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41 results about "Shrinkage strain" patented technology

Large-span box girder bridge time-varying reliability evaluation method considering concrete fatigue creep

The invention discloses a large-span box girder bridge time-varying reliability evaluation method considering concrete fatigue creep. The method comprises the steps that concrete static creep and shrinkage strain are calculated; calculating concrete fatigue creep strain generated by the vehicle load; constructing a concrete unified constitutive model considering a multi-factor coupling effect; establishing a long-term performance fine analysis numerical model of the large-span box girder bridge; establishing a large-span box girder bridge time-varying reliability calculation method; establishing a limit state equation of reliability analysis; and evaluating the structural time-varying reliability considering the concrete fatigue creep effect. According to the method, the time-varying reliability of the large-span box girder bridge under the coupling action of factors such as concrete static creep, cyclic creep and shrinkage can be accurately evaluated, and technical support can be provided for health diagnosis, maintenance and reinforcement of bridges of the same type.
Owner:JIANGSU UNIV OF SCI & TECH

Red-bed mudstone premixed flow state solidified soil and curing agent and preparation method of red-bed mudstone premixed flow state solidified soil

The invention relates to the technical field of building materials, and particularly discloses red-layer mudstone premixed flow-state solidified soil, a curing agent and a preparation method thereof.The curing agent is prepared from, by mass, 30 parts of ordinary Portland cement, 3-15 parts of sulphoaluminate cement, 3-15 parts of alkaline residue powder, 18-90 parts of composite mineral admixture and 5-8 parts of surfactant. 2-5 parts of a high-molecular polymer; the composite mineral admixture comprises the following components in parts by mass: 20 parts of lithium slag powder, 3-20 parts of magnesium slag powder and 5-15 parts of blast furnace ferronickel slag powder. The method has the advantages that the shrinkage strain is reduced on the premise that the fluidity and the early strength of the red-layer mudstone premixed flow-state solidified soil meet the construction requirements of the premixed flow-state solidified soil, and the engineering application performance of the red-layer mudstone is greatly improved.
Owner:SICHUAN INSITITUTE OF BUILDING RES +1

Concrete shrinkage and creep prediction method based on ABAQUS secondary development

The invention discloses a concrete shrinkage creep prediction method based on ABAQUS secondary development, which adopts a dynamic time function and Prony series decomposition method to establish a nonlinear creep model considering concrete strength, environmental humidity, theoretical thickness of a component and loading time, and realizes real-time calculation of shrinkage strain through a parameterized interface. And the fitting precision of the creep coefficient is optimized based on the improved strength correction coefficient and the humidity correction function. According to the method, the analysis capability of the ABAQUS on the long-term deformation effect is expanded through secondary development, the calculation efficiency and engineering applicability of time-varying behavior simulation of the large concrete structure are remarkably improved, and the method is particularly suitable for full-life periodic performance evaluation of deformation sensitive structures such as bridges and dams.
Owner:BEIHANG UNIV

Concrete formwork stress monitoring method and system based on intelligent sensor

The invention relates to the technical field of online monitoring, in particular to a concrete formwork stress monitoring method and system based on an intelligent sensor, and the method specifically comprises the steps: collecting environment data of a concrete pouring site, building a concrete environment coupling dynamic model, and outputting a formwork side pressure correction value; collecting working condition data of the template, and importing the working condition data of the template into the random vibration response coupling model to generate a space-time stress threat cloud picture borne by the template in real time; a hydration heat temperature field in the concrete pouring process is monitored in real time, and chemical shrinkage strain generated in the concrete pouring process is obtained; and obtaining a template comprehensive failure index according to the stress threat and the chemical shrinkage strain in the space-time stress threat cloud picture, calculating a time-varying failure probability, and triggering graded early warning through the template comprehensive failure index and the time-varying failure probability. According to the invention, the problem of lagging or misjudgment of failure early warning of the template in the prior art is solved.
Owner:HEBEI ZHONGYUN ENGINEERING MANAGEMENT SERVICES CO LTD

Curing process online monitoring method for variable-thickness composite material component

