43 results about "Dynamic shear rheometer" patented technology

The invention provides a parameter identification method of an asphalt viscoelastic model based on a comprehensive data optimization criterion and belongs to the technical field of a parameter identification method of an asphalt viscoelastic model. The method comprises a step of carrying out a dynamic frequency scanning test, a static creep test and a stress relaxation test on asphalt by using a dynamic shear rheometer, establishing a dynamic modulus main curve and a phase angle main curve based on the test data, and drawing a creep compliance-time curve and a relaxation modulus-time curve, astep of establishing the asphalt viscoelastic model and deriving an expression of each viscoelastic parameter, which is a fitting value of the model, and a step of identifying model parameters according to the comprehensive data optimization criterion, thus modifying the model parameters, and taking a set of parameters corresponding to a smallest sum-of-squared differences to be parameter values in a final model. According to the method, the dynamic and static viscoelastic properties of the asphalt are comprehensively considered, and the method has important significance for the comprehensivecharacterization of the viscoelastic performance of an asphalt material by the model and the design and maintenance of an asphalt pavement.

The invention discloses a test method for testing the fatigue performance of an asphalt binder. The test method comprises the following steps: making a dynamic shear sample of the asphalt binder; heating the dynamic shear sample of the asphalt binder to a test temperature, and maintaining the temperature for at least 20min, wherein the test temperature is in a range of 10-20DEG C; adopting a continuous flow mode of a dynamic shear rheometer to make the shear strain uniformly increase with time and the shear strain increase rate be 0.005/s, loading the asphalt binder sample, ending the test when the shear stress gradually reduces to 80% of maximum shear stress, and recording the shear stress and shear strain data of the dynamic shear sample of the asphalt binder during the test; and drawing a stress-strain curve according to the tested shear stress and the shear strain data, and calculating to obtain the yielding strength of the asphalt binder. The test method for testing the fatigue performance of the asphalt binder of the invention has the advantages of simple test process, and stable and reliable test result, and adopts the yielding strength index to quantitatively evaluate the fatigue performance of the asphalt binder.

The invention relates to an application of rice hull ash as an asphalt modifier. The test of three indexes of asphalt, the Bush rotary viscosity test and the DSR (dynamic shear rheometer) test prove that the rice hull ash asphalt modifier can effectively improve high-temperature deformation resistance and durability of asphalt cement and an asphalt mixture and guarantee certain low-temperature crack resistance. Therefore, diseases of asphalt pavements in high-temperature regions are effectively reduced, the asphalt pavements can adapt to complicated and changeable environmental conditions, and driving safety and service level are guaranteed. Besides, the microwave heating test and infrared thermal imaging photographing prove that compared with limestone mineral powder filler, the rice hull ash asphalt modifier enables the modified asphalt mortar to have an obviously higher microwave heat absorption temperature-rise rate, so that the rice hull ash asphalt modifier can be applied to technical research of the field of ice and snow smelting for the asphalt pavements.

The invention discloses a pavement petroleum asphalt high temperature and low temperature using performance rapid detection method, and belongs to the field of pavement engineering. According to the pavement petroleum asphalt high temperature and low temperature using performance rapid detection method, a dynamic shear rheometer is adopted, organic combination of time scanning and frequency scanning is realized, and asphalt high temperature performance and low temperature performance are obtained via one time of scanning experiment. The pavement petroleum asphalt high temperature and low temperature using performance rapid detection method comprises following steps: 1, dynamic shear time scanning and frequency scanning of pavement petroleum asphalt are carried out using the dynamic shear rheometer so as to obtain different asphalt frequency scanning curves in a certain temperature range; 2, a temperature-rut factor change curve is drawn for regression analysis, and asphalt high temperature evaluation is carried out; and 4, parallel displacement of different temperature scanning curves is carried out based on time-temperature equivalence principle so as to obtain displacement factors, fitting is carried out based on WLF equation derived formula, pavement petroleum asphalt glass-transition temperature is obtained via back calculation, and low temperature pavement using performance rapid determination is carried out. Compared with the prior art, the pavement petroleum asphalt high temperature and low temperature using performance rapid detection method possesses following advantages: the pavement petroleum asphalt high temperature and low temperature using performance rapid detection method is rapid, and is high in efficiency, credibility, and applicability.

