245 results about "River sand" patented technology

The invention discloses quick-hardening high-strength lightweight aggregate concrete, which is prepared from the following raw materials: ordinary Portland cement, quick-hardening sulphoaluminate cement, a mineral admixture, silica fume, ceramsite, river sand, water and an additive, and the additive is a mixture of a water reducing agent, a slump retaining agent, a retarder, a thickening agent and an air entraining agent; after the ceramsite absorbs water and is saturated, the surface of the ceramsite is coated with a cementing material, and the cementing material is hydrated to form a slurry shell; ordinary Portland cement and quick-hardening sulphoaluminate cement are compounded, mineral admixtures and silica fume are doped, the early strength of the lightweight aggregate concrete can be improved, meanwhile, the development of later strength is guaranteed, a layer of slurry'shell 'is formed on the surface of ceramsite through the hydration effect of the cementing material, and the surface of the ceramsite is wrapped by the composite cementing material. According to the ceramsite wrapped with the ash, firstly, the strength of the ceramsite can be improved, and then the strength of the concrete is improved; 2, the water absorption and water return phenomena of the ceramsite can be avoided; and thirdly, the floating phenomenon of the ceramsite can be improved.

The invention discloses sulfate-erosion-resistant metakaolin-slag-based geopolymer concrete, belongs to the technical field of concrete, and aims to solve the problems that the corrosion resistance of traditional silicate concrete is ineffective and the adaptability of conventional alkali-activated concrete is insufficient in a special environment. The concrete comprises the following components in parts by weight: 60-90 parts of a cementing material, 120-170 parts of aggregate, 15-30 parts of a composite activator, 2-8 parts of a function regulator and the like, the cementing material is prepared from nano TiO2 / KH-550 composite modified metakaolin, slag and silica fume-coal gangue powder-HAP composite powder; the aggregate comprises modified limestone macadam (soaked and dried by a sodium dihydrogen phosphate solution) and river sand; the composite exciting agent comprises water glass, sodium hydroxide, sodium pyrophosphate, propylene glycol and the like; the function regulator comprises superfine fly ash, a naphthalene water reducer, HPMC (Hydroxy Propyl Methyl Cellulose) and boric acid. Through the synergistic effect of the components, the sulfate corrosion resistance, the mechanical property and the environmental adaptation performance of the concrete are improved, and the concrete is suitable for engineering construction under the service environment of high-concentration sulfate and the like.

The invention provides anti-erosion hydraulic concrete and a preparation method thereof, and belongs to the technical field of concrete. The concrete comprises the following components: composite cement, high-activity nano-modified metakaolin, blast furnace slag powder, low-calcium fly ash, coarse aggregate, natural river sand fine aggregate, granite machine-made sand fine aggregate, an erosion inhibitor, a functional additive, an early-strength polycarboxylic high-performance water reducer, a composite air entraining agent and the like. The composite cement comprises sulphoaluminate cement, Portland cement and polymer waterproof mortar. The high-activity nano modified metakaolin is obtained by modifying metakaolin with an organic silicon-ZnO composite emulsion and then drying. The erosion inhibitor comprises organic carboxylate, a hydrophobic-crystallization complexing agent and a pH buffer type corrosion inhibitor. The functional auxiliary agent comprises an itaconic acid and acrylic acid copolymer, a JRY-F concrete waterproof agent and polyethylene glycol-400 dilaurate. The composite air entraining agent comprises liquid sodium abietate and sodium alpha-olefin sulfonate. Through component synergism, modification and grading, an anti-erosion barrier is constructed.

The invention relates to the field of building materials, and discloses high-toughness and high-energy-absorption polymer emulsion modified mortar and a preparation method thereof, and the mortar is composed of ordinary Portland cement, river sand, a polymer emulsion, water, an active admixture and chopped fibers. Wherein the polymer emulsion is selected from styrene-acrylic emulsion (SBR), ethylene-vinyl acetate (EVA), polyurethane emulsion or a combination thereof; the mixing amount is 5-20wt% of the mass of the cementing material. According to the invention, a viscoelastic network is formed in a cement matrix through the polymer emulsion, and the synergistic effect of the active admixture and the chopped fibers is combined, so that the bonding strength, the crack resistance, the impact resistance and the stress wave dissipation capability of the mortar are remarkably improved. Test results show that the mortar provided by the invention is obviously superior to ordinary mortar in the aspects of 28d breaking strength, impact toughness and stress wave attenuation performance, and is suitable for high-performance constructional engineering and protective engineering.

