Information processing device and estimation method for decrease in strength of resin concrete

Abstract

An information processing device according to the present invention comprises an acquisition unit and a control unit. The acquisition unit acquires measurement results obtained by measuring weight increase, decomposition product weight, and bending strength for resin concrete of a prescribed shape and size as immersed in hot water at a plurality of prescribed temperatures for a plurality of test periods. On the basis of the measurement results for weight increase, the control unit finds a first relationship between elapsed time and weight increase at an actual environmental temperature. On the basis of the measurement results for decomposition product weight, the control unit finds a second relationship between elapsed time and decomposition product weight at the actual environmental temperature. On the basis of the measurement results for weight increase, decomposition product weight, and bending strength, the control unit finds a third relationship between weight increase, decomposition product weight, and bending strength. The control unit substitutes the first relationship and the second relationship into the third relationship to find a fourth relationship between elapsed time and bending strength at the actual environmental temperature. The control unit uses the fourth relationship to estimate the decrease in the strength of resin concrete.

Description

Information processing device and method for estimating strength reduction of resin concrete

[0001] This disclosure relates to an information processing device and a method for estimating the strength reduction of resin concrete.

[0002] Resin concrete is a composite material made by adding aggregate and filler to a resin binder and hardening it. Resin concrete is known to have higher strength than cement concrete, allowing for thinner and lighter structures. On the other hand, resin concrete is known to lose strength due to water penetration (see, for example, Non-Patent Document 1), but the strength reduction behavior of resin concrete structures varies considerably depending on the type of resin and / or filler used. For example, resin types include unsaturated polyester, epoxy, and vinyl ester. Filler types include calcium carbonate, fly ash, and silica. Aggregate types include andesite and basalt. Therefore, to investigate the strength reduction behavior of a target structure, it is necessary to conduct tests using the same materials.

[0003] Since the deterioration of strength in actual structures can take more than 50 years, accelerated testing is necessary when investigating the behavior of strength deterioration. In accelerated testing, a method is needed to convert the test period into elapsed time in the actual environment. For example, for the diffusion of moisture into resin, one method is to conduct accelerated testing at a higher temperature and convert it to the actual environment temperature using an Arrhenius plot (see, for example, Non-Patent Document 1).

[0004] Takashi Miwa, Kazue Takahashi, Hiroyuki Takahashi, and Takashi Sawada, "Study on the mechanism of strength reduction and strength estimation of unsaturated polyester resin concrete buried underground," Materials and Environment, Vol. 69, pp. 161-168 (2020).

[0005] However, the mechanism of strength reduction in resin concrete is thought to be due to two mechanisms: "aggregate-resin delamination due to water" and "hydrolysis of the resin" (see, for example, Non-Patent Document 1). The above method of converting to actual ambient temperature using the Arrhenius plot is valid only when there is a single strength reduction mechanism. Therefore, the above method cannot be simply applied when estimating the strength degradation of resin concrete.

[0006] Therefore, the purpose of this disclosure, which focuses on these points, is to provide an information processing device and a method for estimating the strength reduction of resin concrete that can address the two strength reduction mechanisms of resin concrete described above and improve the accuracy of estimating the strength reduction of resin concrete.

[0007] An information processing device according to one embodiment includes: an acquisition unit that acquires measurement results obtained by measuring the increased weight, decomposition product weight, and bending strength of resin concrete of a predetermined shape and size that has been immersed in hot water at a plurality of predetermined temperatures and a plurality of test periods; a control unit that determines a first relationship between the elapsed time at the actual ambient temperature and the increased weight based on the measurement result of the increased weight, determines a second relationship between the elapsed time at the actual ambient temperature and the decomposition product weight based on the measurement result of the decomposition product weight, determines a third relationship between the increased weight and the decomposition product weight and the bending strength based on the measurement results of the increased weight, the decomposition product weight, and the bending strength, determines a fourth relationship between the elapsed time at the actual ambient temperature and the bending strength by substituting the first and second relationships into the third relationship, and estimates the decrease in strength of the resin concrete using the fourth relationship.

