275 results about "Shrinkage cracking" patented technology

The invention belongs to the field of building materials, and especially relates to ultra-high performance concrete with micro-expansion and compensation shrinkage and a preparation method thereof. Raw materials include, by weight, the following components: 1 part of cement, 0.05-0.2 part of fly ash, 0.2-0.5 part of silica fume, 0.1-0.25 part of mineral powder, 0.05-0.2 part of quartz powder, 0.9-1.2 parts of quartz sand, 0.04-0.2 part of an expanding agent, 0.01-0.03 part of a water reducing agent, and 0.01-0.03 part of an expansion promotion reinforcing agent. A mixing amount of super absorbent resin is 0.4%-0.8% of a cementing material; a volume mixing amount of steel fiber is 1%-3% of a total volume of the concrete; the water-to-binder ratio is 0.16-0.22; and the compressive strength is 100-160 MPa. The ultra-high performance concrete with the micro-expansion and the compensation shrinkage has the characteristics of micro-expansion, high strength, high toughness, excellent workingperformance, and the like, and solves the problem that the expanding agent is difficult to produce effective expansion in the ultra-high performance concrete with a low water-to-binder ratio, and so,the risk of early shrinkage cracking of the ultra-high performance concrete is reduced, and the ultra-high performance concrete can maintain the micro-expansion for a long time.

A fiber-reinforced concrete-like material product includes a plurality of fibers containing an effective amount of at least one antimicrobial agent to inhibit organisms and protect the concrete from biological attack. Preferably, the antimicrobial agents are added to the fibers prior to the fibers being dispersed in the concrete. Such a concrete product containing antimicrobial-enhanced fibers simultaneously inhibits organisms from biological attack, reduces plastic shrinkage cracking of the concrete and improve post-peak flexural strength of the concrete.

Portland Cement-based concretes and mortars exhibit significant reduction in shrinkage cracking when combined with Magnesium Oxide (MgO), Shrinkage Reduction Admixtures (SRA) and Super Absorbent Polymers (SAP). However, MgO is a solid that reacts with water, SRA is a liquid, and SAP if not added properly could pull water out of the system and thus increase shrinkage. Unique admixture blends used as supplementary cementing materials that do not significantly affect concrete or cement strength properties of Portland cement itself address such issues. Proper ratios of MgO, SRA and/or SAP perform better against crack reduction when compared to commonly used Expansive Cements (EC).

The invention belongs to the technical field of building material, and more specifically relates to a ternary cementitious system stucco finish, and an application method thereof. The ternary cementitious system stucco finish is composed of white Portland cement, sulphate aluminium cement, gypsum, superfine slag powder, zeolite powder, latex powder, cellulose ether, an air entraining agent, an antifoaming agent, a water repellent, a thixotropic agent, an inorganic pigment, an quartz sand. The ternary cementitious system stucco finish possesses excellent physical mechanical properties; setting time and operable time are controllable; development of early strength is rapid; strength is high; bonding strength with matrix is high; no shrinkage cracking is caused; durability is excellent; no crystalline bloom is caused; stain resistance is excellent; and decorative effect is excellent. The ternary cementitious system stucco finish is suitable for decoration engineering of building internal and external walls and building thermal-insulation decorative integrated systems; relatively mechanical strength is achieved in a relatively short term; construction efficiency is increased; performance of long-term application is excellent; and engineering quality is ensured.

The invention provides application of temperature-sensitive hydrogel in improvement of the anti-dry-shrinkage cracking property of concrete. The concrete is prepared from the temperature-sensitive hydrogel, cement, aggregates and water. A preparation method of the concrete comprises the steps that firstly, the temperature-sensitive hydrogel is prepared; secondly, the aggregates and the water are blended to be uniform; lastly, the temperature-sensitive hydrogel and the water are added, the materials are blended to be uniform, and then the concrete can be prepared. The adopted homemade temperature-sensitive hydrogel is lightly-crosslinked macromolecules which can be polymerized to form a film after releasing water, no hole can be reserved in the cement concrete, and other properties of the cement concrete are not affected while the anti-cracking property of the concrete is improved. The initial volume water content of the concrete is increased along with increasing of the mixing amount of the temperature-sensitive hydrogel, and it is shown that the water storage capacity of the concrete is enhanced by mixing the temperature-sensitive hydrogel; the water absorption rate of the concrete is decreased along with increasing of the mixing amount of the temperature-sensitive hydrogel, and it is shown that the connectivity of capillary pores in the concrete is reduced by mixing the temperature-sensitive hydrogel.

