51results about How to "Improved resistance to fatigue cracking" patented technology

The invention relates to a high-elasticity asphalt modified composition, a modifier, modified asphalt, a modified asphalt mixture and a preparation method. The modified composition comprises 100 parts of a styrene-butadiene-styrene segmented copolymer, 20-40 parts of a tackifier, 20-40 parts of a softener, 3-8 parts of a warm mixing agent, 15-40 parts of a plasticizer and 2-6 parts of a stabilizer. The preparation method of the modifier comprises the following steps: (1) mixing the styrene-butadiene-styrene segmented copolymer, the tackifier and the warm mixing agent according to a formula to obtain a melt; and (2) mixing the softener, the plasticizer and the stabilizer with the melt, and then extruding, cooling and dicing. The modified asphalt is prepared by doping the modifier into matrix asphalt and uniformly mixing. The modified asphalt mixture is prepared by mixing the modified asphalt and a raw material of a mineral mixture. The modified asphalt provided by the invention has good high-temperature and low-temperature stabilities and anti-fatigue capacity, and the modified asphalt mixture is strong in construction workability and good in pavement performance.

The invention relates to a method of preparing polymer asphalt with one step to modify the asphalt by adopting the polymer as a modifying agent. In a peptizator of 80 to 160 DEG C which account for 5 to 27 percent of the total weight of the raw materials, the polymer modifying agent and 0.1 to 2 percent of stabilizer which account for 2 to 9 percent of the total weight of the raw materials are added, and then is poured into a plastic extruder where the rotating speed is 300 to 800 rotations per second to be extruded; the extruding temperature is controlled to be 130 to 210 DEG C; the extruded polymer is directly and mixingly stirred for 0.5 to 6 hours together with the asphalt which accounts for 62 to 89.9 percent of the total weight of the raw materials, then the polymer modified asphalt is gained, which is provided with good heat preservation function, good low temperature expanding performance, anti-fatigue and anti-tearing function and relatively good weatherproof function. After being mixed with the stones, the mixed materials perform good water stability and high and low temperature stability, which can effectively improve the using performance of the asphalt pavement and prolong the service life.

The invention provides rare-earth sol modified composite zinc-aluminum low-temperature sintered coating slurry. Zinc oxide-alumina sol is modified by using rare-earth sol and mixed with water-soluble silicon acrylic resin to form an inorganic/inorganic composite rare earth-zinc oxide-alumina ternary sol bonding material system. The slurry is prepared from the following raw materials in percentage by weight: 4 to 9 percent of nano rare-earth cerium sol, 25 to 35 percent of zinc oxide sol, 6 to 10 percent of alumina sol, 8 to 13 percent of water-soluble silicon acrylic resin, 0.05 to 0.1 percent of dispersant, 0.3 to 0.5 percent of rheological agent, 0.3 to 0.8 percent of antioxidant, 25 to 30 percent of laminar Zn-Sc alloy powder, 5 to 8 percent of laminar aluminum powder and the balance of deionized water. The slurry realizes the non-chromate Dacromet goal, and has the advantages of low curing and sintering temperature, bright and durable coating metal luster and good comprehensive mechanical property; and the integral process has the characteristics of lower carbon, more environmental protection, more energy conservation and the like.

The invention discloses a surface treatment method of a powder metallurgy part. The method comprises the following steps of: firstly, performing complex cementation on the powder metallurgy part with nitrogen gas, sulfur gas and chromium gas to form a dense coating tissue of a nitrogen-sulfur-chromium compound with the size of between 15 microns and 45 microns on the surface of the powder metallurgy part; secondly, polishing the surface of the powder metallurgy part; and lastly, oxidizing the powder metallurgy part at low temperature to form a dense oxide layer. The compound coating tissue is a dense oxide layer covered by a polynary ultra-hard nitrogen-sulfur-chromium compound, so that the powder metallurgy part has high wear resistance, corrosion resistance and high temperature resistance, the friction coefficient is greatly lowered, the seizing resistance magnitude order is raised, the working quality of the powder metallurgy part is remarkably enhanced, and the service life is prolonged.