The invention relates to the technical field of fluid-state solidified soil, and particularly discloses high-fluid-state solidified soil and a preparation method thereof. The high-flow-state solidified soil is prepared from the following raw materials in parts by weight: 1100 to 1200 parts of recycled aggregate, 700 to 800 parts of river sand, 100 to 130 parts of a curing agent, 18 to 22 parts of a polycarboxylic acid water reducing agent, 75 to 85 parts of solidified soil repairing microcapsules and 55 to 95 parts of water, the solidified soil repairing microcapsule is prepared by taking polylactic acid and nano calcium carbonate grafted polyethylene glycol as composite membrane materials, and wrapping and forming sulphoaluminate cement paste through an emulsification-solidification method. The solidified soil repairing microcapsules are introduced into the solidified soil, pores in an interface transition area can be filled, micro cracks can be repaired, and the durability of the solidified soil is improved.

The application belongs to the field of concrete production, and particularly relates to a preparation process for improving the performance of machine-made sand concrete, which comprises the following specific steps: S1: taking ether water-reducing agent, ether slump-retaining water-reducing agent, retarder, mud inhibitor and water in a proportion of 160:35:20:5:780 respectively, and compounding the above-mentioned materials to obtain a composite admixture; S2: taking 585 parts of machine-made sand and cleaning the machine-made sand by using a cleaning device, then drying the cleaned machine-made sand, and then mixing the treated machine-made sand with 200 parts of fine river sand, 25 parts of red mud and 1050 parts of stone for 30-50 seconds to obtain a mixture A; S3: taking 60 parts of fly ash, 60 parts of mineral mud and 240 parts of cement, and adding the mixture A to obtain a mixture B after stirring and mixing for 40-50 seconds; the composite admixture is obtained by compounding the above-mentioned materials in a proper proportion, and the machine-made sand concrete is prepared by using a proper proportion, so that the slump retention performance of the concrete is improved, and the final setting time of the concrete is not greatly affected.

The invention relates to the technical field of concrete 3D printing, in particular to modified alkali-resistant regenerated glass fiber reinforced concrete and a preparation process thereof, and the modified alkali-resistant regenerated glass fiber reinforced concrete is prepared from the following components in parts by weight: 600-650 parts of cement, 90-100 parts of fly ash, 30-35 parts of silica fume, 500-600 parts of river sand, 0.5-6 parts of modified alkali-resistant regenerated glass fibers, 10-15 parts of a water reducing agent and 120-200 parts of water. According to the invention, the regenerated glass fiber obtained by recovering the waste fan blades is used as a reinforcing material of the concrete, so that the resource consumption can be effectively reduced, and the carbon emission is reduced; the invention provides a surface modification method aiming at regenerated glass fibers, so that the long-term durability of the regenerated glass fibers in an alkaline cement matrix is enhanced, the generation of microcracks on a fiber and cement interface is reduced, and the constructability and excellent mechanical properties of the 3D printing concrete are improved. The method not only meets the requirements of digital and intelligent transformation and upgrading of the building industry, but also provides a new method for recycling of waste resources and sustainable development of the building industry, and has relatively high economic and environmental benefits.

The invention relates to the technical field of material performance detection, and discloses a non-destructive evaluation method and system for the strength of microorganism mineralized river sand, and the method comprises the following steps: applying a sweep frequency sound wave excitation signal to a microorganism mineralized river sand standard sample model; performing penetration simulation operation on the microorganism mineralized river sand standard sample model according to the sweep frequency sound wave excitation signal; extracting mineralization specific characteristic parameters corresponding to the sample model through the penetration response signal; according to the mineralization specificity characteristic parameters, constructing a biological cementation index of microorganism mineralization, and according to the biological cementation index, analyzing the compressive strength of the microorganism mineralization river sand standard sample model; constructing a destructive calibration curve of the microorganism mineralized river sand standard sample model; the target compressive strength of the to-be-tested sample model is analyzed through the destructive calibration curve, and the strength non-destructiveness of the microorganism river sand corresponding to the to-be-tested sample model is analyzed based on the target compressive strength. According to the method, the accuracy of non-destructive evaluation of the strength of the microorganism mineralized river sand can be improved.

