32 results about "Fineness modulus" patented technology

The invention discloses concrete suitable for a high-altitude large-temperature-difference environment, and belongs to the technical field of building materials. In order to solve the problems of insufficient durability and easy cracking of traditional concrete in high altitude areas due to large day and night temperature difference, the technical scheme provided by the invention is as follows: a cementing material is a composite system composed of Portland cement, fly ash and slag powder, is matched with 5-20mm continuous grading coarse aggregate and river sand with fineness modulus of 2.3-2.8, and is added with basalt fiber and polypropylene fiber; and an air entraining agent, a polycarboxylate superplasticizer and water. The concrete has excellent crack resistance, freezing and thawing resistance and thermal stability by optimizing aggregate gradation, introducing multi-scale fiber for reinforcement, regulating and controlling the hydration heat of a cementing material and matching with an additive in a specific proportion to improve the working performance. The concrete is suitable for engineering such as plateau bridges and tunnels, the service life of the structure can be remarkably prolonged, and the maintenance cost is reduced.

The invention belongs to the technical field of coal-based solid waste resource utilization, and particularly relates to a high-performance kerb with high salt freezing resistance and high flexural tensile strength, which comprises a cementing material, a fine aggregate, a coarse aggregate and water, the cementing material is cement and CFB fly ash, the fine aggregate is CFB slag and machine-made sand, the coarse aggregate is 3-5mm granite and 5-8mm granite, and the water is water. Comprising the following components in parts by weight: 113 to 245 parts of CFB fly ash, 225 to 809 parts of CFB slag, 506 to 613 parts of cement, 383 to 858 parts of machine-made sand, 338 to 417 parts of granite of 3 to 5mm, 338 to 417 parts of granite of 5 to 8mm and 173 to 240 parts of water, and 2450 parts of the CFB fly ash, the CFB slag, the cement and the granite are taken as the total base number. According to the curb, on one hand, resource utilization of solid waste can be achieved, and on the other hand, the production cost of the curb can be reduced; by utilizing the characteristics of self-hardening, volcanic ash activity and micro-expansibility of CFB ash, the CFB fly ash is used for replacing an expanding agent or expansive cement to compensate the shrinkage of the curb; secondly, the fineness modulus of the CFB slag is in a medium sand range, part of machine-made sand is replaced, closed holes are formed in the kerb, the salt freezing resistance of the kerb is improved, and cellulose and an air entraining agent do not need to be added.

The invention relates to the technical field of mortar, and discloses mortar capable of being used for 3D printing, which solves the problems in the background art, and comprises the following components in parts by weight: 50-60 parts of cement, 40-50 parts of aggregate, 45-55 parts of water, 3-5 parts of fly ash, 3-5 parts of reinforced fiber, 1-3 parts of early strength agent, 1-3 parts of foaming agent, 1-3 parts of plasticizer and 1-3 parts of water reducing agent. The fly ash comprises, by weight, 2-3 parts of fly ash, 2-3 parts of reinforcing fibers, 0.2-0.8 part of an early strength agent, 0.2-0.3 part of a foaming agent, 1-1.5 parts of a plasticizer and 0.5-0.7 part of a water reducing agent, the fineness modulus of the fly ash is 0.5-0.8, and the carbon content of the fly ash is 1t; according to the invention, by adding the reinforced fibers, the formation and expansion of cracks are effectively prevented or slowed down, the tensile strength and crack resistance of the mortar are remarkably improved, the abrasion and particle falling of the surface of the mortar can be reduced, the service life of the mortar is prolonged, and the effect is particularly remarkable in high-flow and high-pressure application.

The application discloses a mechanism sand fineness modulus prediction method and system based on a multiple linear regression algorithm, and the method comprises the following steps: acquiring multiple operation parameters of a mechanism sand production system; analyzing influence factors of the fineness modulus of the mechanism sand by using the multiple operation parameters to obtain influence factor analysis results; obtaining real-time operation parameters of the mechanism sand production system influencing the fineness modulus according to the influence factor analysis results; inputting the real-time operation parameters into a constructed multiple linear regression model to predict the fineness modulus based on a parameter linear relationship and obtain a fineness modulus prediction result. The application can accurately predict the fineness modulus of the mechanism sand to guide industrial production.