The invention discloses micro-expansion fiber reinforced concrete for a steel-concrete combined beam bridge panel wet joint and a preparation method of the micro-expansion fiber reinforced concrete, and relates to the preparation field of the micro-expansion fiber reinforced concrete. The micro-expansion fiber reinforced concrete comprises gel materials (cement, coal ash, slag powder and an expanding agent), aggregate, reinforcing materials, imitated steel fibers, a water reducer and water, wherein the 28 compressive strength of the micro-expansion fiber reinforced concrete is not lower than 69.0MPa, the 28d breaking strength of the micro-expansion fiber reinforced concrete is not lower than 7.0 MPa, the 28d splitting tensile strength of the micro-expansion fiber reinforced concrete is not lower than 5.0 MPa, the 28d elasticity modulus of the micro-expansion fiber reinforced concrete is not lower than 36.0 GPa, the cracking resistance level of the micro-expansion fiber reinforced concrete reaches L-IV level, the 28d bending toughness index I20 of the micro-expansion fiber reinforced concrete is not lower than 8, the 56d chlorine ion diffusion coefficient of the micro-expansion fiber reinforced concrete is lower than 4.0*10<-12>m<2>/s, the 21d shrinkage percentage of the micro-expansion fiber reinforced concrete is lower than 200*10<-6>. By using the preparation method, the shrinkage cracking of the micro-expansion fiber reinforced concrete can be effectively avoided, so that the reinforced concrete is relatively compact. The micro-expansion fiber reinforced concrete disclosed by the invention is relatively high in strength, relatively low in shrinkage percentage, good in bending toughness and durability, relatively low in cost and conveniently to widely use.

The invention discloses an aerated concrete interface agent, and belongs to the technical field of construction materials. The agent comprises, by weight: 20-50% of cellulose ether, 36-73% of a thixotropic thickener, and 5-25% of redispersible latex powder. The agent has the advantages that: with the agent, bonding strength of mortar upon a substrate layer can be improved, construction workability can be improved, surface smoothness can be improved, adhesion with tools during construction can be reduced, water-retention and thickening performances are excellent, mortar operation open time can be prolonged, and problems such as building block falling, adhesion surface shrinkage cracking, and the like can be effectively avoided.

The invention discloses a bottom layer brushing gypsum, which is prepared by mixing the following components in parts by weight: 200-500 parts of building gypsum, 485-785 parts of quartz sand, 3 parts of regulator, 5 parts of inorganic gel, 0.2-0.5 part of retarder and 2 parts of anti-cracking agent, wherein the quartz sand is one or the mixture of more than two of the quartz sands of 30 meshes, 40 meshes and 60 meshes in any proportion, the regulator is hydroxypropyl methyl cellulose, the inorganic gel is sodium bentonite, the retarder is a special retarder for polyphosphate gypsum, and the anti-cracking agent is lignocellulose; and the building gypsum is prepared by desulfurized gypsum according to the following method that the desulfurized gypsum enters a boiling calcinator after being pre-dried at the temperature of 80-90 DEG C, is calcined at the temperature of 120-130 DEG C, then is added into an impact type flour mill to be ground, and is prepared into the building gypsum after being cooled and aged. The invention has strong adhesive force, effectively inhibits the phenomenon of shrinkage cracking in plastering, and has good water resistance.

The invention discloses straw fiber reinforcement air-entrained concrete which comprises a base material, an aluminum powder paste, a straw fiber, an additive and water, wherein the doping amount of the aluminum powder paste accounts for 0.06%-0.09% of the dry weight of the base material; the doping amount of the additive accounts for 0.5%-0.8% of the dry weight of the base material; the doping amount of the straw fiber accounts for 2%-10% of the dry weight of the base material; and the mass ratio of the water and the base material is 0.52-0.60, The invention also discloses a preparation method of the straw fiber reinforcement air-entrained concrete. The straw fiber reinforcement air-entrained concrete disclosed by the invention reduces the shrinkage cracking and production cost of air-entrained concrete and solves the problems of straw resource waste, ceramic waste treatment and environmental pollution to a certain degree.

The invention discloses a cement stabilized base material, a preparation, an application and a preparation method of a road base. The cement stabilized basic material comprises the following materials: 1%-3% of basic slag and 1%-3% of cement and base materials, wherein the basic materials comprises 0.5%-8% of desulfurization gypsum and 92%-99.5% of crushed stone in mass percentage of the basic materials. The preparation method of the cement stabilized base material comprises the step of uniformly mixing the components. According to the preparation method of the road base, the road base is prepared from the cement stabilized base material with the conventional preparation process and conditions. The cement stabilized base material has the advantages as follows: the material cost is reduced, the service life of a road structure is prolonged, the economic benefit is increased, the cement setting time is delayed, the strength, the airtightness, the water retention, the water resistance, the shrinkage crack resistance, the freeze-thaw resistance, the moisture damage resistance and sulfate corrosion resistance of the material are improved, novel application of the desulfurization gypsum is exploited, and the environment is protected effectively.

