3397 results about "Crack resistance" patented technology

The invention relates to the technical field of anti-cracking performance testing, in particular to an ultra-high performance concrete anti-cracking performance testing system and a dynamic monitoring method thereof.The system comprises a dynamic stress field simulation feedback module used for sensing three-dimensional distribution of a micro stress field in concrete in real time by constructing a flexible loading array to obtain dynamic stress field data; the multi-scale damage evolution tracking module is used for deploying a high-resolution acoustic emission network and a distributed optical fiber sensing layer based on dynamic stress field data of the flexible loading array to form a full-scale evolution graph from microdefects to macroscopic cracks; and the intelligent healing efficiency evaluation module obtains stress redistribution data and a full-scale evolution graph, and a repairing medium containing a tracer agent is injected into a preset crack path. According to the method, the whole process of crack resistance of the material from defect initiation to repair and regeneration can be quantitatively evaluated; and finally, outputting a dynamic evolution rule of the crack resistance and enhancing potential evaluation.

The invention relates to the technical field of concrete performance simulation, in particular to a concrete crack resistance simulation monitoring method, device and equipment and a storage medium. The method comprises the following steps: acquiring a plurality of groups of internal microstructure images; carrying out different component region segmentation on the plurality of groups of internal microstructure images, and carrying out mechanism structure quantitative analysis to generate mechanism structure parameters of different regions; real-time environmental parameter monitoring is carried out on to-be-monitored concrete based on the multiple sensor nodes, and concrete environmental sensing parameters are obtained; performing environmental stress load excavation on the concrete environmental perception parameters to generate concrete environmental stress load characteristics; and performing multi-frequency filtering noise reduction on the internal three-dimensional microstructure image based on the mechanism structure parameters of different regions, performing regional structure three-dimensional point cloud modeling, and constructing a concrete three-dimensional point cloud model. According to the invention, high-precision and high-efficiency simulation of the crack resistance of the concrete is realized.

The invention relates to the technical field of concrete wall materials, and discloses a recycled concrete wall material and a preparation method thereof, the recycled concrete wall material comprises the following components by weight: 300-500 parts of recycled coarse aggregate, 200-400 parts of recycled fine aggregate, 150-300 parts of cement, 30-80 parts of fly ash, 3-8 parts of a water reducer, 5-15 parts of reinforced fiber, and 20-30 parts of a modified composition. Comprising the following steps: S1, raw material pretreatment, S2, mixing and stirring, S3, molding and curing, and S4, quality detection. The building waste is efficiently utilized, exploitation of natural aggregate is reduced, energy consumption and carbon emission in the production process are reduced, the landfill amount of the building waste and land occupation are reduced, the material strength and durability are good, the waterproof performance is improved, and the crack resistance and seismic resistance of the wall are enhanced.

The invention relates to the field of concrete, and provides high-strength concrete and a preparation method thereof, and the high-strength concrete comprises modified basalt chopped fiber, a self-repairing agent, cement, fly ash, slag powder, coarse aggregate, natural sand, a water reducing agent and an air entraining agent. The modified basalt chopped fiber is oxidized by hydrogen peroxide, etched by hydrochloric acid and modified by a nano silicon dioxide coating, so that the interface bonding force is enhanced. The self-repairing agent is prepared by adopting expanded perlite to load bacillus through thallus culture, purification, dipping adsorption and low-temperature vacuum drying, CaCO3 deposition can be induced at concrete cracks, and self-repairing is achieved. The invention further provides a preparation method of the concrete. The preparation method comprises the steps of aggregate screening, hydrated liquid preparation, wet mixing, fiber and self-repairing agent adding, vibration forming and curing. The crack resistance of the concrete is improved by enhancing the fiber-matrix interface bonding force, meanwhile, the service life of the concrete is prolonged by utilizing a biological self-repairing technology, and the concrete is suitable for high-durability concrete engineering.