The invention discloses a preparation device and a preparation method for a DSR (Dynamic Shear Rheometer) biplate test piece and a damage-healing assessment method for a bituminous material. The preparation device comprises a knockout rod, an upper test die and a lower test die, wherein the upper test die comprises an upper die body and an upper bottom die; the lower test die comprises a lower diebody and a lower bottom die; a first circular boss is arranged on the lower surface of the upper bottom die; a second circular boss is arranged on the upper surface of the lower bottom die. The preparation device and the preparation method can realize preparation of the DSR biplate test piece; the preparation device is simple in structure and is convenient to operate; the assessment method can effectively assess the interfacial healing effect between different bituminous materials and can reflect the influence of healing time on healing effect.

The invention relates to a modifying method for improving the shape memory property of asphalt and belongs to the technical field of asphalt pavement materials. By adoption of the modifying method, the problems that the shape memory property is poor, the self repairing needs long load interval, low in rate, low in efficiency and poor in effect, and the microcracks only can be repaired once in the existing asphalt are solved, and the durability of the asphalt pavement is improved. The modifying method comprises the following steps: firstly preferring shape memory polymers with matching of revertible-phase phase transformation temperature and pavement temperature field, and adopting a high-speed shearing machine to prepare modified asphalt with the shape memory property; then analyzing the influence of the shape memory polymers on the properties of the asphalt components by utilizing an X-ray diffraction and transmission electron microscope and a dynamic shearing rheometer and the like; and finally testing the shape memory property of the asphalt doped with the shape memory polymers, and by comprehensive consideration of all test results, determining the types of the shape memory polymers and the optimum dosage thereof so as to further improve the shape memory property and the self-repairing efficiency of the asphalt, improve the self-repairing capability of the asphalt pavement and prolong the service life of the pavement pavement.

The invention discloses a method for measuring an SBS content in SBS modified asphalts by virtue of a dynamic shear rheometer (DSR). The method is carried out according to the following steps: configuring a series of modified asphalts with different SBS admixture amounts and a standard SBS content, and carrying out an RTFOT ageing experiment; then carrying out a repeated creep recovery experiment by virtue of the DSR to form a creep recovery graph; calculating the average value Jnr@sigma of a plurality of circulating unrecoverable creep compliances of the modified asphalt RTFOT ageing samples with the various SBS admixture amounts, and the average value Rec@sigma of elastic recovery rates; drawing a Jnr@sigma content curve and a Rec@sigma-SBS content curve; carrying out the RTFOT ageing experiment and the repeated creep recovery experiment on the SBS content to be measured to obtain the unrecoverable creep compliances Jnr@sigma and the elastic recovery rates Rec@sigma of the test samples; and reading the SBS contents CJ and CR on the content curves, wherein the SBS content of the test samples is (CJ+CR)/2. The method is simple to operate, high in applicability, and accurate and reliable in test result.

The invention relates to a method for analyzing the THFS-modified-asphalt temperature sensing performance based on a CAM model. The method includes the following steps that 1) all performances of matrix asphalt and DCLR are tested; 2) through a soxhlet extractor, THF serves as an extracting solvent, the DCLR is extracted; 3) the THFS extracted from the DCLR serves as a modifying agent, and THFS modified asphalt is prepared; 4) the THFS modified asphalt with different mixing amounts at the different test temperatures is subjected to frequency scanning analysis through a dynamic shear rheometer;5) according to the time temperature equivalence principle, trial curves at the different test temperatures transversely move, and modulus master curves at some specific temperature are synthesized;6) multiple modulus G* master curves of the modified asphalt under the different THFS mixing amounts are subjected to fitting calculation based on the CAM model, and the temperature sensing characteristic of the THFS modified asphalt is evaluated through physical parameters in the CAM model; 7) the influence rules of the different THFS mixing amounts on the modified-asphalt temperature sensing performance are analyzed.