The invention discloses a novel modifier with basalt fibers for asphalt mixtures and a method for preparing the novel modifier. The novel modifier is made of the basalt fibers and high-adhesion wetting agents. The novel modifier comprises, by weight, 85-98 parts of the basalt fibers, 0-10 parts of film-forming agents A, 0-10 parts of film-forming agents B, 0.1-0.6 part of antistatic agents, 0.2-3.5 parts of coupling agents, 0.1-2 parts of lubricants and 0.1-1.3 parts of modified nanometer SiO2. The method includes mixing the film-forming agents A, the film-forming agents B, the antistatic agents, the coupling agents, the lubricants and the modified nanometer SiO2 with one another to obtain mixtures and stirring the mixtures; wetting and wrapping the basalt fibers and cutting the basalt fibers into short pieces so as to obtain the novel modifier. The novel modifier and the method have the vantages that irritating odor rarely can be generated in modifier preparation procedures; the novel modifier can be added into the asphalt mixtures, accordingly, various road properties of the asphalt mixtures can be effectively improved, the anti-rutting performance and the fatigue cracking resistance of pavements can be improved, and the service lives of roads can be greatly prolonged.

The invention discloses a bridge deck pavement method for an orthotropic steel bridge. The pavement method comprises the following steps: (1) performing sand-blasting and de-rusting treatment on a steel bridge panel, and coating a mica-containing epoxy anti-corrosion layer; (2) coating a solvent-free epoxy resin water-proof layer; (3) spreading a hot melt particle bonding layer which is partially sunken into the solvent-free epoxy resin water-proof layer, wherein the hot melt particles are high-polymer particles of which the softening point is greater than 150 DEG C; (4) paving a fine-particle asphalt mixture to form a high-elasticity modified asphalt pavement lower layer; (5) spreading a modified emulsified asphalt bonding layer; (6) paving a fine-particle or medium-particle asphalt mixture to form a high-elasticity modified asphalt pavement upper layer. By adopting the pavement method, the construction difficulty is lowered greatly, later maintenance is easy, the universality is high, a pavement lower structure is durable and long in service life, only the surface needs to be maintained in daily use, overall repeated maintenance is avoided, and the investment in a full life cycle is lowered.

In a first aspect, bituminous asphalt binder materials which are modified by the addition of crumb rubber or ground tire rubber are described. In a second aspect, the present invention is directed to methods of producing a modified asphalt binder containing crumb rubber or ground tire rubber. The modified asphalt binders comprise neat asphalt, crumb rubber, one or more synthetic polymers, and one or more acids. The crumb rubber may be obtained from recycled truck and/or automobile tires.

The invention discloses a high-solid-content emulsified asphalt for a stress absorbing layer, a preparation method and a construction method thereof. The high-solid-content emulsified asphalt is prepared from ordinary asphalt, asphalt additive, emulgator, modifier, water and pH regulator; the solid content is 67-75%; the raw materials by weight percent are as follows: 50-70% of ordinary asphalt, 1-12% of asphalt additive, 0.2-3.0% of emulgator, 2.0-10.0% of modifier and the balance of water and pH regulator. The preparation method comprises the following steps: heating ordinary asphalt; addingasphalt additive into ordinary asphalt at a ratio and uniformly stirring, thereby acquiring a mixture of ordinary asphalt and asphalt additive; preparing emulgator into an aqueous solution, and thenadding modifier, thereby acquiring an emulgator liquid soup; using pH regulator for regulating pH value of the emulgator liquid soup, and then heating; successively putting the emulgator liquid soup and the mixture of ordinary asphalt and asphalt additive into a colloid mill, and then milling, thereby acquiring an end product of emulsified asphalt. According to the invention, a synchronous macadamseal coat vehicle is adopted for spraying/spreading emulsified asphalt and macadam; a 'prime coat and stress absorbing layer' effect can be achieved through once construction; construction process isreduced; construction cost is lowered.

The invention relates to sulfur-modified emulsified asphalt and a preparation method thereof. The sulfur-modified emulsified asphalt is prepared from 40 to 50 parts by mass of asphalt, 5 to 20 parts by mass of sulfur, 2 to 10 parts by mass of styrene-butadiene latex, 0.3 to 1 part by mass of a nonionic emulsifier, 0.5 to 3 parts by mass of a cationic composite emulsifier, 0.03 to 2 parts by mass of a stabilizer, 0.5 to 3 parts by mass of an acid and 35 to 50 parts by mass of water. The sulfur-modified emulsified asphalt improves a softening point of the asphalt, improves the high temperature performances of the asphalt, has good low temperature performances, can improve the strength and stability of the asphalt pavement, and improves rutting and fatigue cracking resistance of the pavement. The sulfur-modified emulsified asphalt is prepared through simple processes, is free of heating, prevents generation of harmful gas, reduces the energy consumption and discharge, is beneficial to construction and the health of the construction personnel, and has great economic and social benefits.