The invention provides a curing process online monitoring method for a variable-thickness composite material component, and relates to the technical field of structural health monitoring of composite materials, and the method comprises the steps: collecting original monitoring data of each optical fiber sensing point in the variable-thickness composite material component; based on a preset temperature sensitivity coefficient and a preset strain sensitivity coefficient, performing temperature-strain double-parameter decoupling on the original monitoring data to obtain chemical shrinkage strain; according to the chemical shrinkage strain and the change rate, a gel point, a maximum heat release rate point and a glass transition interval in the resin curing process are obtained, and curing state characteristics are constructed; and determining a curing stage corresponding to the variable-thickness composite material component based on the curing state characteristics, calculating a curing degree gradient, and when the curing degree gradient is greater than or equal to a preset process safety threshold value, sending a closed-loop regulation and control instruction to curing equipment so as to adjust the curing process of the variable-thickness composite material component, according to the invention, the curing monitoring precision and stability can be improved.
Owner:WUHAN UNIV OF TECH

Method, device and storage medium for calculating concrete shrinkage and creep in bridge structure

The application discloses a kind of bridge structure in concrete shrinkage and creep calculation method, equipment and storage medium, the method includes using initial strain method to calculate stress increment and creep strain increment in different period, and then calculate stress and creep strain at different time;According to the stress increment of different period, stress-strain relationship and creep coefficient fitting function calculation period Δt n+1 Internal concrete creep caused by unit equivalent node load increment;According to concrete shrinkage strain increment calculation period Δt n+1 Internal concrete shrinkage caused by unit equivalent node load increment.The application can accurately calculate the shrinkage and creep effect of concrete in the structure when applied to bridge structure analysis, greatly improves the calculation efficiency and saves storage space.
Owner:CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY

A seamless titanium alloy tube for aviation hydraulic system and its preparation method

The present invention discloses a seamless titanium alloy tube for an aviation hydraulic system and a preparation method thereof. The preparation method of the seamless titanium alloy tube for an aviation hydraulic system comprises the following steps: S1, providing a seamless titanium alloy tube blank, the structure of the tube blank being an equiaxed structure; S2, cold rolling the tube blank to obtain a seamless titanium alloy tube; wherein the wall thickness reduction rate of the cold rolling treatment is controlled to be greater than 80%, and the total Q value is greater than 0.88, so that the shrinkage strain ratio of the seamless titanium alloy tube is controlled to be 1.3~3.5; the wall thickness reduction rate is the difference between the wall thickness of the seamless titanium alloy tube and the wall thickness of the tube blank, and Q is the ratio of the relative wall thickness reduction before and after the cold rolling of the tube to the relative reduction in the outer diameter. The present invention can control the CSR value of the titanium alloy tube to be between 1.3 and 3.5, avoid thinning of the tube after bending and cracking during flattening, and improve the safety and reliability of use.
Owner:ZHANGJIAGANG HUAYU NONFERROUS METAL MATERIAL CO LTD

Prediction method for drying shrinkage strain and drying shrinkage stress of concrete

PendingJP2025139134AMaterial testing goodsShrinkage strainRelative humidity
To provide a method for predicting drying shrinkage strain of concrete by using a drying shrinkage prediction formula that includes time (age of concrete) as a parameter.SOLUTION: A method for predicting drying shrinkage strain of concrete is provided by including at least (A) a humidity analysis process, (B) a process for deriving a first regression equation (the following equation (1)), (C) a process for deriving a second regression equation (the following equation (2)), and (D) a process for calculating a predicted value of the drying shrinkage strain. εRH_te / ε60_te=(96-RH) / {c×(96-RH)+d}...(1) ε60_te / ε60_7=-a×(te)1 / 2+b... (2) (where εRH_te / ε60_te represents a ratio of an ultimate value (εRH_te) of drying shrinkage strain at each of three or more kinds of relative humidity at respective positions to an ultimate value (ε60_te) of drying shrinkage strain at reference relative humidity (60%), RH represents relative humidity (%), c and d represent coefficients, etc.).SELECTED DRAWING: Figure 10
Owner:TAIHEIYO CEMENT CORP

