A method and system for evaluating crack resistance based on concrete shrinkage rate

Abstract

The application provides a crack resistance performance evaluation method and system based on concrete shrinkage rate. Firstly, the application collects real-time sequence data of shrinkage rate and acoustic emission signal flow of the concrete sample in the curing process, separates the high-frequency elastic wave energy attenuation characteristic value from the acoustic emission signal flow, and couples the shrinkage rate jump point in the real-time sequence data of shrinkage rate in time and space to generate a crack initiation tendency index. Then, based on the environmental temperature lag effect, the temperature drift error of the crack initiation tendency index is calibrated to obtain a calibrated crack initiation tendency index. Then, according to the grading deviation between the pre-designed grading parameters and the fluctuation range of the calibrated crack initiation tendency index, the crack resistance performance grade is output. The technical scheme provided by the application not only solves the essential defect that the traditional method cannot associate material characteristics and environmental response, but also realizes the direct quantitative mapping of material structure performance and damage evolution, and provides traceable material level basis for engineering crack resistance design.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material testing, in particular to a crack resistance performance evaluation method and system based on concrete shrinkage. BACKGROUND

[0002] In the practice of concrete structure engineering, especially in the scene of bearing complex environmental temperature and humidity changes such as large-span bridge and high-rise building foundation, the coupling effect of concrete shrinkage strain and temperature stress is significantly enhanced due to the influence of day and night temperature difference and seasonal climate cycle, and the traditional static evaluation method is difficult to accurately reflect the dynamic initiation trend of internal micro-cracks.

[0003] The current representative scheme is a non-contact surface displacement monitoring method based on digital image correlation technology: by pre-setting artificial speckle texture on the surface of concrete, using high frame rate camera equipment to capture the surface displacement field in the curing process, combining with three-dimensional reconstruction algorithm to calculate the local strain concentration area, and then inferring the crack development trend. This method avoids the installation interference of contact sensors through computer vision technology, and realizes the visualization analysis of global strain distribution.

[0004] Although this scheme realizes surface displacement monitoring, it is limited by the external image acquisition principle and cannot capture the micro-crack initiation behavior at the aggregate-paste interface inside the concrete, and it is difficult to distinguish the thermal deformation of the bulk material caused by temperature sudden change and the real shrinkage crack. When the surface texture is disturbed by strong light or water vapor, the signal-to-noise ratio of the image data drops sharply, resulting in strain calculation failure, and finally only the apparent strain distribution can be output without correlating the material gradation characteristics to realize the closed-loop evaluation of crack resistance performance. SUMMARY

[0005] The present application provides a crack resistance performance evaluation method and system based on concrete shrinkage, to solve the problem that the existing technology cannot capture internal micro-crack behavior, environmental interference causes data failure, and crack resistance evaluation is implemented without considering material characteristics.

[0006] In a first aspect, the present application provides a crack resistance performance evaluation method based on concrete shrinkage, comprising:

[0007] Collecting shrinkage real-time sequence data and acoustic emission signal stream of the concrete sample after preparing the passive responsive material based on the pre-designed gradation parameters during the curing process;

[0008] Separating the high-frequency elastic wave energy attenuation eigenvalue strongly associated with shrinkage micro-crack expansion from the aggregate-paste interface waveguide effect capture area in the acoustic emission signal stream;

[0009] Spatiotemporal coupling the high-frequency elastic wave energy attenuation eigenvalue with the shrinkage jump point in the shrinkage real-time sequence data to generate a crack initiation tendency index.

[0010] based on the environmental temperature hysteresis effect of the passive responsive material, dynamically calibrating temperature drift error of the crack initiation tendency indicator to obtain a calibrated crack initiation tendency indicator;

[0011] outputting a crack resistance performance grade according to the gradation deviation between the pre-designed gradation parameter and the fluctuation range of the calibrated crack initiation tendency indicator.

[0012] Optionally, the shrinkage rate real-time sequence data and the acoustic emission signal stream of the concrete sample prepared based on the pre-designed gradation parameter during the curing process are collected, including:

[0013] The array acoustic waveguide sensor is deployed in a pre-embedded manner in the aggregate-rich region of the concrete sample;

[0014] When the passive responsive material undergoes volume phase transition with the curing process, stress waves generated by the deformation of the microstructure of the passive responsive material drive the displacement of adjacent aggregates, forming a shrinkage displacement pulse;

[0015] The array acoustic waveguide sensor continuously receives elastic wave signals excited by the shrinkage displacement pulse and reflected via the aggregate paste interface, forming an acoustic emission signal stream;

[0016] According to the sequence distribution and intensity value of the shrinkage displacement pulse on the curing time axis, the shrinkage rate real-time sequence data is constructed.

[0017] Optionally, the high-frequency elastic wave energy attenuation characteristic value strongly associated with the shrinkage microcrack propagation is separated from the aggregate paste interface waveguide effect capture region in the acoustic emission signal stream, including:

[0018] In a single shrinkage displacement pulse cycle, the elastic wave signal segment in the acoustic emission signal stream reflected via the aggregate paste interface is intercepted as a basic wave energy group;

[0019] Identify the signal attenuation blind area boundary points in the basic wave energy group composed of the shortest distance positions between adjacent aggregate particles;

[0020] When the signal intensity between the signal attenuation blind area boundary points is in a continuous decreasing distribution, the wave energy continuous loss node within the shortest distance position is locked;

[0021] According to the density of adjacent wave energy continuous loss nodes in the time sequence, the high-frequency elastic wave energy attenuation characteristic value is separated.

[0022] Optionally, the high-frequency elastic wave energy attenuation characteristic value is spatiotemporally coupled with the shrinkage rate jump point in the shrinkage rate real-time sequence data to generate a crack initiation tendency indicator, including:

[0023] locating a waveform top event at which a high-frequency elastic wave energy attenuation eigenvalue within a single shrinkage displacement pulse cycle reaches a peak value;

[0024] at a moment of occurrence of the waveform top event, intercepting a fluctuation interval of a preset time span before and after the moment of occurrence in a real-time shrinkage rate sequence data;

[0025] converting aggregate average particle size data in the pre-designed grading parameters into a displacement constraint rate of a single displacement pulse in the concrete medium, and marking as an effective shrinkage rate jump point when a shrinkage rate variation amplitude in the fluctuation interval exceeds the displacement constraint rate;

[0026] statistically generating a crack initiation tendency index by deviation amounts of all waveform top events and corresponding effective shrinkage rate jump points in the curing process.

[0027] Optionally, converting aggregate average particle size data in the pre-designed grading parameters into a displacement constraint rate of a single displacement pulse in the concrete medium comprises:

[0028] determining a standard span value of a theoretical gap of an internal aggregate in the concrete sample according to the aggregate average particle size data;

[0029] establishing a single displacement pulse conduction path through the standard span value and a phase transition strain coefficient of the passive responsive material;

[0030] defining a reference value of the displacement constraint rate according to a critical instability inflection point of the displacement pulse conduction path;

[0031] correcting the reference value of the displacement constraint rate by using the standard span value of the theoretical gap of the aggregate to generate a displacement constraint rate of a single displacement pulse in the concrete medium.

[0032] Optionally, based on an environmental temperature hysteresis effect of the passive responsive material, dynamically calibrating a temperature drift error of the crack initiation tendency index to obtain a calibrated crack initiation tendency index, comprising:

[0033] recording an environmental temperature instantaneous value at each temperature collection node of the curing process, while detecting an internal temperature response value of the passive responsive material;

[0034] when a change rate of the environmental temperature instantaneous value exceeds a preset value, triggering a hysteresis interval identification window;

[0035] in the hysteresis interval identification window, constructing a temperature hysteresis compensation factor according to a deviation trend of the internal temperature response value and the environmental temperature instantaneous value;

[0036] The crack initiation tendency index is multiplied by a temperature lag compensation factor to generate a calibrated crack initiation tendency index.