The invention relates to a preparation technology of a cement-based repairing material, and aims to provide a double-component high-strength repairing mortar material and a preparation method thereof. The repairing mortar material comprises two components: a component A, a component B and a component C, wherein the component A is composed of modified cement, sulphoaluminate early strength cement and water-based resin; the component B is prepared from silica fume, silane, cellulose ether, redispersible latex powder, short fibers, a polycarboxylic acid water reducing agent and a defoaming agent; and river sand with the same amount as the component A can be further included. The silicane is used for modifying the silica fume, and a silanol group and a silicon hydroxyl group on the surface of the silica fume are subjected to dehydration condensation to form a stable Si-O-Si covalent bond, so that the adsorbability of the modified silica fume to water is reduced, and the risk of cracking of the repair mortar is avoided. The component B can be used as an auxiliary component for curing the water-based resin in the component A to control the setting time of the repair mortar, improve the early strength of the mortar added with the water-based resin and improve the weather resistance of the water-based resin; the overall strength of the mortar can be improved, and the production cost of the repairing mortar is reduced.

The invention discloses polymer-based anti-crack concrete and a preparation method thereof, and relates to the technical field of concrete. When the polymer-based anti-crack concrete is prepared, acrylic acid is grafted on the surfaces of pretreated polypropylene particles to prepare modified polypropylene particles; coating sodium metasilicate with sodium alginate to prepare a self-repairing microcapsule; the preparation method comprises the following steps: hydrolyzing 3-glycidyl ether oxypropyl trimethoxy silane, and grafting the hydrolyzed 3-glycidyl ether oxypropyl trimethoxy silane on the surface of silicon dioxide to prepare modified silicon dioxide; mixing the modified polypropylene particles, basalt fibers and polyacrylonitrile fibers to obtain a solid functional component; cement, slag powder, silica fume, an expanding agent, a solid functional component, modified silicon dioxide, a water reducing agent, an air entraining agent, deionized water, river sand, gravel and the pre-wetted self-repairing microcapsule are mixed, and the polymer-based anti-crack concrete is prepared. The polymer-based anti-crack concrete prepared by the invention has excellent anti-crack, freeze-thaw-resistant and self-repairing properties.

The invention discloses a geopolymer-based recycled fine aggregate shield synchronous grouting material and a preparation method thereof. The grouting material is composed of a cementing material, an alkali activator, aggregate, a water reducing agent, a retarder and water, and the cementing material is a geopolymer precursor and is composed of fly ash, slag and metakaolin; the aggregate is composed of river sand and recycled fine aggregate. By optimizing the proportion and the preparation process, the material has the characteristics of excellent flowability, controllable setting time, high early strength, good impermeability, good durability and the like, and is suitable for synchronous grouting of shield tunnels in water-rich sand layers, high-water-pressure stratums or corrosion stratums. The invention also provides two optimization methods which are respectively based on a response surface method and a BP neural network combined genetic algorithm to realize multi-objective optimization of slurry performance. According to the material, dependence on traditional cement and gravel resources is remarkably reduced, energy consumption and carbon emission are reduced, high-added-value resource utilization of industrial solid waste and construction waste is achieved, and the material conforms to the development direction of green low-carbon building materials.

The invention relates to a microwave curing concrete based on carbon mineralization wave-absorbing functional aggregate and a preparation method thereof, the microwave curing concrete comprises the following raw materials by weight: 350-400 parts of cement, 40-50 parts of fly ash, 40-50 parts of silica fume, 530-903 parts of carbon mineralization wave-absorbing functional aggregate, 0-414 parts of gravel, 691-712 parts of river sand, 1.5-3.0 parts of a water reducer, 12-20 parts of a nano magnetic fluid functional component, and 134-183 parts of water. Through composite application of the carbon mineralization wave-absorbing functional aggregate and the nano-magnetofluid functional component, the carbon mineralization wave-absorbing functional aggregate mainly provides skeleton type macroscopic wave absorption, the nano-magnetofluid functional component provides diffuse type nano-scale wave absorption, and the carbon mineralization wave-absorbing functional aggregate and the nano-magnetofluid functional component jointly construct an efficient and uniform microwave absorption network on different scales. The microwave energy utilization rate is obviously improved, the microwave curing performance of the concrete can be effectively improved, and the early mechanical property, the long-term strength and the durability of the concrete are improved.