The invention discloses a bridge deck pavement structure for an orthotropic steel bridge. The pavement structure comprises a mica-containing epoxy anti-corrosion layer, a solvent-free epoxy resin water-proof layer, a hot melt particle bonding layer, a high-elasticity modified asphalt pavement lower layer, a modified emulsified asphalt bonding layer and a high-elasticity modified asphalt pavement upper layer from bottom to top, wherein the total pavement thickness is 6-8 centimeters; the hot melt particles are high-polymer particles of which the softening point is greater than 150 DEG C; the high-elasticity modified asphalt is modified asphalt of which the elastic recovery is over 95 percent at 25 DEG C; the pavement lower layer is formed by paving a fine-particle asphalt mixture prepared by mixing the high-elasticity modified asphalt with a mineral mixture; the pavement upper layer is formed by paving a fine-particle or medium-particle asphalt mixture prepared by mixing the high-elasticity modified asphalt with the mineral mixture. By adopting the pavement structure, the water-proof layer and the asphalt pavement layer are combined integrally through the hot melt particle bonding layer, so that the shearing strength and durability of the pavement structure are ensured.

The invention discloses SEBS/biochar compound modified asphalt and a preparation method thereof. The SEBS/biochar compound modified asphalt is prepared from SEBS, biochar and matrix asphalt. The preparation method comprises the steps: heating the matrix asphalt, adding the SEBS into the heated matrix asphalt, stirring, shearing and swelling to obtain modified asphalt for standby application; stoving the biochar and cooling to room temperature to obtain cooled biochar for standby application; adding the cooled biochar into the modified asphalt and stirring and shearing to obtain the SEBS/biochar compound modified asphalt. The compound asphalt disclosed by the invention has the advantages of higher high-temperature stability, no effect on self low-temperature crack resistance, suitability for use in high-temperature plateau areas with strong ultraviolet rays and especially suitability for open-graded roads with higher requirements for aging performance. The preparation method has the advantages of simpleness, ability in reasonably utilizing the biochar, economical effect and environmental friendliness.

The invention relates to modified emulsified asphalt and a preparation method thereof. The modified emulsified asphalt comprises, by mass, 40-50 parts of asphalt, 6-16 parts of sulfur, 2-10 parts of styrene-butadiene latex, 2-5 parts of a cationic emulsifier, 0.1-2 parts of a stabilizer, 0.5-3 parts of an acid and 35-40 parts of water. The modified emulsified asphalt improves high temperature andlow temperature performances of the asphalt, saves the asphalt, reduces a production cost, improves the high temperature stability of the asphalt pavement, prevents the rutting and peeling of the asphalt pavement under a load and improves the anti-fatigue cracking performances of the pavement.

The invention discloses a single-side joint structure and a single-side joint method for expressway extension. The structure includes, from top to bottom successively, an upper surface layer, a middle surface layer, a lower surface layer, a cold regeneration basic layer, a water stability sub-base layer, and a cushion layer. The water stability sub-base has a double-layer composite structure and comprises an upper water stability sub-base layer and a lower water stability sub-base layer. At a joint position, the joint structure has step-like arrangement. In the method, an original medium separation area is removed and the pavement of a to-be-extended half side of the old road until the cushion layer is milled and planed. The two-direction slope of the old road is modified into a one-direction slope to ensure the top surfaces of the two water stability sub-base layers in the old road to be one-directional, thereby effectively enabling a drainage system on the surface of the pavement and inside the pavement to be unobstructed. Two basic layers of the old road are jointed to each other in a semi-rigid manner, so that by means of the method, the deformation of the two basic layers are cooperated, thus prolonging the service life of the pavement. The structure and the method improve anti-reflective crack capability of the pavement structure, wherein the joint seam is arranged at the lane line between a second lane and a third lane. A warp-knitted composite reinforced anti-cracking fabric is employed so as to avoid a load concentration position of wheel track tapes and avoid a large load on the weak positions in the joint seams, thereby improving durability of the pavement structure.