[0037] Optionally, an anti-cracking performance grade is output according to a gradation deviation between the pre-designed gradation parameter and a fluctuation range of the calibrated crack initiation tendency index, including:

[0038] A maximum critical value of the gradation acceptable fluctuation range is extracted from the pre-designed gradation parameter;

[0039] Equal-length detection time frames are divided on a time axis of the curing process, and a numerical interval span of the calibrated crack initiation tendency index in each detection time frame is counted;

[0040] When a proportion of the numerical interval span continuously exceeding the maximum critical value reaches a phase transition sensitivity coefficient of the passive responsive material, the detection time frame is marked as an abnormal time frame;

[0041] An anti-cracking performance grade is output according to a distribution density of the abnormal time frame on a time axis of the curing process.

[0042] In a second aspect, the present application provides an anti-cracking performance evaluation system based on concrete shrinkage, including:

[0043] A collection module is configured to collect real-time shrinkage sequence data and acoustic emission signal streams of a concrete sample prepared based on a pre-designed gradation parameter during a curing process of a passive responsive material;

[0044] A separation module is configured to separate high-frequency elastic wave energy attenuation characteristic values strongly associated with shrinkage micro-crack expansion from an aggregate slurry interface waveguide effect capture area in the acoustic emission signal streams;

[0045] A generation module is configured to perform spatio-temporal coupling between the high-frequency elastic wave energy attenuation characteristic values and shrinkage jump points in the real-time shrinkage sequence data to generate a crack initiation tendency index;

[0046] A calibration module is configured to dynamically calibrate temperature drift errors of the crack initiation tendency index based on an environmental temperature lag effect of the passive responsive material to obtain a calibrated crack initiation tendency index;

[0047] An output module is configured to output an anti-cracking performance grade according to a gradation deviation between the pre-designed gradation parameter and a fluctuation range of the calibrated crack initiation tendency index.

[0048] In a third aspect, the present application provides a computing device, comprising a processing component and a storage component; the storage component stores one or more computer instructions; the one or more computer instructions are used to be called and executed by the processing component, so as to realize the method for evaluating the anti-cracking performance of concrete based on the shrinkage rate according to the first aspect.

[0049] In a fourth aspect, the present application provides a computer storage medium, which stores a computer program; when the computer program is executed by a computer, the method for evaluating the anti-cracking performance of concrete based on the shrinkage rate according to the first aspect is realized.

[0050] The present application synchronously collects the shrinkage rate and the acoustic emission double physical signal streams in the solidification process through the synergistic effect of the passive responsive material and the concrete grading parameters, directly separates the high-frequency energy attenuation characteristic value related to the micro-cracks from the aggregate interface characteristic area of the acoustic emission signal, and realizes the accurate quantification of the crack initiation tendency in combination with the shrinkage rate jump point; further, the temperature disturbance is dynamically calibrated by using the temperature hysteresis effect of the material itself, and finally the deviation degree analysis is performed on the grading parameters and the fluctuation range of the calibrated index, so as to construct a full-chain closed-loop evaluation system from the material internal micro-crack response to the structural anti-cracking performance grade, and solve the essential defect that the traditional method cannot associate the material characteristics and the environmental response.

[0051] Further, the equal-length detection frame is divided on the solidification time axis, and the index interval span is counted, the phase change sensitive coefficient of the passive responsive material is used as a dynamic threshold to determine the abnormal time frame, and finally the anti-cracking performance grade is output according to the abnormal frame distribution density; the method firstly dynamically matches the concrete grading tolerance, the intelligent material phase change characteristics and the crack index fluctuation range in time and space, realizes the direct quantitative mapping of the material structural performance and the damage evolution, and provides traceable material level basis for the engineering anti-cracking design.

[0052] These aspects or other aspects of the present application will be more apparent in the following description of the embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to more clearly illustrate the technical solutions of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0054] Figure 1 The flow chart of the method for evaluating the anti-cracking performance of concrete based on the shrinkage rate provided by the present application is shown;

[0055] Figure 2A structural schematic diagram of a concrete shrinkage-based anti-cracking performance evaluation system provided by the application is shown.

[0056] Figure 3 A structural schematic diagram of a computing device provided by the application is shown. DETAILED DESCRIPTION

[0057] In order to enable persons skilled in the art to better understand the scheme of the present application, the technical scheme of the present application will be clearly and completely described below in combination with the drawings in the present application.

[0058] In some processes described in the specification and claims of the present application and the above-described drawings, a plurality of operations appearing in a specific order are included, but it should be clearly understood that these operations can be executed or in parallel without the order in which they appear in the present text, and the serial numbers of the operations, such as 101, 102, etc., are only used to distinguish different operations, and the serial numbers themselves do not represent any execution order. In addition, these processes can include more or fewer operations, and the operations can be executed in sequence or in parallel. It should be noted that the "first", "second", etc. described herein are used to distinguish different messages, devices, modules, etc., and do not represent the order, nor do "first" and "second" represent different types.

[0059] The technical scheme of the present application will be clearly and completely described below in combination with the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0060] Figure 1 A flowchart of a concrete shrinkage-based anti-cracking performance evaluation method provided by the present application is shown in FIG. 1, which comprises the following steps. Figure 1

[0061] Step 101: Collect the shrinkage real-time sequence data and acoustic emission signal stream of the concrete sample based on the pre-designed grading parameter during the curing process of the passive responsive material.

[0062] ​In this step, the pre-designed grading parameter refers to the material structure ratio data set in advance according to the particle size distribution of the aggregate, the proportion of the mineral admixture and the amount of the cementitious material before the preparation of the concrete, which is used to limit the gap characteristics of the aggregate and the material homogeneity; the passive responsive material refers to the intelligent additive such as the microcapsule phase change material or the shape memory alloy particle mixed into the concrete, which can autonomously expand / contract in volume with the change of the environmental temperature and humidity, and the phase change behavior of which directly drives the internal stress change; the real-time shrinkage rate sequence data refers to the continuous quantitative record of the micro-deformation of the concrete on the solidification time axis captured by the displacement sensor, which directly reflects the displacement pulse accumulation effect triggered by the phase change of the passive responsive material; and the acoustic emission signal stream refers to the time sequence fluctuation signal group composed of the elastic wave reflected by the aggregate slurry interface, and the energy attenuation characteristics of which are related to the dynamic physical process of the micro-crack propagation.

[0063] In this embodiment, first, based on the aggregate distribution map of the pre-designed grading parameter when pouring the concrete sample, the array type acoustic wave guide sensor is pre-buried in the enrichment area with the highest aggregate volume concentration; when the solidification process starts, the passive responsive material triggers the microscopic phase change (such as the melting expansion of the paraffin microcapsule) due to the temperature gradient, and the stress wave generated by the volume change drives the instantaneous displacement of the adjacent aggregate in the form of mechanical vibration, generating a quantifiable shrinkage displacement pulse; when the pulse is conducted to the sensor, the piezoelectric ceramic sheet is used to capture the aggregate interface reflection wave excited by the displacement pulse, and the acoustic emission signal stream is generated synchronously; at the same time, the time sequence distribution and amplitude intensity of the displacement pulse on the solidification time axis are recorded by the laser interferometer, which are mapped as the real-time sequence data of the shrinkage rate, so that the isogenic collection and time stamp synchronous binding of the double physical signals are realized.

[0064] Step 102, the high-frequency elastic wave energy attenuation characteristic value strongly related to the shrinkage micro-crack propagation is separated from the aggregate slurry interface waveguide effect capture area in the acoustic emission signal stream.

