Method for estimating hydraulic composition coagulation time, system for estimating hydraulic composition coagulation time

Abstract

To provide a method for estimating hydraulic composition coagulation time, the method being simple and nonetheless enabling comparatively highly accurate estimation of hydraulic composition coagulation time.SOLUTION: This coagulation time estimation method includes a step (a) for measuring absorption spectral data of an object-hydraulic composition, a step (b) for performing base line correction thereby performing conversion into corrected absorption spectral data, a step (c) for performing arithmetic processing for increasing an influence degree of absorbance of a hydrate with respect to an influence degree of absorbance of water to derive an index value, a step (d) for repeatedly performing the steps (a), (b), and (c) thereby acquiring index time series data showing a chronological change in the index value, a step (e) for detecting the presence / absence of an inflection point of the index time series data, a step (f) for detecting a specific time corresponding to occurrence timing of the inflection point when the existence of the inflection point is detected, and a step (g) for deriving an estimation value of a coagulation time of the object hydraulic composition on the basis of correlations of the coagulation time, blending information of the hydraulic composition and the specific time recorded in advance, and the specific time detected by the blending information of the object- hydraulic composition and the step (f).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and a system for estimating the setting time of a hydraulic composition. [Background technology]

[0002] The initial setting time of concrete is an index that gives an estimate of the time during which concrete can be deformed (workable time), and is derived using a method that conforms to the provisions of JIS A 1147 (Test method for setting time of concrete). In this test method, a specified amount of concrete is sampled, and the coarse aggregate and mortar are separated by wet screening, after which the mortar is poured into a formwork, and the resistance value (penetration resistance value) when a penetration needle is penetrated into the mortar is measured over time. Based on the results of this measurement, the initial setting time of concrete (when the penetration resistance value is 3.5 N / mm 2 Time until the penetration resistance reaches 28.0 N / mm 2 The time it takes for the

[0003] On the other hand, it requires a lot of effort to collect and mold the sample, smooth the penetration surface, prepare and clean the formwork, etc., and in conditions where setting is delayed, such as low temperature environments, it is necessary to obtain the penetration resistance value even after 8 hours from pouring water. Furthermore, there is an issue that the penetration resistance value may vary depending on the person who measures it. Therefore, a method to easily measure (estimate) the setting time is required.

[0004] The setting start time and setting completion time are also used as a guide for determining the timing of concrete surface finishing. Therefore, evaluation methods for easily determining the setting time at construction sites are being considered.

[0005] In addition, Patent Document 1 listed below discloses a method of predicting the timing of finishing work by defining the expected air temperature during the construction period as the "deemed concrete temperature" and applying information on the deemed concrete temperature to the relationship between the concrete temperature and information on the slope of an approximation equation that represents the relationship between penetration resistance value and elapsed time, which has been determined in advance. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-073962 A Summary of the Invention [Problem to be solved by the invention]

[0007] The method described in Patent Document 1 merely predicts the degree of hardening based on predicted changes in temperature, and since it does not predict strength according to the environment of each site, it is difficult to make a highly accurate estimation.

[0008] On the other hand, as mentioned above, if the test method specified in JIS A 1147 is used, it is necessary to prepare a test specimen and a special test device, and to insert a penetration needle vertically to measure the penetration resistance value every time a certain time passes, which may make the work complicated. In addition, it is necessary to train workers on how to operate the test device.

[0009] In view of the above problems, an object of the present invention is to provide a method and system for estimating the setting time of a hydraulic composition with a relatively high accuracy while being simple. [Means for solving the problem]

[0010] The method for estimating the setting time of a hydraulic composition according to the present invention comprises the steps of: A step (a) of measuring absorption spectrum data of a target hydraulic composition, which is a poured hydraulic composition, over a measurement wavelength range including at least a first wavelength corresponding to a maximum value of the absorption spectrum of calcium hydroxide and belonging to the near infrared range; (b) performing baseline correction on the absorption spectrum data to convert the data into corrected absorption spectrum data showing a relationship between the corrected absorbance and the wavelength with respect to the absorbance after the correction; (c) performing a calculation process on the corrected absorption spectrum data to increase the influence of the absorbance of the hydrate relative to the influence of the absorbance of water, thereby deriving an index value; (d) repeatedly performing the steps (a), (b), and (c) continuously or intermittently to obtain index time series data indicating a change in the index value over time; (e) detecting the presence or absence of an inflection point in the index time series data; When the presence of the inflection point is detected in the step (e), a step (f) of detecting a specific time that is an elapsed time from pouring corresponding to the occurrence timing of the inflection point; and (g) deriving an estimate of the setting time of the target hydraulic composition based on the prerecorded correlation between the setting time, the formulation information of the hydraulic composition, and the specific time, the formulation information of the target hydraulic composition, and the specific time detected in step (f).

[0011] In this specification, the term "hydraulic composition" refers to a hardening composition containing a cement composition and water, and the term "cement composition" refers to a cement-containing powder or a material derived therefrom (a material derived from the powder in a mixture containing water, or a hardened material thereof) that does not contain water, aggregate, or a water-reducing agent. Examples of hydraulic compositions include concrete and mortar.

[0012] In this specification, the term "near infrared region" refers to a wavelength range of 800 nm to 2500 nm.

[0013] When the absorption spectrum data of the target hydraulic composition is measured at different times, the hydration reaction progresses over time, and the absorbance due to hydrates increases. Therefore, by detecting the change in the obtained absorption spectrum data, the degree of progress of the hydration reaction can be grasped.

[0014] Incidentally, it is assumed that the measured absorption spectrum data of the target hydraulic composition is affected by the surface state of the target hydraulic composition, bubbles contained therein, or fluctuations in the light source output and detector sensitivity (hereinafter referred to as "disturbance factors"), causing the baseline of the spectrum to fluctuate. On the other hand, it is unlikely that the degree of influence of the disturbance factors contained in the absorption spectrum data will fluctuate over time.

[0015] Therefore, in the above method, a baseline correction is performed on the absorption spectrum data in step (b). This correction method includes statistical methods such as SNV and MSC. In addition, a method with a relatively small computation load is to convert the absorption spectrum data into differential absorption spectrum data based on a difference value with respect to the absorbance at a predetermined reference wavelength.

[0016] When performing baseline correction by the latter method, the "reference wavelength" that is the basis for taking the difference value is selected from a wavelength range that is not affected at all or almost not affected by the absorbance value even depending on the degree of progress of the hydration reaction in the target hydraulic composition. Preferably, the reference wavelength is selected from wavelengths within the range of 900 nm to 1360 nm. As an example, the reference wavelength can be 1350 nm, and as another example, the reference wavelength can be 1200 nm.

[0017] The thus obtained baseline-corrected absorption spectrum data (corrected absorption spectrum data) is used in the subsequent processing to estimate the setting time of the target hydraulic composition.

[0018] Next, in step (c), the corrected absorption spectrum data is subjected to a calculation process for increasing the influence of the absorbance of the hydrate relative to the influence of the absorbance of water. Note that, hereinafter, the wavelength showing the maximum value on the spectrum may be simply referred to as the "peak wavelength".

[0019] As the hydration reaction of the hydraulic composition progresses, the amount of hydrates produced increases. The term "hydrates" used here includes calcium silicate hydrates (hereinafter abbreviated as "CSH") and calcium hydroxide.