The invention discloses fiber-reinforced anti-crack concrete and a preparation method thereof, and relates to the technical field of building materials, the fiber-reinforced anti-crack concrete comprises the following raw material components: 310-450 parts of cement, 150-190 parts of water, 930-1200 parts of coarse aggregate, 630-800 parts of fine aggregate, 80-180 parts of mineral active admixture, 1.2-18 parts of multi-element composite fiber, 1.8-4.5 parts of polycarboxylic acid water reducer, and 20-35 parts of anti-crack synergistic system. Through a quaternary fiber system, a three-dimensional interlocking net-shaped crack-resistant framework is formed in concrete slurry, the problems that the single fiber reinforcement effect is limited, and the interface bonding force with a concrete matrix is insufficient are solved, and the crack resistance and the mechanical property of the concrete are improved.

The invention provides anti-cracking and anti-seepage high-performance concrete, which relates to the technical field of concrete and comprises Portland cement, aggregate, a high-activity mineral admixture, a calcium-magnesium composite expanding agent, nano silicon dioxide particles, a microcapsule-packaged sodium silicate and calcium lactate solution, paraffin / expanded graphite composite phase change microspheres, steel fibers, PVA fibers and nano cellulose. The self-repairing concrete has the characteristics that the anti-cracking performance is comprehensively improved, the anti-seepage grade is broken through, the self-repairing capability is long-acting, the construction adaptability is enhanced, and the like.

The invention discloses an anti-cracking reverse design method for early-age concrete. Comprising the following steps: acquiring material performance parameters; constructing a chemical-thermal-force-phase field damage model of the early-age concrete; constructing a constitutive relationship between early-age behaviors and stress-strain of the concrete; carrying out shrinkage cracking simulation calculation on the early-age concrete, and quantitatively evaluating the damage cracking risk of the early-age concrete by using a damage development index Idd. And performing crack resistance optimization design on the early-age performance of the concrete by using an orthogonal design method to obtain a crack resistance optimization result in the performance combination and development process of the concrete. According to the method, the damage development index peak value is taken as a control target, the shrinkage cracking risk of the early-age concrete structure under different material properties, development processes, constraints and curing temperatures can be quantitatively evaluated, the optimal design of the concrete mix proportion is guided, a large amount of test exploration is avoided, the manpower and material resource cost is reduced, and the method is suitable for large-scale popularization and application. The method has important significance on early crack control of a concrete structure and has remarkable progress.

The invention discloses a low-temperature-resistant heat-insulating composite material and a preparation method thereof, and relates to the technical field of composite materials, and the material comprises an outer protective layer, a middle reinforcing layer and an inner heat insulating layer. The inner heat insulation layer is composed of aerogel, polytetrafluoroethylene micro powder and the like, and good heat insulation performance is provided. The middle reinforcing layer contains ethylene-propylene rubber and the like, so that the material is endowed with elasticity, mechanical strength and flame retardance. And the outer protective layer is made of PVC resin and the like, so that the overall strength and wear resistance are enhanced. The low-temperature-resistant anti-cracking additive is prepared from polyimide resin and the like, so that the anti-cracking performance is improved. The modified filler is prepared through a specific method, and the material performance is improved. During preparation, all the layers are prepared respectively and then subjected to hot-pressing compounding. The internal mixer control system guarantees preparation parameter control of the middle enhancement layer, and a PID control algorithm is adopted. The composite material has the advantages of reasonable structural design, synergistic effect of all layers, mature preparation method and process, excellent performances of low temperature resistance, heat insulation, cracking resistance and the like, and is suitable for being applied to various low-temperature environments.

The invention provides a thermal protection coating as well as a preparation method and application thereof. The thermal protection coating comprises a NiCoCrAlY first bonding layer, a NiCoCrAlY second bonding layer, a CeYSZ first ceramic layer and a GdYbYSZ second ceramic layer which are sequentially arranged on the surface of a base material, and the second NiCoCrAlY bonding layer is made of CeO2 (CeO2) and Al2O3 (Al2O3). According to the invention, a thermal protection coating structure with double bonding layers and double ceramic layers is constructed on the surface of the base material, and CeO2 and Al2O3 nano-particle reinforced phases are introduced, so that the use temperature of the thermal protection coating is increased, and the thermal strain tolerance, the crack resistance and the oxidation resistance are greatly improved.