[0065] In this step, the aggregate slurry interface waveguide effect capture area refers to the acoustic wave reflection path interval formed by the interface between the aggregate particles and the cement slurry inside the concrete. This area has a specific acoustic wave guiding effect due to the heterogeneous structure of the material. The high-frequency elastic wave energy attenuation characteristic value refers to the acoustic wave energy loss characteristic quantity caused by micro-crack propagation in the frequency band above 20 kHz, which is used to characterize the dynamic evolution strength of shrinkage cracks. In this embodiment, first, the acoustic emission signal stream is intercepted according to a single shrinkage displacement pulse period to obtain the elastic wave signal segment reflected by the aggregate interface as the basic wave energy group. Then, the signal attenuation blind area boundary points formed by the shortest distance positions between adjacent aggregates in the energy group are identified. The blind area boundary is caused by the physical blocking effect of the aggregate gap, resulting in acoustic scattering. Then, the continuous downward trend of the acoustic signal intensity between the blind area boundary points is detected to lock the wave energy loss nodes corresponding to the downward trend. Finally, the dense distribution degree of adjacent energy loss nodes on the time axis is counted, and the high-frequency elastic wave energy attenuation characteristic value highly correlated with shrinkage micro-crack propagation is separated out through time series aggregation operation. This process uses the natural structure of the aggregate gap to filter acoustic wave attenuation signals, replacing the artificial feature extraction algorithm with a physical mechanism to achieve high-precision capture of micro-crack characteristics.

[0066] Step 103, spatiotemporal coupling of the high-frequency elastic wave energy attenuation characteristic value with the shrinkage rate jump point in the shrinkage rate real-time sequence data to generate a crack initiation tendency index.

[0067] In this step, the shrinkage rate jump point refers to the mutation position in the shrinkage rate real-time sequence data within a specific time interval with a change amplitude exceeding the displacement constraint rate, which is used to characterize the local failure critical behavior of the material. The crack initiation tendency index is a quantitative value constructed by the cooperative time deviation of acoustic physical response and shrinkage displacement behavior, which directly reflects the dynamic process trend of micro-crack from initiation to propagation, providing early warning for solidification risk.

[0068] In this embodiment, first, the peak time of the high-frequency elastic wave energy attenuation characteristic value in a single shrinkage displacement pulse period is located, which is defined as the waveform top event as the time reference point. Then, the wave fluctuation interval in the shrinkage rate real-time sequence data is intercepted forward and backward for a fixed time length with the waveform top event occurrence time as the center. Subsequently, the aggregate average particle size data in the pre-designed grading parameters is called to generate the displacement constraint rate through the particle size-displacement conversion rule. When the shrinkage rate change amplitude in the intercepted wave fluctuation interval exceeds the constraint rate, it is marked as an effective shrinkage rate jump point. Finally, the time deviation amount of all waveform top events and corresponding jump points in the entire solidification process is counted, and the time difference sequence is aggregated as the crack initiation tendency index.

[0069] Step 104, based on the environmental temperature hysteresis effect of the passive responsive material, dynamically calibrating the temperature drift error of the crack initiation tendency index to obtain a calibrated crack initiation tendency index.

[0070] In this step, the environmental temperature hysteresis effect refers to the asynchronization deviation characteristics between the internal temperature response value of the passive responsive material and the environmental temperature instantaneous value, and the time delay effect formed by the material thermal conduction hysteresis; the temperature drift error refers to the non-crack false fluctuation of the crack initiation tendency index caused by the sudden change of the environmental temperature, and the essence is the signal interference of thermal expansion deformation on the real shrinkage behavior, which needs to be eliminated through a physical compensation mechanism.

[0071] In this embodiment, first, the environmental temperature instantaneous value and the internal temperature response value of the passive responsive material are synchronously acquired at each acquisition node of the curing time axis to construct a double-temperature monitoring data stream; when the environmental temperature change rate is monitored to exceed a preset critical value, a hysteresis interval identification window is immediately triggered; the sustained hysteresis deviation trend of the internal temperature response value relative to the environmental temperature instantaneous value is extracted in the window, and a dynamic temperature hysteresis compensation factor is constructed according to the slope direction and amplitude of the trend; finally, the original value of the crack initiation tendency index at the corresponding time point is multiplied by the compensation factor to generate a calibrated crack initiation tendency index after the temperature drift is eliminated in real time.

[0072] In this step, the gradation deviation degree refers to the cumulative deviation degree of the actual fluctuation range of the calibrated crack initiation tendency index exceeding the allowable critical value of the pre-designed gradation parameter, which is used to quantify the physical deviation of the material structure behavior from the design benchmark; the anti-cracking performance grade is a comprehensive evaluation result divided according to the aggregation density of the crack risk in the time dimension, which directly corresponds to the durability safety threshold of the engineering structure, and provides a grading basis for maintenance decision.

[0073] In this step, the gradation deviation degree refers to the cumulative deviation degree of the actual fluctuation range of the calibrated crack initiation tendency index exceeding the allowable critical value of the pre-designed gradation parameter, which is used to quantify the physical deviation of the material structure behavior from the design benchmark; the anti-cracking performance grade is a comprehensive evaluation result divided according to the aggregation density of the crack risk in the time dimension, which directly corresponds to the durability safety threshold of the engineering structure, and provides a grading basis for maintenance decision.

[0074] In this embodiment, first, the maximum fluctuation critical value allowed by the aggregate gradation tolerance is extracted from the pre-designed gradation parameter as a benchmark; then, the detection time frame is equally divided on the curing process time axis, and the numerical interval span of the calibrated crack initiation tendency index in each time frame is counted, which reflects the local fluctuation intensity; when the span in a single time frame continuously exceeds the proportion of the critical value to the phase change sensitivity coefficient of the passive responsive material, the abnormal time frame is determined to mark the high-risk period; finally, the distribution density of all abnormal time frames on the entire time axis is calculated, and the anti-cracking performance grade is directly output through the density section mapping rule.

[0075] The following are specific embodiments of steps 101 to 105:

[0076] For example, in the solidification process of the concrete pouring of the abutment of a cross-sea bridge, in the face of high salt mist and large temperature difference environment, the pre-embedded sensor array synchronously collects the acoustic emission signal stream and the shrinkage rate real-time sequence data of the concrete sample mixed with microcapsule phase change material; the acoustic emission signal stream captures the elastic wave reflection at the aggregate-paste interface, and the shrinkage rate data is generated by the displacement pulse accumulation triggered by the phase change material, and the two together constitute the physical data basis for monitoring the solidification micro-cracks, providing double-channel signal input for subsequent analysis.

[0077] Based on the above acoustic emission signal stream, the aggregate interface reflection wave signal segment in a single shrinkage displacement pulse cycle is intercepted, and the boundary points of the acoustic wave attenuation blind area composed of the minimum spacing of adjacent aggregates are identified; after detecting the continuous downward trend of the signal intensity between the boundaries, the fluctuation energy loss nodes are locked, and finally the high-frequency elastic wave energy attenuation characteristic value is separated according to the time density of the nodes, accurately capturing the acoustic characteristics of the micro-crack expansion in the concrete under the sea wind load, and avoiding the interference of surface corrosion on the monitoring.

[0078] Further, the peak time of the high-frequency elastic wave energy attenuation characteristic value is taken as the waveform top event, and the shrinkage fluctuation interval is intercepted before and after the time point; based on the aggregate particle size data in the grading parameter, the displacement constraint rate is converted, and the effective shrinkage rate jump points exceeding the threshold in the fluctuation interval are screened; the time difference sequence of the waveform top event and the jump points in the whole solidification period is counted, the crack initiation tendency index reflecting the micro-crack initiation efficiency in the cross-sea environment is generated, and the pseudo-signal coupling caused by tidal cycle is eliminated.