[0008] A method for estimating the strength reduction of resin concrete according to one embodiment includes: obtaining measurement results by measuring the increased weight, the weight of decomposition products, and the bending strength of resin concrete of a predetermined shape and size that has been immersed in hot water at a plurality of predetermined temperatures and a plurality of test periods; determining a first relationship between the elapsed time at the actual ambient temperature and the increased weight based on the measurement result of the increased weight; determining a second relationship between the elapsed time at the actual ambient temperature and the weight of decomposition products based on the measurement result of the weight of decomposition products; determining a third relationship between the increased weight and the weight of decomposition products and the bending strength based on the measurement results of the increased weight, the weight of decomposition products, and the bending strength; determining a fourth relationship between the elapsed time at the actual ambient temperature and the bending strength by substituting the first and second relationships into the third relationship; and estimating the strength reduction of the resin concrete using the fourth relationship.

[0009] This disclosure makes it possible to improve the accuracy of estimating the strength degradation of resin concrete.

[0010] This is a block diagram showing the schematic configuration of an information processing device according to one embodiment. This is a flowchart showing the method for estimating the strength reduction of resin concrete executed by the control unit of the information processing device. This is a diagram showing an example of the measurement result of the increase in weight of resin concrete. This is a diagram showing an example of the measurement result of the weight of decomposition products of resin concrete. This is a diagram showing an example of the measurement result of the bending strength of resin concrete. This is a diagram showing an image of fitting the increase in weight in Figure 3 to the diffusion equation. Diffusion coefficient of water (D Ｔ This is the Arrhenius plot of the reaction. The weight of the decomposition products in Figure 4 is the reaction rate constant (k). Ｔ This figure shows an image of the reaction rate constant (k) fitted to the formula. Ｔ This is an Arrhenius plot. It is a diagram illustrating a method for estimating bending strength at real-world temperatures.

[0011] The embodiments of this disclosure will be described below with reference to the drawings.

[0012] (Information Processing Device) The information processing device 10 shown in Figure 1, according to one embodiment of the present disclosure, is a general-purpose computer such as a PC (Personal Computer), or another computer, for example, a dedicated computer for executing the resin concrete strength reduction estimation method of the present disclosure. The information processing device 10 includes an acquisition unit 11, a control unit 12, a storage unit 13, and an output unit 14.

[0013] The acquisition unit 11 acquires measurement results from measurements performed by the user on resin concrete from outside the information processing device 10. The measurement results include the results of measurements of increased weight, decomposition product weight, and flexural strength of resin concrete of a predetermined shape and size that has been immersed in hot water at multiple predetermined temperatures and test periods by the user. The acquisition unit 11 may be, for example, an input interface of the information processing device 10 that receives input from the user. The input interface may include, for example, a keyboard, mouse, and touch panel. The acquisition unit 11 may also be a communication interface that sends and receives information from an external source via a wired or wireless communication line. The communication interface may include, for example, a LAN (Local Area Network) interface, a USB (Universal Serial Bus), or an interface compatible with mobile communication standards such as 4G (4th generation) or 5G (5th generation). The acquisition unit 11 may include a port for a removable storage medium such as an SD (Secure Digital) card, and acquire measurement results from the storage medium.

[0014] The control unit 12 includes at least one processor, at least one dedicated circuit, or a combination thereof. The processor is a general-purpose processor such as a CPU (central processing unit) or GPU (graphics processing unit), or a dedicated processor specialized for a specific process. The dedicated circuit is, for example, an FPGA (field-programmable gate array) or an ASIC (application-specific integrated circuit). The control unit 12 controls each part of the information processing device 10 and executes processes related to the operation of the information processing device 10. Based on the measurement results acquired from the acquisition unit 11, the control unit 12 performs calculation processing to estimate the bending strength of resin concrete at actual ambient temperatures. Details of the processes executed by the control unit 12 will be described later.

