a collection site of concrete cores (samples) used in the test of the present invention, and (b) is a concrete structure (rubbered). It is a schematic front view of the cross-sectional aspect which shows the undulation weir made of cloth.

FIG. 3 is a characteristic diagram showing a relationship between a sampling depth of a concrete core (sample) and a residual expansion coefficient.

FIG. 4 is a characteristic diagram showing the results of accelerated expansion test using a concrete core (sample).

FIG. 5 is a characteristic diagram showing the effect of the water-cement ratio in cement paste and mortar on the pore solution composition.

FIG. 6 is a characteristic diagram showing the relationship between the sampling depth of a concrete core (sample) and the ion concentration of the pore solution (rubber dam retaining wall).

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-2-73156 (JP, A) JP-A-9-61421 (JP, A) JP-A-57-200841 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G01N 33/38

Claims (3)

(57) [Claims] 1. A concrete structure deteriorated by an alkali-silica reaction according to a correlation between an expansion coefficient of concrete in an accelerated expansion test of concrete taken from a concrete structure and an alkali hydroxide concentration of concrete taken from the concrete structure. A method for predicting deterioration progress of concrete structures due to alkali silica reaction, which is characterized by predicting deterioration progress. 2. The expansion coefficient of the concrete is NBRI.
The method for predicting the progress of deterioration of a concrete structure due to an alkali silica reaction according to claim 1, which is a coefficient of expansion of concrete measured by a test, and the alkali hydroxide concentration is an OH ⁻ ion concentration in a pore solution. 3. The method for predicting the deterioration progress of a concrete structure due to an alkali silica reaction according to claim 1, wherein the deterioration progress of the concrete structure is predicted in four stages.