The invention discloses fly ash-based geopolymer concrete and a preparation method thereof, and the fly ash-based geopolymer concrete is prepared from the following raw materials in parts by mass: a solid waste cementing material including 60-70 parts of fly ash and 15-30 parts of slag; 2-8 parts of a solid alkali activator; 3-6 parts of carbide slag; the aggregate is prepared from 100 to 120 parts of river sand and 240 to 260 parts of gravel; and 30-45 parts of water. According to the fly ash-based geopolymer concrete disclosed by the embodiment of the invention, carbon dioxide generated in the process of preparing a cementing material can be reduced or avoided, the production cost and the environmental load of the concrete are reduced, the potential activity of the coal-based solid waste can be fully exerted, and meanwhile, the efficient utilization of the fly ash is realized; by introducing the carbide slag and the solid alkali activator, the activity of the fly ash and the slag can be activated, an alkaline environment can be provided, active SiO2 and Al2O3 in the fly ash are subjected to a hydration reaction, hydration products such as C-S-H gel are continuously generated, and the long-term performance of the concrete is more stable.

The invention relates to a high-strength MICP reinforced SiO2 aerogel concrete composite material and a preparation method thereof.The method comprises the steps that cement, river sand, pebbles, silicon dioxide aerogel particles and water are added into a stirrer according to the proportion and stirred for 2-3 min till even mixing is achieved, and aerogel concrete slurry is obtained; continuously adding water into the aerogel concrete slurry, stirring for 3-5 minutes until viscous slurry is formed, sequentially adding a bacterial liquid, a saturated urea solution and a saturated calcium chloride solution according to a ratio, and stirring for 2-3 minutes until microorganisms are uniformly distributed to obtain a uniform mixture with the fluidity reaching the standard; and pouring the mixture into a mold, vibrating until bubbles are discharged, transferring the mold into a constant-temperature and constant-humidity curing chamber, and curing to obtain the aerogel concrete composite material. The method is simple in process, the heat conductivity coefficient of the concrete material can be remarkably reduced, and the compressive strength is improved; the prepared concrete composite material has the characteristics of self-repairing and heat-insulating functions, high compressive strength and the like.

This invention relates to the field of building materials technology. It discloses a high-strength modified EPS particle lightweight concrete and its preparation method. The concrete comprises the following raw materials by mass percentage: 0.5-0.8 parts fiber, 10-13 parts 0.5-5mm EPS, 2-4 parts nano-silica (NS), 96-105 parts cement, 30-42 parts fly ash, 20-30 parts slag, 50-60 parts river sand, 30-35 parts quartz sand, 15-22 parts vitrified microspheres, 2.5-3.0 parts water-reducing agent, 58-64 parts water, and a water-cement ratio of 0.35-0.4. This invention, through the combination of fiber and modified EPS, enhances the interfacial bonding with cement, promotes stress transfer, and synergistically enhances the bridging effect of the fiber, significantly improving the mechanical properties of the EPS particle concrete.

The invention relates to a river channel sand body random model generation method and device based on hidden Markov model data filling, a medium and equipment. The method comprises the steps that logging data of a target area are collected and arranged; dividing logging data according to a logging gas-bearing interpretation conclusion, and carrying out analytical statistics on the velocity and density of longitudinal and transverse waves in the logging data; initializing an initial state probability, a state transition matrix, and a mean value and a covariance of Gaussian distribution in the hidden Markov model; inputting a three-dimensional observation vector composed of the velocity and density of the longitudinal and transverse waves into the initialized hidden Markov model for iterative training; performing down-sampling on the lithology data, then constructing a state transition probability matrix, and further constructing a lithology sequence conforming to a geological law through simulation; according to the lithologic sequence, calling a hidden Markov model to generate longitudinal wave velocity, transverse wave velocity and density corresponding to the lithologic sequence; and calculating a reflection coefficient of the synthetic stratum, setting a Ricker wavelet dominant frequency, and obtaining synthetic seismic response data through convolution.

