93 results about "Shrinkage cracking" patented technology

The invention discloses an all-solid-waste cementing material stabilized macadam base mixture which is prepared from the following raw materials in parts by weight: 4-6 parts of an all-solid-waste cementing material, 0-6 parts of wet-discharged fly ash, 0-20 parts of silicon-manganese slag, 10-20 parts of steel slag, 52-65 parts of macadam and 4-6 parts of water. The moisture content of the wet discharged fly ash is 8-12%. According to the all-solid waste cementing material stabilized macadam base mixture provided by the invention, the characteristics of low heat, micro-expansion and relatively high water demand of the all-solid waste cementing material can be utilized, agglomeration of wet-discharged fly ash is reduced, and the uniformity of the water stabilized base mixture is improved, so that the hydration heat is reduced, the risk of quick setting and shrinkage cracking is reduced, meanwhile, the solid waste utilization rate is increased, and the production cost is reduced. And the production cost and the carbon emission are reduced.

According to the low-temperature high-durability magnesium phosphate cement and the preparation method thereof, dead burned magnesia powder serves as a core gelling base material and can provide a large amount of active Mg < 2 + >, ammonium dihydrogen phosphate can provide an acid environment and PO4 < 3->, the dead burned magnesia powder and the ammonium dihydrogen phosphate are subjected to an acid-base neutralization reaction in the presence of water to generate ammonium magnesium phosphate hydration products, and the magnesium phosphate hydration products are subjected to a low-temperature high-durability magnesium phosphate cement. The products are interwoven to form a hardened body framework, and a strength foundation is laid for cement; borax is adopted as a key retarder, borate ions generated after the borax is dissolved in water can be adsorbed on the surfaces of dead burned magnesia powder particles, a magnesium borate complex film is formed, the dissolution of Mg < 2 + > and the reaction of PO4 < 3-> are hindered, the cement setting time is effectively delayed, and the construction requirements are met; and the borax can also refine the crystal structure of a hydration product, reduce the porosity, improve the impermeability and the volume stability of a hardened body, and avoid shrinkage cracking.

The invention belongs to the technical field of high-speed railway ballastless track construction, and particularly discloses an anti-crack functional material for ballastless track roadbed slab concrete and a preparation method of the anti-crack functional material. The anti-cracking functional material provides a whole-course expansion effect and delays early expansion by means of a mode of coating calcium oxide with calcium carbonate and compounding magnesium oxide; the protein modified starch is used as a hydration heat regulation and control layer, so that the regulation and control effect of single starch on cement hydration heat is improved, and a compound expanding agent is slowly released; carbonized and expanded rice husks are used as a biomass water-absorbing and anti-releasing material, so that the self-shrinkage and drying shrinkage of the concrete are reduced; the temperature-sensitive microgel material is used as the outermost layer component, the highest temperature value of the roadbed slab concrete is reduced, the temperature drop shrinkage stress of the concrete is improved, and the temperature shrinkage cracking risk of the roadbed slab concrete is inhibited. Various shrinkage stresses of the roadbed slab are accurately regulated and controlled, the limiting and restraining stress of the prefabricated sleeper and the base on the concrete of the roadbed slab is effectively compensated and improved, and the anti-cracking performance of the concrete of the ballastless track roadbed slab is fundamentally improved.

The method comprises the following steps: preparing an aluminum oxide nanowire precursor with a certain length-diameter ratio by a hydrothermal method, mixing the aluminum oxide nanowire precursor with silicon dioxide nano powder and ceramic fibers, filling the mixture into a honeycomb, and carrying out compression molding, curing, ethanol solvent replacement, subcritical drying and other process steps to obtain the honeycomb filled aerogel thermal insulation material. The honeycomb filled aerogel heat insulation material is successfully prepared. According to the preparation method disclosed by the invention, efficient preparation of the aerogel-filled honeycomb material with controllable filling density and excellent mechanical strength is realized by regulating and controlling a micro-nano hierarchical structure and mixed components. The aerogel is combined with the honeycomb, and the aluminum oxide nanowire cluster and the ceramic fiber are introduced as inorganic components, so that the shrinkage cracking of the aerogel at high temperature is inhibited, and the structural stability and the mechanical property of the material at high temperature are remarkably improved.