[0015] The storage unit 13 includes at least one semiconductor memory, at least one magnetic memory, at least one optical memory, or at least two combinations thereof. The semiconductor memory is, for example, RAM (random access memory) or ROM (read-only memory). The RAM is, for example, SRAM (static random access memory) or DRAM (dynamic random access memory). The ROM is, for example, EEPROM (electrically erasable programmable read-only memory). The storage unit 13 functions, for example, as a main memory, auxiliary memory, or cache memory. The storage unit 13 stores programs and data used for the operation of the information processing device 10, and data obtained by the operation of the information processing device 10.

[0016] The output unit 14 outputs information such as a message notified to a user by the control unit 12 and a processing result of processing executed by the control unit 12 to the outside. The output unit 14 includes, for example, a display and a printer. The information processing apparatus 10 may use the same communication interface as that described in the acquisition unit 11 as the output unit 14 to transmit processing results to an external apparatus.

[0017] The functions of the information processing apparatus 10 are realized by causing a processor corresponding to the control unit 12 to execute a program related to the strength reduction estimation method for resin concrete according to the present embodiment. That is, the functions of the information processing apparatus 10 are realized by software. The program causes a computer to function as the information processing apparatus 10 by causing the computer to execute the operations of the information processing apparatus 10. That is, the computer functions as the information processing apparatus 10 by executing the operations of the information processing apparatus 10 in accordance with the program.

[0018] In the present embodiment, the program can be recorded in a computer-readable recording medium. Computer-readable recording media include non-transitory computer-readable media, for example, magnetic recording devices, optical discs, magneto-optical recording media, or semiconductor memories. Distribution of the program is performed, for example, by selling, assigning, or lending a portable recording medium such as a DVD (digital versatile disc) or a CD-ROM (compact disc read only memory) having the program recorded thereon. Distribution of the program may also be performed by storing the program in a storage of an external server and transmitting the program from the external server to another computer. The program may also be provided as a program product.

[0019] (Method for Estimating Strength Reduction of Resin Concrete) Next, with reference to the flowchart in Figure 2, the method for estimating strength reduction of resin concrete executed by the control unit 12 will be described.

[0020] First, the control unit 12 acquires, via the acquisition unit 11, the measurement results of the increased weight of resin concrete, the weight of (hydrolytic) decomposition products, and the bending strength obtained by a hot water immersion test (step S101). These measurement results are obtained by performing weight measurement, (hydrolytic) decomposition product measurement, and bending strength measurement on resin concrete samples of the same material, shape and size. Hereinafter, the hot water immersion test will be briefly described.

[0021] The hot water immersion test is performed by immersing a plurality of samples respectively in hot water at a plurality of predetermined temperatures. This test assumes, for example, a structure that is constantly in contact with water or soil with high moisture content such as the side wall of a manhole, or a structure placed in an environment with a humidity of approximately 100%.

[0022] A user prepares a sample for the hot water immersion test. The shape and size of the sample need to be such that the strength test can be performed, and water can diffuse to the center of the sample within the longest test period among the plurality of test periods of the hot water immersion test. Since the design standard strength of resin concrete is bending strength, the sample is basically formed into a prismatic shape for performing a bending test. For example, if the resin contained in the resin concrete is unsaturated polyester, the size of the sample can be 4 cm × 4 cm × 16 cm. The shape of the sample is not limited to a prismatic shape. The shape of the sample may be, for example, a cylindrical shape.

[0023] The hot water immersion test is performed at three or more temperature levels. At this time, the highest temperature needs to be within a crystalline temperature range that is higher than the temperature at which water diffuses to the center of the sample in the longest test period among the plurality of test periods, and lower than around the glass transition point of the resin. In addition, the lowest temperature is set to a temperature equal to or higher than the assumed temperature of the actual environment. This is because the test cannot be an accelerated test if the temperature is not higher than the temperature of the actual environment. For example, the three temperature levels can be 60°C, 50°C and 40°C. The user completely immerses (submerges) the sample in a constant temperature water bath set to each temperature.

