260results about How to "Reduce temperature stress" patented technology

The invention discloses a fabricated prestressed heat-resistant cement concrete pavement and a construction process thereof. The pavement is formed by splicing a plurality of fabricated prestressed heat-resistant pavement plates which are parallelly paved and connected into a whole through transverse prestressed steel stranded wires, wherein each fabricated prestressed heat-resistant pavement plate comprises a fabricated prestressed pavement plate which consists of a plurality of pavement plate blocks connected through connecting plates, and a vermiculite concrete heat-resistant paving layer which is paved on the fabricated prestressed pavement plate; each pavement plate block comprises a plurality of common plates which are connected into a whole through longitudinal prestressed steel stranded wires; and the connecting plates and the common plates are cement concrete prefabricated plate blocks. The construction process comprises the following steps of: 1, prefabricating the cement concrete prefabricated plate blocks; 2, transporting the cement concrete prefabricated plate blocks; and 3, paving the pavement. The pavement is reasonable in structural design, convenient to construct, low in input cost and short in construction period, and has heat resistance, construction quality is easy to ensure, and various practical problems of the traditional fabricated cement concrete pavement can be solved.

The invention discloses an ideal temperature control curve model of a concrete dam. A finite element simulation analysis method is utilized, the distribution rule of the various dam types of temperature field and thermal stress is researched based on the existing specifications and temperature control practical experience, and the ideal temperature control curve model of concrete which is poured in different portions, different material partitions and different seasons is obtained through simulation calculation, wherein the temperature stress of the ideal temperature control curve model is minimum under the condition of the same temperature control standard. In addition, the invention also provides an intelligent control method utilizing the ideal temperature control curve model of the concrete dam.

A method for operating a gas and steam turbine plant is provided. In the plant, the flue gas that escapes from a gas turbine is routed through a waste gas steam generator and where a flow medium that is used to drive a steam turbine is conducted in a flow medium circuit that includes several pressure stages. At least one of the pressure stages has an evaporator circuit with a steam collection drum that has a plurality of downpipes connected to the steam collection drum and a plurality of rising pipes downstream of the downpipes that are likewise connected to the steam collection drum and are heated by the flue gas in the waste heat steam generator. The height of the fluid column formed by the flow medium in the downpipes is monitored and a transient dry operation of the evaporator circuit can thus be detected and safeguarded against.

The invention relates to a long-wall structure concrete curing device and a curing method thereof. The curing device comprises a moisturizing device, a heat-preservation device and a temperature measurement device, wherein the moisturizing device comprises a spraying pipe, and the spraying pipe is fixed through a split bolt of a formwork at the top of a wall; the heat-preservation device comprises a plastic film and a heat-preservation material, the spraying pipe and the wall are wrapped with the plastic film, and the plastic film is wrapped with the heat-preservation material; the temperature measurement device comprises a center temperature measurement point and a surface temperature measurement point, the center temperature measurement point and the surface temperature measurement point are buried at the same elevation of the wall, and the center temperature measurement point and the surface temperature measurement point are connected with a numerical control temperature measurement instrument through a temperature measurement line. According to the curing device and the curing method, the outside of the surface of a long-wall concrete structure is provided with the moisturizing device capable of spraying fine water mist slowly and wrapped with the heat-preservatoin device composing of the plastic film and the heat-preservation material, the difference of temperatures inside and outside concrete is controlled, temperature stress in the concrete is reduced, temperature cracks of the concrete are reduced, and the problem of how to control the cracks in long-wall structure construction in the environment with a dry climate and a large temperature difference is solved.

The invention relates to a coating system dedicated for outer wall reflecting and heat-insulating paint and a construction method of the coating system. The coating system is successively provided with heat-insulating leveling putties, an anti-cracking layer, sealing primer and a reflecting and heat-insulating paint finish paint layer from the surface of a base layer wall body, wherein the anti-cracking layer comprises two layers of heat-insulating leveling putties and glass fiber gridding cloth clamped between the two layers of heat-insulating leveling putties. The coating system dedicated for the outer wall reflecting and heat-insulating paint has the functions that the heat-insulating effect is enhanced, the anti-cracking effect is obvious, and the like by regulating the assorting of the base layers and applying the principle design, such as material deformation modulus access, and flexible gradual change.

The invention discloses a retarded cement grinding aid and a preparation method thereof. The retarded cement grinding aid comprises 0.01-0.02wt% of sodium carboxymethyl cellulose, 25-30wt% of molasses calcium, 5-10wt% of citric acid and the balance of water, wherein the total percent is 100%. The retarded cement grinding aid provided by the invention has the beneficial effects that the molasses calcium is used instead of the molasses and cane sugar commonly used at present, is a powdery product prepared by neutralizing the molasses with lime, has better water reducing and retarding effects than the molasses and saves the cost; and the hydration and hardening time of the cement is effectively lengthened so that the freshly mixed cement concrete can maintain the plasticity in a longer time, thus adjusting the setting time of the freshly mixed cement concrete.