The invention relates to the technical field of building materials, in particular to an energy-saving and environment-friendly recycled concrete pipe pile and a preparation method thereof. The recycled concrete is prepared from the following raw materials in parts by weight: 35 to 45 parts of recycled aggregate, 22 to 28 parts of P.O42.5 Portland cement, 6 to 9 parts of magnesium phosphate cement composite admixture, 18 to 22 parts of river sand, 1.0 to 1.3 parts of hydroxylated graphene-chitosan-nano zinc oxide ternary composite modifier, 6 to 8 parts of modified waste tire rubber powder, 0.5 to 0.8 part of basalt fiber and the like. The rubber powder is soaked in a sodium hydroxide solution and then treated with a maleic anhydride grafted polyethylene solution; the metakaolin is prepared by calcining coal gangue; the ternary modifier is prepared by grafting, crosslinking and dispersing; the magnesium phosphate admixture contains light calcined magnesia, ammonium dihydrogen phosphate and borax. The tubular pile is excellent in mechanical and durable performance and high in solid waste utilization rate, carbon emission and production energy consumption are reduced, the cost is reduced, the problems that a traditional regenerated tubular pile is low in strength and poor in environmental protection performance are solved, the tubular pile is suitable for multiple engineering scenes, and economic and environmental benefits are remarkable.

The application discloses a kind of anti-freezing concrete and preparation method of multi-generation recycling, the concrete is by following raw material is formed according to weight parts: cement 405~418 parts, nano silicon dioxide 8~20 parts, river sand 680~735 parts, recycled coarse aggregate 865~890 parts, water 168~194 parts, polycarboxylate superplasticizer 2.2 parts and alkyl benzene sulfonate air entraining agent 0.05~0.1 parts.The application uses nano silicon dioxide as raw material, which has high specific surface area and pozzolanic activity, and the alkyl benzene sulfonate air entraining agent reduces the aggregation of nano silicon dioxide, not only promotes its uniform dispersion in concrete, but also makes the pore distribution in concrete uniform, thereby improving the mechanical properties and frost resistance of concrete, and the second generation and third generation recycled coarse aggregate obtained by crushing after 400 freeze-thaw cycles can be used in structural concrete in cold regions, greatly reducing material waste and environmental pollution.

The invention relates to the technical field of low carbon and environmental protection, in particular to a coal gangue-based solid waste pavement base mixture and a preparation method thereof, and the coal gangue-based solid waste pavement base mixture comprises the following raw materials in parts by weight: 45-55 parts of coal gangue solid waste, 20-30 parts of cement, 10-15 parts of an aggregate agent, 7-11 parts of a functional comprehensive additive, 5-8 parts of a basalt fiber modified reinforcing agent and 35-40 parts of water. According to the coal gangue-based solid waste pavement base mixture, coal gangue solid waste is matched with cement and an aggregating agent, the coal gangue solid waste is obtained by crushing and pickling solid waste coal gangue, and meanwhile, the aggregating agent is obtained by blending and optimizing steel slag, gravel and river sand. According to the present invention, the raw materials are added, the function comprehensive additive is added, and the basalt fiber modified strengthening agent is added so as to achieve mutual coordination and joint synergism, such that the prepared pavement base layer mixture has characteristics of freeze thawing property, crack resistance, and permeation resistance, and further has advantages of excellent temperature change resistance, excellent corrosion resistance, and excellent comprehensive coordination.

The application discloses a kind of fluorite tailing material fatigue-resistant water-stable base and preparation method thereof.Belongs to the technical field of solid waste utilization.Preparation of the fluorite tailing material fatigue-resistant water-stable base aggregate ratio is as follows: gravel, river sand, fluorite tailing material and tap water quality ratio is as follows: 55-65 wt%, 30-35 wt%, 5-10 wt% and 40-45 wt% tap water.In the application, fluorite tailings are used as raw materials for building materials, which is a reasonable way of resource utilization, and is also an inevitable demand for promoting ecological protection and high-quality development in the Yellow River Basin.Compared with traditional natural materials, it can also reduce carbon emissions and production energy consumption.When applied to water-stable base, it improves its fatigue resistance, prolongs the service life of water-stable base and improves economic efficiency.

The invention discloses freeze-thaw-resistant concrete and a preparation method thereof. The freeze-thaw-resistant concrete is prepared from the following raw materials: cement, river sand, gravel, water, isoprene rubber particles coated with paraffin on the surfaces and an additive, the preparation method comprises the following steps: uniformly mixing the river sand and the isoprene rubber particles coated with the paraffin on the surface, adding other raw materials, and uniformly mixing. Space generated after the isoprene rubber particles are extruded provides space for freezing expansion of free water, expansion pressure is relieved, the freeze-thaw resistance of concrete is improved, the surfaces of the isoprene rubber particles are coated with paraffin, and under the freeze-thaw condition, the paraffin is solidified, releases heat and reduces osmotic pressure and ice expansion pressure, so that the freeze-thaw resistance of the concrete is improved, and the service life of the concrete is prolonged. The paraffin surrounds the isoprene rubber particles, erosion of water to the isoprene rubber particles can be reduced, aging of the isoprene rubber particles can be inhibited, the thermal conductivity of the paraffin and the isoprene rubber particles is smaller than that of aggregate, temperature reduction of the aggregate can be inhibited, and the freeze-thaw resistance of the concrete is further improved.