This invention provides a highly protective cement safe resistant to drilling impact, comprising an outer shell, an inner liner within the outer shell, a filling cavity formed between the outer shell and the inner liner, a concrete protective layer within the filling cavity, and a sealing cap on the top of the outer shell. The concrete protective layer, used in the safe, comprises the following components: 4200-4800 parts of hydraulic cementitious material, 1600-2200 parts of pozzolanic mineral admixture, 450-650 parts of active mineral admixture, 450-650 parts of fine inert filler, 4200-5200 parts of graded high-hardness fine aggregate, 850-900 parts of water, 70-85 parts of high-efficiency water-reducing agent, 12-20 parts of defoamer, and 1100-1300 parts of end-hooked steel fiber. The components of this invention work synergistically to effectively improve the bonding performance between concrete and the steel plate matrix, inhibit shrinkage and cracking during curing, and enhance product lifespan and structural stability.

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 invention relates to construction waste recycled aggregate concrete and a preparation method thereof, relates to the technical field of concrete, and improves the workability and durability of the concrete by reasonably proportioning a modified water reducing agent with other raw materials. Wherein the modified water reducing agent is prepared by carrying out primary esterification on maleated rosin and a monomer containing hydroxyl, then carrying out dicarboxylation on the modified water reducing agent and sulfonating the modified water reducing agent through sulfite, has a hydrophobic skeleton and carboxyl and sulfonic acid double hydrophilic groups, and can strongly adsorb cement particles, form a static electricity and steric hindrance double effect, disperse a cement binding material and release water; and workability loss and shrinkage cracking caused by high water absorption of the recycled aggregate are inhibited. The concrete prepared by the invention has the advantages of good water reducing property, good strength and difficulty in collapsing.

A solid waste-based nano-hydrated calcium silicate nucleating agent, its preparation method, and its application in low-heat cement are disclosed. This invention belongs to the field of building materials technology. By weight, it comprises the following components: 10-30 parts of carbide slag, 20-45 parts of yellow phosphorus slag, and 400-2000 parts of sodium hydroxide solution. The calcium hydroxide content in the carbide slag is ≥80%. The silicon dioxide content in the yellow phosphorus slag is ≥35%, and the calcium oxide content is ≥40%. The pH value of the sodium hydroxide solution is 11-12. This invention uses carbide slag, yellow phosphorus slag, and sodium hydroxide solution as raw materials to synthesize a solid waste-based nano-hydrated calcium silicate nucleating agent. Utilizing its nano-sized hydrated calcium silicate as a seed crystal in the early stage of hydration in low-heat cement, it can provide nucleation sites for the hydrated calcium silicate gel, a product of low-heat cement hydration, reducing the nucleation barrier of the hydrated calcium silicate gel, promoting the hydration rate and early strength development of low-heat cement, and providing strong support for the later strength development of low-heat cement, effectively improving the problem of drying shrinkage cracking in low-heat cement.

The application discloses low-shrinkage light-weight high-strength alkali-activated foam concrete and a preparation method and application thereof. The raw material composition of the foam concrete comprises 30-80 parts by weight of slag powder, 40-120 parts by weight of mineral admixture, 2-15 parts by weight of porous filler, 5-20 parts by weight of sodium-potassium water glass, 0.5-10 parts by weight of foaming agent and 0.5-5 parts by weight of anti-shrinkage agent. The anti-shrinkage agent is prepared by the following method: placing water-absorbing resin in a saturated shrinkage reducing agent solution, keeping under heating conditions, making the water-absorbing resin reach a saturated water state, and then separating the water-absorbing resin and draining the liquid to obtain the anti-shrinkage agent. The application not only reduces the self-shrinkage degree of the alkali-activated foam concrete, overcomes the shrinkage and cracking problem of the foam concrete during service, but also increases the compressive strength of the alkali-activated foam concrete.

This invention belongs to the field of industrial solid waste resource utilization technology, and relates to a circulating fluidized bed ash-based cementitious material for road base courses and its preparation method. The raw materials for the road base course cementitious material are composed of the following mass parts: 29-43 parts of circulating fluidized bed ash, 16-27 parts of ground blast furnace slag, 3-6 parts of silica fume, 7-15 parts of P.O42.5 silicate cement, 0.1-0.4 parts of activator, and 27-30 parts of water. The circulating fluidized bed ash is prepared by mixing circulating fluidized bed fly ash and slag in a mass ratio of (2-5):(5-10). This invention effectively alleviates the problems of fast setting time and shrinkage cracking of traditional road base course cementitious materials by utilizing the characteristics of micro-expansion and long hydration time of circulating fluidized bed ash. The advantage of this invention is that it promotes the large-scale utilization of circulating fluidized bed ash and contributes to carbon emission reduction in the road sector.