The invention provides a robot joint dynamic cable made of a self-repairing polyurethane material and a preparation method of the robot joint dynamic cable, and belongs to the field of cables. Polytetrahydrofuran glycol and hexamethylene diisocyanate react to form a soft and hard segment structure, 1, 4-butanediol is added for chain extension, dopamine hydrochloride is introduced, the hard segment structure is enhanced, and a self-repairing hydrogen bond network is formed; carbon nanotubes are introduced, and through plasma treatment and silane coupling agent modification, the tensile resistance, fatigue resistance and electrical properties of the material are improved; montmorillonite is compounded with polyethyleneimine through organic treatment, so that the cracking resistance and wear resistance of the material are enhanced; epoxy groups are introduced to the surface of boron nitride, and dopamine hydrochloride is self-polymerized, so that excellent heat dissipation capability and dimensional stability are provided. Through the synergistic effect of the components, the composite material has excellent mechanical properties, electrical properties, heat dissipation, wear resistance and the like, is especially suitable for a dynamic cable of a robot, and can stably work in a complex environment for a long time.

The invention discloses a quality inspection test device for an automobile casting material, and belongs to the technical field of test devices, the quality inspection test device comprises a conveying disc playing a conveying role and a driving motor which is arranged below the conveying disc and plays an intermittent driving role on the conveying disc, the top end of the conveying disc is provided with a plurality of rotary mounting ports which are distributed circumferentially, and the rotary mounting ports are connected with the driving motor. An annular mounting frame used for placing a brake disc to be tested is rotatably arranged in the rotary mounting port, and a clamping mechanism used for clamping the brake disc to be tested is arranged on the inner side of the annular mounting frame. Through the arrangement of the detection needle, the heating ring, the positive electrode power connection sliding rail and the negative electrode power connection sliding rail, the high temperature generated by friction in the actual use process of the brake disc material can be simulated, and the detection needle is used for detecting whether deformation or cracks exist on the surface of the heated brake disc material to be detected or not; the influence of high temperature on the deformation resistance and cracking resistance of the brake disc material is automatically explored, and it is ensured that the brake disc material after high-temperature operation does not deform or crack.

The invention provides a tear-resistant, wear-resistant, low-smoke and non-dripping sheath material as well as a preparation method and application thereof. The tear-resistant wear-resistant low-smoke non-dripping sheath material is prepared from the following components in parts by weight: 25 to 35 parts of metallocene linear low-density polyethylene, 10 to 15 parts of ethylene-vinyl acetate copolymer, 6 to 8 parts of compatilizer, 50 to 60 parts of aluminum hydroxide, 10 to 15 parts of magnesium hydroxide, 3 to 4 parts of microencapsulated red phosphorus, 5 to 8 parts of lithium oxide synergist, 4 to 6 parts of silicone master batch, 0.3 to 0.7 part of carbon black master batch and 1.5 to 2.5 parts of coupling agent. The tear-resistant wear-resistant low-smoke non-dripping sheath material provided by the invention has the characteristics of being halogen-free, flame-retardant, tear-resistant and wear-resistant, and a low-smoke halogen-free flame-retardant power cable prepared from the sheath material has the characteristics of high smoke light transmittance during combustion, no dripping and cracking resistance.

The invention discloses a mass concrete composite anti-crack structure and a crack control construction method based on the mass concrete composite anti-crack structure. The composite anti-crack structure comprises a core common concrete layer, an outer side anti-crack concrete layer, a reinforcing mesh arranged between the core common concrete layer and the outer side anti-crack concrete layer, and a top anti-crack concrete layer. The method comprises the steps that firstly, the thickness of side face anti-crack concrete and the thickness of top face anti-crack concrete needing to be poured are calculated according to cracking risk assessment, the side face anti-crack concrete is poured firstly, then core common concrete is poured, and it is ensured that the pouring height of the side face concrete is always 20-30 cm higher than the core common concrete; and then the top surface is completely constructed by adopting anti-crack concrete. The reinforcing mesh subjected to special treatment is adopted, so that the overall stress of the composite structure is uniform, the overall anti-cracking performance and durability of the composite structure are improved through the outer side anti-cracking concrete, the construction technology is simple, meanwhile, a large amount of construction cost and operation and maintenance cost can be saved, and the composite structure is suitable for application and popularization.

