JP7538008B2 - Method and device for predicting timing of concrete construction, and method for constructing concrete - Google Patents

Description

The present invention relates to a method and device for predicting the timing of concrete construction, such as for concrete slabs, and a method for constructing concrete.

Conventionally, concrete slabs are constructed in the following order: pouring → leveling → topping → pressing. More specifically, concrete is brought from the plant in a mixer (agitator truck) and poured onto a formwork, and the entire structure is leveled to a set height. The concrete hardens over time, and once it has hardened enough for workers to stand on it, bleeding water is added and the edges are treated, and the surface is repeatedly pressed down with a trowel.

The work from the topping out to the pressing is necessary to smooth and densify the concrete surface, and has a major impact on the quality of the slab. This pressing work is judged by experienced workers based on their senses, such as the hardness of the concrete surface when they touch it, the apparent color, and the amount of bleeding water generated. Due to the recent shortage of workers, this method of construction based on intuition is becoming unfeasible, which may lead to a decline in the construction quality of concrete slabs. In particular, there has been a demand in recent years for mechanization of construction to make up for the labor shortage in the construction industry, and as the weight and power of machines become greater compared to manual work, managing the timing of construction has become extremely important.

Conventional methods for grasping the degree of concrete hardening include the methods described in Patent Documents 1 and 2. The method described in Patent Document 1 uses mortar obtained by removing coarse aggregate from a concrete sample as a test specimen, and uses JIS penetration resistance test data (JIS A 1147:2007) to determine the penetration resistance value when a specified penetration needle is inserted vertically. The method records the relationship between time and conductivity obtained from a conductivity meter (or a resistance meter) installed on the test specimen, and calculates the time at which the concrete hardening rate coefficient A is reached from the time of the inflection point of the waveform and the time of pouring water into the concrete. Patent Document 2 describes a method for predicting the timing of concrete work from the time at which the measured waveform obtained from a conductivity meter or resistance meter for the concrete changes.

JP 2019-73898 A JP 2019-73962 A

However, the conventional method of Patent Document 1 requires waiting for the timing when the conductivity changes, and in order to avoid overlooking anything, the measurer must be tied up until the change is identified, or the measurement must be automated. In addition, the relationship between the conductivity of concrete and the degree of hardening tends to be difficult for concrete workers or construction sites to visualize and therefore difficult to address. Furthermore, the method of managing the timing of construction while measuring the penetration resistance value at the actual construction site is reliable, but requires work to remove the coarse aggregate, work to clean the tools used, and the time-consuming work of measuring the penetration resistance value every hour. For this reason, a method has been demanded that makes it possible to easily predict the timing of concrete construction without much effort.

In response to this, the inventor developed a method to calculate the slope A and intercept B of the approximation equation by measuring the concrete temperature as shown in Figure 1, and to predict the time of the pressing work in advance using A and B as shown in Figure 2. The details of the investigation and the specific steps that led to the discovery of this method are explained below.

There is a high correlation between the time that concrete has elapsed since being poured in summer, mid-season (spring), and winter and its penetration resistance value, and this relationship can be expressed by the logarithmic approximation formula shown below. Therefore, if the slope A and intercept B are obtained, the elapsed time can be calculated from the penetration resistance value.

Logarithm of elapsed time = A x (logarithm of penetration resistance) + B ... formula (1)

The larger the slope A, the larger the logarithm of the elapsed time, and therefore the slower the concrete hardening speed. In other words, A tends to be small in the summer when temperatures are high and large in the winter when temperatures are low. Also, intercept B is a value where the logarithm of the penetration resistance value is 0.0 (zero), which means that the penetration resistance value is 1 (N/ ^mm2 ).

When a sample was taken from the agitator vehicle (concrete mixer) that arrived at the casting site, and the relationship between the initial concrete temperature, the slope A, and the intercept B obtained by actually measuring the penetration resistance value was examined, it was found that the correlation between the initial concrete temperature and the slope A was not very good, but the correlation between the initial concrete temperature and the intercept B was good. Since the logarithm of the penetration resistance value of the intercept B is 0.0, that is, the penetration resistance value is 1 (N/mm ² ), as described above, the logarithm of the elapsed time can be calculated regardless of the slope A by applying it to the above formula (1), and the elapsed time can be obtained by calculating the exponent of this value. In other words, by measuring the initial concrete temperature, the elapsed time until the penetration resistance value of 1 (N/mm ² ) can be calculated. By adding the calculated elapsed time to the concrete water pouring time written on the mill sheet of the agitator vehicle, the time corresponding to the penetration resistance value of 1 (N/mm ² ) can be calculated.

When the concrete is still sufficiently soft (for example, about 0.01 to 0.1 (N/mm ² ) at which measurements can be obtained), there is variation in the measured penetration resistance value, so the slope A tends not to be stable. In addition, the concrete temperature is affected by the surrounding air temperature and solar radiation, and gradually increases over time in summer and intermediate seasons. On the other hand, the concrete temperature in winter can gradually decrease from the beginning. Therefore, it is desirable to determine the slope A at a point when as much data as possible has been obtained.

The elapsed time for all test samples at a penetration resistance value of 1 (N/mm ² ) calculated from the value of intercept B was 129 minutes at the shortest and 545 minutes at the longest. If the start of the pressing work is planned to be from a time corresponding to a penetration resistance value of 0.5 (N/mm ² ), for example, the time prediction for the work timing needs to be calculated earlier. On the other hand, time prediction at too early a stage may result in poor accuracy. Therefore, the concrete temperature at a penetration resistance value of 1 (N/mm ² ) is predicted using the following methods (1) to (4).

(1) A predetermined subtraction time (for example, 60 minutes) is subtracted from the elapsed time at which the penetration resistance value is 1 (N/mm ² ) calculated from the slope B.
(2) Calculate the difference between the actual measured concrete temperature and the initial concrete temperature during the elapsed time in (1).
(3) Since the temperature calculated in (2) has changed during the elapsed time in (1), the rate of temperature change is calculated.
(4) Using the rate of temperature change calculated in (3), the predicted concrete temperature at a penetration resistance value of 1 (N/mm ² ) is calculated.