The present invention discloses a rapid soil salinity measurement method, belonging to the field of soil measurement. The invention involves extracting the fractal dimension characteristics of cracks on the surface of viscous salinized soil using digital image processing. By establishing a mathematical quantitative relationship model between the fractal dimension and soil salinity, crack characteristic parameters extracted from photos of soil surface shrinkage cracking obtained through a standardized field process are incorporated into the prediction model, ultimately achieving rapid, efficient, and non-destructive online measurement of the salt content of cracked salinized soil. The present invention has the advantages of a simple measurement process, low cost, low loss, low cost, strong stability, and real-time and quasi-real-time performance.

The invention relates to the technical field of solid waste material recycling, in particular to a solid waste-based geopolymer and a preparation method thereof. The solid waste-based geopolymer comprises the following components in parts by mass: 400-500 parts of fly ash; 400 to 500 parts of mineral powder; 40-60 parts of a sodium hydroxide aqueous solution; 200 to 400 parts of water; the solid content of the nano waterborne epoxy emulsion is 30-62%, the particle size of the nano waterborne epoxy emulsion is 100-900 nm, and the nano waterborne epoxy emulsion accounts for 3-9% of the total mass. According to the invention, the compactness of a matrix is enhanced, shrinkage cracking caused by water evaporation is reduced, the toughness and anti-permeability of the material are improved, the compactness of an interface is enhanced, the saltpetering condition of the matrix is inhibited, and wide application in the field of building materials is facilitated.

The invention discloses a roller compacted concrete composition adaptive to a high altitude environment and a preparation method thereof, and the roller compacted concrete composition comprises the following components in parts by mass: 60-100 parts of cement, 65-75 parts of fine aggregate, 100-120 parts of coarse aggregate, 10-20 parts of zeolite powder, 1-5 parts of dopamine hydrochloride, 5-15 parts of activated fiber, 0.2-0.4 part of aminated polystyrene microspheres, and 0.1-0.5 part of a carbodiimide cross-linking agent. And 1-2 parts of a water reducing agent. The problems of insufficient early strength, later shrinkage cracking and poor freezing resistance of concrete in a high-altitude environment are solved, a composite system of polydopamine modified zeolite and activated fibers optimizes pore distribution and a stress transfer path, the balance of early strength, crack resistance and durability is realized, and the early strength, crack resistance and durability of the concrete are improved. And a reliable concrete solution is provided for high-cold and high-altitude engineering.

The utility model discloses a seam filling and leveling anti-cracking structure for a window frame with a large rabbet and a window frame structure, and relates to the field of doors and windows. The seam filling and leveling anti-cracking structure for the window frame with the large rabbet comprises a concrete wall body with a hole and the window frame connected to the inner wall of the hole, the concrete wall body protrudes to form an inner side wall pier, and a seam with an L-shaped cross section is defined by the end face and the side face of the window frame, the concrete wall body and the inner side wall pier; the gap is filled with a light cement-based mortar leveling layer, and a waterproof layer and an outer sealing layer which extend to the side face of the window frame are sequentially arranged at the end, away from the inner side wall pier, of the light cement-based mortar leveling layer. The seam filling and leveling anti-cracking structure for the window frame with the large rabbet and the window frame structure have the advantages of being convenient to construct, high in construction efficiency and low in construction cost, and shrinkage, cracking and leakage of the seam filling position of the window frame can be avoided.

The invention discloses a curing method for inhibiting drying shrinkage cracking of cured sludge, and belongs to the technical field of crack prevention of cured sludge in geotechnical engineering. The artificial fine aggregate for inhibiting the cured sludge from drying shrinkage cracking is prepared from the following raw materials in parts by mass: 60 to 70 parts of gypsum powder, 20 to 30 parts of blast furnace slag, 2 to 10 parts of calcium carbide dust, 4 to 8 parts of cement and 0.5 to 1 part of sodium dodecyl benzene sulfonate. After the artificial fine aggregate disclosed by the invention is mixed into sludge, not only can the grading of the sludge be improved, but also the curing hydration reaction can be promoted to be continuously carried out by adsorbing free water through the porous structure, so that the dry shrinkage deformation of the cured sludge is compensated, and the dry shrinkage cracking resistance and the anti-seepage performance of the cured sludge can be improved. According to the invention, the artificial fine aggregate is prepared from a large mixing amount of industrial waste residue, and is mixed into the sludge to be cured, and the dry shrinkage deformation of the cured sludge is inhibited through grading improvement, free water adsorption, self volume expansibility and strength increase.