The invention relates to the technical field of concrete preparation, in particular to fiber-reinforced building solid waste recycled aggregate concrete and a preparation method thereof.The preparation method comprises the following preparation steps that S1, recycled coarse aggregate, slag, fly ash and river sand are mixed and stirred according to the proportion, and a cement mixture is obtained; s2, calcining the cement mixture for 2-3 hours to obtain cement clinker; s3, cement clinker, modified fibers, modified graphene oxide and tetrasodium iminodisuccinate are mixed according to the proportion and then poured into a stirrer to be stirred for 5-6 min; and S4, adding water into the stirrer according to the proportion, continuously stirring for 6-10 minutes, and taking out to obtain the fiber-reinforced building solid waste recycled aggregate concrete. According to the invention, the polystyrene fiber and the concrete are connected more tightly by using the modified fiber, and the polystyrene fiber can be subjected to multiple reactions with components in the concrete in an alkaline environment of the concrete to form a stable network structure, so that mechanical indexes such as crack resistance and breaking strength of the concrete are improved.

The invention provides a modified lithium sulfide solid electrolyte, a sulfide solid electrolyte, a preparation method thereof and a battery, and relates to the technical field of solid electrolyte materials. The preparation method of the sulfide solid electrolyte is different from a traditional doping technology, the high-stability sulfide solid electrolyte is prepared mainly through modification of lithium sulfide, the comprehensive performance of the sulfide solid electrolyte is improved, the ionic conductivity and chemical stability of the sulfide solid electrolyte are improved, and the service life of the sulfide solid electrolyte is prolonged. And the mechanical strength and the crack resistance are also obviously enhanced. The preparation method disclosed by the invention is simple, does not need to be carried out at high temperature, and does not need to use expensive raw materials and complex processes, so that the production cost is reduced, the application range of the sulfide solid electrolyte is expanded, and large-scale production and application of the sulfide solid electrolyte are favorably realized.

The invention relates to a preparation method of a geopolymer composite material based on modified fiber, which comprises the following steps: S1, fiber pretreatment: the fiber is one of basalt fiber and polyformaldehyde fiber; s2, performing surface roughening treatment on the fibers through a polyvinyl alcohol modified impregnating compound to obtain roughened fibers; s3, the roughened fibers are subjected to surface functional modification treatment through a functional modified impregnating compound, and functional modified fibers are prepared; s4, uniformly mixing the powder and an expanding agent according to a mass ratio, and adding an alkali activator solution and the functional modified fibers to prepare a geopolymer gel material; s5, the geopolymer gel material is subjected to stirring, mold filling, steam curing forming, demolding and continuous curing, and the geopolymer composite material based on the modified fiber is obtained.According to the preparation method, the geopolymer composite material with high strength and excellent crack resistance and toughness is obtained through alkali excitation, and the problems that geopolymers are low in toughness and large in brittleness are effectively solved.

The invention provides an aerogel-based heat-preservation, heat-insulation and waterproof composite coating material for a building outer wall and a preparation method thereof, and belongs to the field of building materials. Through hydrophobic modified silicon dioxide aerogel, a lightweight heat insulation frame is provided, and the waterproofness and compatibility are improved; the mechanical property and the crack resistance are enhanced through the modified potassium titanate nanofibers, and self-adaptive heat insulation is achieved; the thermoelectric effect, the wear resistance and the thermal regulation performance are optimized through plasma treatment and polyaniline coated tungsten carbide nanoparticles; the heat management performance, the crack resistance and the comprehensive heat insulation and waterproof capacity are improved through graphene oxide composite modified boron nitride; the flexibility, the hydrophobicity and the interfacial compatibility are improved through organic silicon modified bisphenol A epoxy resin; and the performance of the coating is optimized through the synergistic effect of the components.