The invention particularly relates to an air classification sand making device and method. The device comprises a raw material warehouse, a material winnowing and grading system, an oversize material crushing system, a dust removal device and a stone powder warehouse, wherein the material winnowing and grading system comprises a first-stage sand winnowing system and a second-stage sand winnowing system; the raw material warehouse conveys materials to the material winnowing and grading system, micro powder, first fine particles and first coarse particles are winnowed out by the first-stage sand winnowing system, and micro powder, second fine particles and second coarse particles are winnowed out by the second-stage sand winnowing system; the first fine particles and the second fine particles are mixed to form machine-made sand, the first coarse particles and the second coarse particles are input into the oversize material crushing system to be crushed to form crushed materials, and the crushed materials are input into the material winnowing and grading system to be continuously winnowed. Two-stage winnowing is achieved through the material winnowing grading system, a loop is formed in cooperation with the oversize material crushing system, material circulation is achieved, fineness modulus adjustment is facilitated, product grading continuity is guaranteed, and product quality is effectively guaranteed.

The invention provides a one-stop sandstone physical intelligent detection device, and relates to the technical field of sandstone detection, the one-stop sandstone physical intelligent detection device comprises a truss-type five-axis manipulator and a material distribution mechanism, a feeding platform is arranged below one end of the truss-type five-axis manipulator, and a heating dryer is arranged on one side of the feeding platform; and a vibration screening machine is arranged on one side of the heating dryer. Full-process automation and high integration of gravel component detection are achieved, a container is accurately grabbed and transferred through the truss type five-axis mechanical arm, a sample passes through a series of stations such as heating and drying, vibration screening, weighing and metering, stirring and washing, crushing testing and the like, and therefore gravel key indexes, gravel components and gravel components are detected in a one-stop mode. According to the technical scheme, comprehensive detection of the water content, the grain composition, the fineness modulus, the mud content, the mud block content, the crushing index, the methylene blue value and the stone powder is achieved, the detection range of equipment is greatly expanded, and the consistency of the detection efficiency and the result is remarkably improved through seamless connection assembly line work.

The invention provides localized special mortar as well as a preparation method and application thereof, and relates to the technical field of building materials. According to the method, the target fineness modulus is dynamically corrected by introducing the edge coefficient based on the crushing value of the machine-made sand, so that quantitative response to the edge difference of different batches of machine-made sand is realized; a cement-fly ash-activated recycled concrete micro powder ternary cementing material system is adopted, so that the early strength and the long-term performance are synergistically improved; and redispersible latex powder and hydroxypropyl methyl cellulose are compounded to form a water-retaining, tackifying and film-forming-enhanced composite admixture system, so that multiple targets of stable mortar workability, excellent mechanical properties and solid waste resource utilization are achieved, and the mortar has a wide engineering application prospect.

The invention discloses an engineering muck resource utilization method based on water washing treatment, which comprises the following steps: testing the fineness modulus of waste muck in a factory, trying to calculate the fineness modulus of coarse sand and fine sand which are mixed according to different proportions, and establishing a raw material blending ratio comparison table; the current batch of waste residue soil serves as first raw material sand, the fineness modulus of the first raw material sand is detected, and if the first raw material sand is fine sand, coarse sand needs to be blended; if the sand is coarse sand, fine sand needs to be blended; if the fineness modulus standard range is within the fineness modulus standard range, blending is not needed; if blending is needed, nearby coarse sand / fine sand is selected as second raw material sand, the specific fineness modulus of the second raw material sand is measured, the ratio of the first raw material sand to the second raw material sand is determined according to a raw material blending ratio comparison table, and the first raw material sand and the second raw material sand are jointly used as washing sand production line raw materials; if not, the raw material is first raw material sand; measuring the silt content of the raw materials, and adjusting equipment to proper parameters; the raw materials are put into a production line according to the determined proportion, and water washing treatment is started. According to the method, the waste residue soil treatment efficiency and the qualified rate of finished products are improved, and high universality is achieved.