In addition, in calculating the slope A at present, it is desirable to adopt a relationship that is the concrete temperature measurement value obtained by subtracting 60 minutes from the elapsed time at which the penetration resistance value was 1 (N/ ^mm2 ). In addition, since the temperature change is large during periods of large fluctuations in air temperature, it is desirable to set the subtraction time as short as possible, such as 30 minutes or 20 minutes, rather than 60 minutes.

From the above, the timing of the pressing work can be predicted by the following steps 1 to 6. That is, first, in step 1, the concrete pouring time is obtained and the initial temperature of the concrete is measured. Next, in step 2, the measured initial temperature is applied to the relationship between the intercept B of the approximation formula (1) that represents the relationship between the penetration resistance value obtained by a predetermined penetration resistance test and the elapsed time, which is previously grasped, and the initial temperature of the concrete, to obtain the intercept B corresponding to the measured initial temperature. In step 3, the obtained intercept B is applied to the above approximation formula (1) to obtain the elapsed time until the penetration resistance value 1 (N/mm ² ) is reached, and the obtained elapsed time is added to the concrete pouring time to estimate the elapsed time from the water pouring time to the penetration resistance value 1 (N/mm ² ). In step 4, the concrete temperature is measured at the time obtained by adding the time obtained by subtracting 60 minutes from the estimated elapsed time to the concrete pouring time. In step 5, the measured concrete temperature is applied to the relationship between the slope A of the above approximation formula (1) and the concrete temperature at the time when 60 minutes are subtracted from the elapsed time until the penetration resistance value of 1 ( ^N /mm2) is reached, thereby obtaining the slope A corresponding to the measured concrete temperature. In step 6, the above approximation formula (1) is determined using the obtained slope A and intercept B, the penetration resistance value corresponding to the timing of the holding down work is applied to the determined approximation formula (1) to obtain the elapsed time, and the time obtained by adding the obtained elapsed time to the time of pouring water into the concrete is predicted as the timing of the holding down work.

However, this method has the problem that it is difficult to know where the concrete is at a construction site where many agitator trucks are used to deliver the concrete and pour it into the formwork as a slab.

On the other hand, in the conventional method of Patent Document 2, when obtaining measurement data directly from poured concrete, it is necessary to install a measuring device such as a conductivity meter near the pouring area, which can get in the way of work and can cause the expensive measuring device to be damaged or contaminated by concrete. To avoid this, concrete samples are collected from the agitator truck in a container such as a bucket and measured at a different location, but collecting samples is time-consuming and the conditions are slightly different from those of concrete poured on an actual slab. Ideally, it is desirable to measure actual concrete. For this reason, a method has been demanded that can easily predict the construction timing for each pouring area at construction sites where concrete is delivered by many agitator trucks.

The present invention has been made in consideration of the above, and aims to provide a method, a prediction device, and a concrete construction method for predicting the timing of concrete construction that can easily predict the timing of construction for each pouring area at a construction site where concrete is delivered using many agitator trucks.

In order to solve the above problems and achieve the object, the method of predicting the timing of concrete construction according to the present invention is a method for predicting the optimum construction timing for carrying out pressing work for each casting range before carrying out pressing work on the surface of the concrete being constructed by pouring concrete in a predetermined pouring order from an agitator vehicle assigned to each of a plurality of casting ranges, and includes the steps of acquiring the concrete pouring time of each agitator vehicle, inserting a thermometer into the concrete immediately after the surface has been leveled for the first casting range, and measuring the initial temperature of the concrete using the inserted thermometer. a step of measuring, a step of applying the measured initial temperature to intercept information of an approximation equation expressing the relationship between a penetration resistance value obtained by a predetermined penetration resistance test and elapsed time, which is previously obtained, and the relationship between the initial temperature of the concrete, thereby obtaining intercept information corresponding to the measured initial temperature, a step of applying the obtained intercept information to an approximation equation expressing the relationship between the penetration resistance value and elapsed time, obtaining the elapsed time until the predetermined penetration resistance value is reached by applying the obtained intercept information to the approximation equation expressing the relationship between the penetration resistance value and elapsed time, and a step of estimating the elapsed time from the water pouring time until the predetermined penetration resistance value is reached by adding the obtained elapsed time to the water pouring time of the concrete, and a step of subtracting a predetermined subtraction time from the estimated elapsed time. a step of measuring the temperature of the concrete using the inserted thermometer at a time obtained by adding the time obtained by measuring the temperature of the concrete to the time of pouring water into the concrete; a step of applying the measured concrete temperature to a relationship between the slope information of an approximation equation expressing the relationship between a penetration resistance value obtained by a predetermined penetration resistance test and the elapsed time, which is previously known, and the temperature of the concrete at the time when a predetermined subtraction time is subtracted from the elapsed time until the predetermined penetration resistance value is reached, thereby obtaining slope information corresponding to the measured concrete temperature; and a step of determining an approximation equation expressing the relationship between the penetration resistance value and the elapsed time using the obtained slope information and intercept information. The method is characterized by having a step of calculating the elapsed time by applying a penetration resistance value corresponding to the timing of the holding down work to the determined approximation formula, and predicting the time obtained by adding the calculated elapsed time to the concrete pouring time as the timing of the holding down work in the first pouring range, and a step of predicting the time obtained by adding the time corresponding to the timing of the holding down work in the first pouring range to the concrete pouring time of the agitator car corresponding to the second or subsequent pouring range as the timing of the holding down work in the second or subsequent pouring range.

Moreover, another method for predicting the timing of concrete construction according to the present invention is characterized in that, in the above-mentioned invention, the predetermined penetration resistance value is 1 (N/mm ² ), and the predetermined subtraction time is 60 minutes.