The invention discloses anti-freezing and salt-tolerant high-strength concrete and a preparation method and application thereof, and belongs to the technical field of green high-strength concrete preparation, the anti-freezing and salt-tolerant high-strength concrete comprises, by mass, 400-500 parts of a cementing material, 650-700 parts of fine aggregate, 1000-1100 parts of coarse aggregate, 0.01-0.015 part of an additive and 160-180 parts of water, the fine aggregate comprises machine-made sand and / or river sand, and the coarse aggregate comprises water and / or water. The mass of the machine-made sand accounts for 50% of the total mass of the fine aggregate. The compressive strength, elastic modulus, chloride ion penetration resistance and carbonization depth of the concrete are improved by adopting a double-doping (slag ash and fly ash) or triple-doping (fly ash, slag ash and silica fume) mode, and the concrete is excellent in freezing resistance, wear resistance and permeability resistance.

The utility model relates to river sand production equipment technical field especially is a kind of river sand cleaning dewatering screening device, including screening bucket support assembly, screening bucket subassembly and dehydration drying assembly, in the utility model, by the rotating gas delivery shaft, stirring rod, air heater, gas delivery disc, exhaust box and exhaust nozzle being set, the device can make screening bucket body vibrate by vibration motor, river sand is stirred by stirring rod, air is heated by air heater simultaneously, hot air is shunted by gas delivery disc and rotating gas delivery shaft, hot air is discharged by exhaust box and exhaust nozzle, river sand is dried and dewatered by the hot air of circulating flow, both can make river sand that is agglomerated due to dampness fast dry, improve the speed of river sand screening, also can make the river sand that originally is accumulated together to dry is dispersed to different screen plate and is constantly turned over, improve the speed of drying and dewatering, this mode is shorter in time, and efficiency is higher.

The application relates to the technical field of building materials, in particular to a full-recycled coarse aggregate and fiber composite impact-resistant concrete and a preparation process, which comprises the following components: cement 389-393 parts, river sand 785-793 parts, recycled concrete aggregate 1085-1095 parts, water reducing agent 5.863-5.867 parts, nylon fiber 1.13-1.19 parts, steel fiber 31.1-31.7 parts and tap water 160-200 parts. The full-recycled coarse aggregate is combined with the nylon fiber and the steel fiber in a specific proportion, and the dosage of the cementing material, the aggregate and the water reducing agent is optimized, so that the building solid waste is recycled, the consumption of the natural aggregate is reduced, the integrity and the toughness of the recycled concrete matrix are improved, the generation and the expansion of the micro cracks under the impact load are effectively inhibited, the defects of the traditional recycled concrete, such as the brittleness and the insufficient impact resistance, are improved, and the concrete has better compressive resistance, tensile resistance and impact resistance mechanical properties.

The invention belongs to the technical field of concrete, and particularly relates to plastic waste concrete and a preparation method thereof. The preparation method comprises the following steps: mixing and stirring the cement, the fine aggregate, the coarse aggregate, the additive and the water to obtain a mixture; the fine aggregate comprises plastic waste and river sand; the mixture is compressed and poured, and the plastic waste concrete is obtained. The compactness of the plastic waste (PW) concrete is enhanced through a compression pouring technology, the porosity is reduced, the microstructure of the concrete is densified, the combination of cement and PW is enhanced, the mechanical property of the concrete can be effectively improved, and the compressive strength and the splitting tensile strength are high. The whole preparation process follows a traditional concrete stirring procedure, and no chemical reagent or mineral admixture needs to be added. The invention not only provides a sustainable scheme for solving the problem of river sand shortage, but also deals with the challenge of plastic waste management.

