JP2023144835A - Method for estimating strength development of hydraulic composition and program of estimation processing of strength development of hydraulic composition - Google Patents

Abstract

To provide a method for accurately estimating a strength development of a hydraulic composition by an easy method.SOLUTION: The method for estimating the strength development of a hydraulic composition according to the present invention includes the steps of: collecting a part of a hydraulic composition to be placed in a placing region or of a hydraulic composition placed in a placing region as a sample (step a); heating the sample under a predetermined heating condition after the hydraulic composition is placed in the placing region (step b); measuring the change of mass of the sample before and after step b (step c); and determining whether the hydraulic composition placed in the placing region has reached a strength development time on the basis of the result of measurement in step c.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for estimating the strength development property of a hydraulic composition. The present invention also relates to a program that is executed to estimate the strength development property of a hydraulic composition.

Predicting the strength development in concrete and mortar during the construction stage is important from the perspective of ensuring the durability and quality of concrete structures.

For example, in the construction stage of floor concrete, after fresh concrete is placed, finishing work is performed after hydration progresses and a certain level of strength is developed. Furthermore, during the construction stage of a concrete structure, the work of removing the formwork (demolding) is performed when a certain level of strength has been developed. Furthermore, when prestressed concrete is produced by introducing PC steel into concrete, a prestressing force is introduced at the timing when a predetermined strength is developed. Specifically, in the case of the post-tension method, tension is applied to the prestressing steel material at the timing when a predetermined strength is developed, and conversely, in the case of the pre-tension method, the prestressed steel material is pre-tensioned. After introduction, the tension is released at the timing when a predetermined strength is achieved.

However, conventionally, the determination of whether or not fresh concrete has progressed to harden and reached a predetermined strength, that is, the time to finish the surface, for example, has largely depended on the builder's intuition, and the timing of judgment has depended on the builder's level of proficiency. There was a problem that variations occurred.

Patent Document 1 discloses a technique in which resistance detection sensors are embedded in multiple locations within a concrete structure, and when the sensors reach a predetermined resistance value, it is detected that the leveling period has arrived. There is.

Japanese Patent Application Publication No. 5-340938

A penetration resistance test specified in JIS A 1147 is known as a method for determining the degree of hardening of concrete. In this method, the degree of hardening is detected based on the penetration resistance value when a specified penetration needle is perpendicularly inserted into mortar as a specimen. By measuring the penetration resistance value at multiple points over time, the starting time of concrete (the time until the penetration resistance value reaches, for example, 3.5 N/mm ² ) and the final time (the time until the penetration resistance value reaches, for example, 28.0 N/mm 2 ), can be determined. From the approximate curve of these plots, a relational expression between the penetration resistance value and the ^elapsed time can be obtained.

However, in order to detect the degree of hardening of concrete using this method, it is necessary to prepare a specimen each time the concrete hardens and measure the penetration resistance value by inserting a penetration needle vertically, which is a complicated process. There is a risk that it will become Further, since special test equipment is used when conducting the test, it is necessary to train workers to learn how to operate this equipment.

According to the technique disclosed in Patent Document 1 mentioned above, although it is not necessary to prepare a specimen, a large-scale device is still required, and it is required to be familiar with this device when implementing the technique. Furthermore, since a part of the buried sensor is exposed on the concrete surface, the probe connected to the sensor may get in the way during compaction and leveling work. Furthermore, if the buried sensor is removed after the test is completed, voids may be created, which may affect the leveling work.

In view of the above problems, an object of the present invention is to provide a method for estimating the strength development property of a hydraulic composition with high precision using a simple method. Another object of the present invention is to provide a program that is executed to accurately estimate the strength development of a hydraulic composition using a simple method.

The method for estimating the strength development property of the hydraulic composition according to the present invention is as follows:
a step (a) of collecting as a sample a part of the hydraulic composition that is scheduled to be cast in the casting area or that has been cast in the casting area;
(b) heating the sample under predetermined heating conditions;
a step (c) of measuring a change in the mass of the sample before and after performing the step (b);
The method further comprises a step (d) of determining whether or not the hydraulic composition placed in the placement area has reached a strength development period based on the measurement result in the step (c). do.

As used herein, the term "hydraulic composition" refers to a curable composition containing a cement composition and water, and includes a form before hardening and a form after hardening. As used herein, the term "cement composition" refers to a cement-containing powder or a product derived therefrom (a product derived from the powder in a kneaded material containing water, or a cured product thereof) that does not contain water, aggregate, or water reducing agent. ). Examples of hydraulic compositions include concrete and mortar.

In the hydraulic composition before curing, the hydration reaction progresses as time passes and the curing progresses. That is, as the curing of the hydraulic composition progresses, the amount of free water contained in the hydraulic composition decreases. The reduced free water is utilized in the hydration reaction and becomes bound water. Strictly speaking, a bleeding phenomenon occurs immediately after pouring, which may cause the free water to rise temporarily.