[0024] The user takes a sample from a constant-temperature water bath set to a specific temperature at regular intervals and performs the following measurements in order: (1) weight measurement, (2) bending strength measurement (bending test), and (3) decomposition product measurement. The decomposition product measurement is performed on the sample that has been divided by the bending test. The bending test can be performed by referring to standards such as JIS A 1181:2005, which specifies the test method for resin concrete.

[0025] Decomposition products can be measured, for example, by measuring phthalic acid, a hydrolysis product, using ion chromatography when resin concrete contains unsaturated polyester resin. Ion chromatography requires the sample to be in powder form. Since resin concrete is a matrix of aggregate, resin, and filler, simply grinding it will result in a powder containing a large amount of aggregate, making accurate measurement impossible. Therefore, the user first roughly grinds the sample and removes the aggregate by sieving it through a sieve with a mesh size larger than the minimum aggregate. The user then further grinds the powder, from which the aggregate has been removed, to prepare a sample for ion chromatography.

[0026] The measurement results obtained as described above can be summarized in Figures 3 to 5 and Table 1. Figures 3 to 5 are graphs with the test period on the horizontal axis and the weight increase, weight of decomposition products, and bending strength on the vertical axis, respectively. Table 1 shows the weight increase, weight of decomposition products, and bending strength as a function of the temperature of the immersion water and the immersion period.

[0027]

[0028] The data shown in these figures and tables are hypothetical examples prepared for illustrative purposes and are not actual measurement data. In Figures 3 to 5, the data shown in circles, triangles, and squares respectively represent the data when the immersion water temperature is 60°C, 50°C, and 40°C.

[0029] In FIG. 3, the increased weight is stated as a value obtained by dividing the difference between the weight of the sample and the initial weight of the sample by the initial weight of the sample (that is, the increased weight per unit initial weight of the sample). In FIG. 4, the weight of decomposition products is stated as a value obtained by dividing the measured weight of decomposition products by the initial weight of the sample (that is, the weight of decomposition products per unit initial weight of the sample). In FIGS. 3, 4 and Table 1 above, the units of the increased weight and the weight of decomposition products are dimensionless because they are divided by the initial weight of the sample.

[0030] In step S101, after obtaining the measurement results of the increased weight, the weight of decomposition products and the bending strength, the control unit 12 proceeds to the processes from step S102 to step S110. Each process from steps S102 to S105, steps S106 to S109, and step S110 may be sequentially executed in any order, or may be executed in parallel.

[0031] In the series of processes from step S102 to step S105, the control unit 12 first calculates the diffusion coefficient of water into resin concrete at each temperature based on the measurement results of the increased weight (step S102). The diffusion of water into resin concrete is considered to follow Fick's law of diffusion. Therefore, as shown in FIG. 6, the control unit 12 calculates the diffusion coefficient that is the solution of the diffusion equation that best fits the graph for each temperature. For example, the method described in Non-Patent Document 1 can be used to calculate the diffusion coefficient. As an example, each diffusion coefficient D at 60°C, 50°C and 40°C ６０ , D ５０ and D ４０ are respectively 3.5×10 －１３ , 1.2×10 －１３ and 4.5×10 －１４ .

[0032] The control unit 12 creates an Arrhenius plot for the derived diffusion coefficient D of water at each temperature Ｔ (step S103). In the Arrhenius plot, the reciprocal of absolute temperature (1 / T) is taken on the horizontal axis, and the natural logarithm of the diffusion coefficient D Ｔ (ln(D Ｔ )) is taken on the vertical axis. FIG. 7 shows an example of the Arrhenius plot.