[0079] Based on the harsh environment of the bridge with a day-night temperature difference of 20℃, the temperature hysteresis characteristics of the microcapsule phase change material are used: when the instantaneous value of the environmental temperature is monitored to change suddenly, the hysteresis window is triggered and the deviation trend of the internal temperature response of the material is compared, a dynamic compensation factor is constructed; the crack initiation tendency index and the compensation factor are multiplied point by point on the time axis, the false fluctuations caused by the change of the heat capacity of seawater are eliminated, the real crack index after temperature drift calibration is output, and the data reliability during the typhoon passage is ensured.

[0080] Finally, based on the grading design standard of the abutment concrete, the fluctuation critical value allowed by the aggregate grading is extracted; the calibrated crack index is equally divided into detection frames on the 30-day solidification time axis, and the index span in each frame is counted; when the proportion of the span continuously exceeding the critical value reaches the sensitive coefficient of the phase change material, the abnormal frame is marked; finally, according to the spatio-temporal aggregation density of the abnormal frame in the tidal cycle, the anti-cracking performance level of "A level (low risk) to D level (emergency maintenance)" is output, directly guiding the maintenance decision of the cross-sea bridge.

[0081] As an implementable embodiment, according to step 101, the shrinkage rate real-time sequence data and the acoustic emission signal stream of the concrete sample prepared based on the pre-designed grading parameters during the solidification process of the passive responsive material are collected, including:

[0082] Step 201, deploying arrayed acoustic waveguide sensor in pre-embedded manner in aggregate-rich region of concrete sample.

[0083] In this step, the aggregate-rich region refers to the local high-density aggregate particle gathering area determined according to the pre-designed grading parameters during the preparation of the concrete sample, and this area forms a sound wave reflection hotspot due to the interface effect between the aggregate and the paste; the arrayed acoustic waveguide sensor is a grid-shaped detection assembly composed of multiple piezoelectric ceramic units, and its pre-embedded position strictly matches the aggregate spatial distribution map, which is used to capture the interface elastic wave signal in a directional manner.

[0084] In this embodiment, first, the spatial coordinate cluster with the highest aggregate volume ratio inside the concrete sample is located according to the aggregate spatial distribution model based on the pre-designed grading parameters; then, the arrayed acoustic waveguide sensor is fixed at the core intersection point of the coordinate cluster during the pouring stage, ensuring that the sensor detection surface is directed to the direction of the adjacent aggregate gap; after the concrete is solidified and formed, this deployment method enables the sensor array to be directly embedded in the aggregate-paste interface sound conduction path, thereby establishing a physical channel basis for capturing the reflection signal related to the shrinkage micro-crack in the subsequent process.

[0085] Step 202, when the passive responsive material undergoes volume phase transition with the solidification process, the stress wave generated by the deformation of the microstructure of the passive responsive material drives the displacement of the adjacent aggregate, forming a shrinkage displacement pulse.

[0086] In this step, the volume phase transition refers to the micro-lattice expansion or shrinkage behavior of the passive responsive material under the change of temperature and humidity during the solidification of the concrete, and the strain energy generated is transmitted through intermolecular forces; the stress wave driving refers to the elastic stress wave released by the deformation of the phase change material propagating in the concrete medium, causing the instantaneous movement of the adjacent aggregate to overcome the static friction; the shrinkage displacement pulse is the discrete record of the mechanical displacement event of the adjacent aggregate in the time domain after being driven, which is used to represent the dynamic accumulation process of the micro-shrinkage inside the material.

[0087] In this embodiment, when the passive responsive material triggers lattice reorganization due to environmental temperature change, the elastic stress wave released by the deformation of its microstructure spreads in the form of spherical wave in the concrete medium; when this stress wave conduction reaches the contact position of the aggregate particles, it forces the aggregate to overcome the interface static friction and produce instantaneous displacement; this displacement amount is transmitted through the paste bonding to form a continuous displacement sequence, and finally recorded as a shrinkage displacement pulse in the form of a pulse signal. The entire process utilizes the natural conversion of material phase change energy into mechanical energy, and the physical quantification of shrinkage behavior is achieved without external excitation.

[0088] Step 203, continuously receiving the elastic wave signal excited by the shrinkage displacement pulse and reflected via the aggregate-paste interface through the arrayed acoustic waveguide sensor, forming an acoustic emission signal stream.

[0089] In this step, the shrinkage displacement pulse trigger refers to the process that the kinetic energy of the aggregate particles is converted into the release of elastic vibration energy in the concrete medium when the aggregate particles are driven to produce instantaneous displacement by stress waves; the aggregate slurry interface reflection refers to the signal scattering and turning phenomenon caused by the sudden change of acoustic impedance when the elastic wave propagates to the interface between the aggregate and the cement slurry.

[0090] In this embodiment, when the shrinkage displacement pulse triggers the instantaneous displacement of the aggregate, the released elastic vibration energy propagates along the concrete medium to the aggregate slurry interface and forms a reflected wave due to the difference in material acoustic impedance; the arrayed acoustic waveguide sensor continuously captures the original analog signal of the reflected wave at the pre-embedded position, and generates a time-amplitude sequence stream after analog-digital conversion; the signal stream completely records the attenuation pattern of the reflected wave within each displacement pulse period, forming the acoustic emission data basis required for micro-crack analysis.

[0091] Step 204, constructing a real-time shrinkage rate sequence data according to the sequence distribution and intensity value of the shrinkage displacement pulse on the solidification time axis.

[0092] In this step, the solidification time axis is a continuous time coordinate sequence of the concrete sample from initial setting to final setting, used to mark the absolute timing of physical events; the sequence distribution of the shrinkage displacement pulse refers to the combined mode of the occurrence interval and duration of the pulse event on the time axis, and the intensity value represents the cumulative scalar of the displacement amplitude of a single pulse, both of which together define the spatiotemporal intensity characteristics of the shrinkage behavior.

[0093] In this embodiment, first, the exact occurrence time and duration of all shrinkage displacement pulses on the solidification time axis are extracted to establish a pulse timing distribution map; the corresponding aggregate displacement amplitude integral value of each pulse is simultaneously collected as the intensity value; then the intensity values of the discrete pulses are continuously arranged according to the timing distribution, and the time-displacement amount curve is generated by pulse accumulation; finally, the curve is normalized to the shrinkage rate per unit time according to the solidification process to construct a continuous shrinkage rate real-time sequence data.

[0094] As another embodiment, according to step 102, the high-frequency elastic wave energy attenuation characteristic value strongly associated with the shrinkage micro-crack expansion is separated from the aggregate slurry interface waveguide effect capture area in the acoustic emission signal stream, including:

[0095] Step 301, in a single shrinkage displacement pulse period, the elastic wave signal segment reflected by the aggregate slurry interface in the acoustic emission signal stream is intercepted as the basic wave energy group.

[0096] In this step, the single shrinkage displacement pulse cycle refers to the complete time interval corresponding to the passive response material completing a volume phase change, and the stress release of the material and the aggregate displacement behavior constitute discrete event units in the cycle; the elastic wave signal segment reflected by the aggregate slurry interface refers to the continuous waveform slice of the reflected wave in the time domain formed by the aggregate slurry acoustic impedance difference in the acoustic emission signal stream; and the basic wave energy group is the complete original amplitude value set contained in the signal segment, which is used to represent the original distribution state of the acoustic wave energy in a single physical event.