Free water exists in a state with a high degree of freedom without being bound to the cement composition. Therefore, it evaporates when heated. On the other hand, bound water does not evaporate even when heated because it is bonded to atoms constituting the cement composition.

According to the above method, heat treatment is performed on a sample obtained by collecting a part of the hydraulic composition that is scheduled to be poured in the pouring area or that has been poured in the pouring area, The change in mass before and after heating is measured. In situations where there is a large amount of free water contained in the hydraulic composition after casting, in other words, in situations where curing has not progressed much, the amount of water evaporated by heating increases, resulting in a change in the mass of the sample before and after heating. The quantity is relatively large. On the other hand, in a situation where there is little free water contained in the hydraulic composition after casting, in other words, in a situation where hardening is progressing, the amount of water evaporated by heating is small, so The amount of change in mass is relatively small.

The sample is obtained by collecting a part of the hydraulic composition that is scheduled to be poured in the pouring area or that has been poured in the pouring area, so it may progress over time. The degree of hardening of the sample and the degree of hardening of the hydraulic composition after casting can be considered to be the same. Thereby, the degree of hardening of the hydraulic composition after casting can be estimated from the change in mass of the sample before and after heating. For example, if the amount or rate of change in mass is less than or equal to a predetermined threshold value, it can be determined that the hydraulic composition after casting has reached the strength development stage. In addition, as the above-mentioned sample, it is also possible to use mortar from which coarse aggregate is removed after collecting a part of the hydraulic composition that is scheduled to be poured in the pouring area or that has been poured in the pouring area. do not have.

When performing step (a), the sample may be collected from the hydraulic composition that has actually been cast after the start of the casting work, or the sample may be collected from the hydraulic composition to be cast before the start of the casting work. Alternatively, before the start of the pouring work, a part of the hydraulic composition to be poured can be pooled in advance, and after the start of the pouring work, some of the pooled hydraulic composition can be collected. It does not matter if it is collected.

The step (b) can be a step of heating the sample using a dielectric heating device or an induction heating device. The dielectric heating device is typically a microwave oven. The induction heating device is typically an IH device.

An example of carrying out the above method is as follows. First, after measuring the mass of the sample before heating, the sample is placed in a microwave oven and heated at a predetermined output for a predetermined time. Thereafter, the mass of the sample taken out from the microwave oven, that is, the sample after heating, is measured. Then, the mass of the sample before heating and the mass of the sample after heating are compared to detect the degree of change. The degree of change may be the difference value (amount of change) between the two, the amount of change from the reference value, or the ratio of the difference value to the reference value. Here, the reference value may be the mass of the sample at the time of completion of pouring.

That is, the step (c) includes a step (c1) of measuring the mass of the sample before performing the step (b), and a step (c2) of measuring the mass of the sample after performing the step (b). and a step (c3) of calculating a difference value between the measurement result obtained in the step (c1) and the measurement result obtained in the step (c2). The change in mass of the sample may be measured based on the difference value.

From the viewpoint of increasing estimation accuracy, it is preferable to measure changes in the mass of the sample before and after heating at multiple points in time.

That is, in the estimation method, the step (b) and the step (c) are repeatedly executed a plurality of times at predetermined timing, and the step (b) is performed by heating the sample under the heating condition at each timing. It may be a heating process.

At this time, in the step (d), the amount of change in the mass of the sample measured in the step (c) shows a downward trend over time each time the step (b) is executed, and When it is detected that the amount of change in the mass of the sample measured in c) is less than or equal to a predetermined first threshold, the hydraulic composition placed in the placement area has reached the strength development period. It is okay to judge that.

The step (d) may include a step of estimating the strength development time when it is determined that the hydraulic composition cast in the pouring area has not reached the strength development time. .

More specifically, the estimation method uses a hydraulic composition for data acquisition created with the same formulation as the hydraulic composition scheduled to be poured in the pouring area or poured in the pouring area. a first data string showing a change in mass of the hydraulic composition for data acquisition before and after heating according to the elapsed time after water was mixed with the object; a step (e) of acquiring a second data string indicating a change in the penetration resistance value of the hydraulic composition for data acquisition;
A trend in the amount of change in the mass of the hydraulic composition for data acquisition in a time period before and after the strength determination time of the hydraulic composition for data acquisition that is certified based on the second data string. a step (f) of deriving a calibration curve showing from the first data string,
The step (d) includes changing the mass of the sample measured in the step (c) when it is determined that the hydraulic composition cast in the casting region has not reached the strength development stage. A step (d1) of estimating the time when the hydraulic composition placed in the placement area reaches the strength development time based on the change in amount and the calibration curve derived in the step (f). It does not matter if it includes. This step (d1) corresponds to the step of predicting the time when the hydraulic composition will develop strength after being cast.