The invention provides railway structure concrete protecting coating and a preparation method and a using method thereof. The protecting coating comprises a sealing primer layer, a polyurethane middlepaint layer and a fluorocarbon finish paint layer. The protecting coating has excellent adhesion; when the protecting coating is used for protecting a railway concrete bridge, the protecting coatingcan avoid occurrence of a situation that the railway concrete bridge cracks first and then is repaired in a special environmental region, significantly improves the durability of the railway concretebridge, prolongs the service life the railway concrete bridge, can achieve an excellent concrete protecting effect in the case of relatively thin concrete bridge coating thickness, and is convenient and fast to use; the protecting coating can also be used for protecting the surface of a ballastless track structure, and when the protecting coating is applied to the surface of a concrete track plateunder a steel rail or the surface of a ballast bed plate, the temperature difference between day and night due to sunlight irradiation can be reduced, the warpage amount of the track plate can be reduced, the open joints of plate corners or upwarp of the ballast bed plate or other damages can be reduced or even eliminated, and the effect of improving the durability of a ballastless track high-speed railway with a strict requirement on the smoothness is relatively good.

The invention relates to a spiral condenser, which comprises a heat radiation pipe and fins, wherein the heat radiation pipe forms a cuboid structure through bending and winding, the cuboid structure consists of a plurality of layers of circuitous heat radiation pipe units, the heat radiation pipe units are mutually parallel, in addition, the gap between the heat radiation pipe units is set to be 10mm to 30mm, the fins are spirally arranged on the outer surface of the heat radiation pipe in a winding way and are of a straight sheet type structure, the gap between the adjacent fin blades is set to be 4mm to 10mm, the spiral condenser also comprises a support frame assembly used for supporting and fixing the cuboid structure consisting of the layers of circuitous heat radiation pipe units. The spiral condenser has the characteristics that the cost is low, the manufacturing is simple, the heat radiation effect is good, the refrigeration is fast, and the like.

The invention relates to a water channel structure of a cylinder cover, which comprises a first air inlet hole base, a second air inlet hole base, a first vent hole base, a second vent hole base and a fuel injector sleeve arranged on the cylinder cover. A bolt hole, an oil inlet hole and an oil return hole are formed on the cylinder cover; a lower layer water channel and an upper layer water channel are formed in the cylinder cover around a first inlet valve base hole, a first exhaust valve base hole, a second inlet valve base hole, a second exhaust valve base hole, an inlet channel and an exhaust channel; the lower layer water channel is communicated with the upper layer water channel through a communicating water channel; a first intercommunicating pore is formed between the first exhaust valve base hole and the second exhaust valve base hole to communicate the lower layer water channel on one side with the communicating water channel; and a second intercommunicating pore is formed between the first inlet valve base hole and the second inlet valve base hole to communicate the lower layer water channel on the other side with the communicating water channel. The water channel structure of the cylinder cover can reduce temperature stress of the cylinder cover to ensure that an inlet valve base, an exhaust valve base and the fuel injector sleeve are cooled uniformly, avoid capillary cracks and prolong the service lives of the inlet valve base, the exhaust valve base and the fuel injector sleeve.

The invention discloses a high-temperature retarding and water reducing agent prepared by mixing the following raw materials in parts by weight: 35-45 parts of polycyclic aromatic hydrocarbon sulfonated formaldehyde condensates, 20-30 parts of acyclic hydroxyl sulfonate condensates, 10-15 parts of diethylenetriaminepenta(methylene-phosphonic acid), 8-16 parts of calcium saccharate, 12-18 parts of alunite powder, 5-10 parts of xanthan gum powder, 4-8 parts of barium metaborate, 3-6 parts of sodium lauryl sulfate, 2-4 parts of pentaerythrite di-n-stearate, 6-12 parts of maleic anhydride-styrene sulfoacid copolymers, 10-15 parts of blast furnace slag powder, 5-10 parts of waste saccharide slag powder, 7-13 parts of nekal and 4-7 parts of auxiliary. The water reducing agent disclosed by the invention is excellent in high temperature resistance, relatively wide in applicable temperature range (150-250 DEG C), capable of reducing cement hydration heat release, reducing the temperature stress of the concrete, avoiding generating temperature cracks and completely meeting the construction requirement for high-temperature and high-pressure well cementation, suitable for continuously pouring mass concrete under a high temperature condition, remarkable in water reducing enhancement effect, good in slump loss resistance and wide in market prospect.