[0020] The absorption spectrum of calcium hydroxide, which is a type of hydrate, shows a maximum value near a wavelength of 1412 nm, and the absorbance decreases as the wavelength moves away from that wavelength. In other words, as the hydration reaction progresses, the absorption spectrum data of the target hydraulic composition tends to reflect the tendency of the absorption spectrum of calcium hydroxide.

[0021] In addition, as the hydration reaction progresses, the amount of CSH produced also increases. The absorption spectrum of CSH shows a maximum value in the vicinity of 1370 nm to 1429 nm, which is a range including a wavelength of 1412 nm. In other words, as the hydration reaction progresses, the absorption spectrum data of the target hydraulic composition tends to reflect the tendency of the absorption spectrum of CSH.

[0022] On the other hand, it is known that the absorption spectrum of water (H2O) shows a maximum value near a wavelength of 1450 nm. A hydraulic composition is produced by mixing water with a cement composition and kneading the mixture. For this reason, the absorption spectrum of the hydraulic composition in the near infrared region contains a signal derived from the absorbance of water (H2O) with an intensity corresponding to the amount of water used in producing the hydraulic composition. In other words, the absorption spectrum data of the target hydraulic composition also reflects the tendency of the absorption spectrum of the water contained in the target hydraulic composition.

[0023] As described above, the difference between the peak wavelength of the absorption spectrum data of calcium hydroxide and the peak wavelength of the absorption spectrum data of water is about 50 nm or less. Therefore, simply extracting the change in the shape of the absorption spectrum data (strictly speaking, the corrected absorption spectrum data) of the target hydraulic composition does not clearly show the degree of change, making it difficult to accurately recognize the degree of progress of the hydration reaction.

[0024] Therefore, in the method according to the present invention, in the above step (c), a calculation process is performed on the corrected absorption spectrum data to increase the degree of influence of the absorbance of the hydrate relative to the degree of influence of the absorbance of water, thereby deriving an index value.

[0025] Several methods can be adopted for step (c).

[0026] As an example, the step (c) can be a step of deriving the index value from the corrected absorption spectrum data based on a difference value between the corrected absorbance at the first wavelength, the corrected absorbance at a wavelength located in a nearby range relative to the first wavelength, or the average value of the corrected absorbance in a wavelength range sandwiched between a wavelength shifted from the first wavelength to a shorter wavelength within the nearby range and a wavelength shifted from the first wavelength to a longer wavelength within the nearby range, and the absorbance at a second wavelength that is closer to a wavelength corresponding to a maximum value of the absorption spectrum of water than the first wavelength.

[0027] In short, this method is a method in which an index value is determined by a difference between the absorbance at a wavelength far from the peak wavelength of the absorption spectrum of water and close to the peak wavelength of the absorption spectrum of calcium hydroxide and the absorbance close to the peak wavelength of the absorption spectrum of water, or a calculated value based on this difference value. This makes it possible to obtain an index value in which the influence of the tendency of the absorption spectrum of water, which appears in the corrected absorption spectrum data, is reduced, while the influence of the tendency of the absorption spectrum of hydrates is increased.

[0028] In this specification, the "nearby range" of a certain wavelength λ nm refers to a range of (λ-10) nm or more and (λ+10 nm) or less, preferably refers to a range of (λ-5) nm or more and (λ+5 nm) or less, and more preferably refers to a range of (λ-3) nm or more and (λ+3 nm) or less.

[0029] As another example, the step (c) can be a step of substituting the corrected absorption spectrum data into a function that derives a principal component in which the influence of the absorbance of the hydrate is relatively increased based on a principal component analysis that has been recorded in advance, and setting the value of the obtained principal component as the index value.

[0030] As described above, as the hydration reaction progresses, the absorption spectrum data of the target hydraulic composition reflects the tendency of the absorption spectrum of the hydrate to a greater extent. Here, the fact that the reflection of the tendency of the absorption spectrum of the hydrate is enhanced does not simply mean that the absorbance in the vicinity of the peak wavelength of the absorption spectrum of calcium hydroxide becomes relatively higher than other wavelength regions. Specifically, the absorbance in the peak wavelength region of CSH is also expected to increase relatively, and the manner in which it increases is influenced by the shape of the absorption spectrum of calcium hydroxide and the absorption spectrum of CSH.

[0031] Therefore, in advance, in an inspection / experiment facility or a manufacturing plant, absorption spectrum data is obtained over time for a hydraulic composition cast as a sample, and a principal component analysis is performed on the corrected absorption spectrum data for each elapsed time obtained by performing baseline correction, to derive a principal component reflecting the influence of absorption by hydrates. A formula for deriving this principal component is recorded in advance, and a calculation is performed based on this recorded formula for the corrected absorption spectrum data actually derived from the target hydraulic composition, thereby deriving the value of the principal component contained in the corrected absorption spectrum data derived from the target hydraulic composition. This value of the principal component can be used as the above index value, since the corrected absorption spectrum data has been subjected to a process to increase the influence of absorbance of hydrates relative to the influence of absorbance of water.

[0032] As yet another example, the step (c) can be a step of extracting from the corrected absorption spectrum data the corrected absorbance at the first wavelength, the corrected absorbance at wavelengths located in a vicinity range of the first wavelength, or an average value of the corrected absorbance in a wavelength range sandwiched between a wavelength shifted from the first wavelength to a shorter wavelength side within the vicinity range and a wavelength shifted from the first wavelength to a longer wavelength side within the vicinity range, and setting the average value as the index value.

[0033] In short, this method is a method of extracting absorbance at a wavelength far from the peak wavelength of the absorption spectrum of water and close to the peak wavelength of the absorption spectrum of calcium hydroxide from the corrected absorption spectrum data to obtain an index value. This allows for an index value in which the influence of the tendency of the absorption spectrum of water, which appears in the corrected absorption spectrum data, is reduced while the influence of the tendency of the absorption spectrum of hydrates is increased.

[0034] By repeatedly executing the above steps (a), (b), and (c) continuously or intermittently, index time series data showing the change in index value over time is obtained in step (d). In step (e), it is detected whether or not an inflection point exists in the index time series data.

[0035] As an example of a specific method of step (e), a method can be adopted in which the index time series data is converted into corrected time series data, which is time series data of average values ​​for each predetermined time period, and then, when the first differential value of the approximation line of the corrected time series data exceeds a threshold value that is a value greater than 0 from 0 or a negative value for the first time, it is determined that an inflection point exists in the index time series data.

[0036] When the presence of the inflection point is detected, in step (f), a specific time that is the elapsed time from pouring that corresponds to the occurrence timing of the inflection point is detected.

[0037] The index time series data is data in which the above-mentioned index values, i.e., values ​​in which the degree of influence of the absorbance of hydrates is increased relative to the degree of influence of the absorbance of water, are arranged in a time series from the absorption spectrum data (more specifically, the corrected absorption spectrum data) of the target hydraulic composition. In other words, it can be estimated that the timing at which the index value changes significantly is the timing at which the degree of influence of the absorbance of hydrates increases sharply.

[0038] A hydraulic composition containing water and a cement composition shows a certain reaction immediately after the cement composition comes into contact with water, and then the reaction pauses for a certain period of time. After the pause period, the hydration reaction progresses at an accelerated rate. Therefore, the timing at which the index value changes significantly can be estimated as the timing at which the hydration reaction begins to progress at an accelerated rate. In step (f), the elapsed time from pouring to reaching this timing is detected as the "specific time."

[0039] As described above, this "specific time" is the timing when the progress of the hydration reaction begins to accelerate, and is therefore an element that is highly correlated with the setting time, including the initial time and final time. Therefore, by recording information on these correlations in advance, reading out the recorded information on the correlations, and applying it to the specific time for the target hydraulic composition obtained in step (f), the setting time of the target hydraulic composition can be estimated.