In addition, when preparing the hydraulic composition for data acquisition, it is finely adjusted to have the same conditions as the hydraulic composition after casting, taking into account climate conditions such as temperature and humidity. I don't mind if it is.

Step (e) corresponds to the step of acquiring the change in the degree of hardening over time for the hydraulic composition for data acquisition created with the same formulation as the hydraulic composition after casting. . The data obtained in step (e) is stored in a predetermined storage area such as a server, and is analyzed as data related to a calibration curve, which will be described later. The degree of curing of the hydraulic composition can be ascertained, and it can be used at multiple sites where hydraulic compositions with the same formulation are cast.

In step (f), the hydraulic composition for data acquisition, which was created with the same formulation as the hydraulic composition used at the pouring site, is analyzed according to the elapsed time in the time period before and after the strength determination time. The mode of mass change is derived as a calibration curve. Data regarding this calibration curve is recorded, for example, in a predetermined storage unit.

The step (f) is based on the first data string and the second data string transmitted from the shipping source factory that ships the hydraulic composition scheduled to be poured into the placement area. This may also be a step of deriving a calibration curve. The shipping factory here is typically a ready-mixed concrete factory. That is, this step (f) may be executed by an arithmetic processing device such as a server or a terminal computer based on the first data string and the second data string transmitted from the ready-mixed concrete factory.

By comparing the data of this calibration curve with the transition of the amount of change in the mass of the sample measured in step (c), the time of intensity development can be easily estimated.

The data obtained in step (e) may be stored in a server, for example, and step (f) may be executed within the server. In this case, the change in the mass of the sample measured in step (c) is performed by accessing the server using a communication terminal (e.g., smartphone, notebook computer, tablet computer, etc.) that can be connected to the server at the site. By inputting information regarding the amount transition, calculation processing for estimating the intensity onset time may be performed on the server side.

As another example, data regarding the calibration curve may be stored in a server, and this data may be downloaded to the communication terminal. In this case, information regarding the change in mass of the sample measured in step (c) is input on the communication terminal side, and data regarding the downloaded calibration curve is used to estimate the time of intensity development. It does not matter if the arithmetic processing is performed.

Further, in the step (d1), the hydraulic composition to be poured into the pouring region is applied to the pouring region based on data regarding the calibration curve transmitted from a shipping source factory that ships the hydraulic composition to be poured into the pouring region. The step may also be a step of estimating the time when the cast hydraulic composition reaches the strength development time. In this case, after the calibration curve is derived at the ready-mixed concrete factory based on the first data string and the second data string, the server or terminal It may be executed by an arithmetic processing device such as a type computer.

The present invention also provides a program for estimating the strength development property of a hydraulic composition, which is installed in an arithmetic processing device, and includes:
The amount of change in mass of the sample when heat treatment is performed on the sample that is scheduled to be poured in the placement area or is part of the hydraulic composition placed in the placement area. a first process of calculating first information regarding changes over time;
Heat treatment was performed on a hydraulic composition for data acquisition that was created with the same formulation as the hydraulic composition that was scheduled to be cast in the casting area or that was cast in the casting area. A second calibration curve corresponding to a trend in the amount of change in the mass of the hydraulic composition for data acquisition in a time period before and after the strength determination time of the hydraulic composition for data acquisition at a second process of accepting information input;
a third process of determining by calculation whether or not the hydraulic composition cast in the casting area has reached a strength development time based on the first information and the second information;
The present invention is characterized in that the arithmetic processing device executes a fourth process of outputting the result obtained in the third process.

Examples of the arithmetic processing device that performs arithmetic processing using the above program include one or more types belonging to the group consisting of a notebook computer, a tablet computer, a smartphone, and a server.

When it is determined that the hydraulic composition after pouring has not reached the strength development period, the third processing is performed based on the transition of the amount of change in the mass of the sample described in the first information and the second processing. The method may include a process of estimating, by calculation, a time when the hydraulic composition after casting reaches a strength development time based on the calibration curve described in the information. In addition, if the arithmetic processing device is a server, the fourth process will send the results to the user's operating terminal (typically a portable computer or smartphone held by a worker located in the pouring area). Corresponds to the process to send. Furthermore, when the arithmetic processing device is a user's operating terminal, the fourth process corresponds to a process of displaying the result on the display screen of the user's operating terminal. ,

According to the present invention, a method for estimating the strength development property of a hydraulic composition with high accuracy is realized using a simple method.

It is a flowchart which shows an example of the implementation procedure of the estimation method of the strength development property of a hydraulic composition. FIG. 1 is a block diagram schematically showing a configuration of a system for estimating the timing of strength development of a hydraulic composition. 2 is a graph schematically showing how the dehydration rate corresponding to the first data string and the penetration resistance value corresponding to the second data string change over time. It is a block diagram which shows typically another structure of the system which estimates the strength development time of a hydraulic composition. It is a block diagram which shows typically another structure of the system which estimates the strength development time of a hydraulic composition. It is a graph showing the mode of change over time in the penetration resistance value and the dehydration rate of the test mortar. FIG. 2 is a graph showing how the penetration resistance value and free water reduction rate of test mortar change over time.