The invention belongs to the technical field of building materials, and discloses anti-cracking and rebound-reducing tunnel shotcrete and a preparation and use method thereof.The tunnel shotcrete is prepared from, by mass, 135-195 parts of water, 300-350 parts of Portland cement with the strength grade not lower than 42.5, 50-100 parts of F-class I-grade fly ash and 815-905 parts of machine-made sand with the fineness modulus of 2.5-2.8. The concrete is prepared from the following raw materials in parts by weight: 855-925 parts of 5-10mm continuous graded broken stone, 2-4 parts of a polycarboxylic acid type water reducing agent with the water reducing rate of more than 25%, 13-22 parts of an alkali-free accelerator, 5-8 parts of an anti-cracking component and 3-5 parts of a rebound reducing component. Wherein the anti-cracking component is a composition of sodium alginate and nano silicon dioxide, and the resilience reducing component is a composition of nanocrystalline cellulose, Ti2C, methyl anyl alcohol and fatty acid macrogol ester. The tunnel shotcrete disclosed by the invention has the advantages that the cracking resistance and the springback resistance of the tunnel shotcrete are remarkably enhanced through the effects of forming a gel network, in-situ reinforcing a nano material and the like played by the anti-cracking component and the springback reducing component.

The invention discloses a concrete compressive strength prediction method based on a Stacking ensemble learning model, and the method comprises the steps: obtaining concrete characteristic parameters, including a water-binder ratio, a sand ratio, a mortar-to-bone ratio, the 28d compressive strength of a cementing material, a coarse aggregate grading parameter, a coarse aggregate void ratio, a fine aggregate grading parameter, a fineness modulus and a mortar surplus coefficient; the concrete characteristic parameters are input into a Stacking ensemble learning model, the Stacking ensemble learning model comprises a base model layer and a meta model layer, the base model layer integrates at least two different machine learning models and is used for generating primary prediction results, and the meta model layer is used for fusing all the primary prediction results; and outputting the 28d compressive strength prediction value of the concrete. The invention further discloses a prediction model based on the prediction method, a related computer program product and a storage medium, the concrete strength level can be rapidly predicted based on the method, and real-time and accurate data support is provided.

The invention relates to the technical field of building admixtures, in particular to a quick-setting early-strength low-temperature applicable concrete pavement patching material, which is prepared from the following raw materials in parts by weight: quick-hardening sulphoaluminate cement, NaNO, a crystal nucleus early strength agent, sand, a polycarboxylate superplasticizer, an expanding agent and water. The quick-hardening sulphoaluminate cement is prepared from CaO, AlO and CaSOin a specific proportion, the sand is preferably machine-made sand with specific fineness modulus, bulk density and crushing index value, and all the components play an important role. The preparation method comprises the steps of material preparation, stirring, forming, curing and the like, and each step has specific process conditions. The repairing material has the advantages that the raw materials are convenient to transport, and construction is convenient; the materials are not required to be heated at-17 DEG C to-12 DEG C, and water and equipment are not required to be mixed; the compressive strength within 2 hours reaches 30 MPa, and the open traffic requirement is met; the transportation is convenient in emergency repair engineering, the repair time can be shortened, and the problem of pavement repair in cold regions is effectively solved.

The invention belongs to the technical field of coal mine safety mining, and relates to a coal-based solid waste roadway bottom plate surface layer concrete material and a proportion determination method. The coal-based solid waste roadway bottom plate surface layer concrete material is prepared by mixing the following raw materials in parts by weight: 10 to 90 parts of cement, 80 to 150 parts of sand, 200 to 300 parts of gangue, 15 to 150 parts of coarse slag in coal gasification ash, 10 to 100 parts of fine slag in coal gasification ash and 35 to 60 parts of water. Wherein the crushed and screened gangue serves as coarse aggregate, the sand and coarse slag of the coal gasification ash serve as fine aggregate, the cement and the activated fine slag of the coal gasification ash serve as binding materials, the crushed and screened gangue particles are larger than or equal to 4.75 mm, and the fineness modulus of the coarse slag in the coal gasification ash is 1.6-3.7. The use requirements of the mine laneway bottom plate are met, the technical problems of low solid waste mixing amount, high material cost and poor high-temperature resistance are solved, and remarkable economic and environmental benefits are achieved.