In addition, the concrete construction timing prediction device of the present invention is a device for predicting the construction timing suitable for carrying out pressing work for each casting range before carrying out pressing work on the surface of the concrete being constructed by pouring concrete in a predetermined pouring order from agitator cars assigned to each of a plurality of casting ranges, and includes a means for acquiring the concrete water pouring time of each agitator car, a thermometer that is inserted into the inside of the concrete immediately after the surface is leveled for the first casting range and measures the initial temperature of the concrete, a means for obtaining intercept information corresponding to the measured initial temperature by applying the measured initial temperature to the intercept information of an approximation equation that represents the relationship between a penetration resistance value obtained by a predetermined penetration resistance test and elapsed time that is previously known, and a means for obtaining the elapsed time until the predetermined penetration resistance value is reached by applying the obtained intercept information to an approximation equation that represents the relationship between the penetration resistance value and elapsed time, and adding the obtained elapsed time to the concrete water pouring time to estimate the elapsed time from the water pouring time until the predetermined penetration resistance value is reached, and a means for calculating the time obtained by subtracting a predetermined subtraction time from the estimated elapsed time, and a thermometer for measuring the temperature of the concrete at a time obtained by adding the time of pouring water into the concrete, means for applying the measured concrete temperature to a relationship between a thermometer for measuring the temperature of the concrete, information on the slope of an approximation equation showing the relationship between a penetration resistance value obtained by a predetermined penetration resistance test and elapsed time, and the temperature of the concrete at a time when a predetermined subtraction time is subtracted from the elapsed time until the predetermined penetration resistance value is reached, thereby obtaining information on the slope corresponding to the measured concrete temperature; and means for determining an approximation equation showing the relationship between the penetration resistance value and elapsed time using the obtained slope information and intercept information, and The system is characterized by having a means for calculating the elapsed time by applying a penetration resistance value corresponding to the timing of the holding down work, and predicting the time obtained by adding the calculated elapsed time to the concrete pouring time as the timing of the holding down work in the first pouring range, and for the second and subsequent pouring ranges, having a means for predicting the time obtained by adding the time corresponding to the timing of the holding down work in the first pouring range to the concrete pouring time of the agitator car corresponding to the second and subsequent pouring ranges as the timing of the holding down work in the second and subsequent pouring ranges.

Moreover, another concrete construction timing prediction device according to the present invention is characterized in that, in the above-mentioned invention, the predetermined penetration resistance value is 1 (N/mm ² ), and the predetermined subtraction time is 60 minutes.

The concrete construction method according to the present invention is characterized by having a step of predicting the timing of construction using the above-mentioned method for predicting the timing of concrete construction, a step of pouring concrete, and a step of performing pressing work on the surface of the concrete based on the predicted timing of construction.

According to the method for predicting the timing of concrete construction according to the present invention, the method is for predicting the optimum construction timing for carrying out the pressing work for each casting range before carrying out the pressing work on the surface of the concrete being constructed by pouring concrete in a predetermined pouring order from an agitator vehicle assigned to each of a plurality of casting ranges, and includes the steps of acquiring the concrete pouring time of each agitator vehicle, inserting a thermometer into the concrete immediately after the surface has been leveled for the first casting range, measuring the initial temperature of the concrete using the inserted thermometer, and comparing the penetration resistance value obtained by a predetermined penetration resistance test and the time course of the concrete. a step of applying the measured initial temperature to intercept information of an approximation formula expressing the relationship between the elapsed time and the initial temperature of the concrete to obtain intercept information corresponding to the measured initial temperature; a step of applying the obtained intercept information to an approximation formula expressing the relationship between the penetration resistance value and the elapsed time to obtain a predetermined penetration resistance value, and adding the obtained elapsed time to the concrete pouring time to estimate the elapsed time from the water pouring time to the predetermined penetration resistance value; and a step of measuring the temperature of the concrete using the inserted thermometer at a time obtained by adding the time obtained by subtracting the predetermined subtraction time from the estimated elapsed time to the concrete pouring time. a step of applying the measured concrete temperature to a relationship between slope information of an approximation equation expressing the relationship between a penetration resistance value obtained by a predetermined penetration resistance test and elapsed time, and the concrete temperature at a time when a predetermined subtraction time is subtracted from the elapsed time until the predetermined penetration resistance value is reached, thereby obtaining slope information corresponding to the measured concrete temperature; a step of determining an approximation equation expressing the relationship between the penetration resistance value and elapsed time using the obtained slope information and intercept information, obtaining the elapsed time by applying a penetration resistance value corresponding to the execution timing of the pressing work to the determined approximation equation, and determining a time obtained by adding the obtained elapsed time to the concrete water pouring time. , the step of predicting the timing of the holding down work in the first pouring range as the timing of the holding down work in the first pouring range, and for the second and subsequent pouring ranges, the step of predicting the time obtained by adding the time corresponding to the timing of the holding down work in the first pouring range to the time of pouring concrete from the agitator car corresponding to the second and subsequent pouring range as the timing of the holding down work in the second and subsequent pouring ranges as the timing of the holding down work in the second and subsequent pouring ranges. Therefore, by measuring the time of pouring concrete from each agitator car, the initial temperature of the first pouring range, and the temperature of the concrete at a specified time, the effect is achieved that the timing of the subsequent holding down work can be easily predicted for each pouring range.

In addition, according to another method for predicting the timing of concrete construction of the present invention, the predetermined penetration resistance value is 1 (N/ ^mm2 ) and the predetermined subtraction time is 60 minutes, so that it is possible to easily and accurately determine an approximation equation expressing the relationship between the penetration resistance value and the elapsed time.