[0097] In this embodiment, first, the starting and ending time marks of a single shrinkage displacement pulse are determined, and the corresponding section of the acoustic emission signal stream is intercepted in the time window; then, all the elastic wave signals reflected by the aggregate slurry interface in the section are extracted, and the original amplitude envelope changing with time is retained; the signal envelope completely records the interface reflection energy distribution excited by a single material phase change, forming a basic wave energy group that is not polluted by environmental noise.

[0098] Step 302, identifying the signal attenuation blind area boundary point constituted by the shortest distance position between adjacent aggregate particles in the basic wave energy group.

[0099] In this step, the shortest distance position between adjacent aggregate particles is the spatially adjacent region of the aggregate determined by the grading parameter, and the position forms the smallest path in the acoustic wave propagation path due to the physical gap of the aggregate; the signal attenuation blind area boundary point specifically refers to the energy drop inflection point at both ends of the shortest distance position caused by acoustic scattering, and the spatial coordinates are uniquely determined by the aggregate arrangement configuration.

[0100] In this embodiment, based on the spatial coordinates of the pre-embedded sensor array and the aggregate grading distribution model, the shortest distance spatial coordinates of the adjacent aggregate pair corresponding to the basic wave energy group are located; by comparing the amplitude attenuation slopes on both sides of the coordinates, the starting point of the energy drop and the terminal point of the recovery of the acoustic wave energy from normal propagation into the aggregate gap region are identified; the two points are the attenuation blind area boundary points.

[0101] Step 303, when the signal intensity between the signal attenuation blind area boundary points is in a continuous decreasing distribution, locking the wave energy continuous loss node in the shortest distance position.

[0102] In this step, the continuous decreasing distribution of signal intensity refers to the monotonous decreasing non-fluctuating attenuation form of the acoustic wave amplitude between the attenuation blind area boundary points over time, which represents the physical process of continuous absorption of acoustic wave energy; and the wave energy continuous loss node is the discrete time position of the energy dissipation rate mutation in the continuous decreasing segment, which corresponds to the characteristic moment when the micro-crack stably expands through the aggregate gap.

[0103] In this embodiment, by monitoring the amplitude change of the sound wave in the interval of the attenuation blind area boundary point in real time, all continuous decreasing sequences with amplitude value strictly less than the previous moment are detected; when the decreasing sequence continues for more than the sound wave conduction time length corresponding to the blind area boundary point distance, it is determined that the energy is in a continuous loss state; the amplitude-time curve of the interval is scanned for slope change points in the locked state, the momentary inflection point of the sharp increase of the energy dissipation rate is captured, and the inflection point time position is defined as the wave energy continuous loss node.

[0104] Step 304, according to the density of adjacent wave energy continuous loss nodes in time sequence, separate out the high-frequency elastic wave energy attenuation characteristic value.

[0105] In this step, the density of wave energy continuous loss nodes refers to the spatiotemporal aggregation degree of multiple loss nodes on the solidification time axis, which is calculated by the inverse quantization of the time interval between adjacent nodes.

[0106] In this embodiment, first, the occurrence time of all wave energy continuous loss nodes in a single shrinkage displacement pulse period is counted, and a discrete node sequence is constructed in time sequence; the time interval between nodes is calculated and an interval distribution histogram is generated; the node cluster corresponding to the minimum interval value in the histogram is identified, and the sound wave energy loss integral of the nodes in the cluster is extracted; finally, the high-loss node energy spectrum of all pulse periods in the whole solidification process is aggregated into the high-frequency elastic wave energy attenuation characteristic value.

[0107] As another embodiment, according to step 103, the high-frequency elastic wave energy attenuation characteristic value is spatiotemporally coupled with the shrinkage rate jump point in the real-time sequence data of the shrinkage rate to generate a crack initiation tendency index, including:

[0108] Step 401, locate the waveform top event of the peak value of the high-frequency elastic wave energy attenuation characteristic value in a single shrinkage displacement pulse period.

[0109] In this step, the waveform top event refers to the physical event time when the high-frequency elastic wave energy attenuation characteristic value reaches the highest point of energy amplitude in a single shrinkage displacement pulse period, which corresponds to the peak release state of sound wave energy in the reflection process of aggregate interface, and represents the acoustic response extreme point of micro-crack propagation; the positioning result is used as the time reference anchor point of spatiotemporal coupling, for synchronous correlation of the shrinkage rate jump behavior.

[0110] In this embodiment, by monitoring the energy amplitude change curve of the high-frequency elastic wave energy attenuation characteristic value in a single shrinkage displacement pulse period, the amplitude increment sign of adjacent time points is continuously recorded; when the mutation inflection point of the increment sign from positive to negative is detected, it is determined that the previous time point of the inflection point is the global highest position of energy amplitude; the time corresponding to the position is defined as the occurrence time of the waveform top event.

[0111] Step 402, at the occurrence time of the waveform top event, the fluctuation interval of the preset time span before and after the occurrence time in the shrinkage rate real-time sequence data is intercepted.

[0112] In this step, the preset time span is a physical time window determined by the concrete sound wave conduction velocity and the average particle size of the aggregate, and the width thereof ensures covering the complete path length of the sound wave from excitation to reflection; the fluctuation interval is a data section in the shrinkage rate real-time sequence data, which is defined by extending the time span before and after the waveform top event time as the center, and is used to capture the shrinkage displacement mutation behavior strongly associated with the acoustic event.

[0113] In the present embodiment, firstly, the theoretical conduction time of the sound wave in the aggregate gap is calculated based on the aggregate particle size data and the concrete elastic modulus in the pre-designed grading parameters; the conduction time is expanded to a fixed time span as an interception window; then, the corresponding section of the shrinkage rate real-time sequence data is intercepted by extending the time span forward and backward with the waveform top event occurrence time output in step 401 as the time axis center point; the section completely contains the shrinkage displacement response that may be triggered by the sound wave event, forming the data basis for subsequent jump point identification.

[0114] Step 403, the average particle size data of the aggregate in the pre-designed grading parameters is converted into the displacement constraint rate of a single displacement pulse in the concrete medium, and when the shrinkage rate variation amplitude in the fluctuation interval exceeds the displacement constraint rate, it is marked as an effective shrinkage rate jump point.

[0115] In this step, the displacement constraint rate refers to the maximum allowable displacement variation of a single displacement pulse in the concrete medium, which is a physical displacement conduction upper limit determined by the average particle size of the aggregate, and is used to distinguish between real shrinkage cracks and thermal expansion false signals; the effective shrinkage rate jump point is a mutation event marked when the shrinkage rate variation amplitude in the fluctuation interval exceeds the constraint rate, which represents the critical state of local instability of the material.

[0116] In the present embodiment, firstly, the average particle size data of the aggregate in the pre-designed grading parameters is called, and the maximum transmissible displacement of a single displacement pulse in the aggregate gap is calculated in combination with the concrete elastic modulus, which is defined as the displacement constraint rate; then, the shrinkage rate fluctuation interval intercepted in step 402 is scanned, and the cumulative value of the shrinkage rate variation at consecutive time points in the interval is identified; when the cumulative value exceeds the displacement constraint rate, it is determined that there is a local yielding behavior of the material in the interval, and is marked as an effective shrinkage rate jump point.

[0117] Step 404, the time deviation amount of all waveform top events and corresponding effective shrinkage rate jump points in the solidification process is counted, and a crack initiation tendency index is generated.

[0118] In this step, the time deviation amount refers to the absolute time difference between the waveform top event and the corresponding effective shrinkage rate jump point, reflecting the conduction delay between the release of acoustic energy and the shrinkage displacement response; the crack initiation tendency indicator is the statistical distribution value of all deviation amounts in the time sequence aggregation in the full curing process, and the time difference concentration maps the evolution trend strength of micro-cracks from initiation to expansion.