Embodiments of a method for estimating the strength development property of a hydraulic composition and a program for estimating the strength development property of a hydraulic composition according to the present invention will be described with reference to the drawings as appropriate.

FIG. 1 is a flowchart showing an example of a procedure for estimating the strength development property of a hydraulic composition (hereinafter abbreviated as "this estimating method" as appropriate) according to the present invention. In the following description, step numbers attached to the flowchart shown in FIG. 1 will be referred to as appropriate.

This estimation method is typically performed at the site where the hydraulic composition is placed after the work of placing the hydraulic composition. However, in the present invention, the location where the present estimation method is executed is not limited.

(Step S1: Sample collection)
A part of the hydraulic composition poured at the pouring location (within the pouring area) is collected as a sample. This sample is used for estimating the strength development of the hydraulic composition at the pouring site. When collecting a sample, it is preferably collected as a mortar sample by wet screening or by removing coarse aggregate from the hydraulic composition cast at the placement site. Note that a part of the hydraulic composition to be cast may be collected as a sample before the casting.

This sample is subjected to heat treatment as described below, and the change in mass before and after heating is measured. Therefore, the amount of sample to be collected is arbitrary as long as it is enough to detect a change in mass before and after heating.

Any method can be used for the heat treatment, but the simplest method is a method using a dielectric heating device typified by a microwave oven. Considering heating in a microwave oven, the amount of sample to be collected is preferably 100 g to 600 g, more preferably 150 g to 400 g. By setting such an amount, it is possible to prevent the sample from bursting due to the internal moisture being heated by the induction heating device, and it is possible to improve the measurement accuracy of the mass change before and after heating. Typically, an amount of about 200g±10g is collected.

Furthermore, in view of the handling of the heat treatment in the next step, it is preferable to collect the sample in a paper plate, a magnetic container, or a heat-resistant container.

This step S1 corresponds to step (a).

(Step S2: Mass measurement before heating)
The mass of the sample collected in step S1 is measured. Although the method for measuring the mass is arbitrary, from the viewpoint of ensuring high accuracy, a mass measuring device such as an electronic balance can be used. The measured mass data is recorded in a storage unit mounted on the mass measuring instrument or provided outside the mass measuring instrument.

Note that in step S3, which will be described later, if the sample is heated in a container or the like, the mass may be measured while the sample is in the container.

This step S2 corresponds to step (c1).

(Step S3: Sample heating)
The sample collected in step S1 is heated by a heating device. As the heating device, any device can be used, but from the viewpoint of suppressing the progress of hardening of the sample during the heat treatment, it is preferable to heat the sample in as short a time as possible. From this point of view, as the heating device, a dielectric heating device such as a microwave oven or an induction heating device such as an IH device is preferably used, and more preferably a dielectric heating device is used.

When heating a sample using a dielectric heating device, it is preferable to heat the sample while it is placed in a heat-resistant container, for example, from the viewpoint of improving handleability.

The time for heating the sample is set within a range in which curing of the hydraulic composition constituting the sample does not proceed significantly during the heat treatment. When a dielectric heating device is used as the heating device, the heating time for the sample is, for example, about 3 to 6 minutes. The heating time is appropriately set according to the value of energy (power consumption) added to the heat treatment.

This step S3 corresponds to step (b).

(Step S4: Mass measurement after heating)
In step S3, the mass of the sample after the heat treatment is measured. A method similar to step S2 can be used to measure the mass.

This step S4 corresponds to step (c2).

(Step S5: Calculation of mass change before and after heating)
Based on the mass of the sample before heat treatment obtained in step S2 and the mass of the sample after heat treatment obtained in step S4, a change in the mass of the sample before and after heat treatment is calculated. For convenience, the difference value between the mass of the sample before heat treatment obtained in step S2 and the mass of the sample after heat treatment obtained in step S4 is calculated. Note that the change in mass before and after heating may be recognized by calculating the ratio of mass before and after heat treatment.

Note that the calculation of this mass change may be performed by an arithmetic processing device or may be performed manually by an operator.

This step S5 corresponds to step (c3). Note that the steps including step S2, step S4, and step S5 above correspond to step (c).

Note that the procedure of steps S2 to S5 is not limited as long as the change in mass of the sample before and after the heat treatment can be measured. For example, the heat treatment and the mass measurement process may be performed in parallel.