In addition, according to the concrete construction timing prediction device of the present invention, the device predicts the optimum construction timing for carrying out pressing work for each casting range before carrying out pressing work on the surface of the concrete being constructed by pouring concrete in a predetermined pouring order from agitator cars assigned to each of a plurality of casting ranges, and includes a means for acquiring the concrete pouring time of each agitator car, a thermometer that is inserted into the concrete immediately after the surface has been leveled for the first casting range and measures the initial temperature of the concrete, and a relationship between the penetration resistance value obtained by a predetermined penetration resistance test and the elapsed time that has been previously determined. and a concrete initial temperature by applying the measured initial temperature to intercept information of an approximation formula expressing the relationship between the intercept information and the initial temperature of the concrete, a means for calculating an elapsed time until a predetermined penetration resistance value is reached by applying the calculated intercept information to an approximation formula expressing the relationship between the penetration resistance value and elapsed time, and estimating an elapsed time from the water pouring time until the predetermined penetration resistance value is reached by adding the calculated elapsed time to the concrete pouring time, a thermometer for measuring the temperature of the concrete at a time obtained by adding a time obtained by subtracting a predetermined subtraction time from the estimated elapsed time to the concrete pouring time, and a means for applying the measured concrete temperature to the relationship between the slope information of an approximation equation expressing the relationship between a penetration resistance value obtained by a prescribed penetration resistance test and elapsed time, and the concrete temperature at the time when a prescribed subtraction time is subtracted from the elapsed time until the prescribed penetration resistance value is reached, thereby obtaining slope information corresponding to the measured concrete temperature; a means for determining an approximation equation expressing the relationship between a penetration resistance value and elapsed time using the obtained slope information and intercept information, obtaining the elapsed time by applying a penetration resistance value corresponding to the execution timing of the pressing work to the determined approximation equation, and adding the obtained elapsed time to the concrete water pouring time, thereby obtaining a time, The system has a means for predicting the timing of the holding down work in the pouring range, and for the second and subsequent pouring ranges, a means for predicting the timing of the holding down work in the second and subsequent pouring ranges by adding the time corresponding to the timing of the holding down work in the first pouring range to the time of pouring concrete from the agitator car corresponding to the second and subsequent pouring ranges. Therefore, by measuring the time of pouring concrete from each agitator car, the initial temperature of the first pouring range, and the temperature of the concrete at a specified time, the system has the effect of easily predicting the timing of the subsequent holding down work for each pouring range.

In addition, according to another concrete construction timing prediction device of the present invention, the predetermined penetration resistance value is 1 (N/ ^mm2 ) and the predetermined subtraction time is 60 minutes, so that it is possible to easily and accurately determine an approximation equation expressing the relationship between the penetration resistance value and the elapsed time.

The concrete construction method according to the present invention includes the steps of predicting the timing of construction using the above-mentioned method for predicting the timing of concrete construction, pouring the concrete, and carrying out pressing work on the surface of the concrete based on the predicted timing of construction. This makes it possible to properly perform pressing work on the surface of the concrete based on the predicted timing of construction before construction. This has the effect of enabling concrete of stable quality to be constructed.

FIG. 1 is a diagram showing an example of calculation of the slope A and intercept B depending on the concrete temperature. FIG. 2 is a diagram showing an example of calculation of a predicted pressing timing. FIG. 3 is a diagram showing an example of a wireless thermometer. FIG. 4 is a diagram showing an example of measurement of air temperature and concrete temperature. FIG. 5 is a diagram showing an input/output screen illustrating an embodiment of a concrete construction timing prediction device according to the present invention. FIG. 6 shows examples of displaying the construction range, where (1) shows a case where the construction range is checked using a mobile terminal, and (2) shows a case where the construction range is checked by placing a colored piece of paper with the time written on it on the floor. FIG. 7 is a flow chart showing an embodiment of a method for predicting timing of concrete construction according to the present invention.

Below, the concrete construction timing prediction method, prediction device, and concrete construction method according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to these embodiments.

[Method for predicting timing of concrete construction]
First, an embodiment of a method for predicting timing of concrete construction according to the present invention will be described.

As described above, the slope A and intercept B of the above approximate formula (1) can be obtained if the initial temperature of the concrete and the temperature of the concrete 60 minutes before the time when the penetration resistance value after pouring reaches 1 (N/ ^mm2 ) can be measured. Therefore, if a wireless thermometer capable of transmitting measurement data via a wireless communication line is installed in the area where the concrete is poured, the concrete temperature can be obtained even from a remote location.

The thermometer is to be installed in concrete that is sufficiently soft immediately after it has been leveled, so a rod-shaped one that can be inserted into concrete, as shown in Figure 3 (1), is ideal as it is easy to handle, but it is also possible to insert a rod-shaped sensor part into the concrete, as shown in Figure 3 (2). The data from the thermometer is set to be sent to a PC (personal computer) in the management office or to a mobile device carried by the worker. In this way, there are no restrictions on where the thermometer can be installed, and the person taking the measurement can obtain data from a remote location. However, it should be noted that the distance over which a thermometer can transmit data varies depending on the product. The ideal transmission distance for a wireless thermometer is around 30 m, but in most cases a distance of 10 m or more will be sufficient.

The procedure for measuring temperature data when pouring concrete is shown below.

(1) Pour concrete into the formwork, and immediately after leveling the surface to the required height, insert the sensor part of the wireless thermometer into the concrete. In this way, temperature data can be obtained directly from the poured concrete. The sensor part should be inserted about 50 mm deep, avoiding the internal rebar, so that the sensor is stable.

(2) The more thermometers, the more detailed the data can be obtained, but on the other hand, the more management work is required, so the minimum number is desirable. Basically, it is assumed that the quality of the concrete delivered from the plant is constant, but the temperature of the poured concrete may change depending on the on-site environment, such as direct sunlight and wind. For example, FIG. 4 shows the air temperature when a concrete slab was poured on a sunny day in mid-March, when the temperature change during the day is large, and the temperature change of the concrete exposed to sunlight. The concrete temperature changes from 15°C to 30°C in 4 hours, and the change may be larger than the surrounding air temperature. When the concrete hardening degree is basically calculated based on the concrete temperature of the first agitator car, it is desirable to measure the concrete temperature of the agitator car several hours later. For example, if the predicted time for a penetration resistance value of 1 (N/mm ² ) is calculated as 360 minutes later (6 hours later), the time 60 minutes before is 300 minutes later (5 hours later), so the temperature change after 5 hours cannot be known. This may result in a large difference in the predicted time. Therefore, if the pouring area is large and will take more than five hours, or if there is a lunch break, it is advisable to install a second wireless thermometer in the concrete poured from the agitator vehicle five hours later, or if the number of agitator vehicles per hour is planned to be six, install a thermometer in the 30th or subsequent agitator vehicle. Also, if the construction area is divided, it is advisable to decide in advance on a method that is easy to manage, such as using the first thermometer in each area.