[0119] In this embodiment, the occurrence time of each waveform top event and the occurrence time of its corresponding effective shrinkage rate jump point are extracted, and the absolute time difference between the two is calculated; all time differences in the full curing period are arranged in time sequence to generate a discrete time difference sequence; the sequence is subjected to time axis alignment aggregation operation, and the main peak area is identified through time difference density distribution histogram; finally, the time difference concentration of the main peak area is quantified as the crack initiation tendency indicator.

[0120] As another embodiment, according to step 403, the aggregate average particle size data in the pre-designed grading parameters is converted into the displacement constraint rate of a single displacement pulse in the concrete medium, including:

[0121] Step 501, according to the aggregate average particle size data, determine the standard span value of the theoretical gap of the aggregate inside the concrete sample.

[0122] In this step, the standard span value of the theoretical gap of the aggregate refers to the theoretical expected value of the minimum clearance distance between adjacent aggregate particles calculated according to the aggregate particle size distribution model in the pre-designed grading parameters, which reflects the physical path limit of the aggregate stacking structure inside the concrete, and is used to define the spatial constraint boundary of displacement conduction.

[0123] In this embodiment, first, the aggregate particle size distribution histogram of the pre-designed grading parameters is analyzed to identify the median value of the dominant particle size interval; based on the spatial geometric relationship of the sphere dense packing theory, the minimum gap distance of the median value aggregate in the hexagonal closest packing model is calculated; the distance is modified by combining the cement paste shrinkage compensation coefficient, and finally the standard span value of the theoretical gap of the aggregate inside the concrete sample is output.

[0124] Step 502, establish a single displacement pulse conduction path through the standard span value and the phase transition strain coefficient of the passive responsive material.

[0125] In this step, the phase transition strain coefficient is an inherent attribute parameter that characterizes the micro-lattice deformation ability of passive responsive materials under unit temperature change, and its value is uniquely determined by the material chemical composition; the single displacement pulse conduction path refers to the energy transfer trajectory of the stress wave released by the phase change material when propagating in the aggregate gap network, which is jointly constrained by the gap span and the material strain characteristics, and the integrity of the path determines the effective conduction range of the displacement pulse.

[0126] In this embodiment, based on the theoretical gap standard span value of the aggregate output in step 501, the maximum transmissible strain energy of the stress wave when crossing the minimum gap is calculated in combination with the phase transition strain coefficient of the passive responsive material; according to the spatial attenuation gradient of the strain energy threshold in the concrete medium, the optimal energy transfer trajectory from the phase change material excitation point to the aggregate displacement point is drawn; finally, the trajectory is defined as the single displacement pulse conduction path, and the spatial coordinates are integrated as the physical basis for subsequent displacement constraint rate calculation.

[0127] Step 503, according to the critical instability inflection point of the displacement pulse conduction path, the reference value of the displacement constraint rate is defined.

[0128] In this step, the critical instability inflection point refers to the spatial position where the strain energy transfer efficiency in the displacement pulse conduction path drops sharply, which is caused by the geometric mutation of the aggregate gap or the defect of the paste, resulting in the local interruption of the stress wave conduction path; the reference value of the displacement constraint rate is the initial displacement upper limit defined according to the maximum transmissible strain energy loss ratio at the inflection point, which represents the physical conduction limit of a single displacement pulse in an ideal material state.

[0129] In this embodiment, first, the strain energy spatial attenuation gradient analysis is performed on the displacement pulse conduction path established in step 502 to detect the geometric discontinuity point with a sharp increase in slope on the path curve; by calculating the jump amplitude of the strain energy attenuation rate before and after the point, the critical instability inflection point is determined as the cliff-like drop position of the path conduction efficiency; then the maximum allowed strain energy loss ratio of the inflection point position is extracted and mapped as the initial reference value of the displacement constraint rate.

[0130] Step 504, using the standard span value of the theoretical gap of the aggregate to correct the reference value of the displacement constraint rate to generate the displacement constraint rate of a single displacement pulse in the concrete medium.

[0131] In this step, the standard span value of the theoretical gap of the aggregate is the minimum net distance physical quantity output in step 501, which is rigidly determined by the grading parameters and geometric topology rules; the displacement constraint rate is the final displacement conduction upper limit after geometric correction of the reference value by the standard span value, which reflects the actual constraint ability of the aggregate gap to the displacement pulse in the real concrete medium.

[0132] In this embodiment, based on the standard span value of the theoretical gap of the aggregate in step 501, a negative correlation mapping function of the span value and the displacement constraint rate correction coefficient is established; the displacement constraint rate reference value defined in step 503 is called and input into the mapping function to generate a geometric correction factor; finally, the reference value is multiplied by the correction factor to output the displacement constraint rate of a single displacement pulse in the concrete medium.

[0133] As a further example, according to step 104, based on the environmental temperature hysteresis effect of the passive responsive material, the temperature drift error of the crack initiation tendency index is dynamically calibrated to obtain a calibrated crack initiation tendency index, including:

[0134] Step 601, at each temperature collection node of the curing process, record the environmental temperature instantaneous value, while detecting the internal temperature response value of the passive responsive material.

[0135] In this step, the temperature collection node refers to the temperature recording position point divided by fixed time interval on the concrete curing time axis, and the density is determined by the heat conduction rate of the passive responsive material; the environmental temperature instantaneous value is the real-time temperature sampling value in the micro-environment of the concrete sample surface, reflecting the external thermal disturbance input; the internal temperature response value is the hysteresis temperature feedback generated when the crystal lattice structure of the passive responsive material is deformed by heat, which characterizes the thermal inertia characteristics of the material itself.

[0136] In this embodiment, at each fixed time interval node of the curing process, the environmental temperature instantaneous value is synchronously collected by the surface contact thermocouple, and the internal temperature response value generated by the lattice deformation hysteresis of the passive responsive material is detected by the micro-temperature sensor embedded in the material; the double temperature data stream records the response delay characteristics of the material to external temperature change in real time, providing a physical comparison basis for subsequent hysteresis compensation, and the collection frequency is dynamically adjusted by the material heat conduction coefficient.

[0137] Step 602, when the change rate of the environmental temperature instantaneous value exceeds the preset value, trigger the hysteresis interval identification window.

[0138] In this step, the hysteresis interval identification window is the analysis interval for focusing on the temperature hysteresis effect when the change rate exceeds the threshold value, and the width is proportional to the material thermal inertia constant. In this embodiment, the differential change amount of the environmental temperature instantaneous value between adjacent collection nodes is calculated in real time, and when the absolute value of the change amount exceeds the preset critical threshold of thermal disturbance, the hysteresis interval identification window is immediately extended backward from the current time by the time length corresponding to the material thermal inertia constant, and the window dynamically locks the maximum delay influence period of external temperature change on the material internal response, providing a time boundary for accurately constructing the compensation factor.

[0139] Step 603, within the hysteresis interval identification window, construct a temperature hysteresis compensation factor according to the deviation trend of the internal temperature response value and the environmental temperature instantaneous value.

[0140] In this step, the deviation trend refers to the monotonicity of the difference between the internal temperature response value and the ambient temperature instantaneous value within the lag window over time, including linear lag and exponential convergence as two typical patterns; the temperature lag compensation factor is a dynamic scaling coefficient generated according to the slope sign and amplitude of the trend, used to correct the signal distortion caused by thermal expansion in reverse.

[0141] In this embodiment, the difference between the internal temperature response value and the corresponding ambient temperature instantaneous value is calculated in time sequence within the lag window, and a first-order trend line of the difference sequence is fitted; when the trend line is monotonically increasing, a negative compensation factor less than 1 is generated, and when the trend line is decreasing, a positive compensation factor greater than 1 is generated, and the factor amplitude is determined by the product of the absolute value of the trend line slope and the latent heat of phase transition of the material.