The invention relates to a high-performance polymer-cement-based composite repair material and a preparation method thereof, and the high-performance polymer-cement-based composite repair material comprises the following components by mass: 690-710 parts of cement; 130 to 150 parts of fly ash; 45 to 55 parts of silica fume; 200 to 210 parts of mixing water; 950 to 1050 parts of fine aggregate; 21-23 parts of a modified polymer; 9-10 parts of an expanding agent; 4-5 parts of a water reducing agent; 5-6 parts of modified fiber; and 0.16 to 0.18 part of a defoaming agent. The nano-toughened modified polymer and the modified fiber are used, the nano-modified polymer can improve the microstructure of the repair material, the modified fiber can limit shrinkage of the repair material and enhance the crack resistance of a matrix, the toughness and the mechanical property of the repair material can be effectively improved through the synergistic effect of the nano-modified polymer and the modified fiber, and it is guaranteed that the repair material does not crack in the early stage.

The invention further discloses a preparation method of the wide-temperature-range, high-performance and high-binding-force soft and hard composite coating. The preparation method comprises the steps of cleaning, ion implantation, preparation of a soft layer metal Ti, preparation of a hard layer TiZrAlCrSiMN, preparation of a soft layer metal Zr and preparation of the hard layer TiZrAlCrSiMN. The invention further discloses application of the wide-temperature-range, high-performance and high-binding-force soft and hard composite coating in a dry cutting tool. The invention discloses the wide-temperature-range high-performance high-binding-force soft and hard composite coating which is prepared through the preparation method, and the wide-temperature-range high-performance high-binding-force soft and hard composite coating solves the problems that an existing tool coating is low in high-temperature hardness, poor in abrasion resistance and poor in erosion resistance and cracking resistance.

The invention provides steam-cured alkali-activated fly ash concrete and a preparation method thereof. The steam-cured alkali-activated fly ash concrete is prepared from the following components in parts by mass: 30 to 40 parts of fly ash, 10 to 15 parts of slag, 10 to 20 parts of water glass, 60 to 80 parts of fine aggregate, 110 to 140 parts of coarse aggregate, 2 to 6 parts of water, 1 to 3 parts of nano SiO2 and 0.1 to 0.5 part of basalt fiber. The content of alkali in the water glass is 8.5-9.5%, and the modulus of the water glass is adjusted to 1.3-1.5 by using sodium hydroxide; the mass ratio of short fibers with the length of 6-12mm to long fibers with the length of 12-24mm in the basalt fibers is (0.5-2): 1. The alkali content, the water glass modulus and steam curing parameters are optimized, and meanwhile, nano SiO2 and basalt fibers are added for synergistic enhancement, so that the concrete has good crack resistance and compressive strength.

The present invention proposes an intermediate diaphragm-free, suspended formwork-free, and negative moment tooth block-free beam bridge, and a design method thereof. The beam bridge includes prefabricated main girders, a wet joint, lower structures, and pier cap transverse beams above the lower structures. The concrete deck slabs of adjacent prefabricated main girders are connected by the wet joint. The design method of the above beam bridge includes the following steps: S1, initial design of the main girders; S2, calculation of the non-uniform deflection of the main girders and the indirect transverse stress of the deck slabs; S3, calculation of the direct transverse stress of the deck slabs; S4, crack resistance verification of the deck slab; S5, optimization of bridge parameters to reduce the stress on the driving surface; S6, completion of the beam bridge design. The beam bridge and its design method effectively solve the problem that the existing intermediate diaphragm-free beam bridge is prone to longitudinal cracking at the joints, and realize the suspension tension without the wet joint suspended formwork of the deck slab and the negative bending moment tendon, and have better mechanical properties and better economic, environmental and social benefits, which can facilitate the promotion and application of such bridges in various types of highways , railways and municipal engineering.