[0040] Specifically, the specific time is detected in advance in a test / experiment facility, a manufacturing plant, or the like for a sample of hydraulic composition cast in the same manner as above. The setting time of the sample is also measured based on the penetration resistance value measured for the sample by a method conforming to JIS A 1147. Then, a multiple regression analysis is performed using the specific time detected for the sample and the mix information of the sample (more specifically, the water-cement ratio) as explanatory variables, and the setting time (more specifically, the initial setting time or final setting time) as the objective variable. This allows information regarding the correlation between the specific time, the mix information of the hydraulic composition, and the setting time to be obtained in advance.

[0041] By applying the specific time for the target hydraulic composition that is the subject of this estimation and the formulation information of the target hydraulic composition to the correlation that was obtained and recorded in advance in this manner, an estimate of the setting time of the target hydraulic composition is derived.

[0042] As described above, according to the above method, the absorption spectrum data of the target hydraulic composition is measured over time, and an estimated value of the setting time of the target hydraulic composition is derived by performing a calculation process based on the measured data. In other words, at the casting site, it is only necessary to install an instrument for measuring the absorption spectrum data of the target hydraulic composition, and the subsequent processing can be automatically performed by a calculation device. In addition, as will be described later in the section "Form for carrying out the invention", the correlation between the setting time estimated by the above method and the setting time based on the actual penetration resistance value measured by a method conforming to JIS A 1147 is extremely high. Therefore, according to the above method, it can be said that the setting time of the target hydraulic composition can be accurately estimated in a simple manner.

[0043] The step (a) may be a step of measuring the absorption spectrum data from the side of the target hydraulic composition cast in an area surrounded by a formwork, using an absorbance measuring unit.

[0044] The upper surface (cast surface) of the cast hydraulic composition may have unevenness in some places or bleeding water may be present. Due to these circumstances, when the absorption spectrum data is measured from above the hydraulic composition, the influence of the absorption spectrum data derived from hydrates may not be easily reflected.

[0045] In contrast, by measuring the absorption spectrum data from the side of the target hydraulic composition using an absorbance measuring unit as in the above method, the influence of unevenness of the pouring surface and bleeding water can be suppressed, and the influence of the absorption spectrum data derived from hydrates can be easily reflected in the obtained absorption spectrum data. As a result, the accuracy of estimating the setting time of the target hydraulic composition can be improved.

[0046] However, when the surface of the target hydraulic composition is highly flat or when the detection criteria for the presence or absence of an inflection point in the index time series data in step (e) are appropriately adjusted, it is possible to estimate the setting time of the target hydraulic composition with high accuracy even if the absorption spectrum data is measured from above the target hydraulic composition using an absorbance measuring unit.

[0047] The hydraulic composition setting time estimation system according to the present invention comprises: an absorbance measurement unit capable of measuring absorption spectrum data of an object over a measurement wavelength range that includes a first wavelength corresponding to a maximum value of the absorption spectrum of calcium hydroxide and that belongs to a near-infrared range; A calculation processing unit to which information regarding the absorption spectrum data of a target hydraulic composition, which is a poured hydraulic composition, measured by the absorbance measuring unit is input; A storage unit in which correlations between information on setting time, information on blending of hydraulic compositions, and information on specific times are recorded, The arithmetic processing unit is performing baseline correction on each of the absorption spectrum data inputted continuously or intermittently to generate corrected absorption spectrum data; performing a calculation process for each of the plurality of corrected absorption spectrum data generated over time to increase the degree of influence of the absorbance of the hydrate relative to the degree of influence of the absorbance of water, thereby deriving an index value; and generating index time series data showing a change in the index value over time; The index time series data is subjected to arithmetic processing to detect the presence or absence of an inflection point, and when the presence of the inflection point is detected, the specific time, which is the elapsed time from pouring corresponding to the occurrence timing of the inflection point, is detected; The method is characterized in that an estimated value of the setting time of the target hydraulic composition is derived based on the detected specific time, the input formulation information of the target hydraulic composition, and the correlation read from the memory unit.

[0048] The target hydraulic composition is cast in an area surrounded by a formwork, the mold has a window portion on a part of a side surface, the window portion exhibiting transparency to at least light in the near-infrared region; The absorbance measuring unit may measure the absorption spectrum data of the target hydraulic composition through the window.

[0049] The target hydraulic composition is cast in an area surrounded by a formwork, an insert attached to the form; The insert has a window portion that is transparent to at least light in the near infrared region on a surface that is opposite to the formwork and that is in contact with the target hydraulic composition, The absorbance measuring unit may measure the absorption spectrum data of the target hydraulic composition through the window.

[0050] The formwork has an opening hole in a part of a side surface, The absorbance measuring section may measure the absorption spectrum data of the target hydraulic composition by a probe connected to the window section through the opening hole.

[0051] the arithmetic processing unit and the memory unit are mounted on an arithmetic processing device that is installed in a location different from the absorbance measurement unit, Information relating to the absorption spectrum data measured by the absorbance measuring unit may be input to the arithmetic processing device via a wired or wireless connection. Effect of the Invention

[0052] According to the present invention, the setting time of a hydraulic composition can be estimated simply and relatively accurately. [Brief description of the drawings]

[0053] [Figure 1] 1 is a flowchart showing an example of a procedure for carrying out a method for estimating the setting time of a hydraulic composition according to the present invention. [Diagram 2]1 is a diagram showing a schematic configuration of an embodiment of a hydraulic composition setting time estimation system according to the present invention. [Diagram 3] 1 is a diagram showing a schematic diagram of one embodiment of a method for measuring absorption spectrum data of a target hydraulic composition. [Figure 4] FIG. 4 is a cross-sectional view that illustrates the method shown in FIG. [Diagram 5] 1 is a diagram showing a schematic diagram of another embodiment of a method for measuring absorption spectrum data of a target hydraulic composition. [Figure 6A] 1 is a diagram showing a schematic diagram of another embodiment of a method for measuring absorption spectrum data of a target hydraulic composition. [Figure 6B] 1 is a diagram showing a schematic diagram of another embodiment of a method for measuring absorption spectrum data of a target hydraulic composition. [Figure 7] 1 is an example of absorption spectrum data of a target hydraulic composition immediately after pouring. [Figure 8] 1 is a graph showing the change over time in absorption spectrum data of a subject hydraulic composition. [Figure 9] 8 is an example of differential absorption spectrum data generated based on the absorption spectrum data of FIG. 7. [Figure 10] 9 is an example of each differential absorption spectrum data generated based on each absorption spectrum data of FIG. 8. [Figure 11A] 1 is an example of a graph showing index values ​​obtained by the first method as time-series data. [Figure 11B] 13 is an example of a graph showing index values ​​obtained by the second method as time-series data. [Figure 11C] 13 is an example of a graph showing index values ​​obtained by the third method as time-series data. [Figure 12] 1 is an example of a result of performing a principal component analysis on a group of time-dependent corrected absorption spectrum data. [Figure 13] The index time series data shown in FIG. 11B is converted into corrected time series data based on the average value for each predetermined time period, and is displayed as a graph. [Figure 14]14 is a graph for explaining an example of a method for deriving an inflection point from the corrected time-series data shown in FIG. 13, and corresponds to data of test mortar of level No. 1. [Figure 15] 1 is a graph showing the setting time test results of test mortars. [Figure 16A] 13 is a graph for explaining a method for deriving an inflection point from the corrected time series data of test mortar of level No. 2. [Figure 16B] 13 is a graph for explaining a method for deriving an inflection point from the corrected time series data of the test mortar of Level No. 3. [Figure 16C] 13 is a graph for explaining a method for deriving an inflection point from the corrected time series data of the test mortar of Level No. 4. [Figure 17A] 1 is a graph showing the relationship between the estimated and actually measured values ​​of the start time for each test mortar. [Figure 17B] 1 is a graph showing the relationship between the estimated and actually measured setting times of each test mortar. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for estimating the setting time of a hydraulic composition and a system for estimating the setting time of a hydraulic composition according to the present invention will be described with reference to the drawings as appropriate.