(3) The concrete temperature is measured when the thermometer is first installed and 60 minutes before the time when the penetration resistance value reaches 1 (N/ ^mm2 ). The thermometer should be removed when the concrete gradually hardens and the penetration resistance value reaches 0.5 (N/ ^mm2 ), at which point a person standing on the concrete can begin to remove any burrs or correct any surface irregularities. At this point, if a person wearing mesh clogs stands on the concrete, the concrete surface will only deform slightly, so the hole made by the thermometer's sensor can be easily filled. In addition, the thermometer is easy to remove, and any concrete that has adhered to the sensor part can be easily washed away.

(4) By measuring the temperature of the concrete, the time of each operation from the time of pouring can be calculated using the method shown in Figures 1 and 2. This method will be described in more detail. First, the time of pouring concrete is recorded by referring to the mill sheet of the agitator vehicle, etc. The intercept B corresponding to the measured initial temperature is obtained by applying the measured initial temperature to the relationship between intercept B (intercept information) of the above approximation formula (1) and the initial temperature of the concrete. The obtained intercept B is substituted into the above formula (1) to obtain the logarithmic value of the elapsed time. Then, the exponential value of this value is added to the time of pouring concrete to calculate the elapsed time from the time of pouring water to the penetration resistance value 1 (N/ ^mm2 ) (predetermined penetration resistance value).

Next, the time is calculated by adding the time obtained by subtracting 60 minutes (subtraction time) from the elapsed time until the calculated penetration resistance value 1 (N/ ^mm2 ) is reached to the water pouring time, and the concrete temperature at that time is measured. Next, the measured concrete temperature is applied to the relationship between the slope A (slope information) of the above approximation formula (1) and the concrete temperature at the time when 60 minutes is subtracted from the elapsed time until the penetration resistance value 1 (N/ ^mm2 ) is reached, to obtain the slope A corresponding to the measured concrete temperature. Next, the start time of each pressing operation as shown in Figure 2 is calculated, and the pressing timing of the concrete slab construction is managed. This makes it possible to predict the time and duration of each operation (construction timing) before construction.

The above-mentioned Fig. 1 and Fig. 2 are images of an input/output screen for implementing the above-mentioned method on a PC or a mobile terminal. On the left side of Fig. 1, input cells consisting of four items are provided. Each cell is a cell (1) for inputting the "water pouring time" of concrete from a mill sheet, a cell (2) for inputting the "measurement time" of the initial temperature of concrete from the concrete at the site, a cell (3) for inputting the "initial temperature of concrete", and a cell (4) for inputting the "concrete temperature" at a time 60 minutes before the penetration resistance value 1 (N/mm ² ) from the concrete at the site. The input data for each cell is used for the calculation processing of the calculation unit. The data to be input are the above four data, and the other items are automatically calculated in the output unit described later, and the slope A and the intercept B can be obtained.

On the right side of Fig. 1, output cells consisting of a plurality of items are provided. Each cell is for outputting "intercept B", "time elapsed until penetration resistance value 1 (N/ ^mm2 )", "time 60 minutes before penetration resistance value 1 (N/ ^mm2 )", "predicted concrete temperature at penetration resistance value 1 (N/ ^mm2 )", and "slope A". A value calculated by the calculation process of the calculation unit is output to each cell.

When the three items of "water pouring time", "measurement time", and "initial concrete temperature" are inputted into the input cell, the calculation unit calculates "intercept B" and calculates "elapsed time until penetration resistance value 1 (N/mm ² )" and "time 60 minutes before penetration resistance value 1 (N/mm ² )". These calculated values are instantly output and displayed in the output cell. After that, the concrete temperature is measured at a time 60 minutes before penetration resistance value 1 (N/mm ² ) and this measured value is inputted into the input cell "concrete temperature", and the calculation unit calculates "predicted concrete temperature at penetration resistance value 1 (N/mm ² )" and "slope A". These calculated values are instantly output and displayed in the output cell. In the example shown in the figure, the water pouring time of 8:00, the measurement time of 9:31, the initial concrete temperature of 15.0°C, and the concrete temperature of 29.2°C are inputted, and the intercept B = 5.82 and the slope A = 0.10 are calculated.

Once the slope A and intercept B are calculated, the calculation unit automatically calculates the start time for each task as shown in Figure 2. Therefore, the user can easily understand the time of each task through this screen. In this example, the initial concrete temperature is measured at 9:31, and when the concrete temperature is measured at that time at 12:37, the time that people can stand on it is calculated to be after 13:14. The work ends at 14:43, which makes it less likely that problems such as peeling, cracking, and uneven coloring due to excessive pressure will occur, and the elimination of subsequent tasks also leads to time savings.

Next, a method for predicting the construction timing at a construction site where many agitator vehicles are in operation will be described.
FIG. 5 is an example of an input/output screen assuming a case where concrete pouring is started by the first agitator truck at 9:00, followed by a one-hour lunch break at 12:00 three hours later, and then resumed at 13:00. This figure shows a rectangular concrete pouring area in a plan view, and the entire area is divided into a number of rectangular pouring areas by grid division. As shown by the arrows in the figure, concrete pouring is set to proceed from the upper left section to the right, move down from the rightmost section to the left, and move down from the leftmost section to the right. Each section is a pouring area poured by one agitator truck.