The invention provides a laser welding method for tailor-welding hot forming steel with the tensile strength exceeding 1500 Mpa after hot forming before hot forming, and particularly relates to a method capable of avoiding cracking of a heat affected zone after welding. The hardness distribution of a heat affected zone is controlled during laser welding cooling, so that the hardness of the heat affected zone after welding does not exceed the highest hardness of a weld joint melting zone, and the highest hardness value does not exceed H / 3-20 HV; (H is the tensile strength of the material obtained after thermal forming); the minimum width of the heat affected zone is not less than 0.2 m; the method specifically comprises the steps that energy distribution of a laser welding heat source is controlled in the welding process, a laser beam forms a flat-top light source on the surface of a workpiece, a welding pool is formed when the light source irradiates the workpiece for welding, the welding pool has the length L and the width B, and L / B is larger than or equal to 3. A welded joint obtained through the laser welding method has excellent post-welding cracking resistance for welding of high-strength steel with the tensile strength exceeding 1500 Mpa after thermal forming.

The invention relates to the field of coating performance testing, in particular to a real stone paint coating performance detection device which comprises a box body, a supporting rod, a clamping mechanism, an overturning mechanism, a box cover, a testing mechanism and a flushing mechanism. The clamping mechanism, the testing mechanism, the overturning mechanism and the flushing mechanism are matched with one another, so that the anti-cracking performance test, the stain resistance test and the scratch resistance test can be carried out on the real stone paint coating, the test cost is reduced, and the tests are carried out in a closed space formed by the box body and the box cover; according to the utility model, the left side of the closed space formed in the box body and the box cover is respectively provided with the refrigerating device, the heating device and the temperature sensor, so that the temperature of the closed space is increased; the two parts cooperate with each other to test the freeze-thaw performance of the stone-like coating on the left side of the closed space, another stone-like coating playing a contrast role is clamped on the right side of the closed space, and a freeze-thaw performance test result can be compared and observed.

The invention discloses low-alloy NM600-grade wear-resistant steel and a preparation method thereof. The preparation method comprises the following steps: KR desulfurization and smelting treatment; refining and continuous casting treatment; heating and hot rolling treatment; slow cooling and cutting treatment; quenching and tempering treatment; the low-alloy NM600 wear-resistant steel with the hardness of 570-630 HBW is prepared through performance regulation and control treatment, a base body of the low-alloy NM600 wear-resistant steel is nanoscale martensite, and nanoscale precipitated phases and high-density dislocation clusters are distributed in martensite laths. By optimizing chemical components and strictly controlling smelting and heat treatment processes, the wear-resistant steel has excellent wear resistance. Refining of a martensite phase and uniform distribution of a precipitated phase are achieved, and the abrasion resistance and the crack resistance of the steel are further improved. By introducing trace elements such as Nb, Ti and the like, nanoscale precipitated phases such as (NbxTiy) C, NbC, TiC and the like are formed in martensite laths, so that the strength, hardness and wear resistance of the material are greatly improved, and the service life of the steel is prolonged.

The invention relates to the field of building material preparation, in particular to a high-strength concrete material and a preparation method thereof.According to the high-strength concrete material, through the synergistic effect of core-shell type temperature-sensitive resin particles, a pH response type expanding agent and industrial solid waste composite micro powder, multi-environment self-adaptive crack resistance and mechanical property breakthrough are achieved. The core component is prepared from 180 to 240 parts of cement, industrial solid waste composite micro powder (30 to 50 parts of fly ash-based nano SiO2 and 50 to 70 parts of steel slag micro powder), 10 to 15 parts of core-shell resin particles and 8 to 12 parts of pH response type expanding agent. According to the preparation process, multi-section intelligent stirring (ultra-high-speed shearing and dispersing of the nanometer material) and dynamic maintenance of the internet of things are adopted, the hydration process is precisely regulated and controlled, and the finally prepared material has excellent compressive strength and anti-cracking performance. The method is suitable for severe scenes such as ocean engineering and plateau buildings, and has wide application prospects.