The use of recycled materials can have significant economic value. With the increasing quantity of recycled material used in viscoelastic materials, especially asphalt mixture, understanding how they interact with original materials to produce a mixture that performs successfully, becomes critical. Currently, the technology to determine the effect of additives on the performance of asphalt mixture is lacking. The present invention relates to a new unified methodology for mechanical testing of asphalt mixture and other viscoelastic materials that improves the current practice in speed, convenience, and accuracy. A new improved specimen mounting method on Dynamic Shear Rheometer (DSR), a new recovery method for fine portion of asphalt mixture, and three new tests for the performance of recovered material using DSR is disclosed. The new methods provide performance grading of asphalt mixtures that is new to the industry and provide necessary tools for determining the effect of recycled materials on performance.

The invention relates to a method for determining the critical volume fraction of asphalt mortar filler. The method includes the steps of firstly, preparing a series of asphalt mortar samples; secondly, measuring complex moduli G* of all the asphalt mortar samples obtained in the first step through a dynamic shear rheometer; thirdly, fitting a nonlinear function between the filler volume fraction and the complex moduli G* through Origin software according to the filler volume fractions of the series of asphalt mortar samples and the corresponding complex moduli G*, and then determining the filler critical volume fraction phi m of asphalt mortar. By determining the filler critical volume fraction, it can be clearly known that when the filler volume fraction is within a certain determined range, which of asphalt/filler interaction and filler particle interaction has a leading effect on the enhancement of asphalt mortar complex moduli and has a positive effect on the research of asphalt mortar performance; meanwhile, the calculation formula of the filler critical volume fraction is simple, the fitting process confirms to the reality, and the result is precise and reliable.

The invention discloses a method for measuring and calculating the influence on high-temperature of asphalt caused by oil content, and relates to a method for measuring and calculating the high-temperature performance of asphalt for a road, which solves the problem of low efficiency when the influence on the high-temperature performance of the asphalt caused by the oil content in the existing process of producing the asphalt. The method comprises the steps of: 1. carrying out dynamic sine strain test on matrix asphalt by using a dynamic shear rhometer to obtain an index for representing the high-temperature performance of the asphalt; 2. carrying out dynamic sine strain test on modified asphalt I with low oil content by using the dynamic shear rhometer to obtain an index for representing the high-temperature performance of the asphalt; 3. carrying out dynamic sine strain test on modified asphalt II with high oil content by using the dynamic shear rhometer to obtain an index for representing the high-temperature performance of the asphalt; and 4. establishing a standard curve to obtain a regression equation and measuring and calculating the influence on the high-temperature performance of the asphalt caused by the oil content under the condition of any oil content mixing amount through the regression equation. The method can be used for measuring and calculating the influence on the high-temperature performance of the asphalt caused by the oil content.

The invention relates to a method for evaluating the consistency between direct coal liquefaction residues and petroleum asphalt. The method comprises the following steps: (1) adding a certain dosage of DCLR into the petroleum asphalt, so as to prepare a blend of the DCLR and the petroleum asphalt;(2) carrying out dynamic shearing rheological test on the blend of the DCLR and the petroleum asphalt by virtue of a dynamic shearing rheometer DSR; (3) calculating a real part n' and a virtual part n'' of complex viscosity according to a DSR test result, and drawing a Cole-Cole graph (a n'-n'' relation graph); (4) calculating change ratios of longitudinal and transverse short axis ratios according to the Cole-Cole graph; and (5) evaluating the consistency between the DCLR and the petroleum asphalt according to the change ratios of longitudinal and transverse short axis ratios in the Cole-Cole graph of the blend of the DCLR and the petroleum asphalt. The method disclosed by the invention is an economic and practical method, is simple, easy in operation, low in energy consumption and cost and beneficial to environmental protection.

The invention discloses a dynamic shear rheometer which comprises a frame body, a tool cabinet, a servo motor and a fixed plate, wherein a fixed shaft end is installed at the bottom in a work tank ofthe frame body through a bolt, a fixed plate is installed at the top end of the fixed shaft end through a screw, a first semiconductor chilling plate is arranged in the fixed plate, a first external-connection water bath pipeline is arranged at one end of the fixed plate through a limiting hole, the servo motor is arranged at the top end of the frame body through an installation cavity, a rotatingmain shaft is arranged on an output shaft of the servo motor through a bolt, a torque stress sensor is sleeved on the end of the output shaft of the servo motor, an oscillation plate is arranged at the bottom end of the rotating main shaft through a bolt, and a second semiconductor chilling plate is arranged in the oscillation plate through an installation part. The dynamic shear rheometer disclosed by the invention has the advantages of accurate detection data and certain representativeness; a single chip microprocessor controller can automatically program and control treatment operation, sothat the work efficiency is effectively improved, and practicability is strong; the dynamic shear rheometer is suitable for being widely applied and popularized.