(Step S6: Intensity onset time determination)
Based on the results of the change in mass of the sample before and after the heat treatment obtained in step S5, it is determined whether the sample has reached the strength development stage. As mentioned above, since the sample is a sample of a part of the hydraulic composition poured at the placement location, this step S6 is performed at the time when the hydraulic composition at the placement location develops strength. This corresponds to the process of determining whether or not the value has been reached.

When the sample collected in step S1 is a hydraulic composition before curing, it contains a lot of free water. In this case, the heating in step S3 evaporates some of the free water, so the measurement result in step S4 is significantly lower than the measurement result in step S2. On the other hand, if the sample collected in step S1 is a hydraulic composition that has undergone hardening, most of the free water has changed to bound water. In this case, even if heated in step S3, the amount of water that evaporates is small, so the measurement results in step S4 do not show a large change compared to the measurement results in step S2.

In other words, as an example, if the change in mass of the sample before and after heat treatment is below the predetermined first threshold Th1, it is determined that the sample has reached the strength development stage, and the change in mass of the sample before and after heat treatment is If it exceeds the predetermined second threshold Th2 (Th2≧Th1), it can be determined that the sample has not yet reached the strength development period. In the case of this method, information regarding each threshold value may be recorded in advance in a storage unit of a communication terminal such as a smartphone or a notebook computer of the worker.

As another method, it can be determined that the sample has reached the strength development period by considering the aspect of the change in mass of the sample over time before and after the heat treatment. This point will be discussed later.

(Step S7: Post-process)
If it is determined in step S6 that the sample has reached the strength development period (Yes in step S6a), post-processing is performed at the pouring location. An example of a post-process is finishing work such as leveling work.

(Repeat steps S3 to S6)
If it is determined in step S6 that the sample has not reached the strength development stage (No in step S6a), steps S3 to S6 are executed again after a predetermined waiting time. In this case, the heat treatment in step S3 is performed under substantially the same heating conditions (output, time) as the previously performed heat treatment.

In this case, in step S6, in addition to the determination criterion of whether the mass change of the sample before and after the heat treatment is less than a predetermined first threshold Th1, Change trends may also be added to the criteria.

As described above, if not much time has passed since the hydraulic composition was placed at the placement site, the sample will contain a large amount of free water. Therefore, by performing the heat treatment in step S3, the amount of water depending on the heating conditions is evaporated. In other words, when step S3 is performed under the same heating conditions, it is assumed that the amount of change in mass will show approximately the same tendency.

Immediately after the hydraulic composition is cast, free water may temporarily rise due to a bleeding phenomenon. In this case, it is assumed that the amount of change in mass shows an upward trend.

On the other hand, when a certain amount of time passes after the hydraulic composition is cast, the hydration reaction progresses and hardening progresses, so the amount of free water decreases. In this case, the amount of water that evaporates when the heat treatment is performed in step S3 tends to decrease.

Therefore, if the amount of change in mass before and after heating shows a downward trend over time, and the change in mass of the sample before and after heat treatment is below the predetermined first threshold Th1, the sample has reached the strength development stage. It can be determined that

The timing at which steps S3 to S6 are repeatedly executed is arbitrary. However, if the time interval is too close, there is a possibility that the trend of the obtained results will not change, but if the time interval is too long, the timing of the intensity onset will be significantly exceeded. There is a possibility that it may be determined that the hydraulic composition at the pouring location has reached the period of strength development. From this point of view, the repetition time interval is preferably 10 minutes to 60 minutes, more preferably 15 minutes to 30 minutes. Note that the repetition time interval does not always need to be constant. For example, the repetition time interval may be set shorter as time passes from the start of pouring.

Note that when repeatedly measuring the amount of change in mass of a sample before and after heating, a sample may be taken each time. In other words, steps S1 to S6 may be repeatedly executed.

(Step S11: Intensity onset time estimation)
If it is determined in step S6 that the sample has not yet reached the strength onset time (No in step S6a), it is also possible to estimate the strength onset time of the sample as an option. This point will be explained with reference to FIG. 2 and the subsequent drawings.

FIG. 2 is a block diagram schematically showing the configuration of a system having a function of estimating the time of intensity onset.

The communication terminal 10 shown in FIG. 2 is a terminal that can be operated by a worker at the pouring site, and is typically a smartphone, a notebook computer, or a tablet computer. The communication terminal 10 includes an input section 11, a display section 12, and a communication section 13. The input unit 11 is a means for inputting information to the communication terminal 10, and is composed of an operator, a keyboard, a mouse, a touch panel, or the like. The display unit 12 is a means for displaying information, and is, for example, a monitor. The communication unit 13 is a communication interface. Note that when information is input through the communication section 13, the communication section 13 may also function as the input section 11.

The in-factory operation terminal 30 shown in FIG. 2 is an operation terminal installed in a shipping factory (typically a ready-mixed concrete factory) that ships hydraulic composition to a pouring site, and is an optional terminal with a communication function. It is a type of computer. The in-factory operation terminal 30 includes an input section 31 and a communication section 32. The input unit 31 is a means for inputting information to the in-factory operation terminal 30. The communication unit 32 is a communication interface. Note that when information is input through the communication section 32, the communication section 32 may also function as the input section 31.