The invention relates to the technical field of building materials, in particular to anti-crack mass concrete and a preparation method thereof, and the concrete is prepared from a gelling system, composite aggregate, a gradient functional additive and water according to a specific ratio. The preparation method is achieved through premixing, gradient stirring and gradient temperature control curing, the three-stage expansion effect of the compound expanding agent is utilized to be matched with the concrete shrinkage process, the hydration heat inhibitor is combined for reducing the temperature peak, basalt fiber is used for reinforcing, and the cracking risk is quantitatively evaluated, so that the 28-day restrained expansion rate of the concrete reaches 0.012% or above, the cracking risk coefficient is smaller than or equal to 0.7, and the concrete has the good crack resistance. The hydration heat peak value is reduced to 48 DEG C or below, and the cement is suitable for engineering of ultra-long structures, large-volume side walls and the like, has no harmful cracks within one year or above, has crack resistance and mechanical properties, and is wide in application prospect.

An austenitic stainless steel material is provided that has high creep strength even when used at an average operation temperature of more than 600 to 750° C. after welding with higher heat input, and furthermore, has excellent stress relaxation cracking resistance even after use for a long time period at the average operation temperature after welding with higher heat input. The steel material has a chemical composition which consists of, in mass %, C: 0.030% or less, Si: 1.50% or less, Mn: 2.00% or less, P: 0.045% or less, S: 0.0300% or less, Cr: 15.00 to 25.00%, Ni: 8.00 to 20.00%, N: 0.050 to 0.250%, Nb: 0.10 to 1.00%, Mo: 0.05 to 5.00%, and B: 0.0005 to 0.0100%, with the balance being Fe and impurities, and a ratio of the dissolved N amount (mass %) with respect to the content of N (mass %) in the steel material is 0.40 to 0.90.

The utility model discloses an anti-crack type multi-layer composite cement blanket, belongs to the technical field of building materials, and is particularly suitable for the construction field with higher waterproof requirements. The cement blanket sequentially comprises a top layer fabric, a water storage and moisture preservation layer, a heat preservation layer, a micro-expansive cement layer, a bottom layer fabric and an anti-skid layer from top to bottom. Wherein steel wire meshes are arranged between the micro-expansive cement layer and the heat preservation layer as well as between the micro-expansive cement layer and the bottom layer fabric, and a fiber reinforced layer is laid in the micro-expansive cement layer, so that the brittleness of hardened set cement can be effectively reduced; meanwhile, chemical energy released by hydration of the micro-expansive cement layer can be converted into mechanical energy, so that the hardened cement body generates self volume expansion, the cracking risk is reduced, the waterproof service life of the cement blanket is prolonged, a structural layer and a waterproof layer of the cement blanket are combined into a whole, and the production process is simplified; meanwhile, the fiber reinforced layer and the steel wire mesh layer are arranged on the cement blanket, so that the brittleness of hardened set cement is further reduced, and the crack resistance is enhanced.

The invention provides a nano modified composite cementing material, which relates to the technical field of cementing materials, and comprises the following components: slag, construction waste powder, a nano material, an alkali activator and water. By introducing the nano material, the pore structure of the solid waste-based material is remarkably improved, and the gelling capacity, mechanical property and durability of the solid waste-based material are improved. Meanwhile, the material also has relatively strong crack resistance, and the photocatalytic performance and the self-cleaning function of the material can be improved by introducing a functional nano material.

The invention provides a coating for casting an alloy steel lost foam as well as a preparation method and application of the coating. The coating comprises the following raw materials in parts by weight: 79-89 parts of aggregate, 3-7 parts of a binder, 4-7 parts of a suspending agent, 1.5-3 parts of a surfactant, 1.5-2.5 parts of a defoaming agent and 1-1.5 parts of a preservative, the aggregate is prepared from the following components in percentage by mass: 78 to 82 weight percent of bauxite, 12 to 15 weight percent of mica and 3 to 10 weight percent of quartz powder; the binder is prepared from the following components in percentage by mass: 42 to 50 weight percent of anhydrous aluminum dihydrogen phosphate, 18 to 25 weight percent of white carbon black, 12 to 17 weight percent of ethylene glycol and 8 to 28 weight percent of magnesium oxide; the coating for casting the alloy steel evanescent mode keeps good suspension property, high-temperature air permeability, coating property, high-temperature crack resistance and shedding property of the coating, the surface of a casting is smooth and free of burnt-on sand, less harmful gas is volatilized during firing, and harmful gas generated by burning of a white mold can be absorbed.