[0033] The control unit 12 approximates each point of the graph by the straight line l １ The following is derived. For example, the control unit 12 sets T to absolute temperature and D to Ｔ When l is the diffusion coefficient at temperature T, the approximate straight line l １ Express this as the following equation (1), and use the least squares method to obtain α １ and β １ Calculate ln(D Ｔ ) = α １ (1 / T) + β １ (1)

[0034] The control unit 12 substitutes the actual ambient temperature for the temperature T in formula (1) and calculates the diffusion coefficient D at the actual ambient temperature. Ｔ The result is derived (step S104). The actual ambient temperature is determined based on the temperature of the environment in which the resin concrete is actually installed. For example, the actual ambient temperature may be the average temperature of the environment in which it is actually installed over a year.

[0035] The control unit 12 determines the diffusion coefficient D at actual ambient temperature. Ｔ Using this method, the increase in weight in the actual environment is estimated (step S105). An example of the obtained results is shown in Table 2. Table 1 shows the first relationship, which is the relationship between elapsed time and increase in weight at the actual ambient temperature.

[0036]

[0037] Next, the series of processes from step S106 to step S109 will be described. First, the control unit 12 calculates the reaction rate constant for the hydrolysis of the resin concrete at each temperature based on the measurement results of the decomposition product weight (step S106). If the resin contained in the resin concrete is unsaturated polyester, phthalic acid is produced by the hydrolysis of unsaturated polyester. The amount of phthalic acid produced at temperature T and immersion period t is [F]. t [F] is the amount of phthalic acid produced at the end of the reaction. ∞ Therefore, the reaction rate constant k Ｔ This is expressed by formula (2).

[0038]

[0039] Figure 8 is a graph in which the curve of equation (2) is fitted to the measurement points at each temperature. The reaction rate constant k at each temperature. Ｔ Since this will be present for the number of immersion periods t for which measurements were taken, the reaction rate constant k will be used in the Arrhenius plot in the next step S107. Ｔ The average value may be used for each temperature. Amount of phthalic acid produced at the end of the reaction [F] ∞ This value represents the point at which the weight of the decomposition product on the graph stops increasing (the range enclosed by the oval in Figure 8). Amount of phthalic acid produced at the end of the reaction [F] ∞ Since the reaction rate constant k is a common value regardless of the temperature at which it is measured, if it can be determined that the increase has stopped at one temperature, the test can be terminated even if it is increasing at other temperatures. As an example, the reaction rate constants k at 60°C, 50°C, and 40°C. ６０ ,k ５０ ,k ４０ These are 4.1 × 10 －８ , 1.3 × 10 －９ and 6.2 × 10 －９ This is the result.

[0040] The control unit 12 calculates the reaction rate constant k for each temperature that has been derived. Ｔ An Arrhenius plot is created for (step S107). The Arrhenius plot has the reciprocal of absolute temperature (1 / T) on the horizontal axis and the reaction rate constant k. Ｔ The natural logarithm of (ln(k)) Ｔ It is created with the vertical axis being )). Figure 9 shows an example of an Arrhenius plot.

[0041] The control unit 12 approximates each point of the graph by the straight line l ２ The following is derived. For example, the control unit 12 sets T to absolute temperature and k to k. Ｔ When l is the diffusion coefficient at temperature T, the approximate straight line l ２ This can be expressed as the following equation (3), and by the least squares method, α ２ and β ２ Calculate ln(k). Ｔ ) = α ２ (1 / T) + β ２ (3)

[0042] The control unit 12 substitutes the actual ambient temperature for the temperature T in formula (3) and calculates the diffusion coefficient D at the actual ambient temperature. Ｔ Derive the following (step S108).

[0043] The control unit 12 determines the reaction rate constant k at actual ambient temperature. Ｔ Using this method, the weight of decomposition products in the actual environment is estimated (step S109). An example of the obtained results is shown in Table 3. Table 3 shows the second relationship, which is the relationship between elapsed time at the actual environmental temperature and the weight of decomposition products.