The invention relates to a method for preparing silica aerogel by supercritical drying with a high-pressure liquid medium, which comprises the following steps of: (1) adding silicon tetrachloride and water to perform reaction with stirring under the acidic condition that the pH is between 3 and 5, adjusting the pH to be between 8 and 10 by using ammonia water, adding the water and ethanol to perform hydrolysis and polycondensation reaction to form alcogel; (2) loading the alcogel into a high-pressure reaction kettle, filling the high-pressure liquid medium into the reaction kettle, and slowly raising the temperature to reach supercritical pressure after the reaction kettle is filled with the high-pressure liquid medium; and (3) slowly releasing gas medium while slowly raising the temperature until the pressure in the kettle and external atmosphere are balanced, opening the reaction kettle, taking the sample out and drying the sample. The method has the advantages of readily available raw materials, simple process and low cost, solves the problem of easy shrinkage cracking of the SiO2 aerogel when dry, and can stably improve the reaction speed at the same time.

A monofilament plastic fiber useful in reducing plastic shrinkage cracking of concrete articles has been discovered. The fiber has a core that is a polyolefin that is at least partially enveloped by a sheath that is a copolymer of an olefin and at least one olefinically unsaturated comonomer selected from the group consisting of an unsaturated carboxylic acid, alkyl acrylate, alkyl methacrylate and vinyl ester.

The invention discloses an environment-friendly anti-cracking waterproof agent for concrete and a preparation method thereof. The anti-cracking waterproof agent comprises the following raw materials in percentage by weight: 1%-3% of graphite phase carbon nitride nanosheets, 5%-20% of modified ardealite powder, 10%-30% of ultrafine lithium slag powder, 5%-10% of nano titanium dioxide, 5%-15% of bauxite, 20%-50% of modified bentonite, 5%-15% of a magnesium oxide expanding agent, 1%-5% of zirconium silicone, 5%-15% of an organosilicon water repellent, 0.5%-2% of high alkali resistant water absorbent resin, and 1%-5% of a polycarboxylic acid water reducer. the waterproof agent provided by the invention not only can improve the pore structure of concrete, improve the compactness of concrete andenhance the impermeability of concrete, but also can reduce the risk of shrinkage cracking of concrete by utilizing the micro-expansion characteristic, and improves the crack resistance of concrete under the synergistic action of the waterproof agent and an alkali-aggregate reaction inhibition component; by utilizing the excitation effect of the nano titanium dioxide on the graphite-phase carbonnitride nanosheet, the nano titanium dioxide shows efficient photocatalytic performance under natural light, can effectively degrade harmful components such as nitric oxide in the air, and plays a positive role in purifying the environment.

This invention relates to preparation and application of high-performance and anti-crack self-tight concrete reinforced with fiber and fly ashes. This invention uses fly ashes as a substitute for part of cement, and high-alkali-resistant glass fiber modified polypropylene fiber as the reinforcing materials. Besides, an appropriate quantity of water-reducer is used to improve the processability of the mixture. The obtained self-tight concrete has such advantages as high performance and good anti-crack property. The method for preparing sound barrier from the self-tight concrete is simple and needs no complicated equipments. The obtained sound barrier has better performance when compared with conventional concrete sound barriers, metal-plate sound barriers, and plastic organic glass sound barriers.

The invention discloses a high performance concrete with water quenching manganese slag and a preparation method thereof. The high performance concrete is prepared by hydraulic cementing materials, gravel, sand, water and a small amount of surfactant, wherein the hydraulic cementing materials comprise the following components in percentage by weight: 15%-30% of water quenching manganese slag doped with 4%-10% of natural anhydrite, 8%-10% of expanding agent and 60%-77% of cement. In the invention, the manganese slag and the expanding agent are used for preparing the high performance concrete in a double-doped way; firstly, aiming at potential hydraulicity of the manganese slag, high-value comprehensive application is carried out, thereby reducing the hydration heat of the cement, saving the cement consumption in the concrete and lowering the cost of the concrete; the expanding agent is also used for solving the problem of shrinkage cracking of the concrete, thereby ensuring the dimensional stability of the high performance concrete; and meanwhile, a large amount of industrial solid wastes (manganese slag) can be slaked by the invention, thereby strengthening the comprehensive utilization of waste slag and reducing the environmental pollution.