The server 20 shown in FIG. 2 is configured to be able to communicate with the communication terminal 10 and the factory operation terminal 30 via the telecommunications line 5, and includes a storage section 21, an arithmetic processing section 22, and a communication section 23. . The storage unit 21 is a storage medium such as a hard disk or a memory. The calculation processing unit 22 is a calculation processing means such as a CPU. The communication unit 23 is a communication interface.

The storage unit 21 of the server 20 stores data before and after heating according to the elapsed time since water was mixed with the hydraulic composition for data acquisition, which was created with the same composition as the hydraulic composition after pouring. A first data string related to the change in the amount of change in the mass at , and a second data string showing the change in the penetration resistance value depending on the elapsed time are recorded. In detail, a first data string and a second data string obtained by measurement at a ready-mixed concrete factory are inputted to the factory operating terminal 30 through the input section 31, and are transmitted from the communication section 32 via the telecommunication line 5. It is sent to the server 20. The server 20 receives the first data string and the second data string transmitted by the communication section 23 and records them in the storage section 21 . The telecommunications line 5 is, for example, the Internet, an intranet, or the like.

The first data string is obtained by executing steps similar to steps S2 to S5 described above in a ready-mixed concrete factory. Further, the second data string is obtained by executing a method based on JIS A 1147 at a ready-mixed concrete factory. Each process for obtaining the first data string and the second data string can be performed at a point in time before the pouring operation is performed at the pouring site. Each step of obtaining the first data string and the second data string corresponds to step (e).

FIG. 3 is a graph schematically showing how the dehydration rate corresponding to the first data string and the penetration resistance value corresponding to the second data string change over time. In addition, "dehydration rate" here refers to the mass of the hydraulic composition for data acquisition in the initial stage (mortar state) as A0, the mass of the hydraulic composition for data acquisition immediately before heating as A1, and the mass of the hydraulic composition for data acquisition as A1 after heating. It is a value defined by (A1-A2)/A0, where A2 is the mass of the hydraulic composition for data acquisition. In other words, the change over time in the dehydration rate corresponds to the first data string regarding the change in mass before and after heating according to the elapsed time after water was mixed. Note that the value of A1 may be the same as the value of A0.

The time when the hydraulic composition for data acquisition starts to harden can be determined by the value of the penetration resistance value. Typically, the time when the slope of the second data string changes by a predetermined value or more can be recognized as the time to start curing, that is, the time to develop strength. For example, in FIG. 3, the time point of elapsed time tα can be recognized as the strength onset time.

The communication terminal 10 receives from the input unit 11 a data string regarding the change in mass of the sample before and after heating (hereinafter referred to as "sample data string"), which is associated with the elapsed time since the start of the pouring work. It is entered in the same state. Specifically, a worker at the pouring site may input a sample data string by operating the communication terminal 10, or a mass measuring instrument such as an electronic balance may automatically input the sample data to the communication terminal 10. It does not matter if the data is input by being transferred.

The communication terminal 10 transmits the sample data string input from the input section 11 from the communication section 13 to the server 20 via the telecommunication line 5. By comparing the sample data string received via the communication unit 23 and the first data string recorded in the storage unit 21, the server 20 determines what the sample data string will indicate in the future as time passes. Estimate likely behavior by calculation.

As mentioned above, the first data row is obtained by applying the same processing as when obtaining the sample data row to the hydraulic composition for data acquisition created with the same formulation as the hydraulic composition after pouring. This is what was obtained by executing it. For this reason, it is assumed that the change in mass of the sample before and after heating will show almost the same tendency as the first data string.

As described above, the server 20 can specify the intensity onset time on the first data string based on the second data string recorded in the storage unit 21. Therefore, the strength onset time of the sample can be estimated based on the information regarding the strength onset time on the first data string and the comparison result between the first data row and the sample data row. More specifically, by comparing the calibration curve obtained by associating the strength onset time certified based on the second data row with the first data row and the sample data row, the strength onset time of the sample can be determined. It can be estimated. This estimation process is executed in the arithmetic processing unit 22 of the server 20. Note that the server 20 records information regarding the calibration curve in the storage unit 21, and the arithmetic processing unit 22 stores the calibration curve read from the storage unit 21 and the sample data string received by the communication unit 23. By comparison, the time of strength development of the sample may be estimated. The step of deriving data regarding this calibration curve corresponds to step (f).

The estimation result of the intensity onset time obtained by the arithmetic processing section 22 is transmitted from the communication section 23 to the communication terminal 10 via the telecommunication line 5. The communication terminal 10 displays the estimation result received by the communication unit 13 on the display unit 12. This allows the worker at the pouring site to recognize the estimated time when the hydraulic composition at the pouring site will develop strength.