The invention aims to provide low-cost C80 concrete and a preparation method thereof, and belongs to the technical field of building construction. Comprising the following components in parts by weight: 730 parts of P.O42.5 ordinary Portland cement, 27 to 28 parts of F-class II-grade fly ash, 71 to 75 parts of S95 slag powder, 78.5 to 94.2 parts of copper-plated microfilament type steel fiber, 739 to 790 parts of broken stone with a particle size range of 5 to 15 mm, 520 to 525 parts of sand with a fineness modulus of 2.4 to 2.8, 2.7 to 4.8 parts of a polycarboxylic acid high-performance water reducing agent and 210 to 240 parts of water. The concrete disclosed by the invention is relatively low in cost and also has good comprehensive performance.

The application provides a kind of iron tailings sand-containing machine-made sand concrete and a preparation method thereof, relates to the technical field of building materials and solid waste resource utilization, and includes obtaining iron tailings sand and machine-made sand, respectively detecting the fineness modulus, 0.075mm below particle content, water absorption and moisture content of the iron tailings sand, and the fineness modulus, stone powder content, water absorption and moisture content of the machine-made sand.The iron tailings sand-containing machine-made sand concrete and the preparation method thereof detect the performance state of the iron tailings sand and the machine-made sand, and combine saturated surface dry conversion, mixing water correction, pre-wetting correction, compound control and segmented mixing, etc.Processing flow, effectively regulate the preparation process of composite fine aggregate, thereby improving the mix proportion adaptability and preparation stability of the iron tailings sand-containing machine-made sand concrete, and reducing the workability fluctuation and performance instability caused by the difference in particle composition and water absorption characteristics of the two types of fine aggregate.

The invention belongs to the technical field of constructional engineering, and particularly relates to a screening device for detecting the fineness modulus of sand and a screening detection method. According to the sand screening device, the sealing assemblies of the sealing parts are matched with the fixing assemblies, elastic sealing rings are arranged at the top and the bottom of each screening ring, tight sealing between the adjacent screening layers is achieved through vertical pressing of the upper pressing rings, the lower pressing rings and the connecting rods, and sand can be effectively prevented from being scattered from gaps in the screening process; the whole device is comprehensively protected through a protection barrel body and a sealing cover assembly of the protection part, external impurities can be prevented from entering the device, parts can be prevented from being collided and damaged, a stable frame structure is formed in combination with the fixing assembly, and the screen layer can be effectively prevented from loosening and shifting in the screening process; meanwhile, a spring assembly is adopted to buffer vibration impact force, and damage of vibration to the weighing sensor and other parts is reduced; and a preset sand fineness modulus algorithm is adopted, so that the sand sample fineness modulus can be accurately and efficiently obtained.

The invention belongs to the technical field of concrete pipe piles, and particularly relates to an ultrahigh-strength prestressed thin-wall pipe pile and production equipment thereof. Pouring is conducted through the following steps that S1, Portland cement or ordinary Portland cement with the strength grade not lower than 42.5 is adopted as cement, and the quality of the Portland cement or ordinary Portland cement meets the GB175 specification; clean natural hard medium-coarse sand should be adopted as the fine aggregate, the fineness modulus should be 2.6-3.0, the quality should meet the requirements of the class I in GB and T14684-2022, hard granite or basalt gravel should be adopted as the coarse aggregate, particles are round, various parameter indexes meet the requirements of the class I in GB and T14685-2022, a polycarboxylic acid high-performance water reducing agent should be selected, various indexes should meet the GB8076 specification, and the fine aggregate and the coarse aggregate should meet the requirements of the class I in GB and T14685-2022. The admixture is preferably silica fume or fly ash sinking beads, the content of silicon dioxide in the silica fume is not lower than 90%, and the mass of the silica fume meets relevant regulations in GB and T18736; s2, high-quality raw materials and high-activity mineral admixtures are adopted to prepare concrete with the low water-binder ratio of 0.22-0.25, and the concrete C105 strength grade is achieved.