[0142] Step 604, multiply the value of the crack initiation tendency index on the corresponding time axis by the temperature lag compensation factor to generate a calibrated crack initiation tendency index.

[0143] In this step, the time axis correspondence refers to the mapping relationship that each data point of the crack initiation tendency index is strictly time-aligned with the temperature collection node; the calibrated crack initiation tendency index is the output sequence obtained by multiplying the original index value and the compensation factor point by point at the same time point, and its physical nature is the real crack evolution signal after removing the temperature drift.

[0144] In this embodiment, the original crack initiation tendency index data points in the lag window covered time period are extracted, and their time stamps are accurately matched with the temperature collection nodes; the temperature lag compensation factor generated in step 603 is mapped to each data point according to the time stamp; point-to-point multiplication operation is performed to output the calibrated crack initiation tendency index after removing thermal noise.

[0145] As another embodiment, according to step 105, according to the gradation deviation degree between the pre-designed gradation parameters and the fluctuation range of the calibrated crack initiation tendency index, the anti-cracking performance grade is output, including:

[0146] Step 701, extracting the maximum critical value of the acceptable fluctuation range of the gradation in the pre-designed gradation parameters.

[0147] In this step, the maximum critical value of the acceptable fluctuation range of the gradation refers to the upper limit threshold of the allowable displacement fluctuation of the aggregate particle size distribution tolerance in the pre-designed gradation parameters, which is determined by the safety factor in the concrete structure design specification and the extreme point of the aggregate gradation curve, and is used to define the physical safety boundary of the material shrinkage behavior.

[0148] In the embodiment, the cumulative distribution curve of the aggregate gradation of the pre-designed gradation parameters is analyzed, and the particle size extreme interval corresponding to the inflection point slope mutation position in the curve is located; combined with the displacement tolerance coefficient in the concrete structure durability design standard, the maximum allowable displacement fluctuation corresponding to the particle size interval is calculated; finally, the fluctuation is output as the maximum critical value of the acceptable fluctuation range of the gradation, and the extraction process strictly follows the rigid mapping relationship of the material mechanics and structural design specification.

[0149] Step 702, divide equal-length detection time frames on the time axis of the curing process, and count the numerical interval span of the calibration crack initiation tendency index in each detection time frame.

[0150] In this step, the detection time frame is an analysis unit divided by equal-length time periods on the time axis of the curing process, and the division density is determined by the phase change response period of the passive responsive material; the numerical interval span is the difference between the maximum value and the minimum value of the calibration crack initiation tendency index in a single detection time frame, reflecting the absolute fluctuation range of the crack evolution intensity in that time period.

[0151] In the embodiment, first, according to the typical phase change period length of the passive responsive material, the curing process time axis is divided into several equal-length time periods as detection time frames; for each time frame, all the calibration crack initiation tendency index data points in the frame are extracted, and the global maximum value and the minimum value are identified; the difference between the two is calculated as the numerical interval span of the time frame, and the span value sequence is generated for subsequent anomaly detection.

[0152] Step 703, when the proportion of the numerical interval span continuously exceeding the maximum critical value reaches the phase change sensitivity coefficient of the passive responsive material, mark it as an abnormal time frame.

[0153] In this step, the phase change sensitivity coefficient is an inherent attribute parameter representing the sensitivity of the passive responsive material to crack propagation energy fluctuation response, and its value is determined by the microstructure of the material; the abnormal time frame is a time marker unit that determines a high-risk crack evolution period when the proportion of the numerical interval span in the detection time frame continuously exceeding the maximum critical value reaches the coefficient.

[0154] In the embodiment, the proportion of the numerical interval span exceeding the maximum critical value in each detection time frame is calculated; the proportion is compared with the phase change sensitivity coefficient of the passive responsive material, and when the proportion value is greater than or equal to the phase change sensitivity coefficient, it is determined that the time frame is in an abnormal state; finally, the abnormal state time frame is marked as a red warning interval on the time axis to form a crack risk spatiotemporal distribution thermodynamic map.

[0155] Step 704, output the anti-cracking performance level according to the distribution density of the abnormal time frame on the time axis of the curing process.

[0156] In this step, the distribution density of the abnormal time frame refers to the ratio of the number of time frames marked as an abnormal state to the total number of detected time frames, and the density value directly maps the overall crack risk level of the concrete structure.

[0157] In this embodiment, the number of marked abnormal time frames is counted, and the percentage of the total number of detected time frames is calculated as the distribution density value; according to the density classification threshold interval (such as 0-20% for A level, 20-40% for B level, etc.) preset by the engineering acceptance standard, the density value is mapped to the corresponding crack resistance performance level; and finally the level is output as the final evaluation conclusion of the crack resistance performance of the concrete sample.

[0158] Figure 2 A structural diagram of a concrete shrinkage-based crack resistance performance evaluation system is provided for the present application, as shown in Figure 2 The system comprises:

[0159] The acquisition module 21 is configured to acquire real-time sequence data of shrinkage and acoustic emission signal streams of a concrete sample prepared based on pre-designed grading parameters after the passive responsive material.

[0160] The separation module 22 is configured to separate high-frequency elastic wave energy attenuation characteristic values strongly associated with shrinkage micro-crack propagation from the aggregate slurry interface waveguide effect capture region in the acoustic emission signal stream.

[0161] The generation module 23 is configured to perform spatio-temporal coupling of the high-frequency elastic wave energy attenuation characteristic values and the shrinkage jump points in the real-time sequence data of shrinkage, to generate a crack initiation tendency index.

[0162] The calibration module 24 is configured to dynamically calibrate the temperature drift error of the crack initiation tendency index based on the environmental temperature hysteresis effect of the passive responsive material, to obtain a calibrated crack initiation tendency index.

[0163] The output module 25 is configured to output a crack resistance performance level according to the grading deviation between the pre-designed grading parameters and the fluctuation range of the calibrated crack initiation tendency index.

[0164] Figure 2 The concrete shrinkage-based crack resistance performance evaluation system can perform Figure 1 The implementation principle and technical effects of the concrete shrinkage-based crack resistance performance evaluation method described in the embodiment shown in

[0165] In one possible design,Figure 2 The anti-cracking performance evaluation system based on concrete shrinkage rate of the illustrated embodiment can be implemented as a computing device, such as Figure 3 As illustrated, the computing device can include a storage component 31 and a processing component 32.

[0166] The storage component 31 stores one or more computer instructions, wherein the one or more computer instructions are called for execution by the processing component 32.

[0167] The processing component 32 is configured to perform the above Figure 1 The anti-cracking performance evaluation method based on concrete shrinkage rate of the illustrated embodiment.

[0168] The processing component 32 can include one or more processors to execute computer instructions to complete all or part of the steps in the above method. Of course, the processing component can also be one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors or other electronic components, configured to execute the above method.

[0169] The storage component 31 is configured to store various types of data to support the operation of the terminal. The storage component can be implemented by any type of volatile or non-volatile storage device or their combination, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk.

[0170] Of course, the computing device can also include other components, such as input / output interfaces, display components, communication components, etc.

[0171] The input / output interface provides an interface between the processing component and the peripheral interface module, which can be an output device, an input device, etc.

[0172] The communication component is configured to facilitate wired or wireless communication between the computing device and other devices, etc.

[0173] The computing device can be a physical device or an elastic computing host provided by a cloud computing platform, and the computing device can be a cloud server, and the processing component, the storage component, etc. can be basic server resources rented or purchased from the cloud computing platform.