The invention discloses a steel slag stress absorption layer material and a preparation method thereof. The method comprises the following steps of: (1) respectively weighing 7-14 parts by weight of mineral powder, 100-200 parts by weight of steel slag aggregate, 9-19 parts by weight of SBS modified asphalt and 0-0.4 parts by weight of brucite mineral fibers; (2) heating the aggregate and the mineral powder at a constant temperature of 170-180 DEG C for more than 4 hours for later use; (3) heating the SBS modified asphalt to 170-180 DEG C, and fully and uniformly stirring for later use; and (4) carrying out dry mixing on the steel slag aggregate subjected to constant-temperature heating for 25-35 seconds, then adding brucite mineral fibers, carrying out dry mixing for 8-12 seconds, then adding the heated SBS modified asphalt, carrying out wet mixing for 85-95 seconds, and finally adding mineral powder, and carrying out mixing for 15-25 seconds. The stress absorption layer material manufactured by the method is high in viscoelasticity and good in fatigue cracking resistance. The preparation method is simple in process, economical and environment-friendly, and has important practicalsignificance and economic value.

The invention discloses a high-toughness, durable and antiskid steel bridge deck pavement structure and a construction method thereof. The steel bridge deck pavement structure comprises a steel bridgedeck steel plate; a bonding bottom layer, a buffer layer, an adhesion layer and a wearing layer are sequentially laid on the surface of the steel bridge deck steel plate from bottom to top; the buffer layer and the wearing layer are both made of high-toughness modified asphalt concrete composed of aggregate, filler and asphalt cement, the thickness of the buffer layer is 1-3 cm, and the thicknessof the wearing layer is 2-3 cm. The bridge deck pavement structure has good high-temperature rut resistance, fatigue durability, skid resistance, bonding strength and deformation compliance, comparedwith epoxy asphalt concrete, the engineering cost is greatly reduced, the construction process is simple, and later maintenance is convenient.

The invention discloses a screw lifter which can convert rotation into straight motion, comprising an upper case, a lower case, a motor, a speed reducer, a bearing, a lead screw and a nut, wherein the upper and lower cases are fixed, the motor via the speed reducer is geared with the lead screw meshed with a nut, the outer wall of the case around the bearing base of the upper and lower cases is in taper shape whose outer wall can be taper face or taper face disposed with bars. The invention has reasonable force on upper and lower cases, with long service life.

The invention relates to an orthotropic steel bridge deck structure with a transverse straining beam. The structure comprises a cover plate, a plurality of longitudinal reinforcing ribs which are arranged on the lower surface of the cover plate in parallel and a plurality of transverse reinforcing ribs which are arranged on the lower surfaces of the longitudinal reinforcing ribs in parallel and are vertical to the longitudinal reinforcing ribs, wherein the longitudinal reinforcing ribs are opening reinforcing ribs; tops of vertical parts of the longitudinal reinforcing ribs are fixedly connected with the cover plate through double-faced welding lines; the transverse straining beam is used for fixedly connecting the plurality of longitudinal reinforcing ribs through horizontal parts of the longitudinal reinforcing ribs. Compared with the prior art, the opening reinforcing ribs are used as the longitudinal reinforcing ribs, so that the longitudinal reinforcing ribs and the cover plate can be fixedly welded together through the double-faced welding lines and stress concentration is reduced; an anti-fatigue cracking performance of the structure is effectively improved, the service life of the structure is prolonged and the safety is good; the longitudinal opening reinforcing ribs, which are arranged in parallel, are fixedly connected together through the transverse straining beam so that the whole stress performance of the structure is improved.

The invention discloses a sealant for pavement cracks, characterized by compounding organo-bentonite with SBS modified asphalt to prepare the sealant. Results of studying the impact of the modifier and its amount on the high temperature performance and low temperature performance of the modified asphalt show that by adding organo-bentonite and the SBS composition, the high temperature composite modulus of the asphalt is raised, the temperature sensitivity is significantly weakened, thus the high temperature performance of the asphalt is improved; simultaneously the creep stiffness of the modified asphalt after aging is reduced, the creep rate is increased, the low temperature performance of the asphalt after aging is raised, and in the long-term use process, good fatigue cracking resistance is achieved.