Floor structure and construction method of floor structure

This will suppress cracking and reduce costs. [Solution] A floor structure having a lower floor slab and an upper floor slab provided on the lower floor slab, wherein the lower floor slab is made of unreinforced concrete or reinforced concrete using first concrete, and the upper floor slab is made of reinforced concrete using second concrete, and the shrinkage strain of the second concrete is smaller than the shrinkage strain of the first concrete.
Owner:OHBAYASHI GUMI LTD

Long wall concrete structure crack control method based on limited horizontal shrinkage strain

The invention discloses a long-wall concrete structure crack control method based on limited horizontal shrinkage strain, and belongs to the technical field of water transportation and hydraulic engineering. The long wall concrete structure crack control method based on the limited horizontal shrinkage strain comprises the steps that S1, the horizontal shrinkage strain of each gradient structure preset elevation position in a same-proportion concrete small model section is obtained; s2, calculating and obtaining the limited horizontal shrinkage strain of the preset elevation position of each gradient structure in the same-proportion concrete small model section, and determining the limited horizontal shrinkage strain value of each gradient structure; s3, carrying out a restrained expansion rate test of the expansive concrete; s4, determining the expansive concrete mix proportion of each gradient structure; and S5, vertical gradient concrete construction of the long wall concrete structure is conducted according to the mixing proportion of the gradient expansive concrete. According to the invention, the total mixing amount of the expanding agent can be effectively reduced while the same shrinkage compensation effect of the concrete is ensured, and the anti-cracking cost of the structure is reduced.
Owner:CCCC FOURTH HARBOR ENG INST CO LTD +1

A method for predicting the leakage of water from a water-sealed cavern sealing plug

This invention discloses a method for predicting the leakage of water from the sealing plug of a water-sealed cavern, relating to the field of seepage control technology in underground water-sealed cavern engineering. The method includes: calculating the spatiotemporal temperature distribution and effective cooling difference during the hydration heat process and subsequent cooling process of the concrete sealing plug; introducing a stress relaxation coefficient to calculate net shrinkage strain, thereby obtaining real-time tensile stress and tensile strength; comparing the two, determining the occurrence of opening cracks when the tensile stress exceeds the tensile strength, and calculating the equivalent crack width; establishing a seepage prediction calculation model based on the cubic law of fluid mechanics and obtaining the seepage volume; finally, converting the seepage volume into a capacitance value to establish a time curve, and comparing it with acceptance standards. This invention upgrades empirical seepage control measures into a quantifiable and predictable guidance system, providing a scientific basis for temperature control and precise timing of grouting during sealing plug construction.
Owner:POWERCHINA ZHONGNAN ENG

Bridge deck structure paved and reinforced by low-shrinkage ultra-high performance concrete

The utility model relates to the technical field of bridge deck slab reinforcement and repair, and discloses a low-shrinkage ultra-high performance concrete pavement reinforced bridge deck structure which comprises a bridge deck slab, a reinforcement layer and anchoring parts. The reinforcing layer at least covers the upper surface and is formed by pouring ultra-high performance concrete with shrinkage strain smaller than 150 mu epsilon when the ultra-high performance concrete reaches a stable state, and the anchoring part is embedded between the bridge deck slab and the reinforcing layer. According to the utility model, the concave-convex textures enhance the interface friction force between the reinforcing layer and the bridge deck slab, so that the integrity of the bridge deck structure is stronger; the reinforcing layer poured by the low-shrinkage ultra-high performance concrete has better bearing capacity, rigidity and ductility; the connection firmness of the reinforcing layer and the bridge deck slab is improved through the anchoring parts; by means of the improvement, the bridge deck structure is not prone to interface void phenomena, cracks, voids, pitted surfaces and the like, the overall mechanical property of the bridge deck structure is effectively improved, and the service life of the bridge deck structure is effectively prolonged.
Owner:GUANGZHOU TRAFFIC INVESTMENT URBAN ROAD CONSTR CO LTD +2