The invention discloses high-water-retention and anti-cracking all-solid waste sludge-based foam light-weight fluid-state soil and a preparation method thereof, and belongs to the technical field of solid waste resource utilization and civil engineering filling materials, the high-water-retention and anti-cracking all-solid waste sludge-based foam light-weight fluid-state soil comprises aggregate, an alkali-activated gelling system, a water-retention and anti-cracking agent and light-weight filler, the aggregate comprises high-water-content sludge, and the alkali-activated gelling system comprises water-retaining and anti-cracking the alkali-activated gelling system comprises fly ash, red mud, steel slag and an alkali activator, the water-retaining anti-cracking agent comprises xanthan gum, the light filler comprises foam, layered pouring is performed during construction, a foam-stabilizing anti-collapse layer is arranged between two layers of fluid-state soil, and a water-retaining anti-cracking layer is sprayed on each layer. According to the invention, the problems of large cement consumption, high carbon emission and easy dry shrinkage and cracking in the traditional foam light fluid soil are effectively solved, and the water-retaining property and the crack resistance of the material are obviously improved; meanwhile, a cement-like gel structure is formed through solid waste synergistic excitation, efficient resource utilization of the waste sludge is achieved, and the engineering cost and the environmental burden are reduced.

This invention discloses a method for improving the crack resistance of ultra-high performance concrete structures, relating to the field of concrete materials. The invention involves bonding polylactic acid (PLA) fibers and metal fibers with polyurethane adhesive to form a composite fiber. After treatment with polyurethane adhesive, the composite fiber forms a three-dimensional support network, which is alternately laid with a fine slag layer to form a gradient structure, effectively inhibiting the initiation and propagation of microcracks. The cementitious system, combined with composite admixtures, reduces the heat of hydration, and the micropores of the fine slag buffer shrinkage stress, significantly reducing shrinkage cracking. The self-healing microcapsules loaded with fine slag are uniformly dispersed, releasing a repair agent when cracks occur, rapidly healing microcracks, significantly restoring mechanical properties and impermeability, and improving durability. Furthermore, under the alkali-activated effect during the PLA fiber curing process, the fine slag can bond tightly with the composite fiber, achieving a synergistic "crack prevention-repair" effect, adapting to the construction of complex components, reducing material costs, shortening the curing cycle, and significantly reducing the total life-cycle cost.

The present application relates to the field of solidifying agent, and more particularly to a kind of composite solidifying agent for construction waste recycled material flow state solidified soil and preparation method thereof, comprising the following raw materials: sulphoaluminate cement 20-30 parts, slag powder 15-25 parts, recycled brick powder 10-15 parts, amino-terminated hyperbranched polymer 4-7 parts, silane coupling agent 2-4 parts, urease composite material 2-3 parts, urea microspheres 1-3 parts, calcium chloride 0.5-2 parts, construction waste recycled micro powder 10-18 parts, fly ash 5-10 parts.The solidifying agent solves the technical problems of weak interface in construction waste recycled material flow state solidified soil, enzyme activity easy deactivation, large strength fluctuation, serious shrinkage and cracking and the like through multi-component synergistic effect.

This invention relates to a method for preparing a silicon nitride wear-resistant coating on the surface of a graphite part. The method involves coating the graphite part with polynitrosilane, followed by drying and subsequent decoking and high-temperature ceramization treatments. The process is precisely designed as a multi-stage heating decoking and high-temperature ceramization process. By strictly controlling the heating rate and holding time, the method avoids coating shrinkage and cracking caused by rapid heating, as well as resource waste and increased internal stress caused by excessively slow heating. Simultaneously, the decoking temperature is optimized to prevent excessive decomposition and escape of polynitrosilane or residual small molecules. This effectively solves the coating cracking problem caused by the difference in thermal expansion coefficients between graphite and silicon nitride, thereby obtaining a dense, uniform, and crack-free silicon nitride coating.