The invention discloses a preparation method of carbonized steel slag lightweight aggregate and concrete containing the carbonized steel slag lightweight aggregate. The preparation method of the carbonized steel slag lightweight aggregate comprises the following steps: step 1, weighing 40-60 parts by mass of steel slag powder, 30-50 parts by mass of vitrified micro bubbles and 10-30 parts by massof quick lime, putting into a tray, and performing mixing to form uniform mixed powder; step 2, uniformly spraying water drops to the surface of the mixed powder according to a certain water-cement ratio, continuously shaking the oscillation tray, and mixing the powder with water to form small balls, so as to obtain steel slag lightweight aggregate; 3, placing the steel slag lightweight aggregatein a curing chamber with the temperature being 20 +/-1 DEG C and the relative humidity being 55 +/-5% to be cured for 48 h; and step 4, putting the cured steel slag lightweight aggregate into a carbonization box to be carbonized for 24 hours. The invention has the advantages of simple preparation process, light weight and high strength of aggregate, low cost, low-carbon and environment-friendly production and the like. When applied to concrete, the carbonized steel slag lightweight aggregate can provide internal curing, promote hydration of a cementing material and reduce shrinkage cracking ofthe concrete.

Belonging to the technical field of building materials, the invention relates to a flexible anti-cracking protective mortar and also relates to its preparation method. The flexible anti-cracking protective mortar comprises the following components by weight part: 30-50 of ordinary portland cement, 50-65 of quartz sand, 5-10 of slaked lime, 3-6 of anti-cracking fibers, 1.2-2.5 of redispersible emulsion powder, 0.2-0.5 of cellulose ether, 0.05-0.2 of a plastic expansion agent, and 0.3-0.6 of a water repellent agent. The flexible anti-cracking protective mortar provided in the invention has the characteristics of excellent construction performance, high breaking strength and compressive strength, good flexibility, high bonding tensile strength, good anti-cracking performance, excellent waterproof and hydrophobic effects, etc. When the flexible anti-cracking protective mortar is used for anti-cracking protection of a building wall heat preservation and energy saving system, the drying shrinkage cracking problem caused by various stress can be solved. With good and stable performance, the flexible anti-cracking protective mortar can be used directly by adding water at construction sites. The flexible anti-cracking protective mortar provided in the invention can also be used in plastering anti-cracking protective construction processes of various novel building wall materials so as to play a part in anti-cracking protection and water resistance.

The invention discloses a gypsum based light energy-saving plate and a method for preparing the same. The gypsum based light energy-saving plate comprises 40-60 parts of desulfurization gypsum, 10-15 parts of cement, 5-15 parts of vitrified micro-spheres, 10-20 parts of calcite powder and 4-10 parts of functional auxiliaries. The functional auxiliaries comprise 0.2-1 part of retarders, 0.1-5 parts of water reducing agents, 0.001-0.003 part of air entraining agents, 1.5-4 parts of redispersible latex powder, 0.2-0.3 part of cellulose ether and 0.1-0.4 part of defoaming agents. The gypsum based light energy-saving plate and the method have the advantages that the gypsum based light energy-saving plate is relatively high in compactness and comprehensive performance, and the problems of shrinkage cracking, long maintenance periods and the like of existing light partition walls can be effectively solved; the building construction costs can be reduced to a great extent, the construction periods can be shortened, the cost of partition walls can be lowered, and accordingly the gypsum based light energy-saving plate and the method have obvious technical and economical benefits.

The invention relates to a method for predicting plastic shrinkage cracking of a cement mortar material. The method comprises the following step of: substituting four cement-based material composition parameters comprising water cement ratio (Wc), cement sand ratio (Cs), fiber content (Fc) and fiber length (F1), water evaporation speed (Er) and demixing degree (Dd) and restraint degree (Rd) of the cement-based material into the following formula: K = 13.8822 - 14.0949Wc - 2.8247Cs + 0.5293Fc + 0.0022F1 - 17.0650Er + 0.2582Dd + 0.9436Rd, wherein the K is anti-cracking index. When the K value is more than 1.41, the cement-based material test piece is not cracked; when the K value is less than 0.99, the test piece is cracked; and when the K value is between 0.99 and 1.41, the test piece is cracked in certain probability. A multiplex constitutive equation of plastic shrinkage cracking of the mortar is constructed by using the parameters with great influence on the cement-based plastic shrinkage cracking, the tendency of early plastic shrinkage cracking of the cement-based material can be accurately predicted, and the method can be widely applied to early prediction of the plastic shrinkage cracking of the mortar.