[0044]

[0045] Next, the derivation of the bending strength estimation formula in step S110 will be explained. The control unit 12 estimates the relationship between the bending strength of the measurement results shown in Table 1 and the increased weight and decomposition product weight. The control unit 12 generates a relationship formula between the bending strength and the increased weight and decomposition product weight using multiple regression analysis or Bayesian estimation. For example, the control unit 12 can perform multiple regression analysis with the bending strength as the dependent variable and the increased weight and decomposition product weight as the independent variables. For example, the relationship between the bending strength and the increased weight and decomposition product weight is γ １ gamma ２ and γ ０ Using γ as a coefficient, it can be expressed as follows: [Bending strength] = γ １ × [Increased weight] + γ ２ × [Decomposition product weight] + γ ０ (4) As an example, for the measurement results in Table 1, the relationship in (4) is given by the following equation (5): [Bending strength] = 120 × [Increased weight] + 141 × [Weight of decomposition products] + 10 (5) Equations (4) and (5) show a third relationship, which is the relationship between increased weight, weight of decomposition products and bending strength.

[0046] After steps S105, S109, and S110, the control unit 12 estimates the bending strength at the actual ambient temperature by substituting the increased weight estimated in step S105 and the weight of decomposition products estimated in step S109 into formula (4) (step S111). As a more specific example, as shown in Figure 10, the control unit 12 estimates the bending strength at the actual ambient temperature for each elapsed time (year) by substituting the increased weight shown in Table 2 and the weight of decomposition products shown in Table 3 into formula (5) for the measurement results shown in Table 1. This allows the control unit 12 to estimate the long-term strength reduction of the resin concrete. Figure 10 shows the fourth relationship between elapsed time at the actual ambient temperature and bending strength.

[0047] The control unit 12 stores the estimated bending strength of the resin concrete in the storage unit 13 and / or outputs it via the output unit 14.

[0048] Generally, the strength degradation of resin concrete can last for more than 50 years depending on environmental conditions, but the apparatus and method of this disclosure make it possible to estimate the long-term strength degradation behavior from the results of accelerated tests over several years.

[0049] As explained above, this disclosure provides a first relationship between elapsed time and increased weight due to "aggregate-resin separation due to water," and a second relationship between elapsed time and the weight of decomposition products due to "hydrolysis of the resin." Furthermore, by substituting these first and second relationships into a third relationship obtained for increased weight and weight of decomposition products and flexural strength, a fourth relationship between elapsed time and flexural strength is obtained. As a result, the information processing device 10 of this disclosure can estimate the strength degradation of resin concrete due to two strength reduction mechanisms: "aggregate-resin separation due to water" and "hydrolysis of the resin." This improves the accuracy of estimating the strength degradation of resin concrete.

[0050] The following additional information is disclosed regarding the embodiments described above.