The invention relates to the technical field of track traffic, and discloses an ice and snow melting device for a steel track beam. The device comprises a top surface heating strip arranged on the top surface of a beam body of the steel track beam, and side surface heating strips respectively arranged on the two side surfaces of the beam body, wherein the top surface heating strip is used for heating a steel plate on a walking surface of the beam body; the side surface heating strips are used for heating a steel plate on a guide surface and a steel plate on a stable surface of the beam body; the top surface heating strip is bonded with the lower side of the steel plate on the walking surface; the side surface heating strips are respectively bonded with the inner sides of the steel plate on the guide surface and the steel plate on the stable surface; and the top surface heating strip and the side surface heating strips are respectively wrapped with thermal insulating layers for reducing the loss of heat and transferring the heat to the internal of the beam body. The device can quickly and totally melt ice and snow on the steel track beam without generating greater temperature stress, so that the safety performance is guaranteed, and the effects of energy conservation and environmental protection are achieved.

The invention discloses a preparation method of composite cement with low clinker dosage and high flexural compression ratio. The preparation method is to mix three size ranges of powder particles and obtain the composite cement. The three size ranges of powder particles are as follows: 1) the grain size of particles is less than 8mu m, the particles are composed of high-activity supplementary cementing material with the grain size; 2) the grain size of particles is 8-24mu m, the particles are composed of cement clinker particles with the grain size; and 3) the grain size of particles is 24-80mu m, and the particles are composed of low-activity supplementary cementing material or inert filler. The volume percentages of the three size ranges of powder particles are 25-40%, 25-30% and 30-45% respectively. The clinker volume percentage of the composite cement is 25-30%, the 28-day compressive strength is up to 35-50MPa, the flexural strength is up to 10-12Mpa, the flexural compression ratio is 1/3-1/4; and the composite cement has low hydration heat and good anti-cracking capability and can be used in the civil construction/engineering with the demand on the anti-cracking capability.

The invention relates to an underground station strong constraint superposed wall lining cast-in-place concrete structure crack control method. The underground station strong constraint superposed wall lining cast-in-place concrete structure crack control method comprises the following steps: performing cracking risk evaluation on the key influence factors of superposed wall lining concrete and calculating the quantitative influence on the cracking risk coefficient by different factors; optimally designing lining C35P8 concrete mixed proportion and burying temperature and deformation sensors in parts with high cracking risk; soaking jointing surface concrete with clean water before pouring, performing high-temperature construction, controlling the concrete casting temperature to be less than 26 DEG C, increasing the temperature of a core part to the highest peak value after concrete pouring is completed, dismantling a template after the temperature is obviously reduced, sticking the surface and the top at once after dismantling the template and covering with heat-insulating and moisturizing maintaining cloth; and after maintaining, observing and counting the surface crack condition. By the method provided by the invention, the cracking risk of the superposed wall lining is reduced, the technical problem that the superposed wall lining is liable to crack is effectively controlled and prevented and construction quality is guaranteed.

The invention discloses an intelligent adjusting method for temperature loads of an arched concrete dam. The method is characterized by comprising the following steps that the average temperature load of a dam body in every month is calculated; an allowed temperature load is determined, and temperature load increments, needing to be reduced, at different times and different portions are obtained; according to the allowed temperature load and the temperature load increments needing to be reduced, allowed temperatures at different times and different portions of the dam are inversely calculated; according to temperature values, needing to be reached through control, at different times and different portions and the temperature distribution condition of upstream reservoir water, by considering temperature control requirements during the operation period, the arrangement of cooling water pipes during the construction period is optimized, the cooling water pipes are reserved, and water passing temperatures and flows of the water pipes during the operation period are determined; a water fetching elevation range is determined; and water passes according to the determined water fetching elevation range, and temperature control is conducted by controlling the flows in the water pipes. According to the intelligent adjusting method, part of the cooling water pipes in the construction period are reserved, intelligent water passing is carried out during the operation period to control the temperature of the dam body, the temperature loads are reduced, and the working condition of the dam body is improved; safety stock is increased, and durability is improved.