In the example shown, pouring will begin at 1 pm with the 19th agitator truck, and the example shows the pouring range and work time of each agitator truck when a thermometer is inserted into the pouring range of the 19th truck. If the pouring range of each agitator truck is entered with the agitator truck's mill sheet or the concrete pouring time of each agitator truck sent from the plant, the time of each work can be calculated simply by adding the elapsed time of each work calculated from the pouring range of the first agitator truck.

(5) If a second thermometer is installed in the pouring range of the 19th agitator truck, the time for each task obtained from the temperature measurement of the 19th truck can be added to the water injection time of the 20th truck and onwards. On the other hand, if for some reason the elapsed time is calculated from the pouring range of the third agitator truck, the time for each task can be obtained by adding it to the water injection times of the first and second agitator trucks. However, if calculations are made going back too many trucks, there is a possibility that the actual task time will be earlier than the predicted time, especially in the summer when the hardening rate is fast, so it is desirable to predict the time as much as possible after the agitator truck being measured for temperature.

In this way, the time for the holding down work calculated in Figures 1 and 2 can be displayed in a visually easy-to-understand manner. In order to make it easier for the worker to understand the construction time in the concrete pouring area, the screen display in Figure 5 is displayed on the display of a mobile terminal, for example, as shown in Figure 6 (1). In this way, the construction area can be confirmed while working. The time can also be displayed by placing a piece of paper (colored paper) with the time written on it next to the slab construction area, as shown in Figure 6 (2). This method using paper is a simpler and more reliable method.

(Specific prediction procedure)
Next, a procedure for predicting the pressing timing during concrete slab construction using the prediction method according to this embodiment will be described.

As shown in FIG. 7, first, a thermometer is installed in the pouring area of the first agitator vehicle, for example, immediately after the concrete is leveled. The initial temperature of the concrete and the time are also measured (step S1).

Next, the time elapsed until the penetration resistance value 1 (N/mm ² ) is calculated by the method described above, and the time 60 minutes before the penetration resistance value 1 (N/mm ² ) is calculated (step S2).

Next, the concrete temperature 60 minutes before the penetration resistance value 1 (N/mm ² ) is measured, and the work start time and work end time are calculated (step S3).

Next, the start and end times of each task in the pouring range of the second and subsequent agitator vehicles are calculated by adding the elapsed time obtained for the first agitator vehicle to the water injection time of each agitator vehicle (step S4).

Next, the construction area and the time of each task are presented to the construction site by displaying it on a mobile device or writing it on paper (step S5).

Next, when a person is able to stand on the concrete and begin removing the concrete, the thermometer is retrieved and each task is carried out according to the predicted and displayed time (step S6).

Thus, according to the prediction method of this embodiment, the work time in the pouring range of each agitator truck can be calculated from the initial temperature of the concrete and the concrete temperature 60 minutes before the penetration resistance value of 1 (N/ ^mm2 ), and displayed to the worker. Also, by adding thermometers to an appropriate number of agitator trucks, it becomes possible to predict the work time more accurately. Since the work range and work time are known in advance, work preparation can be done in advance, reliable construction can be achieved, and unnecessary work can be eliminated, which is expected to reduce time and labor.

[Concrete construction timing prediction device]
Next, an embodiment of the concrete construction timing prediction device according to the present invention will be described.

The concrete construction timing prediction device according to this embodiment is an embodiment of the above-mentioned method for predicting concrete construction timing as a device, and is composed of, for example, an input unit, an output unit, a calculation unit, a display unit, and a thermometer. The input unit, output unit, calculation unit, and display unit can be configured using, for example, hardware such as a computer having a CPU, a memory, and a display, and software such as a computer program that runs on this hardware. The thermometer can be configured using the wireless thermometer described above.

The display unit displays a screen such as that shown in FIG. 5, and can be configured, for example, as a display of a mobile terminal.

The input section is the section of the item <INPUT> shown in Fig. 5. That is, this input section includes (1) the water pouring time of the first agitator car at the top left, (2) the initial concrete temperature measured by the first thermometer installed in the pouring range of the first agitator car, (3) the time at that time, (4) the temperature 60 minutes before the penetration resistance value 1 (N/ ^mm2 ), (1) the water pouring time of the 19th agitator car, (2) the initial concrete temperature measured by the second thermometer installed in the pouring range of the 19th agitator car, (3) the time at that time, (4) the temperature 60 minutes before the penetration resistance value 1 (N/ ^mm2 ), and the water pouring times for the other agitator cars. The input data for each item is used for the calculation process of the calculation section.

The output section is the <OUTPUT> item shown in Figure 5. In other words, this output section is the start time, end time, and time until each task in each casting range. Each item displays the calculated value calculated by the calculation processing of the calculation section.

According to the prediction device of this embodiment, the work time in the pouring range of each agitator truck can be calculated from the initial temperature of the concrete and the concrete temperature 60 minutes before the penetration resistance value of 1 (N/ ^mm2 ), and displayed to the worker. In addition, by adding thermometers to an appropriate number of agitator trucks, it becomes possible to predict the work time more accurately. Since the work range and work time are known in advance, work preparation can be done in advance, reliable construction can be performed, and unnecessary work can be eliminated, which is expected to reduce time and labor.

[Concrete construction method]
Next, an embodiment of the concrete construction method according to the present invention will be described taking as an example the case of constructing a concrete slab.

First, before constructing the concrete slab, the construction timing of each pouring area is predicted using the above-mentioned method for predicting the timing of concrete construction. This makes it possible to grasp the construction timing of each holding work before construction of each pouring area. As a result, construction timing information such as that shown in Figure 5 is obtained for each pouring area.

Next, fresh concrete is poured onto the formwork to construct the concrete slab. Then, referring to Figure 5, the construction timing for each pouring area is confirmed, and when it is time for people to stand on it, the workers stand on the hardening concrete slab and carry out tasks such as bleeding water and treating the edges. After that, the disc and ridges are removed, and when it is time to start the first trowel, the surface is repeatedly pressed down with the trowel. Then, when it is time to start the second trowel, the surface is finished with the trowel.