Solid waste lightweight aggregate low-shrinkage ultra-high performance concrete and preparation method thereof

The invention relates to the technical field of concrete, and particularly discloses solid waste lightweight aggregate low-shrinkage ultra-high performance concrete and a preparation method thereof. The solid waste light aggregate low-shrinkage ultra-high performance concrete is prepared from the following raw materials in parts by weight: 300 to 400 parts of solid waste mixed light aggregate, 900 to 1000 parts of light cement-based cementing material, 65 to 75 parts of composite micro-expansion agent, 200 to 350 parts of high-flow-state fine aggregate, 25 to 35 parts of water reducing agent, 0.1 to 3 parts of retarder, 15 to 156 parts of anti-cracking fiber, 200 to 250 parts of water, 3 to 6 parts of shrinkage reducing agent and 1 to 5 parts of defoaming agent. The solid waste lightweight aggregate low-shrinkage ultra-high performance concrete provided by the invention has the advantages of high compressive strength, low shrinkage strain, low volume weight, good working performance and good crack resistance.
Owner:FOSHAN TRANSPORTATION SCI & TECH CO LTD

Processing method of TA18 alloy pipe

The invention discloses a processing method of a TA18 alloy pipe in the technical field of metal processing, which comprises the following steps: S1, carrying out two-roller cold rolling on a titanium alloy pipe blank; s2, the titanium alloy pipe subjected to two-roller cold rolling is subjected to degreasing treatment; s3, the titanium alloy pipe subjected to degreasing treatment is subjected to heat treatment and straightened; s4, the step S1, the step S2 and the step S3 are sequentially completed as a cold rolling cycle, the cold rolling cycle is repeated for multiple times, and machining of a titanium alloy pipe semi-finished product is completed; s5, the titanium alloy pipe semi-finished product is subjected to heat treatment and straightening; s6, the straightened titanium alloy pipe semi-finished product is subjected to three-roller cold rolling; s7, the titanium alloy pipe subjected to three-roller cold rolling is subjected to degreasing and acid pickling treatment; and S8, the titanium alloy pipe subjected to degreasing and acid pickling treatment is subjected to heat treatment and straightened again, the problem that the shrinkage strain ratio is too large due to rolling with the large machining deformation value is effectively solved, and the flattening performance of the titanium alloy pipe is greatly improved while the strict requirements for the mechanical property and the shrinkage strain ratio in the aerospace field are met.
Owner:CHENGDU ADVANCED METAL MATERIALS IND TECH RES INST CO LTD

Construction method and device for resisting shrinkage cracking of tunnel wall concrete

The invention relates to the technical field of underground tunnel engineering construction, in particular to a construction method and device for resisting shrinkage cracking of tunnel wall concrete. The construction method comprises the steps that S1, before wall concrete is poured, prestressed tendons are evenly distributed in a wall; s2, the prestressed tendons are subjected to graded tensioning for m times, m is larger than or equal to 2, the tensioning force of each time of tensioning is 0.15 sigmacon < = 0.5 sigmacon, and sigmacon is tensioning control stress; and S3, wall concrete pouring and curing are conducted, the concrete strength and the shrinkage strain value are monitored during curing, when the concrete strength reaches 30% or above of the design strength and the shrinkage strain value is larger than or equal to 50 mu epsilon, the prestressed tendons are released in a grading mode, and the releasing stress of each grade is smaller than or equal to 0.5 sigmacon. According to the method, cooperative control of graded tensioning and graded releasing is carried out in the wall concrete, so that the concrete keeps reasonable pre-compressive stress in each hardening stage, the tensile stress generated by shrinkage is counteracted, cracks of the wall are avoided, and the structural integrity of the tunnel wall is guaranteed.
Owner:CCCC FOURTH HARBOR ENG CO LTD +1

Preparation method of alpha and near-alpha type titanium alloy pipe with high strength and high shrinkage strain ratio