The invention discloses an application of a key technology of waste stone chips in medium and low strength grade concrete, and relates to the technical field of building materials, which comprises cement, waste stone chips, machine-made sand, broken stone, secondary fly ash, S95 mineral powder, and a polycarboxylic acid high performance water reducer. The water reducing rate of the polycarboxylic acid high-performance water reducing agent is 22%, and the solid content is 8.5%; the breaking strength of the cement in 28 days is 8.7 MPa, and the compressive strength of the cement in 28 days is 52.13 MPa; the apparent density of the machine-made sand is 2.68 g / cm < 3 >, the silt content is 2.2%, and the fineness modulus is 2.8, and the broken stones are configured in a continuous particle size of 5mm-25mm. The method has the beneficial effects that the pollution of the waste stone chips to the environment and the occupation of land resources are reduced; and as the price of the waste stone chips is far lower than that of the machine-made sand, the cost of raw materials can be remarkably reduced by partially replacing the machine-made sand with the waste stone chips.

The invention relates to the technical field of building materials, in particular to a high-performance light self-compacting concrete material and a preparation method thereof. The high-performance light self-compacting concrete material is prepared from the following raw materials in parts by weight: 300 to 400 parts of a cementing material, 150 to 200 parts of water, 90 to 120 parts of coarse aggregate, 600 to 800 parts of fine aggregate, 10 to 20 parts of ettringite, 3 to 6 parts of a water reducing agent, 150 to 200 parts of fly ash and 20 to 30 parts of a fiber reinforcement, p.O42.5 ordinary Portland cement is selected as the gel material, and river sand with the fineness modulus of 2.4-3.0 is selected as the fine aggregate; ceramsite with the particle size of 5-10 mm is selected as the coarse aggregate; according to the prepared fiber reinforcement, the mechanical property and the self-constriction performance of a concrete material are remarkably enhanced, meanwhile, the waterproof anti-permeability performance and the self-compacting performance of the concrete material are effectively improved, the quality of the concrete material is guaranteed, and meanwhile the service life of the concrete material is prolonged to a certain degree.

To provide a mortar material having good fluidity and excellent filling properties.SOLUTION: In the mortar material, the mortar has a vibration viscosity, measured by a vibration viscometer immediately after kneading at a standard water ratio, of 50-600 (mPa s g / cm3). The fine aggregate contained preferably has a fineness modulus of 1.2 or more and 2.2 or less, and the mass ratio of the fine aggregate to the total mass of cement and expansive material is preferably 60-230%.SELECTED DRAWING: None

The present application provides a seawater-resistant concrete repair material, which consists of two ingredients: a repairable high-bonding concrete ingredient M1 and a salt-resistant and antibacterial dense concrete ingredient M2. The composition of the repairing high-bonding concrete mix M1 is 55-65wt.% modified magnesium phosphate cement, 1.5-2.5wt.% ternary copolymer polyacrylamide, 25-35wt.% quartz sand with a fineness modulus of 2.5-2.7, and 5-10wt.% ultrafine steel fiber with a cross-sectional area of ​​0.01mm2 or less. The composition of the salt-resistant and antibacterial dense concrete mix M2 is 55-60wt.% modified magnesium phosphate cement, 0.4-0.8wt.% ternary copolymer polyacrylamide, 10-20wt.% coarse aggregate, 10-15wt.% fine aggregate, 5-10wt.% ordinary steel fiber, 0.1-0.5wt.% water reducer, and 0.01-0.5wt.% cuprous oxide. By combining the two concrete mixes, a stable and excellent repair effect can be achieved.

This invention belongs to the field of concrete technology and provides a method for inhibiting aggregate sulfate attack based on gradation control, cementitious material optimization, and ion curing synergy. The method involves using the initial aggregate with an SO3 content ≥0.5% as fine aggregate, rather than coarse aggregate, in concrete or mortar. The fine aggregate is composed of the initial aggregate and compliant aggregates, with a fineness modulus of 2.4~2.8. The invention employs different treatment methods for different SO3 contents in the initial aggregate: when the SO3 content is low, the aggregate is compounded according to a specific gradation curve; when the SO3 content is high, the aggregate is pretreated. The cement used in the cementitious material is low-C3A or low-C3S silicate cement, and the admixtures are single or double admixtures of F-type fly ash and silica fume to improve the matrix's corrosion resistance. A sulfate curing agent is added to fix sulfate ions and reduce attack.