In this way, according to this embodiment, it is possible to perform the pressing work on the surface of the concrete slab appropriately based on the construction timing predicted before construction. This makes it possible to construct a concrete slab of consistent quality.

As described above, the method for predicting the timing of concrete construction according to the present invention is a method for predicting the optimum construction timing for carrying out pressing work for each casting range before carrying out pressing work on the surface of the concrete being constructed by pouring concrete in a predetermined pouring order from agitator vehicles assigned to each of a plurality of casting ranges, and includes the steps of acquiring the concrete pouring time of each agitator vehicle, inserting a thermometer into the concrete immediately after the surface has been leveled for the first casting range, measuring the initial temperature of the concrete using the inserted thermometer, and measuring the temperature of the concrete obtained by a predetermined penetration resistance test that has been determined in advance. the step of applying the measured initial temperature to intercept information of an approximation formula expressing the relationship between the penetration resistance value and elapsed time to be measured and the relationship between the initial temperature of the concrete to obtain intercept information corresponding to the measured initial temperature; the step of applying the obtained intercept information to the approximation formula expressing the relationship between the penetration resistance value and elapsed time to obtain the elapsed time until the predetermined penetration resistance value is reached, and adding the obtained elapsed time to the concrete water pouring time to estimate the elapsed time from the water pouring time to the predetermined penetration resistance value; and measuring the concrete temperature using the inserted thermometer at a time obtained by adding the time obtained by subtracting the predetermined subtraction time from the estimated elapsed time to the concrete water pouring time. measuring the temperature of the concrete; applying the measured concrete temperature to a relationship between slope information of an approximation equation expressing the relationship between a penetration resistance value obtained by a predetermined penetration resistance test and elapsed time, and the concrete temperature at a time when a predetermined subtraction time is subtracted from the elapsed time until the predetermined penetration resistance value is reached, thereby obtaining slope information corresponding to the measured concrete temperature; determining an approximation equation expressing the relationship between the penetration resistance value and elapsed time using the obtained slope information and intercept information, obtaining the elapsed time by applying a penetration resistance value corresponding to the execution timing of the pressing work to the determined approximation equation, and adding the obtained elapsed time to the concrete water pouring time. The system includes a step of predicting the time obtained by adding the time corresponding to the timing of the holding down work in the first pouring range to the time of pouring concrete from the agitator car corresponding to the second or subsequent pouring range as the timing of the holding down work in the second or subsequent pouring range, and a step of predicting the time obtained by adding the time corresponding to the timing of the holding down work in the first pouring range to the time of pouring concrete from the agitator car corresponding to the second or subsequent pouring range as the timing of the holding down work in the second or subsequent pouring range. Therefore, by measuring the time of pouring concrete from each agitator car, the initial temperature of the first pouring range, and the temperature of the concrete at a specified time, the timing of the subsequent holding down work can be easily predicted for each pouring range.

In addition, according to another method for predicting the timing of concrete construction of the present invention, the predetermined penetration resistance value is 1 (N/ ^mm2 ) and the predetermined subtraction time is 60 minutes, so that an approximation formula expressing the relationship between the penetration resistance value and the elapsed time can be easily and accurately determined.

In addition, according to the concrete construction timing prediction device of the present invention, the device predicts the optimum construction timing for carrying out the pressing work for each casting range before carrying out the pressing work on the surface of the concrete being constructed by pouring concrete in a predetermined pouring order from an agitator car assigned to each of a plurality of casting ranges, and includes a means for acquiring the concrete pouring time of each agitator car, a thermometer that is inserted into the concrete immediately after the surface has been leveled for the first casting range and measures the initial temperature of the concrete, and a penetration resistance value obtained by a predetermined penetration resistance test and a measurement of the elapsed time. means for applying the measured initial temperature to the relationship between intercept information of an approximation formula expressing the relationship and the initial temperature of the concrete to obtain intercept information corresponding to the measured initial temperature; means for obtaining the elapsed time until a predetermined penetration resistance value is reached by applying the obtained intercept information to the approximation formula expressing the relationship between the penetration resistance value and elapsed time, and estimating the elapsed time from the water pouring time until the predetermined penetration resistance value is reached by adding the obtained elapsed time to the water pouring time of the concrete; a thermometer for measuring the temperature of the concrete at a time obtained by adding the time obtained by subtracting a predetermined subtraction time from the estimated elapsed time to the water pouring time of the concrete; A means for determining slope information corresponding to a measured concrete temperature by applying the measured concrete temperature to the relationship between slope information of an approximation equation expressing the relationship between a penetration resistance value obtained by a predetermined penetration resistance test and elapsed time and the concrete temperature at the time when a predetermined subtraction time is subtracted from the elapsed time until the predetermined penetration resistance value is reached, and a means for determining slope information corresponding to a measured concrete temperature by applying the obtained slope information and intercept information to an approximation equation expressing the relationship between a penetration resistance value and elapsed time, determining the elapsed time by applying a penetration resistance value corresponding to the execution timing of the pressing work to the determined approximation equation, and adding the obtained elapsed time to the concrete water pouring time. The system has a means for predicting the time corresponding to the timing of the holding down work in the first pouring range as the timing of the holding down work in the first pouring range, and for the second and subsequent pouring ranges, a means for predicting the time obtained by adding the time corresponding to the timing of the holding down work in the first pouring range to the time of pouring concrete from the agitator car corresponding to the second and subsequent pouring range as the timing of the holding down work in the second and subsequent pouring ranges. Therefore, by measuring the time of pouring concrete from each agitator car, the initial temperature of the first pouring range, and the temperature of the concrete at a specified time, the timing of the subsequent holding down work can be easily predicted for each pouring range.