[0055] Fig. 1 is a flow chart showing an example of the procedure for carrying out the method for estimating the setting time of a hydraulic composition according to the present invention. In the following description, the step numbers given in the flow chart shown in Fig. 1 will be referred to as appropriate. Fig. 2 is a diagram showing a schematic configuration of a system for estimating the setting time of a hydraulic composition according to the present invention, as one embodiment for carrying out the estimation method.

[0056] The setting time estimation system 1 is a system that can be used to estimate the setting time of a hydraulic composition 3 such as cast concrete, and includes an absorbance measuring unit 5 and a calculation processing device 10. Hereinafter, one procedure of the method for estimating the setting time of a hydraulic composition according to the present invention will be described with reference to the configuration of the setting time estimation system 1. The hydraulic composition 3 is a hydraulic composition whose setting time is to be estimated, and is hereinafter referred to as the "target hydraulic composition 3."

[0057] In this embodiment, the setting time as the estimation target time is described as the first setting time (simply abbreviated as "first setting time") and the final setting time (simply abbreviated as "finishing time"). However, the present invention can be similarly applied to the case of estimating setting times other than the first setting time and the finishing time.

[0058] (Step #1: Measurement of absorption spectrum data) The absorption spectrum data of the target hydraulic composition 3 is measured. As a specific example, near-infrared light L1 is irradiated onto the target hydraulic composition 3 from an absorbance measuring unit 5 consisting of an absorptiometer or the like, the reflected light L2 is separated, and the spectrum of the irradiated light L1 and the received light L2 are compared to obtain the absorption spectrum data of the target hydraulic composition 3 over the near-infrared range (measurement wavelength range). The near-infrared light L1 is, for example, light that shows an intensity in the wavelength range of 800 nm to 2500 nm, typically light from a halogen lamp. However, in the present invention, the light source that emits the near-infrared light L1 is not limited.

[0059] The absorbance measurement unit 5 may be a spectrophotometer in which a light source and a light receiver are integrated, or may be a configuration in which the light source and the light receiver are separate. In addition, the light source is not limited to an infrared light source, and may be a light source that emits light showing a wide spectrum from the visible range to the infrared range.

[0060] Fig. 3 is a diagram showing a typical embodiment of measuring absorption spectrum data of a target hydraulic composition 3. Fig. 4 is a typical cross-sectional view corresponding to Fig. 3. The target hydraulic composition 3 is cast in an area surrounded by a formwork 30. An opening 31 is formed in a part of the side of the formwork 30, and a window 32 exhibiting transparency to light in the near-infrared region is provided in the bottom surface of the formwork 30. The window 32 is preferably made of glass. The absorbance measuring unit 5 is connected to the arithmetic processing device 10 via a signal line 21.

[0061] Fig. 5 is a diagram showing a schematic diagram of another embodiment for measuring the absorption spectrum data of the target hydraulic composition 3. As shown in Fig. 5, an insert 36 is attached to a part of a formwork 30. The insert 36 has a window 35 that is transparent to light in the near infrared region on the surface opposite to the formwork 30, i.e., the surface that contacts the target hydraulic composition 3. The window 35 is preferably made of glass. An opening 31 for inserting the fiber probe 23 is formed in the formwork 30 at the place where the insert 36 is attached.

[0062] 5, near-infrared light L1 emitted from the absorbance measurement unit 5 is irradiated onto the side surface of the target hydraulic composition 3 through the fiber probe 23 and the window 35. Then, reflected light L2 from the target hydraulic composition 3 is received by the absorbance measurement unit 5 through the window 35 and the fiber probe 23.

[0063] According to the method shown in FIGS. 3 to 5, near-infrared light L1 is irradiated onto the side surface of a target hydraulic composition 3, and the reflected light L2 is received by an absorbance measuring unit 5.

[0064] 6A and 6B are diagrams that diagrammatically show another embodiment of measuring absorption spectrum data of a target hydraulic composition 3. In addition, in order to avoid complexity of the drawings, the illustration of the arithmetic processing device 10 is omitted in Figs. 6A and 6B.

[0065] In both the methods shown in Figures 6A and 6B, near-infrared light L1 is irradiated from the upper surface (casting surface 3a) of the target hydraulic composition 3, and the reflected light is received by the absorbance measurement unit 5. In the method shown in Figure 6A, irradiation of near-infrared light L1 and reception of reflected light L2 are performed via a fiber probe 23, while in the method shown in Figure 6B, near-infrared light L1 is directly irradiated from the absorbance measurement unit 5 to the target hydraulic composition 3, and reflected light L2 from the target hydraulic composition 3 is directly guided to the absorbance measurement unit 5.

[0066] The absorption spectrum data of the target hydraulic composition 3 is acquired for the purpose of detecting the change in the degree of influence of absorbance derived from hydrates that occurs with the progress of the hydration reaction, as described later. The pouring surface 3a of the target hydraulic composition 3 may have unevenness in some places and may contain bleeding water. When the above disturbance factors are superimposed on the spectrum of the reflected light L2 received by the absorbance measuring unit 5, the influence of the absorbance derived from the hydrates contained in the target hydraulic composition 3 tends to become relatively small.

[0067] From the viewpoint of easily reflecting the influence of absorbance derived from hydrates in the absorption spectrum data of the target hydraulic composition 3, it is preferable to irradiate near-infrared light L1 onto the side surface of the target hydraulic composition 3 and receive the reflected light L2 in a manner as illustrated in Figures 3 to 5.

[0068] However, when the casting surface 3a of the target hydraulic composition 3 is highly flat, it is acceptable to irradiate the casting surface 3a of the target hydraulic composition 3 with near-infrared light L1 and receive the reflected light L2, as illustrated in Figures 6A and 6B. In addition, by appropriately setting a threshold value that serves as a judgment index for detecting the presence or absence of an inflection point in step #5 described later, it is also possible to reduce the influence of factors such as unevenness of the casting surface 3a. Even in such a case, it is acceptable to irradiate the casting surface 3a of the target hydraulic composition 3 with near-infrared light L1.

[0069] It should be noted that this step #1, as well as steps #2 and #3 described below, are repeatedly executed continuously or intermittently.

[0070] Step #1 corresponds to process (a).

[0071] (Step #2: Baseline correction) Next, baseline correction is performed on the absorption spectrum data measured by the absorbance measurement unit 5. Data indicating the relationship between absorbance after correction (corrected absorbance) and wavelength obtained by performing baseline correction on the absorption spectrum data is called "corrected absorption spectrum data."

[0072] As a baseline correction method, for example, a statistical method such as SNV or MSC can be used. In addition, as a method with a smaller computation load than the statistical methods, a method of converting the absorption spectrum data into data based on a difference value with respect to the absorbance at a predetermined reference wavelength can also be used. The latter method will be described in detail below.