The invention discloses a high-performance environment-friendly curing agent based on industrial solid waste and a nano material, which comprises the following components in parts by weight: 50-70 parts of an industrial solid waste-based cementing material, 5-15 parts of a nano reinforcing material, 3-8 parts of a bio-based dispersing agent, 10-20 parts of a composite exciting agent and 5-10 parts of a micro-expanding agent, wherein the industrial solid waste-based cementing material is a mixture of steel slag, red mud and ardealite; wherein the nano reinforcing material is formed by compounding hydrophobic nano silicon dioxide and a carbon nano tube; wherein the bio-based dispersant is a loofah sponge extract; wherein the composite exciting agent is a compound of sodium sulfate, sodium silicate and sodium gluconate; wherein the micro-expanding agent is a compound of magnesium oxide and alunite. According to the high-performance environment-friendly curing agent based on the industrial solid waste and the nano material, the compressive strength of the curing agent can be improved and the shrinkage cracking of the curing agent can be reduced while the high flowability of the fluid-state cured soil is ensured.

The invention discloses low-density alkali slag foamed concrete and a preparation method thereof, and belongs to the technical field of concrete. Comprising 100 parts of a gelling base material, 18-22 parts of a composite alkali activator, 4-7 parts of a controlled-release foaming agent, 1-2 parts of a composite foam-stabilizing anti-shrinkage agent, 0.4-0.6 part of a bonding enhancer, 0.05-0.1 part of a bio-based delayed coagulation regulator and 0.2-0.3 part of a foaming-foam-stabilizing regulator. The preparation method comprises the following steps: mixing the gelling base material, the composite alkali activator, the bonding enhancer and the bio-based delayed coagulation regulator, adding water to prepare base slurry, sequentially adding the composite foam-stabilizing anti-shrinking agent, the foaming-foam-stabilizing regulator and the controlled-release foaming agent, and stirring until the slurry is foamed; and pouring the slurry into a mold for molding, and curing for molding. The concrete provided by the invention can realize balance of low density and mechanical properties, improves shrinkage cracking resistance, water resistance and fitting performance with an old base layer, adapts to old building reconstruction scenes with high humidity, temperature and humidity fluctuation and poor base layer flatness, is high in construction adaptability, and can guarantee the structural stability and long-term use reliability after reconstruction.

The invention discloses an ultrathin UHPC (Ultra High Performance Concrete) planting frame and a preparation method thereof. The ultrathin UHPC planting frame comprises a bearing frame and an edge frame, the edge frames are arranged on the two sides of the bearing frame, the bearing frame comprises a bottom contact plate, an inclined supporting plate and a top contact plate, the bottom contact plate, the inclined supporting plate and the top contact plate are sequentially arranged between the edge frames to form a wave groove structure, and water permeable holes can be formed in the bottom contact plate; according to the scheme, through a fiber synergistic reinforcement and shrinkage compensation system, the breaking strength of the planting frame is larger than or equal to 30 MPa, the compressive strength is larger than or equal to 125 MPa, the fracture rate is reduced to 0, the shrinkage rate is smaller than or equal to 0.02%, and the core problems of brittle fracture and shrinkage cracking of an ultrathin wall body are solved; and after 10 times of cold and heat cycles (-20 DEG C to 60 DEG C), no crack or fracture is generated, the number of freeze-thaw cycles is larger than or equal to 300, and the performance of the planting frame is far better than that of an existing planting frame.

The application discloses a kind of low shrinkage 3D printing zirconia ceramic and its preparation process, select photosensitive polyimide, photosensitive polyimide has imine ring and photosensitive group on high molecular chain, with excellent photosensitivity, thermal stability, low volume shrinkage and other advantages, product system does not need to add photo initiator, can be directly completed curing under ultraviolet irradiation, avoid the volatilization or decomposition of photo initiator in workpiece during debinding, resulting in ceramic shrinkage, cracking and other problems;And optimize the ratio of dispersing agent and plasticizer in product system, reduce the viscosity of slurry, while increasing solid content, reduce shrinkage after sintering, and ensure the flowability of slurry and printing precision.In addition, combined with flash sintering process, inhibit grain growth coarsening, realize nanoscale dense structure, reduce internal defects, the zirconia ceramic prepared by the application is defect-free, dense structure, grain size is smaller, less than 1 μm, and has excellent fracture toughness and higher relative density.

This invention discloses a fly ash-based fluidized solidification material, its preparation method, and its application. The fluidized solidification material is obtained by curing fly ash with a curing agent composed of an alkali-activated material, a cementing material, a water-reducing agent, and a filler. The alkali-activated material is sodium hydroxide or carbide slag; the cementing material is granulated blast furnace slag powder; the filler is desulfurized gypsum; and the water-reducing agent is sodium hexametaphosphate, magnesium lignosulfonate, or a mixture of both. The alkali-activated material has a synergistic activating effect on the Ca-Si-Al active components in the cementing material, promoting the formation of hydrated calcium silicate gel and ettringite crystal phases, strengthening the material's mechanical properties, and increasing the density of the pore structure. The water-reducing agent optimizes the hydration reaction process, reduces the water-ash ratio, and inhibits the system's tendency to shrink and crack. The desulfurized gypsum partially replaces the alkali-activated material, filling the material's pores, improving the material's unconfined compressive strength, and reducing the material's permeability coefficient. It can be used as an ex-situ barrier material with excellent mechanical properties, impermeability, and durability.