When it is determined that the sample has not reached the strength development time, this step S11 of estimating the strength development time of the sample corresponds to step (d1).

[Modified example]
As for the system having the function of estimating the time of intensity onset, various modifications can be adopted. This will be explained below.

<1> The calculation process related to estimating the strength development time of the hydraulic composition at the placement site may be performed on the communication terminal 10 side. FIG. 4 is a block diagram schematically showing another configuration of a system having a function of estimating the time of intensity onset. In the embodiment shown in FIG. 4, the communication terminal 10 includes an arithmetic processing section 14 and a storage section 15.

Also in the modification shown in FIG. 4, water is mixed in the storage unit 21 of the server 20 with the hydraulic composition for data acquisition created with the same composition as the hydraulic composition after pouring. A first data string relating to changes in the amount of change in mass before and after heating according to the elapsed time, and a second data string indicating changes in penetration resistance value depending on the elapsed time are recorded.

The communication terminal 10 receives from the input unit 11 a data string (sample data string) regarding the transition of the amount of change in mass of the sample before and after heating, in a state in which it is associated with the elapsed time from the start of the pouring work. . In this modification, the communication terminal 10 receives from the communication unit 13 the first data string and the second data string themselves recorded in the storage unit 21 of the server 20, or the data regarding the calibration curve, and records them in the storage unit 15. do. In the communication terminal 10, the arithmetic processing unit 14 compares the sample data string with the first data string recorded in the storage unit 15 to estimate the strength onset time of the sample.

<2> In the ready-mixed concrete factory, the first data string and the second data string may be directly input to the server 20 (see FIG. 5). That is, in FIG. 2, the server 20 may also serve as the factory operating terminal 30. In addition, in FIG. 5, the server 20 is written as "in-factory server" to clearly indicate that it exists within the ready-mixed concrete factory.

Note that this aspect can also be adopted in another configuration shown in FIG.

[Another embodiment]
In the above embodiment, a case has been described in which it is determined whether the time for developing the strength of the hydraulic composition at the pouring site has arrived, but the method can also be used to determine when the time for leveling has arrived. Note that the leveling period is included in the period of strength development in a broad sense.

The following description will be made with reference to examples.

Test mortar made of the materials shown in Tables 1 and 2 below was cast, and the penetration resistance value was measured over a predetermined period of time by a method based on JIS A 1147. The results are shown in graph (a) of FIGS. 6A and 6B. In Table 1, W/C refers to the water-cement ratio, and S/C refers to the sand-cement ratio.

Next, a plurality of 200g±10g of test mortar was collected on a paper plate, and was placed in a 500W microwave oven every hour and heated for 4 minutes. Then, when each heat treatment was performed, the change in mass before and after heating was measured, and the dehydration rate was determined by calculation. As mentioned above, the dehydration rate is defined as (A1-A2)/A0, where the mass at the initial stage (mortar state) is A0, the mass immediately before heating is A1, and the mass after heating is A2. It is a value. Graph (b) in FIG. 6A shows the change in dehydration rate over time.

Note that the free water reduction rate was determined by calculation from the change in mass before and after heating when each heat treatment was performed. The free water reduction rate is calculated as (B1-B2)/B2, where the amount of water removed by heat treatment is B1 (=A1-A2), and the theoretical amount of water contained in the test mortar estimated from the formulation is B2. This is the value specified by . Note that the value of B2 above can be calculated from the values in Table 1. That is, when the water-cement ratio W/C is 0.5 and the cement-sand ratio S/C is 2.8, the ideal water content B2 contained in 200 g of test mortar is:
It can be calculated as 200/(0.5+1+2.8)*0.5=23.3[g].
The graph (b) in FIG. 6B shows the change over time in the free water reduction rate.

According to FIG. 6A(a) or FIG. 6B(a), it can be seen that the penetration resistance value shows an increasing tendency from the time when the elapsed time reaches about 2 hours and 30 minutes to 3 hours. As a result of extensive studies, the present inventors have found that when the penetration resistance value reaches 0.3 N/mm ² to 1.0 N/mm ² , it can be determined that the strength development period has been reached. In other words, this time period corresponds to the time of strength development and can be recognized as the leveling time. In addition, in FIGS. 6A and 6B, the time point when the penetration resistance value reaches 3.5 N/mm ² is described as "first train." According to the graph, the time when the elapsed time reaches 4 hours and 22 minutes corresponds to the first train.

According to FIG. 6A(b), it is confirmed that the dehydration rate shows a decreasing tendency during this period of strength development. Moreover, according to FIG. 6B(b), it is confirmed that the free water reduction rate shows an increasing tendency during this strength development period. It can be seen from both graphs that the strength of the test mortar is developed.