[0073] Fig. 7 shows the absorption spectrum of the target hydraulic composition 3 immediately after casting, measured using the absorbance measuring unit 5. Fig. 8 shows the absorption spectrum of the target hydraulic composition 3 measured every hour using the absorbance measuring unit 5, and the measurement results are superimposed. The graphs in Figs. 7 and 8 also correspond to the data of test mortar of level No. 1, which will be described later in the "Examples" section.

[0074] It is confirmed from Fig. 8 that the shape of the absorption spectrum changes with time. It is presumed that the hydration reaction of the subject hydraulic composition 3 progresses with time, the amount of hydrates produced increases, and the shape of the absorption spectrum changes with time as a result of the influence of the absorbance derived from the hydrates being reflected.

[0075] According to Fig. 8, the absorption spectrum of the target hydraulic composition 3 is generally shifted in the up and down direction, in other words, the baseline is fluctuating. This is considered to be due to the influence of unevenness formed on the surface of the target hydraulic composition 3, air bubbles present in the target hydraulic composition 3, or fluctuations in the light source output and detector sensitivity, as time has passed since the target hydraulic composition 3 was produced and then poured into the field. These influencing factors are collectively referred to as "disturbance factors".

[0076] In other words, when the shapes of the absorption spectra at different times are simply compared, the influence of the progress of the hydration reaction and the influence of the presence of disturbance factors are mixed, and the change in the shape of the absorption spectrum caused by the former influence cannot be evaluated with high accuracy. On the other hand, in consideration of the cause of the occurrence of the disturbance factors, it is assumed that the disturbance factors do not affect a specific wavelength of the absorption spectrum, but affect almost the entire wavelength range.

[0077] Therefore, from the viewpoint of eliminating the influence of disturbance factors as much as possible, the absorption spectrum data of the target hydraulic composition 3 is converted into data defined as a relative value to the absorbance at a certain reference wavelength, thereby correcting the baseline. The corrected data (corrected absorbance) obtained in this way, expressed as a data group by wavelength, corresponds to the "corrected absorption spectrum data." In this method, the correction process is a difference calculation process for obtaining a relative value to a reference value, so the corrected absorbance is a difference absorbance.

[0078] As an example, Fig. 9 is a graph showing the absorption spectrum data shown in Fig. 7 after being converted into differential absorption spectrum data with a reference wavelength of 1350 nm, and Fig. 10 is a graph showing the time-dependent absorption spectrum data over 12 hours shown in Fig. 8 after being converted into differential absorption spectrum data in a similar manner.

[0079] It can be seen from FIG. 10 that the differential absorbance value in the wavelength band around 1400 nm to 1420 nm shows an increasing tendency with time.

[0080] As time passes after the subject hydraulic composition 3 is installed, the hydration reaction progresses with the passage of time, and the amount of hydrates produced increases. The hydrates typically include calcium silicate hydrate (CSH) and calcium hydroxide. The absorption spectrum of calcium hydroxide shows a peak near 1412 nm, and the absorbance decreases as the wavelength moves away from this wavelength. The absorption spectrum of CSH shows a peak near 1370 nm to 1429 nm, which is a range including the wavelength of 1412 nm, and the absorbance decreases as the wavelength moves away from this wavelength range.

[0081] From FIG. 10, it can be inferred that there is a tendency for the absorbance (difference absorbance) value derived from hydrates to increase over time.

[0082] This step #2 is specifically performed in the arithmetic processing device 10. The arithmetic processing device 10 is a device equipped with an arithmetic processing unit 11, a storage unit 13, and an output unit 15, and is, for example, a smartphone, a notebook PC, a tablet PC, a desktop PC, or a cloud server. The absorbance measurement unit 5 and the arithmetic processing device 10 are configured to be able to communicate with each other via wire or wirelessly, and data can be exchanged between them.

[0083] The arithmetic processing unit 11 is an arithmetic processing means such as a CPU, an MPU, etc. The storage unit 13 is a storage medium such as a memory, a hard disk, etc., and not only temporarily records the results of the arithmetic processing performed by the arithmetic processing unit 11, but also records in advance predetermined relationships described below. The output unit 15 is an interface that outputs data such as the results of the arithmetic processing performed by the arithmetic processing unit 11, and is typically a display screen, but may be an interface that transmits the data to an external terminal, or may be both.

[0084] When the calculation processing device 10 receives the absorption spectrum data of the target hydraulic composition 3 transmitted from the absorbance measurement unit 5, the calculation processing unit 11 creates absorption spectrum data after baseline correction (corrected absorption spectrum data) for each measurement point of the absorption spectrum.

[0085] Information on the reference wavelength may be recorded in advance in the storage unit 13. Here, the reference wavelength is selected from a wavelength range in which the absorbance value is not affected at all or is almost not affected by the degree of progress of the hydration reaction in the target hydraulic composition 3. Preferably, the reference wavelength is selected from wavelengths within the range of 900 nm to 1360 nm. For example, the reference wavelength can be 1200 nm, in addition to the 1350 nm exemplified above.

[0086] The absorption spectrum data may be transmitted directly from the absorbance measurement unit 5 to the arithmetic processing device 10, or may be transmitted to the arithmetic processing device 10 via another relay device.

[0087] Step #2 corresponds to process (b).

[0088] (Step #3: Calculate the index value) Next, the corrected absorption spectrum data obtained in step #2 is subjected to further arithmetic processing to calculate an index value. This index value will be described below.

[0089] As described above with reference to FIG. 10, by checking the manner in which the shape of the corrected absorption spectrum data changes over time, the progress of the hydration reaction of the target hydraulic composition 3 can be understood to some extent.

[0090] Incidentally, it is known that the absorption spectrum of water (H2O) shows a maximum value near a wavelength of 1450 nm, and this value is not a wavelength that is extremely far from the wavelength band near 1400 nm to 1420 nm. In other words, even if the change in the shape of the corrected absorption spectrum data shown in Fig. 10 over time is simply confirmed, the influence of the absorbance of water is reflected, albeit to a certain extent, so that the progress of the hydration reaction of the target hydraulic composition 3 may not be detected with high accuracy. In other words, in order to estimate the degree of progress of the hydration reaction with higher accuracy, it is preferable to perform a process that reduces the influence of the absorbance of water relative to the influence of the absorbance of the hydrate.

[0091] Therefore, in step #3, a calculation process is performed on the corrected absorption spectrum data to increase the influence of the absorbance of the hydrate relative to the influence of the absorbance of water. The value obtained by this calculation process is called an "index value."

[0092] As a calculation processing method for deriving the index value, several methods are available. In this specification, three methods will be described as examples.

[0093] First Method The first method is to extract the corrected absorbance (difference absorbance in the above example) of the absorption peak wavelength of calcium hydroxide from the corrected absorption spectrum data based on the absorption spectrum data obtained at each time, or a value equivalent thereto, and use it as an index value. Note that in the following description, the corrected absorbance is assumed to be the difference absorbance.

[0094] FIG. 11A is a graph in which the differential absorbance at 1412 nm, which is the absorption peak wavelength of calcium hydroxide, is extracted from the corrected absorption spectrum data shown in FIG. 10 in accordance with the first method and displayed as time-series data.