In addition, according to another concrete construction timing prediction device of the present invention, the predetermined penetration resistance value is 1 (N/ ^mm2 ) and the predetermined subtraction time is 60 minutes, so that an approximation equation expressing the relationship between the penetration resistance value and the elapsed time can be easily and accurately determined.

The concrete construction method according to the present invention includes the steps of predicting the timing of construction using the above-mentioned method for predicting the timing of concrete construction, pouring the concrete, and carrying out pressing work on the surface of the concrete based on the predicted timing of construction. This makes it possible to properly perform pressing work on the surface of the concrete based on the predicted timing of construction before construction. This allows concrete of consistent quality to be constructed.

As described above, the concrete construction timing prediction method, prediction device, and concrete construction method of the present invention are useful for the construction of concrete slabs, and are particularly suitable for predicting the construction timing of the pressing work of concrete slabs in each pouring area at construction sites where many agitator vehicles are in operation.

Claims (5)

A method for predicting a suitable construction timing for carrying out a pressing operation for each casting range before carrying out a pressing operation on a surface of concrete being constructed by pouring concrete in a predetermined pouring order from an agitator vehicle assigned to each of a plurality of casting ranges, comprising:
Obtaining the concrete pouring time of each agitator car;
For a first pouring area, inserting a thermometer into the concrete immediately after the surface is leveled;
measuring the initial temperature of the concrete using an inserted thermometer;
A step of applying the measured initial temperature to the relationship between intercept information of an approximation equation that represents the relationship between a penetration resistance value obtained by a predetermined penetration resistance test and elapsed time, and the initial temperature of concrete, thereby obtaining intercept information corresponding to the measured initial temperature;
A step of applying the obtained intercept information to an approximation formula expressing the relationship between the penetration resistance value and the elapsed time to obtain the elapsed time until the predetermined penetration resistance value is reached, and adding the obtained elapsed time to the concrete water pouring time to estimate the elapsed time from the water pouring time to the predetermined penetration resistance value;
measuring the temperature of the concrete using the inserted thermometer at a time obtained by adding a time obtained by subtracting a predetermined subtraction time from the estimated elapsed time to a time of pouring water into the concrete;
A step of applying the measured concrete temperature to a relationship between slope information of an approximation equation that represents a relationship between a penetration resistance value obtained by a predetermined penetration resistance test and elapsed time, which is previously determined, and the concrete temperature at a time when a predetermined subtraction time is subtracted from the elapsed time until the predetermined penetration resistance value is reached, thereby obtaining slope information corresponding to the measured concrete temperature;
A step of determining an approximation formula expressing the relationship between the penetration resistance value and the elapsed time using the obtained slope information and intercept information, calculating the elapsed time by applying the penetration resistance value corresponding to the construction timing of the holding down work to the determined approximation formula, and predicting the time obtained by adding the calculated elapsed time to the concrete pouring time as the construction timing of the holding down work in the first casting range;
A method for predicting the timing of concrete construction, comprising the step of predicting, for a second or subsequent pouring range, the time corresponding to the construction timing of the holding down work in the first pouring range to the concrete pouring time of the agitator truck corresponding to the second or subsequent pouring range as the construction timing of the holding down work in the second or subsequent pouring range. 2. The method for predicting timing of concrete construction according to claim 1, wherein the predetermined penetration resistance value is 1 (N/mm ² ), and the predetermined subtraction time is 60 minutes. A device for predicting a suitable construction timing for carrying out a pressing operation for each casting range before carrying out a pressing operation on a surface of concrete being constructed by pouring concrete in a predetermined pouring order from an agitator vehicle assigned to each of a plurality of casting ranges, comprising:
A means for acquiring the concrete pouring time of each agitator car;
For the first casting area, a thermometer is inserted into the concrete immediately after the surface is leveled and measures the initial temperature of the concrete;
A means for applying the measured initial temperature to the relationship between intercept information of an approximation equation that represents the relationship between a penetration resistance value obtained by a predetermined penetration resistance test and elapsed time, and the initial temperature of concrete, thereby obtaining intercept information corresponding to the measured initial temperature;
A means for applying the obtained intercept information to an approximation formula expressing the relationship between the penetration resistance value and the elapsed time to obtain the elapsed time until the predetermined penetration resistance value is reached, and adding the obtained elapsed time to the time of pouring water into the concrete to estimate the elapsed time from the time of pouring water to the time of reaching the predetermined penetration resistance value;
a thermometer for measuring the temperature of the concrete at a time obtained by adding a time obtained by subtracting a predetermined subtraction time from the estimated elapsed time to a time when water is poured into the concrete;
A means for obtaining slope information corresponding to a measured concrete temperature by applying the measured concrete temperature to a relationship between slope information of an approximation equation that represents a relationship between a penetration resistance value obtained by a predetermined penetration resistance test and elapsed time, and a concrete temperature at a time when a predetermined subtraction time is subtracted from the elapsed time until the predetermined penetration resistance value is reached;
A means for determining an approximation formula expressing the relationship between the penetration resistance value and the elapsed time using the obtained slope information and intercept information, determining the elapsed time by applying the penetration resistance value corresponding to the execution timing of the holding down work to the determined approximation formula, and predicting the time obtained by adding the determined elapsed time to the concrete pouring time as the execution timing of the holding down work in the first casting range;
A concrete construction timing prediction device characterized by having a means for predicting, for the second and subsequent pouring ranges, the time corresponding to the construction timing of the holding down work in the first pouring range to the concrete pouring time of the agitator truck corresponding to the second and subsequent pouring ranges as the construction timing of the holding down work in the second and subsequent pouring ranges. 4. The apparatus for predicting timing of concrete construction according to claim 3, wherein the predetermined penetration resistance value is 1 (N/mm ² ), and the predetermined subtraction time is 60 minutes. A method for constructing concrete, comprising the steps of predicting construction timing using the method for predicting the timing of concrete construction described in claim 1 or 2, pouring concrete, and carrying out pressing work on the surface of the concrete based on the predicted construction timing.

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