[0051] (Note 1) An information processing device comprising: an acquisition unit that acquires measurement results obtained by measuring the increased weight, decomposition product weight, and flexural strength of resin concrete of a predetermined shape and size that has been immersed in hot water at multiple predetermined temperatures and multiple test periods; and a control unit that determines a first relationship between the elapsed time at the actual ambient temperature and the increased weight based on the measurement result of the increased weight, determines a second relationship between the elapsed time at the actual ambient temperature and the decomposition product weight based on the measurement result of the decomposition product weight, determines a third relationship between the increased weight and the decomposition product weight and the flexural strength based on the measurement results of the increased weight, the decomposition product weight, and the flexural strength, determines a fourth relationship between the elapsed time at the actual ambient temperature and the flexural strength by substituting the first and second relationships into the third relationship, and estimates the decrease in strength of the resin concrete using the fourth relationship. (Appendix 2) A method for estimating the strength reduction of resin concrete, comprising: obtaining measurement results for resin concrete of a predetermined shape and size that has been immersed in hot water at multiple predetermined temperatures and multiple test periods, measuring the increased weight, the weight of decomposition products, and the bending strength; determining a first relationship between the elapsed time at the actual ambient temperature and the increased weight based on the measurement results of the increased weight; determining a second relationship between the elapsed time at the actual ambient temperature and the weight of decomposition products based on the measurement results of the weight of decomposition products; determining a third relationship between the increased weight and the weight of decomposition products and the bending strength based on the measurement results of the increased weight, the weight of decomposition products, and the bending strength; determining a fourth relationship between the elapsed time at the actual ambient temperature and the bending strength by substituting the first and second relationships into the third relationship; and estimating the strength reduction of the resin concrete using the fourth relationship. (Appendix 3) The method for estimating the strength reduction of resin concrete according to Appendix 2, wherein the plurality of predetermined temperatures are set to at least three temperature levels, the lowest temperature among the plurality of predetermined temperatures is higher than the actual ambient temperature, and the highest temperature is the temperature within the range of the crystallinity temperature of the resin contained in the resin concrete, during the longest test period among the plurality of test periods.(Note 4) A method for estimating the strength reduction of resin concrete according to Note 2 or 3, comprising crushing the resin concrete and sieving it to remove aggregate from the resin concrete, further grinding the resin concrete from which the aggregate has been removed into a powder, and measuring the weight of the decomposition products by ion chromatography using the powdered resin concrete as a sample.

[0052] 10 Information processing device 11 Acquisition unit 12 Control unit 13 Storage unit 14 Output unit

Claims

1. An information processing device comprising: an acquisition unit that acquires measurement results obtained by measuring the increased weight, decomposition product weight, and flexural strength of resin concrete of a predetermined shape and size that has been immersed in hot water at multiple predetermined temperatures and multiple test periods; and a control unit that determines a first relationship between the elapsed time at the actual ambient temperature and the increased weight based on the measurement result of the increased weight, determines a second relationship between the elapsed time at the actual ambient temperature and the decomposition product weight based on the measurement result of the decomposition product weight, determines a third relationship between the increased weight and the decomposition product weight and the flexural strength based on the measurement results of the increased weight, the decomposition product weight, and the flexural strength, determines a fourth relationship between the elapsed time at the actual ambient temperature and the flexural strength by substituting the first and second relationships into the third relationship, and estimates the decrease in strength of the resin concrete using the fourth relationship.

2. A method for estimating the strength reduction of resin concrete, comprising: obtaining measurement results for the increased weight, decomposition product weight, and flexural strength of resin concrete of a predetermined shape and size that has been immersed in hot water at multiple predetermined temperatures and multiple test periods; determining a first relationship between the elapsed time at the actual ambient temperature and the increased weight based on the measurement results of the increased weight; determining a second relationship between the elapsed time at the actual ambient temperature and the decomposition product weight based on the measurement results of the decomposition product weight; determining a third relationship between the increased weight and the decomposition product weight and the flexural strength based on the measurement results of the increased weight, the decomposition product weight, and the flexural strength; determining a fourth relationship between the elapsed time at the actual ambient temperature and the flexural strength by substituting the first and second relationships into the third relationship; and estimating the strength reduction of the resin concrete using the fourth relationship.

3. The method for estimating the strength reduction of resin concrete according to claim 2, wherein the plurality of predetermined temperatures are set to at least three temperature levels, the lowest temperature among the plurality of predetermined temperatures is higher than the actual ambient temperature, and the highest temperature is the temperature within the range of the crystallinity temperature of the resin contained in the resin concrete, during the longest test period among the plurality of test periods.

4. The method for estimating the strength reduction of resin concrete according to claim 2, comprising crushing the resin concrete and sieving it to remove aggregate, further grinding the resin concrete from which the aggregate has been removed into a powder, and measuring the weight of the decomposition products by ion chromatography using the powdered resin concrete as a sample.

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