[0095] It is presumed that the change over time in the difference absorbance at 1412 nm shown in the corrected absorption spectrum data strongly reflects the change in the amount of hydrates produced in the subject hydraulic composition 3. In other words, this data can be said to be the data obtained by increasing the degree of influence of the absorbance of hydrates relative to the degree of influence of the absorbance of water from the corrected absorption spectrum data. Therefore, the data obtained by extracting the difference absorbance at 1412 nm from the corrected absorption spectrum data can be used as an "index value."

[0096] From a similar viewpoint, the differential absorbance at wavelengths in the vicinity of 1412 nm may be extracted from the corrected absorption spectrum data and used as the index value, or the average value of the differential absorbance in the wavelength range around 1412 nm may be calculated and used as the index value.

[0097] Second Method The second method is a method in which the difference between the corrected absorbance at the absorption peak wavelength of calcium hydroxide or a value equivalent thereto and the corrected absorbance at a wavelength close to the absorption peak wavelength of water is calculated from the corrected absorption spectrum data, and the calculated difference is used as an index value.

[0098] FIG. 11B is a graph in which the difference absorbance at 1412 nm, which is the absorption peak wavelength of calcium hydroxide (corresponding to the "first wavelength"), and the difference absorbance at 1433 nm, which is close to 1450 nm, which is the absorption peak wavelength of water (corresponding to the "second wavelength"), are extracted from the corrected absorption spectrum data shown in FIG. 10 in accordance with the second method, and the difference between the two values ​​is calculated and displayed as time-series data.

[0099] The value (difference value) obtained by this method strongly reflects the change in the amount of hydrate produced, and furthermore, the influence of the absorbance of water is reduced, so that it can be used as the above-mentioned "index value."

[0100] That is, the second method uses the difference between a value (hereinafter referred to as "value A") that is considered to reflect the absorbance of the hydrate relatively strongly and a value (hereinafter referred to as "value B") that is considered to reflect the absorbance of water relatively more strongly than the absorbance of the hydrate, as the index value. On the other hand, the first method uses value A as the index value.

[0101] From this perspective, as in the first method, the value A may be not only the differential absorbance value at 1412 nm, but also the differential absorbance value at wavelengths in the vicinity of 1412 nm, or the average value of the differential absorbance in the wavelength range around 1412 nm may be calculated and used.

[0102] Furthermore, as value B, the value of differential absorbance at a wavelength closer to 1450 nm, which is the peak absorption wavelength of water, than 1412 nm, which is the peak absorption wavelength of calcium hydroxide, can be used, and further, the average value of differential absorbance in a wavelength range closer to 1450 nm than 1412 nm can also be used.

[0103] The third method The third method is a method in which each data item included in the corrected absorption spectrum data is substituted into a function that derives a principal component that relatively enhances the influence of the absorbance of the hydrate based on a principal component analysis that has been recorded in advance, and the value of the obtained principal component is used as the index value.

[0104] FIG. 11C is a graph in which the values ​​of the principal components are obtained from the corrected absorption spectrum data shown in FIG. 10 in accordance with this third method, and are plotted as time-series data.

[0105] For example, in advance, corrected absorption spectrum data is obtained over time in the same manner as above for a hydraulic composition cast as a sample in an inspection / experiment facility, a manufacturing plant, etc., and a principal component analysis is performed on a group of corrected absorption spectrum data by time. Figure 12 is a graph showing the results of a principal component analysis performed on the corrected absorption spectrum data shown in Figure 10, assuming that the corrected absorption spectrum data is data obtained in advance.

[0106] According to FIG. 12, the corrected absorption spectrum data shown in FIG. 10 is summarized into two principal components (principal component α and principal component β). Here, it is confirmed that the factor loading (strength of correlation of the corrected absorbance of the principal components) of the principal component α is relatively high in the wavelength range near 1412 nm, which is the absorption peak wavelength of calcium hydroxide. On the other hand, it is confirmed that the factor loading of the principal component β is relatively high in the wavelength range close to 1450 nm, which is the absorption peak wavelength of water, compared to the wavelength range near 1412 nm, which is the absorption peak wavelength of calcium hydroxide. From this result, it can be concluded from the corrected absorption spectrum data that the principal component α is a variable that reduces the influence of the absorbance of water and increases the influence of the absorbance of the hydrate.

[0107] The principal component α can be calculated from the corrected absorption spectrum data. Therefore, a calculation method for the principal component α is determined in advance, and the value of the principal component α can be calculated by performing calculation processing based on this calculation method on the corrected absorption spectrum data obtained in step #2. The value of the principal component α obtained by this method strongly reflects the change in the amount of hydrate generated, and furthermore, the influence of the absorbance of water is reduced, so that it can be used as the above-mentioned "index value".

[0108] In the first to third methods, it is also possible to use as the index value a value obtained by performing arithmetic operations using the value obtained by the calculation method described above and a predetermined reference value.

[0109] Step #3 corresponds to process (c). This step #3 is also performed by the calculation processing unit 11. Note that the method for the calculation processing executed in step #3 may be recorded in the storage unit 13.

[0110] (Step #4: Calculating the indicator time series data) The above-mentioned steps #1 to #3 are performed intermittently or continuously to obtain data on index values ​​over time. Step #4 corresponds to the process of rearranging the index values ​​as time-series data.

[0111] That is, by this step #4, time-series data such as those shown in Figures 11A to 11C is obtained. Note that in this specification, the data on index values ​​over time is called "index time-series data".

[0112] Step #4 corresponds to process (d). This step #4 is also performed by the processor 11.

[0113] (Step #5: Detecting inflection points, Step #6: Detecting specific times) Next, in step #5, the presence or absence of an inflection point in the index time series data obtained in step #4 is detected. If an inflection point is not detected in step #5 (No in step #5), steps #1 to #4 are repeated again. If an inflection point is detected in step #5 (Yes in step #5), a "specific time" corresponding to the occurrence time of the inflection point is detected. This specific time will be described later.

[0114] An inflection point in the index time series data corresponds to a timing at which the trend of the index value over time changes. Any method can be used to detect an inflection point, and an example will be described below.

[0115] As described above, steps #1 to #3 are repeated continuously or intermittently to obtain data on index values ​​over time. Here, the time intervals at which step #1 is executed may differ. Therefore, in order to align the time intervals, the average value of each index value for each recent predetermined time is calculated, and time series data of this average value (hereinafter referred to as "corrected time series data") is generated. FIG. 13 shows the index time series data shown in FIG. 11B converted into time series data of the average value for each recent 15 minutes and graphed.

[0116] A change in the first derivative value of the approximation line is detected from the corrected time series data thus obtained. A more detailed example will be described with reference to FIG.

[0117] Figure 14 is a graph in which the first derivative value is calculated every four points (i.e., every hour in the above example) from the corrected time series data shown in Figure 13, and is superimposed on the corrected time series data. Note that the first derivative value here is equivalent to the slope of the approximation line.

[0118] In this way, the change in the first derivative of the corrected time series data is extracted, and when the first derivative exceeds a threshold value that is greater than 0 from 0 or a negative value for the first time, it is determined that an inflection point has occurred. In FIG. 14, the threshold value is set to 0.0006, and the occurrence time in this case is 4.38 hours after the start of pouring. In this way, the time that has elapsed from pouring to the timing when the inflection point occurs corresponds to the "specific time."

[0119] In the above example, the index time series data is converted into corrected time series data, which is time series data of average values ​​for each specified time period, and the presence or absence of an inflection point is detected based on the corrected time series data. However, the presence or absence of an inflection point may also be detected based on the index time series data itself.