The invention relates to the technical field of material forming, in particular to a preparation method of a high-strength and high-shrinkage-strain-ratio alpha and near-alpha type titanium alloy pipe. The method comprises the following steps: 1) carrying out Pilger two-roller cogging rolling on a titanium alloy pipe blank to obtain a cogging rolled pipe; (2) after cogging rolling, recrystallization annealing is conducted, and an annealed pipe is obtained; (3) three-roller intermediate rolling is conducted on the titanium alloy pipe subjected to cogging annealing, and an intermediate rolled pipe is obtained; 4) performing vacuum stress relief annealing after intermediate rolling to obtain an intermediate annealed pipe; 5) performing Pilger two-roller finished product rolling on the intermediate annealed pipe to obtain a finished rolled pipe; according to the method, the shrinkage strain ratio of the pipe is remarkably increased, and the technical index requirements for high strength and the high shrinkage strain ratio of the pipe are met. The method comprises the following steps of (1) rolling the pipe into a finished product, (2) carrying out vacuum stress relief annealing on the finished product rolled pipe to obtain a finished product annealed pipe, (3) carrying out finished product straightening on the finished product annealed pipe and (4) carrying out finished product acid pickling on the straightened finished product annealed pipe to obtain the titanium alloy pipe.
Owner:XIAN WESTERN ENERGY MATERIAL TECH CO LTD

Method for calculating random shrinkage creep of concrete structure

The invention relates to the technical field of civil engineering, in particular to a concrete structure random shrinkage creep calculation method which comprises the following steps: acquiring data of a concrete structure needing to be calculated; calculating a creep coefficient and shrinkage strain curve of the concrete structure; a concrete shrinkage and creep calculation model is constructed, and an updated stress-strain relation is obtained; combining a concrete shrinkage creep test database to construct a concrete shrinkage creep randomness coefficient, and finally obtaining a shrinkage creep deformation calculation result priori interval of the concrete structure; establishing a Gaussian process regression model; and performing Bayesian inference by adopting a Monte Carlo-Markov chain method and a Gaussian process regression model to obtain a posterior interval of a concrete structure shrinkage creep calculation result needing to be calculated. The problems that an existing concrete structure is high in shrinkage creep randomness and insufficient in prediction precision are solved. According to the method, Gaussian process regression is adopted, and the problem that a large amount of calculation cost of finite element calculation is needed in Bayesian inference is solved.
Owner:NAT ENG LAB FOR HIGH SPEED RAILWAY CONSTR +2

Concrete shrinkage stress calculation method and system based on humidity diffusion coefficient

The invention discloses a concrete shrinkage stress calculation method and system based on a humidity diffusion coefficient, and relates to the technical field of concrete mechanics, and the method comprises the steps: carrying out the error inversion of space humidity distribution data and multi-point actual measurement humidity data, constructing a humidity diffusion coefficient multi-point fitting problem, carrying out the multi-point fitting solving through employing a least square method, and calculating the shrinkage stress of concrete. Outputting a local humidity diffusion coefficient; inputting the local humidity diffusion coefficient and the spatial humidity distribution data into a hybrid intelligent model, performing humidity-induced shrinkage strain prediction, and outputting a shrinkage strain time sequence result; combining a shrinkage strain time sequence result with a material aging parameter, calculating an equivalent shrinkage stress tensor field of each space node, and constructing a stress migration path map; and calculating the conductivity and path dependence of each time-space node in the stress migration path map, and generating a shrinkage stress evolution path map. According to the method, the scientificity and reliability of structural performance evaluation are enhanced, and the safety and durability management level of the concrete structure are improved.
Owner:BAY AREA SUPER MAJOR BRIDGE MAINTENANCE TECH CENT OF GUANGDONG HIGHWAY CONSTR CO LTD +1