The present invention discloses an asphalt material dynamic shear modulus low temperature test method, comprising following steps: a test mold is placed on a dynamic shear rheometer; S2. a liquid asphalt material is injected into a cavity of the test mold, and the test mold is removed after the liquid asphalt material solidifies; S3. dynamic shear modulus data is collected from the solidified asphalt material, and the dynamic shear modulus data includes a complex shear modulus, a phase angle, a storage shear modulus, and a loss shear modulus; S4. the dynamic shear modulus data is fitted to form a relational graph between the complex shear modulus and the phase angle, a relational graph between the storage shear modulus and the loss shear modulus, a complex shear modulus main curve, and a phase angle main curve. The asphalt material dynamic shear modulus low temperature test method can set a larger sample height to better measure rheological properties of different kinds of asphaltene materials under low temperature conditions while standardizing a sample preparation process.

The invention discloses an improved dynamic shear rheometer parallel-plate and a test method thereof. The improved dynamic shear rheometer parallel-plate comprises an upper parallel-plate and a lowerparallel-plate, the upper parallel-plate comprises a bottom platform and a first handle, the lower parallel-plate comprises a second handle, a top platform, a boss, and a sleeve;the lower surface of the top platform is fixedly connected with the second handle, and the upper surface of the top platform is fixedly connected with the boss; the edge of the periphery of the upper surface of the top platform is detachably connected with the upright sleeve; the bottom platform is correspondingly arranged on the top of the boss, and the upper surface of the bottom platform is fixedly connected with the first handle; a to-be-tested sample is placed between the boss and the bottom platform; and the first handle and the second handle are both in erection joint witha dynamic shear rheometer. Accordingto the improved dynamic shear rheometer parallel-plate, the rheological properties ofasphalt or mortar can be quantitatively tested when the surface of a real mineral material is in a contact state under the condition of water, and thusquantitative evaluation of water damage resistance of different types of asphalt or mortar based on an asphalt shear rheometer is possible.

The invention discloses an edge trimmer used for a dynamic shear rheometer. The edge trimmer comprises two clamping grooves, two handles, two cutting frames and a spindle, wherein each clamping grooveconsists of a groove bottom and groove edges; a round cavity cooperated with the outer edge of the lower fixture of the dynamic shear rheometer is formed between the bottoms of two grooves. The edgetrimmer is characterized in that the end parts of the two clamping grooves are respectively fixedly provided with a connecting rod; two connecting rods and two bent rods are in cross connection and are hinged to the spindle; each cutting frame consists of semi-circular slices, wherein two ends of each semi-circular slice are respectively fixedly provided with a rectangular sheet; the rectangular sheet on one end is fixedly provided with a vertical insertion rod; the end part of each clamping groove is provided with a jack cooperated with the insertion rod. According to the edge trimmer, asphalt on the outer edge of a dynamic shear rheometer fixture can be dynamically sheared in one time, shearing efficiency is high, an influence on an asphalt specimen is low, the experience accuracy of thedynamic shearing rheology of the asphalt is guaranteed, and the beneficial effect is obvious.

The invention relates to a physical method for compatibilizing direct coal liquefaction residue modified asphalt, comprising the following steps: 1) testing various performance indexes of matrix asphalt, DCLR and aromatic hydrocarbon oil; 2) using DCLR as an asphalt modifier, adding different dosages of aromatic hydrocarbon oil, and preparing DCLR modified asphalt under different shear time conditions; 3) using low-temperature ductility as the main control index, supplemented by softening point and needle penetration index, and carrying out primary selection of the DCLR modified asphalt addedwith different dosages of aromatic hydrocarbon oil and at different shear times; 4) adding aromatic hydrocarbon oil into the DCLR modified asphalt according to the optimal dosage and the best shear time based on the results of primary selection, and carrying out dynamic shear rheological test by the use of a dynamic shear rheometer (DSR); and 5) making a Cole-Cole chart according to the DSR test results, and further judging the compatibilization effect of aromatic hydrocarbon oil on DCLR and petroleum asphalt. The physical compatibilization method proposed for DCLR modified asphalt is economical and practical, simple, easy to operate, low in energy consumption, low in cost and environmentally friendly.