[0120] Step #5 corresponds to step (e), and step #6 corresponds to step (f). These steps #5 and #6 are also performed by the calculation processing unit 11. The method for the calculation processing executed in steps #5 and #6 may be recorded in the storage unit 13. In other words, the method for deriving the first differential value and information regarding the threshold value for detecting the inflection point may be recorded in the storage unit 13 in advance.

[0121] (Step #7: Derive an estimate of setting time) Based on the specific time obtained in step #6, an estimate of the setting time of the target hydraulic composition 3 is derived.

[0122] The storage unit 13 of the arithmetic processing device 10 stores in advance information on the correlation between the specific time, the blending information of the hydraulic composition, and the setting time. The setting time may be the initial setting time, the final setting time, or the like. The blending information of the hydraulic composition is typically the water-cement ratio of the hydraulic composition, but may include other elements. The other elements may include the types and amounts of cement, fine aggregate, admixtures, and admixtures. Furthermore, environmental information (outdoor temperature, etc.) may be included.

[0123] The information on this correlation can be data that is measured in advance in, for example, an inspection / experiment facility or a manufacturing factory and recorded in the storage unit 13. The correlation information can be measured, for example, as follows.

[0124] Water and a cement composition are mixed under a certain water-cement ratio, and fine aggregate and the like are further mixed to produce a hydraulic composition for verification (hereinafter referred to as a "first sample"). The first sample is installed in a predetermined experimental facility or experimental site, and a specific time corresponding to the first sample is detected from the time of installation by a method conforming to steps #1 to #6 described above.

[0125] In parallel with the above, the setting time (for example, initial setting time and final setting time) of the first sample is measured based on the penetration resistance value measured by a method conforming to JIS A 1147.

[0126] By such a method, a group of data on the specific time, the blending information of the hydraulic composition represented by the water-cement ratio, and the setting time are obtained for the first sample as one of the hydraulic compositions for verification.

[0127] This kind of advance measurement is carried out in the same way for N samples (N is an integer of 2 or more). As a result, N sets of data relating to the specific time, the hydraulic composition mix information represented by the water-cement ratio, and the setting time are obtained. Based on the N sets of data obtained, a multiple regression analysis is performed with the specific time and the mix information as explanatory variables and the setting time as the objective variable. Information relating to the regression equation obtained by this multiple regression analysis is recorded in memory unit 13 as the above-mentioned "correlation."

[0128] That is, after steps #1 to #6, when the specific time for the target hydraulic composition 3 is detected, the calculation processing unit 11 reads out information on the correlation (more specifically, a regression equation) from the storage unit 13, and applies the specific time for the target hydraulic composition 3 and the blending information of the target hydraulic composition 3 to the above correlation. This derives an estimated value of the setting time of the target hydraulic composition 3. The derived information on the estimated value of the setting time is output from the output unit 15.

[0129] The "inflection point" detected in step #5 is the timing at which the "tendency" of the change in the index value over time changes, as described above. And this "index value" is a value obtained by processing the corrected absorption spectrum data obtained in step #2 to increase the influence of the absorbance of the hydrate relative to the influence of the absorbance of water, as described above.

[0130] Therefore, it can be estimated that the timing when the inflection point is detected, in other words, the timing when the "specific time" has elapsed since pouring, is the timing when the degree of influence of the hydrate absorbance increases rapidly. In other words, it can be estimated that the "specific time" corresponds to the time required from immediately after pouring until the degree of influence of the hydrate absorbance begins to increase rapidly, in other words, until the progress of the hydration reaction begins to progress at an accelerated rate. Therefore, the specific time is an element that is highly correlated with the setting time, including the initial setting time and final setting time.

[0131] From the above results, by deriving and recording the correlation between the specific time and the setting time in advance using a verification sample, it is possible to use this recorded information to estimate the setting time of the target hydraulic composition 3. The fact that this estimation method allows for highly accurate estimation of the setting time will be described later with reference to examples.

[0132] Step #7 corresponds to process (g). EXAMPLES

[0133] The present invention will be described below with reference to examples. Note that the following examples are merely illustrative and are not intended to limit the present invention.

[0134] Test mortars were cast from the materials shown in Tables 1 and 2 below. Four types of test mortars with different water-cement ratios (W / C) were prepared (Levels 1-4). In Table 1, W / C refers to the water-cement ratio, and S / C refers to the sand-cement ratio.

[0135] [Table 1]

[0136] [Table 2]

[0137] The penetration resistance of each test mortar was measured and the initial setting time and final setting time were calculated using the test method specified in JIS A 1147. The test results are shown in Figure 15, and the initial setting time and final setting time extracted from Figure 15 are shown in Table 3. [Table 3]

[0138] Test mortar with an age of 1 hour was poured into each of the Φ5cm x 10cm cylindrical bodies, and the top surface was sealed with stretch film. A cover glass was placed on the top surface of the stretch film, and the window surface of the absorption spectrometer was placed against the cover glass. The absorption spectrum of the test mortar was measured by irradiating the surface of the test mortar with infrared light from the absorption spectrometer. This measurement was carried out at intervals of 5 to 15 minutes. The cover glass was placed to prevent the window surface of the absorption spectrometer from becoming dirty.

[0139] The change over time in the absorption spectrum data obtained for one test mortar (Level No. 1) is shown in Figure 8. The same absorption spectrum data as in Figure 8 was also measured for the other three levels of test mortar.

[0140] Next, a computer was used to perform baseline correction on the absorption spectrum data of each test mortar in the same manner as described above in step #2. Specifically, each absorption spectrum data was converted into corrected absorption spectrum data with a reference wavelength of 1350 nm. As a result, corrected absorption spectrum data as shown in Figure 8 was derived for each test mortar.

[0141] Next, using a computer, the time-course data of the index value is obtained from the corrected absorption spectrum data of each test mortar in the same manner as described above in steps #3 to #4. Here, in accordance with the second method described above, the difference value between the difference absorbance at 1412 nm and 1433 nm from the corrected absorption spectrum data is taken as the index value, and the change over time of this index value (index time series data) is obtained.

[0142] Next, using a computer, in the same manner as described above in steps #5 to #6, an inflection point was detected from the index time series data of each test mortar, and the specific time was determined. Here, as in the method described above, the index time series data was converted into time series data of the average value for the most recent 15 minutes (corrected time series data), and the first derivative value was calculated for each hour and compared with the threshold. 0.0006 was adopted as the threshold.

[0143] FIG. 14 described above corresponds to a graph for explaining a method for deriving an inflection point from the corrected time series data of the test mortar of level No. 1. FIG. 16A to FIG. 16C are graphs showing the corrected time series data and inflection points of the test mortars of levels No. 2 to No. 4, respectively, following FIG. 14. As shown in each graph of FIG. 16A to FIG. 16C, the specific times were derived as 5.79 h, 8.46 h, and 11.23 h for the test mortars of levels No. 2 to No. 4, respectively. Also, as shown in the graph of FIG. 14, the specific time was derived as 4.38 h for the test mortar of level No. 1. The results are shown in Table 4. In addition, Table 4 also shows the setting times of the test mortars shown in Table 3 for comparison.

[0144] [Table 4]

[0145] Next, the specific time for each test mortar and the information on the water-cement ratio of the test mortar were applied to a regression equation that had been derived in advance using a computer to obtain an estimated value of the setting time for each test mortar. Here, the following regression equations were used for the initial setting time and final setting time, respectively. (First time) = 2.134 - 0.116 × (water-cement ratio) + 1.721 × (specific time) … (1) (Final setting time) = 3.484 - 0.117 × (water-cement ratio) + 1.891 × (specific time) …(2)

[0146] The above regression equation was obtained by preparing a large number of samples in advance, measuring a group of data related to a specific time, water-cement ratio, and setting time, and performing multiple regression analysis. However, the above regression equation is merely an example, and the present invention is not limited to this equation. For example, an explanatory variable may be added when performing the regression analysis.