Cryogenic rock mechanics response monitoring method, system and device

ActiveCN121954720BEliminate huge measurement errorsThermodynamicsRock sample
The application discloses a kind of super-low temperature rock mechanics response monitoring method, system and equipment, and the super-low temperature rock mechanics response monitoring method includes: the rock sample with strain-temperature sensitive grating array and temperature reference grating array being mutually connected in series is placed in super-low temperature environment loading system;Start super-low temperature environment loading system, and the wavelength shift of each grating and the wavelength shift of each grating are measured in real time;The wavelength shift of one of temperature reference grating measured in temperature reference grating array is used to calculate the real temperature of rock sample corresponding grating measuring point;The physical model of strain-temperature sensitive grating center wavelength shift in strain-temperature sensitive grating array is established, and the total strain of rock sample grating measuring point is calculated according to real temperature and the physical model;According to the total strain of rock sample and the natural freeze shrinkage strain of rock sample, the mechanical strain generated by the ice expansion of pore water of rock sample is calculated, and frost heaving stress.
Owner:INST OF ROCK & SOIL MECHANICS CHINESE ACAD OF SCI

Concrete composition

PendingJP2025070219ASolid waste managementChemical admixtureChemical mixtures
To provide a concrete composition that can improve initial strength development and can suppress autogenous shrinkage strain.SOLUTION: A concrete composition of the present invention is a concrete composition including a hydraulic powder, water, an aggregate, and a chemical admixture. The hydraulic powder includes a blast furnace slag fine powder, an expansive admixture, and a hydrated lime, a content of the blast furnace slag fine powder is 80 pts.mass or over to 100 pts.mass of the hydraulic powder, the chemical admixture is a shrinkage reduction agent and satisfies at least one of the conditions of: a water powder ratio being 28% or under, and, containing a hardening accelerator.SELECTED DRAWING: Figure 3
Owner:TAISEI CORP

A device for detecting concrete autogenous shrinkage deformation by laser sensing measurement

ActiveCN224480140UAxial displacementGrating
This utility model discloses a laser-sensor-based concrete self-shrinkage deformation detection device, belonging to the field of building material performance testing technology. The device includes a base plate. Through the arrangement of the detection components and corrugated pipe, the corrugated pipe linearly converts the concrete shrinkage strain into axial displacement during use, while guide rollers constrain radial displacement. The laser optical path and the fiber optic sensor sensing path are physically isolated, allowing the two systems to operate independently. Furthermore, a laser displacement sensor replaces the infrared sensor, utilizing the strong monochromaticity and good directionality of laser light, along with a laser reflector, to eliminate the influence of environmental temperature and humidity changes on the optical path and improve resolution. Distributed fiber optic sensors are pre-embedded within the corrugated pipe wall, fusing with laser displacement data to construct a "global displacement-local strain" dual feedback mechanism. This multi-sensor collaborative design significantly improves system reliability.
Owner:GUANGZHOU NORTH SECOND RING TRANSPORT TECH CO LTD +1

Prediction method and system for shrinkage and creep deformation of high-performance concrete of early-age loaded steel pipe

The invention provides a method and system for predicting shrinkage and creep deformation of high-performance concrete of an early-age loaded steel pipe, and belongs to the field of concrete. The problem that self-constriction of steel pipe high-performance concrete is underestimated is solved The problem that the creep deformation prediction result of the steel pipe high-performance concrete is not accurate due to the fact that different influences of loading periods on the creep deformation of the component under different water-binder ratios are not considered is solved. The method comprises the following steps: carrying out shrinkage and creep tests of different loading ages on steel tube high-performance concrete with different concrete water-binder ratios to obtain shrinkage strain and creep strain experimental results; performing nonlinear regression analysis on shrinkage and creep test results of the steel tube high-performance concrete with different concrete water-binder ratios in different loading periods, introducing influence coefficients of the concrete water-binder ratios on shrinkage and creep, and establishing a high-performance concrete shrinkage and creep model; and adopting a step-by-step integral method to consider the shrinkage and creep deformation after the stress redistribution of the high-performance concrete of the steel pipe.
Owner:HARBIN INST OF TECH

High-durability anti-cracking water-stable composite material, preparation method and application thereof