The invention relates to the technical field of cement-based material preparation, and particularly discloses a process for modifying blast furnace slag aggregate and an early-strength low-shrinkage cement stabilized macadam mixture. The process comprises the following steps: (1) quenching slag particles discharged from a smelting furnace to room temperature to obtain pretreated slag particles; and (2) reheating the pretreated slag particles for temperature return treatment, then quickly cooling to a set temperature, and then slowly cooling to room temperature to obtain the modified blast furnace slag aggregate. The cement stabilized macadam mixture comprises ordinary Portland cement, sulphoaluminate cement, modified blast furnace slag aggregate, granulated blast furnace slag powder, fluorgypsum powder, carbide slag powder, river sand, a water reducing agent, fibers, nano MgO and mixing water. According to the invention, not only are the strength, hardness and stability of the blast furnace slag improved, but also the problem of mechanical property degradation caused by internal shrinkage and cracking of the cement stabilized macadam mixture is effectively relieved.

The present application relates to the technical field of building materials, and particularly relates to a polymer modified silica sand, a preparation method and application thereof.The polymer modified silica sand provided by the present application comprises, by mass fraction, polymer emulsion 2-8 parts, water-soluble resin solution 0.2-2 parts, coupling agent 0.1-0.3 parts and machine-made sand 90-97 parts.The polymer modified silica sand provided by the present application replaces river sand with machine-made sand, and directly coats the polymer emulsion on the surface of sand particles, thereby omitting the spray drying step of traditional redispersible emulsion powder, simplifying the production process of downstream ceramic tile glue, reducing the raw material cost, fundamentally solving the problem of uneven dispersion of emulsion powder in the traditional process, ensuring the stability of the performance of the final product through the prefabrication of uniform polymer film, and significantly improving the bonding strength of the ceramic tile glue after no treatment, water treatment and heat treatment.

The invention provides a geopolymer mortar-based fireproof protective layer of a concrete filled steel tubular column and a construction method. The fireproof protective layer sequentially comprises a galling material layer, a geopolymer mortar layer and a wire mesh reinforcing layer embedded in the geopolymer mortar layer from inside to outside, wherein the geopolymer mortar is prepared from the following raw materials in parts by weight: 30 to 35 parts of sodium hydroxide, 200 to 210 parts of water glass solution, 1490 to 1510 parts of blast furnace slag, 1490 to 1510 parts of fly ash, 90 to 450 parts of silica fume, 4490 to 4510 parts of natural river sand, 5 to 8 parts of polypropylene fiber and 1080 to 1140 parts of water. According to the geopolymer-based fireproof protective layer, the fire endurance of the concrete-filled steel tubular column can be remarkably improved, and the fire endurance of the concrete-filled steel tubular column can reach 3-4 hours or above; and the compressive strength of the geopolymer mortar at high temperature is higher, and the fireproof protection layer based on the geopolymer mortar can bear a part of vertical load in a fire disaster, so that the fireproof effect is better.

The invention discloses PVA fiber reinforced Yellow River sediment geopolymer concrete as well as a preparation method and application thereof, and belongs to the technical field of concrete. According to the concrete, fly ash and slag powder are used as precursors, an alkali activator is used for excitation, Yellow River silt is used for replacing 10-40% of natural river sand to serve as fine aggregate, and PVA fibers with the volume fraction being 0.2-0.8% are doped for reinforcement and toughening. The water-glue ratio is 0.45, the bone-glue ratio is 3.0, and the sand ratio is 40%. The preparation method comprises the steps of alkali activator preparation, dry mixing, wet mixing, fiber dispersion, forming and curing. The material can be applied to hydraulic engineering, building structures and road engineering, and has the advantages of excellent mechanical properties, low carbon, environmental protection, resource utilization of Yellow River silt and the like.

The invention relates to a molten steel denitrification agent for steelmaking, and a manufacturing method and application thereof. The denitrification agent comprises the following components in percentage by mass: 20-50% of Si3N4; mn3N2: 10%-30%; 10% to 20% of CaO; 10%-20% of carbon powder; 5% to 10% of SiO2; 5% to 10% of B2O3; 2%-5% of a binder and the balance of an inert filler, and the binder is bentonite; the inert filler is river sand or emery powder. The preparation method of the denitrification agent comprises the steps of raw material pretreatment, raw material mixing, forming, drying and roasting. The prepared denitrification agent is used for iron and steel smelting, the denitrification agent is added at the last stage of smelting, the denitrification agent is rapidly molten and emulsified and separated to form tiny liquid drops to be dispersed in molten steel, it is guaranteed that the denitrification reaction is smoothly conducted, and the denitrification rate can reach 80% or above.