The invention discloses an asphalt apparent viscosity testing method based on a dynamic shear rheometer. The comprises three stages, namely an experiment preparation stage, an operation testing stage and a data processing stage. According to the three stages, firstly, a temperature change mode and shear rate system of tested asphalt through three stages is established, a program code on a dynamic shear rheometer is set, and controllable test is carried out on various data of the asphalt by starting the program code. Due to the fact that the dynamic shear rheometer can achieve active temperature change and active rotating speed (shear rate) change in the viscosity testing process through programming, viscosity-temperature scanning curve testing of asphalt viscosity along temperature change at the fixed shear rate can be achieved on the basis of the method; a viscosity-shear rate scanning curve of asphalt viscosity changes along the shear rate at a fixed temperature; and the viscosity-temperature-shearing rate comprehensive scanning of the asphalt viscosity changing along the temperature and the shearing rate is comprehensive.

The invention provides a method for measuring the shear deformation resistance of a sand grain type mixture, which comprises the following steps: preheating the sand grain type mixture and a mold to 150-170 DEG C, the mold comprising a base, a sleeve, a pressure head and a demolding rod; according to the density of the mixture, weighing the mixture according to the weight of the mixture by taking 2.5-3 times of the maximum particle size as a target height; the mixture is poured into the containing cavity to be tamped, and then the pressing head is inserted into the sleeve; connecting an air pressure device or a universal press machine with a pressure head so as to perform pressure forming on the mixture in the accommodating cavity, wherein at least five test pieces are formed in each test piece; placing the mold filled with the test piece at 5-15 DEG C, dismounting the base, and inserting a demolding rod into the sleeve to demold the test piece; and carrying out an anti-shear deformation capability experiment on the demolded test piece in a dynamic shear rheometer. Therefore, the shear deformation resistance of the mixture can be evaluated simply, visually and reliably.

The invention discloses a basalt fiber asphalt preparation and performance evaluation method for simulating an actual mixing process. The method comprises the following steps: selecting coarse aggregate with the particle size range of 16-26.5 mm, cleaning, drying, heating for 4-5 hours in a drying oven with the temperature of 162-178 DEG C, and carrying out dry mixing on the coarse aggregate and bunchy basalt fibers for 85-95 seconds; and taking out the dry-mixed and scattered basalt fibers, weighing a certain mass of basalt fibers, adding the basalt fibers into asphalt with the temperature of 162-178 DEG C in batches, and fully stirring at a high speed by using an electric stirrer to obtain the basalt fiber asphalt. The basalt fiber asphalt is subjected to a temperature scanning test through a dynamic shear rheometer, and complex moduli, phase angles and rut factors corresponding to the basalt fiber asphalt at different temperatures are obtained to evaluate the high-temperature deformation resistance of the basalt fiber asphalt. The basalt fiber and the aggregate are subjected to pre-dry-mixing, the actual mixing process of the basalt fiber and asphalt mixture is simulated, and the improvement of the basalt fiber on the pavement performance of the asphalt and asphalt mixture in engineering practice is facilitated.

The invention discloses a machine learning-based asphalt dynamic viscoelastic characteristic prediction method, which comprises the following steps of: testing the dynamic viscoelastic characteristic of a sample by adopting a dynamic shear rheometer, and testing the microscopic composition structure of the sample by adopting an element analyzer and an infrared spectrometer; carrying out feature extraction on the microcosmic composition structure parameters by using a principal component analysis method; determining the mapping relation between the dynamic viscoelastic characteristic parameters and the microscopic composition structure parameters through adoption of a distance correlation coefficient method; and establishing an asphalt dynamic viscoelastic characteristic prediction model based on a support vector machine learning algorithm. The method disclosed by the invention reveals the corresponding relationship between the dynamic viscoelastic characteristic and the microscopic composition structure of the asphalt material, is beneficial to quickly obtaining the dynamic viscoelastic mechanical response of the asphalt, provides basic theoretical support for design and production of the asphalt material, and has positive significance for guiding on-demand design of the asphalt and other materials.