The present disclosure proposes a method for adjusting the quality of machine-made sand, including: obtaining machine-made sand, and dividing the machine-made sand into a first machine-made sand and a second machine-made sand with different particle sizes; mixing the first machine-made sand and the second machine-made sand into fine sand; adjusting the flow rate of the first machine-made sand and the flow rate of the second machine-made sand according to the fineness modulus of the fine sand, so that the fineness modulus of the fine sand tends to a set value; if the fineness modulus of the fine sand cannot reach the set value, adjusting the particle size of the machine-made sand according to the fineness modulus of the fine sand until the fineness modulus of the fine sand reaches the set value. In a method for adjusting the quality of machine-made sand disclosed in the present disclosure, the fineness modulus of the fine sand is ensured to reach the set value by adjusting the flow rate and the particle size, thereby realizing online automatic adjustment of the quality of fine sand preparation, thereby saving a long time consumed by test determination, effectively taking into account the preparation quality and preparation efficiency of fine sand, and reducing the preparation cost of fine sand.

The invention discloses sulfate-corrosion-resistant high-performance concrete for a photovoltaic pipe pile. The concrete comprises cement, coarse aggregate, fine aggregate, water, silicon powder, a water-reducing air-entraining agent and an anti-corrosion and anti-rust agent, gravel with the particle size not larger than 25 mm is selected as coarse aggregate, medium sand with the fineness modulus of 2.6-3.2 is selected as fine aggregate, 25-30% of silicon powder is doped, micro bubbles are introduced in combination with a water reducing and air entraining agent, the compactness, chloride ion permeability resistance and sulfate corrosion resistance of the concrete are improved, the concrete is suitable for a photovoltaic pipe pile foundation in a high-salt-alkali environment, and durability and stability are improved. The preparation method comprises the processes of raw material mixing, stirring and curing.

The present application belongs to the field of civil engineering material research and application technology, and particularly relates to a method for measuring and calculating sand fineness modulus and grading, which is based on the relationship between two-dimensional mortar section particle size and three-dimensional real particle size, establishes the relationship between the number of particles in each group of two-dimensional section and the number of particles in each group of sieving method, and combines with image analysis method to calculate sand fineness modulus and particle grading, which can not only avoid the defects such as large labor intensity and low efficiency of conventional sieving method, but also avoid the error caused by repeated weighing, effectively solve the problems of small particle radius invisible and large error caused by difficult dispersion of sand in image analysis process, and has important reference value for the research on sand in hardened concrete; the principle is scientific and reliable, the labor intensity is low, the efficiency is high, and good consistency is obtained compared with conventional sieving method.

The invention discloses machine-made sand quality on-line detection equipment and a detection method thereof, and relates to the technical field of machine-made sand quality detection.The machine-made sand quality on-line detection equipment comprises a sample feeding barrel, a solution volume measurer is communicated with the sample feeding barrel, and a sand sample circulating barrel is communicated with a discharging opening of the sample feeding barrel; the filtering mechanism is arranged in the sand sample circulating cylinder and divides the sand sample circulating cylinder into an upper cavity and a lower cavity; the water content can be calculated through the machine-made sand quality online detection equipment in combination with a specific gravity method, and the drying step is omitted. Through classification and partition detection of the stone powder and the stone-powder-removed sand sample, the content of the stone powder is measured by adopting a nephelometry, so that redundant calculation of an image method on extremely fine particles can be reduced, the testing precision of the content of the stone powder is improved, the particle number of sand per unit mass and the turbidity of testing liquid are reduced, and by adopting circular flowing and recognition of the stone-powder-removed sand sample, the detection accuracy of the stone powder content is improved. The reliability and repeatability of sand sample particle detection by an image method are improved, and the measurement precision of the fineness modulus of the sand sample is improved.

The purpose of this invention is to address the problems existing in the calculation methods of the representative value of the 28-day compressive strength of concrete in the prior art, and to provide a method for calculating the representative value of the 28-day compressive strength of concrete and related parameters. This includes: 1. Calculation methods for the 28-day compressive strength of concrete, the calculated value of the 28-day compressive strength of cementitious materials, the water-cement ratio, the aggregate fineness modulus, and the dosage of water-reducing agent; 2. Calculation of fcu,o; 3. Calculation of W÷C; 4. Calculation of Q; 5. Calculation of f′ce. This invention's calculation method explains how to calculate the mix proportion parameters of concrete with mineral admixtures and high-flowability concrete. When other conditions are known, it is not necessary to look up tables to directly calculate the water-cement ratio, concrete strength, and verify the dosage of concrete water-reducing agent; the calculated value of the 28-day compressive strength of concrete can be directly verified from the concrete strength value.