The invention relates to an ultralow-heat binder composition with a high-temperature type latent-heat compound and a method for lowering the hydration heat of concrete by using the ultralow-heat binder composition with the high-temperature type latent-heat compound, wherein the ultralow-heat binder composition is prepared by mixing an inorganic latent-heat compound having the phase transition temperature of 60 DEG C or higher, with a concrete binder through a premixing method. The invention provides the ultralow-heat binder composition which is prepared by mixing a 0.5-10 wt% compound selected from strontium-based latent-heat compound [Sr(OH)2 8H2O], barium-based latent-heat compound [Ba(OH)2 8H2O], magnesium-based latent-heat compound [Mg(NO3)2 6H2O] and ferrum-based latent-heat compound [Fe(NO3)2 6H2O], with a 100wt% ternary binder through the premixing method, wherein the ternary binder consists of 20-70 wt% I type ordinary Portland cement (OPC), 20-60 wt% blast furnace slag (BFS) and 10-60 wt% fly ash (FA); and the invention further provides the method for controlling the hydration heat of the concrete.

The invention discloses a method for determining a mass concrete cooling rate dynamic limit value. The method comprises the following determination steps: S1, obtaining external constraint stress anda relative deformation value of a concrete pouring body according to the thickness, the length and the age range of the concrete pouring body, and calculating the equivalent temperature of the relative deformation value; S2, according to the equivalent temperature of the external constraint stress and the relative deformation value, obtaining the comprehensive cooling difference increment of the concrete pouring body at different lengths and different ages S3, obtaining the cooling rates of different lengths and different ages by integrating the cooling difference increment and the ages; and S4, making a list of concrete cooling rate limit values at different lengths and different ages, and drawing a concrete cooling rate limit value curve graph. The concrete cooling rate standard can be formed, a visual chart is provided for on-site constructors, the constructors can take positive intervention measures conveniently, an on-site monitoring system is optimized, and intelligent development of construction engineering construction can be promoted.

The invention relates to the technical field of track traffic, and discloses an ice and snow preventing device of a steel track beam. The ice and snow preventing device comprises heat tracking belts and ice and snow preventing coatings, wherein the heat tracing belts are arranged on the top face of a beam body of the steel track beam, and the ice and snow preventing coatings are arranged on the two side faces of the beam body; the heat tracing belts are used for heating walking face steel plates of the beam body; and the snow preventing coatings are used for preventing ice and snow from being attached to guide face steel plates and stabilizing face steel plates of the beam body. The heat tracing belts are attached to the lower side of the walking face steel plate, and remaining portions of the heat tracking belts are wrapped by a heat insulation layer; and the heat insulation layer is used for reducing heat losses and preventing heat from being transmitted to the interior of the beam body. According to the device, whole-line ice and snow melting of the steel track beam can be rapidly carried out, large temperature stress cannot be generated, safety performance of the device is ensured, and the construction difficulty is simplified.

The present invention relates to rolled concente arch dam artificial short seam structure, which includes artificial folding seam set on left and right dam shoulder of rolled concrete arch dam; water stopping, water draining and grouting systems are set water stopping, water draining and grouting systems are set in the seam, seam end has anticracking material; arch crown at down stream of arch dam is set ortificial radial short seam, seam end has anticracking material. The present invention can effectively release temperature stress of large surface rolled concrete during dam construction, temperature drop tensile stress of arch dam during operation and water load tensile stressk, if grouting is applied to dam shoulder artificial folding seam at the end of construction, it can improve the stability of dam seat.

The invention discloses a PC rail beam which comprises a rail beam ice and snow melting assembly. The rail beam ice and snow melting assembly comprises a surface layer heat conduction plate, heat conduction pipes which are located at the bottom of the surface layer heat conduction plate and fixedly connected with the surface layer heat conduction plate, heating cables laid in the heat conduction pipes, and a plurality of anchor bars which are fixedly arranged at the bottom of the surface layer heat conduction plate and used for fixedly connecting the surface layer heat conduction plate and beam body concrete. By means of the rail beam ice and snow melting assembly, ice and snow which freeze on the PC rail beam can be rapidly and efficiently processed, and therefore the normal running of trains can be ensured, and obvious social and economical benefits are achieved. In addition, the invention further discloses the rail beam ice and snow melting assembly forming the PC rail beam and a laying method of the PC rail beam.

The invention discloses a construction method of an annually-perforated long-span mass concrete tunnel lining structure. The method includes: a, erecting a formwork and binding lining steel bars (2) at a construction position of a lining (1); b, welding arc-shaped steel pipes (3) on erection bars (2A) in the lining steel bars (2), wherein the central axis of each arc-shaped steel pipe (3) is coincident with an annular axis (1B) of the lining (1) above an inverted arch (1A), and the arc-shaped steel pipes (3) are distributed longitudinally along a tunnel at an equal interval; and c, pouring concrete. The long-span mass concrete tunnel lining structure construction by the method is high in shear capacity and flexural capacity, high in safety and reliability, simple to construct and easy to popularize.