The application discloses a kind of high durability crack resistance type water stable composite material and its preparation method and application, belong to road engineering and building material technical field.The high durability crack resistance type water stable composite material provided in the application includes aggregate, composite cementitious material, internal curing agent, toughening fiber, shrinkage-reducing toughening agent and water.The composite cementitious material is prepared from Portland cement, S95 grade slag powder, modified steel slag powder;The internal curing agent is porous ultra-fine mineral particles pre-adsorbed with liquid curing agent;The toughening fiber includes at least two of polyester fiber, polyvinyl alcohol fiber, polypropylene fiber;The shrinkage-reducing toughening agent includes polyether shrinkage-reducing agent-nanosilica composite.The material of the application realizes the unity of high later strength, low drying shrinkage strain, high toughness and excellent frost resistance through multi-component synergy, especially suitable for high durability and crack resistance requirement high road base and building cushion engineering, with environmental protection and economic benefit.
Owner:BEIJING HENGDE NEW MATERIAL TECHNOLOGY CO LTD

A concrete structure and construction method for preventing cracks in a cast-in-place tunnel main structure

The present application is a kind of concrete structure for preventing cast-in-place tunnel main structure cracking and its construction method, the concrete structure is by targeted zoning of the tunnel main body concrete structure, and by regulating the formula of concrete to make the zoning of concrete has different expansion coefficient, so that the concrete structure of different zoning has different deformation performance and deformation timing, the constraint stress of concrete structure also decreases with the zoning interface gradient, to change the expansion performance of concrete, compensate shrinkage strain, so that the constraint stress of concrete in different zoning is significantly weakened, the anti-cracking property of concrete structure itself is significantly improved, and the shrinkage cracking problem of concrete is significantly improved; and the concrete structure for preventing cast-in-place tunnel main structure cracking is simple, low in cost, has significant improvement effect on the shrinkage cracking problem of concrete, and is suitable for large-scale application in immersed tube open section and open-cut tunnel main structure.
Owner:CCCC FOURTH HARBOR ENG CO LTD

A cast-in-situ plain concrete wind tunnel body anti-cracking construction method

PendingCN122263208ASolve technical problems of early cracksAvoid tensile stress exceeding the limitGeometric CADDesign optimisation/simulationCrack resistanceWater flow
The present application provides a kind of cast-in-place fair-faced concrete wind tunnel body crack resistance construction method, belong to wind tunnel technical field, the present application is by preparing low heat high crack resistance concrete and incorporating basalt fiber and double expansion source expansion agent, pre-embedded cooling water pipe network and temperature monitoring point in tunnel body, according to hydration heat temperature rise control equation dynamic adjustment cooling water flow, using formwork pre-deformation compensation design eliminates forming error, according to the way of layered pouring control temperature rise rate, implement early curing and through shrinkage strain game model optimization curing parameter, after stripping, carry out precision measurement and feedback correction formwork deformation prediction equation, solve the technical problem that cast-in-place fair-faced concrete wind tunnel body is caused by hydration heat temperature rise and produces early crack due to internal and external temperature difference too large.
Owner:CHINA CONSTR EIGHT ENG DIV CORP LTD

Method for testing plastic shrinkage of 3D printing cement-based material

The invention relates to the technical field of building material testing, and discloses a 3D printing cement-based material plastic shrinkage testing method which comprises the following steps: filling a detachable mold with a to-be-tested cement-based material, and compacting the to-be-tested cement-based material; removing a side template of the detachable mold within 1-2 hours after the initial setting of the material; placing the sample in a dry hot air environment, and enabling the sample to generate a crack at the stress constraint device; observing and measuring the width of a crack generated at the stress constraint device; and calculating the plastic shrinkage strain according to the ratio of the sum of the crack widths of the plurality of observation points to the length of the sample. According to the invention, accurate quantification of the plastic shrinkage strain is realized through the detachable three-surface exposed mold, the stress constraint device induces the crack, and the crack width is measured at multiple observation points.
Owner:SHANDONG UNIV +1

A concrete shrinkage and cracking prediction method and system based on multi-dimensional perception data coupling