The invention discloses a grain shape optimization grading control device for tuff machine-made sand, and relates to the technical field of building material processing. The device comprises a feeding unit, a grain shape optimization unit, a real-time monitoring unit, a grading control unit and an intelligent control system. The core of the invention lies in that the intelligent control system carries out calculation through a built-in comprehensive quality evaluation model containing sphericity, fineness modulus and stone powder content based on real-time grain shape, grading data and stone powder content fed back by a real-time monitoring unit; and the rotating speed of the grain shape optimization unit and the vibration frequency and the airflow speed of the grading control unit are dynamically adjusted by using a feedback control algorithm, so that integrated and intelligent closed-loop control of grain shape optimization and grading control is realized. The method is particularly suitable for solving the technical problem that in tuff machine-made sand production, the content of needle-sheet-shaped particles and stone powder is difficult to stably control, and the stability of product quality and production benefits can be effectively improved.

The utility model belongs to the technical field of material granularity detection, and provides fineness modulus detection equipment which comprises a grading unit, a weighing unit and a control unit, the grading unit comprises a plurality of screening machines which are sequentially connected, each screening machine comprises a machine body and a screen arranged in the machine body, and each screening machine is provided with a feeding port and a first discharging port; the weighing unit comprises a first weighing assembly and a second weighing assembly, and the second weighing assembly is connected to a first discharging opening of the screening machine on the rearmost side and used for weighing the weight value of materials discharged by the screening machine; the number of the first weighing assemblies corresponds to the number of the screens, and the first weighing assemblies weigh the weight value of materials on the screen corresponding to the screen; the control unit is connected with the second weighing assembly and the first weighing assembly and obtains the fineness modulus based on the weight value. After screening is completed, the weight of the oversize material and the weight of the final undersize material on the screen can be weighed through the weighing unit, the materials do not need to be guided out and weighed after screening is completed, and therefore the weighing step is simplified, and the detection efficiency is improved.

The present invention relates to the technical field of manufactured sand crushing, and particularly relates to a manufactured sand double-mainframe crushing device and process. The present invention provides a manufactured sand double-mainframe crushing device and process that uses a double-mainframe intermixing process for manufactured sand crushing. A manufactured sand double-mainframe crushing device and process includes a first mounting frame, a housing, a lid, a feeding cylinder, etc. Two housings are installed on the lower part of the first mounting frame, lids are rotatably connected to the upper sides of the housings, and feeding cylinders are connected to the upper sides of the lids. By using two first servo motors to crush materials with different gradations and particle sizes, the present invention reduces the number of repeated crushing times of the materials in the crusher, improves the sand production rate, and adjusts the feeding ratio and particle size. Furthermore, it realizes intermixing and blending to produce concrete with different gradations and fineness moduli to meet different functional requirements, while ensuring the continuity and stability of the gradation, and avoiding the problems of unstable fineness modulus and poor gradation of manufactured sand produced by traditional single-machine production.

The invention discloses a pavement positive concrete mix proportion design method, and relates to the technical field of mix proportion design of hard concrete for roads and airport runways. The method comprises the following steps: setting the volume fraction Vg of coarse aggregate in concrete according to the grain shape of the coarse aggregate; determining the volume sand ratio beta v according to the maximum particle size of the coarse aggregate and the fineness modulus of the fine aggregate, and calculating the volume fraction Vs of the fine aggregate; calculating a water-cement ratio based on the target strength and adapting an additive; calculating the volume fraction Vp = 1-Vg-Vs of the slurry, and determining the mass of the slurry and the use amount of the cementing material in combination with the water-cement ratio and the density of the cementing material; correcting the dosage of each component according to the designed gas content Va; and determining the gradation of the coarse aggregate and the mixing amount of the additive through an adaptation test. By means of the method, the problems of'insufficient and bulking 'and'slurry redundancy' can be fundamentally solved, the volume stability of the concrete is accurately controlled while the using amount of the cementing material is remarkably reduced, and the mechanical performance and the durability of the concrete are improved.