5: Telecommunication line 10: Communication terminal 11: Input section 12: Display section 13: Communication section 14: Arithmetic processing section 15: Storage section 20: Server 21: Storage section 22: Arithmetic processing section 23: Communication section 30: Inside the factory Operation terminal 31: Input section 32: Communication section

Claims (9)

a step (a) of collecting as a sample a part of the hydraulic composition that is scheduled to be cast in the casting area or that has been cast in the casting area;
After the hydraulic composition is placed in the placement area, a step (b) of heating the sample under predetermined heating conditions;
a step (c) of measuring a change in the mass of the sample before and after performing the step (b);
The method further comprises a step (d) of determining whether or not the hydraulic composition placed in the placement area has reached a strength development period based on the measurement result in the step (c). A method for estimating the strength development property of a hydraulic composition. The step (b) and the step (c) are repeatedly executed multiple times at predetermined timing,
The step (b) is a step of heating the sample under the heating conditions at each of the timings,
The step (d) is such that the amount of change in the mass of the sample measured in the step (c) shows a downward trend over time each time the step (b) is performed, and When it is detected that the measured amount of change in the mass of the sample is less than or equal to a predetermined first threshold value, it is determined that the hydraulic composition placed in the placement area has reached a strength development time. A method for estimating strength development properties of a hydraulic composition according to claim 1. The step (c) includes:
a step (c1) of measuring the mass of the sample before performing the step (b);
a step (c2) of measuring the mass of the sample after performing the step (b);
A step (c3) of calculating a difference value between the measurement result obtained in the step (c1) and the measurement result obtained in the step (c2),
The method for estimating the strength development property of a hydraulic composition according to claim 2, characterized in that the method is a step of measuring a change in the mass of the sample based on the difference value obtained in the step (c3). . After water is mixed with a hydraulic composition for data acquisition created with the same composition as the hydraulic composition scheduled to be poured in the pouring area or poured in the pouring area. a first data string showing a change in mass of the hydraulic composition for data acquisition before and after heating according to the elapsed time; and a first data string of the hydraulic composition for data acquisition according to the elapsed time. a step (e) of acquiring a second data string indicating the transition of change in penetration resistance value;
A trend in the amount of change in the mass of the hydraulic composition for data acquisition in a time period before and after the strength determination time of the hydraulic composition for data acquisition that is certified based on the second data string. a step (f) of deriving a calibration curve showing from the first data string,
The step (d) includes changing the mass of the sample measured in the step (c) when it is determined that the hydraulic composition cast in the casting region has not reached the strength development stage. A step (d1) of estimating the time when the hydraulic composition placed in the placement area reaches the strength development time based on the change in amount and the calibration curve derived in the step (f). The method for estimating the strength development property of a hydraulic composition according to claim 2 or 3, comprising: The step (f) is based on the first data string and the second data string transmitted from the shipping source factory that ships the hydraulic composition scheduled to be poured into the placement area. 5. The method for estimating strength development of a hydraulic composition according to claim 4, which is a step of deriving a calibration curve. In the step (d1), the hydraulic composition to be poured into the placement area is placed in the placement area based on data regarding the calibration curve sent from a shipping source factory that ships the hydraulic composition to be placed in the placement area. 5. The method for estimating strength development of a hydraulic composition according to claim 4, characterized in that the step is a step of estimating a time when the hydraulic composition reaches a strength development time. Strength of the hydraulic composition according to any one of claims 1 to 6, wherein the step (b) is a step of heating the sample using a dielectric heating device or an induction heating device. Method for estimating expressivity. A program for estimating the strength development property of a hydraulic composition, which is installed in a calculation processing device,
The amount of change in mass of the sample when heat treatment is performed on the sample that is scheduled to be poured in the placement area or is part of the hydraulic composition placed in the placement area. a first process of calculating first information regarding changes over time;
When heat treatment is performed on a hydraulic composition for data acquisition that is scheduled to be poured in the pouring area or is made with the same formulation as the hydraulic composition that has been poured in the pouring area. , second information regarding a calibration curve corresponding to a trend in the amount of change in the mass of the hydraulic composition for data acquisition in a time period before and after the strength determination time of the hydraulic composition for data acquisition; a second process of accepting input;
a third process of determining by calculation whether or not the hydraulic composition cast in the casting area has reached a strength development time based on the first information and the second information;
A program for estimating the strength development property of a hydraulic composition, characterized in that it causes the arithmetic processing device to execute a fourth process of outputting the result obtained in the third process. In the third process, when it is determined that the hydraulic composition cast in the casting area has not reached the strength development stage, the third process includes determining the change in the amount of change in the mass of the sample described in the first information. and the calibration curve described in the second information, the method includes a process of estimating by calculation a time when the hydraulic composition poured in the pouring area reaches a strength development time, based on the calibration curve described in the second information. A program for estimating the strength development property of the hydraulic composition according to claim 8.

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