The application provides a concrete shrinkage and cracking prediction method based on multi-dimensional sensing data coupling, relates to the technical field of concrete shrinkage and cracking prediction methods, and comprises the following steps: a multi-parameter weighted degradation evaluation method is used to calculate the degradation parameters of concrete; a temperature and humidity coupling parameter of concrete is constructed; the autogenous shrinkage strain, the drying shrinkage strain and the temperature shrinkage value of the concrete in a monitoring period are weighted and calculated to obtain the theoretical shrinkage strain value of the concrete in the monitoring period; based on the corrected theoretical shrinkage strain value and the full-cycle crack coefficient, a threshold response method is used to construct a comprehensive risk index, and the comprehensive risk index is classified and early warned. Through time-varying normalization and nonlinear correction, the dynamic interaction between the hydration process and the environmental influence is quantified by synchronously integrating the resistivity, the porosity, the temperature difference and the external environmental data.
Owner:中电建路桥集团有限公司

Underground overpass main body side wall structure concrete anti-cracking waterproof construction method

PendingCN122453113AFiberCrack resistance
The application provides a kind of underground interchange main body side wall structure concrete crack resistance waterproof construction method, it is related to underground engineering concrete construction technical field, the application is by dividing side wall into multiple sub-regions, obtains the geometric curvature of each sub-region, structural constraint, cross section variation, temperature action, shrinkage strain, load tensile stress, joint adjacent and waterproof weak parameter;Based on the first six parameters, calculate the crack resistance risk value, combined with the last two parameters to calculate the waterproof failure risk value, and determine the comprehensive protection requirement value accordingly;According to the comprehensive protection requirement value, the sub-regions are classified, and the target areas that need to be strengthened are identified;Different regions are respectively used C40 concrete with conventional or hybrid fiber optimal ratio, and the pouring segment length is dynamically determined according to the maximum crack resistance risk value, to realize differentiated crack resistance waterproof construction.
Owner:ANHUI UNIV OF SCI & TECH

Machine learning based cast-in-place concrete anti-cracking waterproof integrated intelligent evaluation system

The present application belongs to the field of concrete risk analysis, and discloses a cast-in-place concrete anti-cracking and waterproof integrated intelligent evaluation system based on machine learning; comprising: acquiring temperature sequences, strain sequences, surface thermal image sequences and water seepage sensitive area image sequences of different monitoring partitions; extracting internal and external temperature difference growth, cooling duration, shrinkage strain growth, strain gradient enhancement, crack width growth, crack extension, wet trace expansion and thermal anomaly migration fragments; obtaining anti-cracking risk characterization results by analyzing the relevance of the change attributes in the internal and external temperature difference growth fragments and the change attributes in the shrinkage strain growth fragments; obtaining waterproof risk characterization results by analyzing the relevance of the expansion change attributes in the crack extension fragments and the diffusion change attributes in the wet trace expansion fragments; performing integrated evaluation to obtain anti-cracking and waterproof comprehensive evaluation results. The present application realizes anti-cracking and waterproof risk linkage evaluation and enhances risk identification capability.
Owner:SHENZHEN ANTUSN CONCRETE

Concrete shrinkage cracking prediction method and system based on multi-dimensional perception data coupling

The invention provides a concrete shrinkage cracking prediction method based on multi-dimensional perception data coupling, and relates to the technical field of concrete shrinkage cracking prediction methods, and the method comprises the steps: employing a multi-parameter weighted degradation evaluation method to calculate concrete degradation parameters; constructing temperature and humidity coupling parameters of the concrete, and performing weighted calculation on the authigenic shrinkage strain, the drying shrinkage strain and the temperature shrinkage value of the concrete in the monitoring period to obtain a theoretical shrinkage strain value of the concrete in the monitoring period; and on the basis of the corrected theoretical shrinkage strain value and the complete-period crack coefficient, constructing a comprehensive risk index by adopting a threshold response method, and carrying out classified early warning on the comprehensive risk index. The resistivity, the porosity, the temperature difference and the external environment data are synchronously integrated, and the dynamic interaction between the hydration process and the environment influence is quantified through a time-varying normalization method and a nonlinear correction method.
Owner:中电建路桥集团有限公司