[0147] The correlation between the estimated setting times obtained by applying the above regression equation to the test mortars of levels No. 1 to No. 4 and the actual measured setting times of the test mortars of levels No. 1 to No. 4 shown in Table 3 is shown in Figures 17A and 17B.

[0148] 17A and 17B, it can be seen that there is a high correlation between the estimated and measured values ​​of the setting time of each test mortar for both the initial and final setting times. As described above with reference to Table 1, the test mortars of levels No. 1 to No. 4 have different water-cement ratios. From this result, it can be determined that the setting time estimated based on the method of the present invention is close to the actual setting time even for test mortars with different water-cement ratios. Therefore, it can be seen that the setting time of the target hydraulic composition 3 can be estimated by, for example, recording the above-mentioned formulas (1) and (2) in advance in the storage unit 13 as correlation information and performing the above steps #1 to #7. [Explanation of symbols]

[0149] 1: Setting time estimation system 3: Target hydraulic composition 3a: pouring surface of target hydraulic composition 5: Absorbance measuring section 10: Processing unit 11: Processing unit 13: Storage section 15: Output section 21: Signal line 23: Fiber probe 30: Formwork 31: Opening hole 32: Window section 35: Window section 36: Insert

Claims

1. A step (a) of measuring absorption spectrum data of a target hydraulic composition, which is a poured hydraulic composition, over a measurement wavelength range including at least a first wavelength corresponding to a maximum value of the absorption spectrum of calcium hydroxide and belonging to the near infrared range; (b) performing baseline correction on the absorption spectrum data to convert the data into corrected absorption spectrum data showing a relationship between a corrected absorbance and a wavelength with respect to the absorbance after the correction; A step (c) of performing a calculation process on the corrected absorption spectrum data to increase the influence of the absorbance of the hydrate relative to the influence of the absorbance of water to derive an index value; (d) repeatedly performing the steps (a), (b), and (c) continuously or intermittently to obtain index time-series data indicating a change in the index value over time; (e) detecting the presence or absence of an inflection point in the indicator time series data; When the presence of the inflection point is detected in the step (e), a step (f) of detecting a specific time that is an elapsed time from pouring that corresponds to the occurrence timing of the inflection point; A method for estimating the setting time of a hydraulic composition, comprising: a step (g) of deriving an estimate of the setting time of the target hydraulic composition based on a correlation between the setting time, the formulation information of the hydraulic composition, and the specific time recorded in advance, the formulation information of the target hydraulic composition, and the specific time detected in step (f).

2. 2. The method for estimating the setting time of a hydraulic composition according to claim 1, characterized in that the step (c) is a step of deriving the index value from the corrected absorption spectrum data based on a difference value between the corrected absorbance at the first wavelength, the corrected absorbance at wavelengths located in a vicinity range of the first wavelength, or the average value of the corrected absorbance in a wavelength range sandwiched between a wavelength shifted from the first wavelength to a shorter wavelength side within the vicinity range and a wavelength shifted from the first wavelength to a longer wavelength side within the vicinity range, and the corrected absorbance at a second wavelength closer to a wavelength corresponding to a maximum value of the absorption spectrum of water than the first wavelength.

3. The method for estimating the setting time of a hydraulic composition according to claim 1, characterized in that the step (c) comprises substituting the corrected absorption spectrum data into a function recorded in advance, which derives a principal component that relatively enhances the influence of the absorbance of the hydrate based on a principal component analysis, and setting the value of the obtained principal component as the index value.

4. 2. The method for estimating the setting time of a hydraulic composition according to claim 1, characterized in that in the step (c), an average value of the corrected absorbance at the first wavelength, the corrected absorbance at wavelengths in a vicinity of the first wavelength, or the corrected absorbance in a wavelength range sandwiched between a wavelength shifted from the first wavelength to a shorter wavelength side within the vicinity range and a wavelength shifted from the first wavelength to a longer wavelength side within the vicinity range is extracted from the corrected absorption spectrum data, and used as the index value.

5. 2. The method for estimating the setting time of a hydraulic composition according to claim 1, characterized in that in the step (e), after converting the index time series data into corrected time series data which is time series data of average values ​​for each predetermined time, it is determined that an inflection point exists in the index time series data when a first differential value of an approximation line of the corrected time series data exceeds a threshold value which is a value greater than 0 from 0 or a negative value for the first time.

6. The method for estimating the setting time of a hydraulic composition according to claim 1, characterized in that the step (a) is a step of measuring the absorption spectrum data from the side of the target hydraulic composition cast in an area surrounded by a formwork using an absorbance measuring unit.

7. A system for estimating the setting time of a hydraulic composition, comprising: an absorbance measurement unit capable of measuring absorption spectrum data of an object over a measurement wavelength range that includes a first wavelength corresponding to a maximum value of the absorption spectrum of calcium hydroxide and that belongs to a near-infrared range; A calculation processing unit to which information regarding the absorption spectrum data of a target hydraulic composition, which is a poured hydraulic composition, measured by the absorbance measuring unit is input; A storage unit in which correlations between information on setting time, information on blending of hydraulic compositions, and information on specific times are recorded, The arithmetic processing unit is performing baseline correction on each of the absorption spectrum data inputted continuously or intermittently to generate corrected absorption spectrum data; performing a calculation process for each of the plurality of corrected absorption spectrum data generated over time to increase the degree of influence of the absorbance of the hydrate relative to the degree of influence of the absorbance of water, thereby deriving an index value; and generating index time series data showing a change in the index value over time; The index time series data is subjected to arithmetic processing to detect the presence or absence of an inflection point, and when the presence of the inflection point is detected, the specific time, which is the elapsed time from pouring corresponding to the occurrence timing of the inflection point, is detected; A hydraulic composition setting time estimation system, characterized in that an estimated value of the setting time of the target hydraulic composition is derived based on the detected specific time, the input formulation information of the target hydraulic composition, and the correlation read from the memory unit.

8. The target hydraulic composition is cast in an area surrounded by a formwork, the mold has a window portion on a part of a side surface that is transparent to at least light in the near-infrared region, The hydraulic composition setting time estimation system according to claim 7, wherein the absorbance measurement unit measures the absorption spectrum data of the target hydraulic composition through the window unit.

9. The target hydraulic composition is cast in an area surrounded by a formwork, an insert attached to the form; The insert has a window portion that is transparent to at least light in the near infrared region on a surface that is opposite to the formwork and that is in contact with the target hydraulic composition, The hydraulic composition setting time estimation system according to claim 7, wherein the absorbance measurement unit measures the absorption spectrum data of the target hydraulic composition through the window unit.

10. The formwork has an opening hole in a part of a side surface, The hydraulic composition setting time estimation system according to claim 9, characterized in that the absorbance measuring unit measures the absorption spectrum data of the target hydraulic composition using a probe connected to the window portion through the opening hole.

11. the arithmetic processing unit and the memory unit are mounted on an arithmetic processing device that is installed in a location different from the absorbance measurement unit, The hydraulic composition setting time estimation system according to any one of claims 7 to 10, characterized in that information about the absorption spectrum data measured by the absorbance measurement unit is input to the arithmetic processing device via wired or wireless communication.

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