The invention discloses a minimally invasive repair method for wood defects of a guqin body, which comprises the following steps: S1, forming a slotted hole at the wood defect part of the guqin body, enabling the middle part of the slotted hole to stretch across the wood defect part, and forming the outer edge of the slotted hole to a defect-free wood guqin body; s2, preparing a repaired wood block, wherein the material of the wood block is the same as the wood of the guitar body; s3, gluing and embedding are conducted, specifically, the wood blocks are embedded into the corresponding groove holes after being coated with adhesives, and gaps between the groove holes and the wood blocks are filled with the adhesives; and S4, after the adhesive is solidified, polishing the surface of the wooden guitar body, so that the exposed parts of the adhesive and the wood blocks are flush with the surface of the guitar body. The method can effectively solve the problems in the prior art that the vertical texture of the wooden wedge for repairing the Guqin shrinks and cracks, the adhesive is single and loses efficacy, the sound quality is damaged by a large wound surface, and the repaired structure is easy to fall off.

The invention relates to the field of building materials, and discloses high-strength, high-elasticity and low-shrinkage concrete and a preparation method thereof.The concrete comprises a core-shell structure microcapsule, superabsorbent resin fully absorbing a reactive surfactant aqueous solution serves as a core, and a pH sensitive polymer serves as a shell. During preparation, the shell is triggered to be dissolved within a preset time and release the inner core substance by utilizing the reduction of the pH value in the cement hydration process. The scheme has the remarkable beneficial effects that 1, water is released at regular time for internal curing, so that the self-constriction of the concrete is remarkably reduced; 2, the interface bonding of the fiber and the matrix is reinforced by releasing the surfactant in a timed manner, so that the elasticity and toughness of the material are greatly improved. The invention synergistically solves the technical problems of poor workability, shrinkage cracking and weak interface bonding of high-toughness concrete.

The preparation method comprises the following steps: preparing an aluminum oxide nanowire ball with a certain length-diameter ratio by adopting a solvothermal method, performing high-shear mixing on the aluminum oxide nanowire ball, silicon resin, a silane coupling agent and quartz fibers to form a multi-stage enhanced network, and performing compression molding, curing, subcritical drying and other process steps to obtain the aerogel thermal insulation material capable of being quickly dried. The inorganic-organic hybrid aerogel thermal insulation material with high temperature resistance is successfully prepared. Through collaborative optimization of in-situ compounding of organic and inorganic components and subcritical drying, efficient preparation of the aerogel with low cost and good mechanical strength is realized. The aluminum oxide nanowire clusters and the quartz fibers are introduced as inorganic components, effective support is provided, shrinkage cracking does not occur in the silicon resin pyrolysis process, and the structural stability and ablation resistance of the material at high temperature are remarkably improved.

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

The present application relates to the field of concrete temperature control and crack prevention, and particularly relates to a microcapsule slow-release material, a preparation method and application thereof. The microcapsule slow-release material comprises a core and a coating layer. The core comprises a porous carbon material and a temperature suppression material, and the coating layer is a hot melt adhesive film. The microcapsule slow-release material can achieve three-stage slow-release of heat release, porous structure slow-release and temperature suppression material dissolution slow-release, and has a persistent and excellent temperature suppression effect. In the early stage, the temperature suppression material is not consumed, and the setting and demolding of the concrete are basically not affected. In the later stage, the temperature suppression material is continuously released, the maximum temperature of the concrete is reduced, and the risk of temperature shrinkage cracking of the concrete is reduced.

The application belongs to material evaluation method, and relates to a testing device and method for anti-shrinkage cracking toughness of pavement cementitious material. i and shrinkage deformation data l i of the test specimen at the i-th collection time; and S4, calculating the shrinkage cracking toughness. The shrinkage cracking toughness can truly reflect the mechanical properties of the material, the shrinkage state of the pavement cementitious material is accurately simulated, the accuracy, scientificity and rationality of the test result are improved.