[0174] The embodiment of the application further provides a computer storage medium, which stores a computer program, and the computer program can realize the above method when being executed by a computer. Figure 1 The application further provides a method for evaluating the anti-cracking performance of concrete based on the shrinkage rate.

[0175] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be described here.

[0176] The device embodiments described above are only schematic, and the units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, they can be located in one place, or distributed on multiple network units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment. Those skilled in the art can understand and implement without creative labor.

[0177] Through the description of the foregoing embodiments, those skilled in the art can clearly understand that each embodiment can be realized by means of software and a necessary general hardware platform, and of course, it can also be realized by hardware. Based on such understanding, the above technical solutions can be embodied in the form of a software product, which can be stored in a computer readable storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the method described in each embodiment or some parts of the embodiment.

[0178] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the application.

Claims

1. A method for evaluating the anti-cracking performance based on the shrinkage of concrete, characterized by, The method comprises the following steps: Collecting real-time shrinkage rate sequence data and acoustic emission signal stream of a concrete sample prepared based on a pre-designed grading parameter during the solidification process of the passive responsive material; Separating high-frequency elastic wave energy attenuation eigenvalues strongly associated with shrinkage micro-crack propagation from the aggregate paste interface waveguide effect capture area in the acoustic emission signal stream; Spatiotemporally coupling the high-frequency elastic wave energy attenuation eigenvalues with the shrinkage rate sudden change points in the real-time shrinkage rate sequence data to generate a crack initiation tendency index; Based on the environmental temperature hysteresis effect of the passive responsive material, dynamically calibrating the temperature drift error of the crack initiation tendency index to obtain a calibrated crack initiation tendency index; Outputting a crack resistance performance level according to the grading deviation between the pre-designed grading parameter and the fluctuation range of the calibrated crack initiation tendency index; The method comprises the following steps: Embedding an array acoustic waveguide sensor in the aggregate-rich area of the concrete sample; When the passive responsive material undergoes volume phase transition during the solidification process, stress waves generated by the deformation of the microstructure of the passive responsive material drive the displacement of adjacent aggregates, forming shrinkage displacement pulses; The array acoustic waveguide sensor continuously receives elastic wave signals excited by the shrinkage displacement pulses and reflected by the aggregate-paste interface to form an acoustic emission signal stream; According to the sequence distribution and intensity value of the shrinkage displacement pulses on the solidification time axis, real-time shrinkage rate sequence data is constructed; The method comprises the following steps: In a single shrinkage displacement pulse cycle, the elastic wave signal segment reflected by the aggregate-paste interface in the acoustic emission signal stream is intercepted as the basic wave energy group; Identifying signal attenuation blind area boundary points in the basic wave energy group composed of the shortest distance positions between adjacent aggregate particles; When the signal intensity between the signal attenuation blind area boundary points is in a continuous decreasing distribution, the wave energy continuous loss nodes in the shortest distance positions are locked; According to the density of adjacent wave energy continuous loss nodes in the time sequence, high-frequency elastic wave energy attenuation eigenvalues are separated; The method comprises the following steps: Locating the waveform top event of the peak value of the high-frequency elastic wave energy attenuation eigenvalues in a single shrinkage displacement pulse cycle; At the occurrence time of the waveform top event, a fluctuation interval with a preset time span before and after the occurrence time in the real-time shrinkage rate sequence data is intercepted; Converting the aggregate average particle size data in the pre-designed grading parameter into a displacement constraint rate of a single displacement pulse in the concrete medium, and marking the effective shrinkage rate sudden change point when the shrinkage rate change amplitude in the fluctuation interval exceeds the displacement constraint rate; The statistical solidification process of all waveform top events and the occurrence time deviation of corresponding effective shrinkage rate jump points is generated to generate a crack initiation tendency index.

2. The method of claim 1, wherein, The aggregate average particle size data in the pre-designed grading parameters are converted into displacement constraint rates of single displacement pulse in the concrete medium, including: The standard span value of the theoretical gap of the aggregate inside the concrete sample is determined according to the aggregate average particle size data; A single displacement pulse conduction path is established through the standard span value and the phase transition strain coefficient of the passive responsive material; According to the critical instability inflection point of the displacement pulse conduction path, the baseline value of the displacement constraint rate is defined; The baseline value of the displacement constraint rate is corrected by the standard span value of the theoretical gap of the aggregate to generate the displacement constraint rate of single displacement pulse in the concrete medium.

3. The method of claim 1, wherein, Based on the environmental temperature hysteresis effect of the passive responsive material, the temperature drift error of the crack initiation tendency index is dynamically calibrated to obtain a calibrated crack initiation tendency index, including: At each temperature collection node of the solidification process, the instantaneous value of the environmental temperature is recorded, and the internal temperature response value of the passive responsive material is detected; When the change rate of the instantaneous value of the environmental temperature exceeds a preset value, a hysteresis interval identification window is triggered; In the hysteresis interval identification window, a temperature hysteresis compensation factor is constructed according to the deviation trend of the internal temperature response value and the instantaneous value of the environmental temperature; The value of the crack initiation tendency index on the corresponding time axis is multiplied by the temperature hysteresis compensation factor to generate the calibrated crack initiation tendency index.

4. The method of claim 1, wherein, According to the grading deviation between the pre-designed grading parameters and the fluctuation range of the calibrated crack initiation tendency index, an anti-cracking performance grade is output, including: The maximum critical value of the grading acceptable fluctuation range is extracted in the pre-designed grading parameters; Equal-length detection time boxes are divided on the time axis of the solidification process, and the numerical interval span of the calibrated crack initiation tendency index in each detection time box is counted; When the proportion of the numerical interval span continuously exceeding the maximum critical value reaches the phase transition sensitivity coefficient of the passive responsive material, the abnormal time box is marked; According to the distribution density of the abnormal time box on the time axis of the solidification process, the anti-cracking performance grade is output.

5. A system for evaluating the anti-cracking performance based on the shrinkage of concrete, applied to the method for evaluating the anti-cracking performance based on the shrinkage of concrete according to any one of claims 1-4, characterized in that, Including: The acquisition module is used to acquire the shrinkage rate real-time sequence data and acoustic emission signal stream of the concrete sample prepared based on the pre-designed grading parameters during the solidification process of the passive responsive material; The separation module is used to separate the high-frequency elastic wave energy attenuation characteristic value highly associated with the shrinkage micro-crack expansion from the aggregate slurry interface waveguide effect capture area in the acoustic emission signal stream; The generation module is used to generate a crack initiation tendency index by spatiotemporally coupling the high-frequency elastic wave energy attenuation characteristic value with the shrinkage rate jump point in the shrinkage rate real-time sequence data; The calibration module is used to dynamically calibrate the temperature drift error of the crack initiation tendency index based on the environmental temperature hysteresis effect of the passive responsive material to obtain a calibrated crack initiation tendency index; The output module is used to output an anti-cracking performance grade according to the grading deviation between the pre-designed grading parameters and the fluctuation range of the calibrated crack initiation tendency index.

6. A computing device, comprising: The application relates to a computer device for evaluating the anti-cracking performance of concrete shrinkage, which comprises a processing component and a storage component; the storage component stores one or more computer instructions; the one or more computer instructions are used to be called and executed by the processing component to realize the method for evaluating the anti-cracking performance of concrete shrinkage according to any one of claims 1-4.

7. A computer storage medium, characterized in that The application relates to a computer device for evaluating the anti-cracking performance of concrete shrinkage, which comprises a processing component and a storage component; the storage component stores one or more computer instructions; the one or more computer instructions are used to be called and executed by the processing component to realize the method for evaluating the anti-cracking performance of concrete shrinkage according to any one of claims 1-4.

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