611 results about "Dry density" patented technology

A structural fiber cement sheet containing cementitious matrix and reinforcing cellulose fibers distributed throughout the matrix having a dry density less than 1.25 g/cm³, a thickness less than 0.7500 in, and able to withstand uniform loads of 200 psf or greater according to test method of Section 6.4.2.4 of PS2 and with a deflection of less than 0.067 inches at 60 psf when spaced on a span of 24 inches or less on center.

The invention relates to a cement-based lightweight porous heat insulating material and a preparation method thereof. The material is prepared from portland cement or ordinary portland cement, water reducing agent, foam stabilizer, early strength agent, fiber, emulsion powder, water repellent, foaming agent and water according to a certain ratio. The weight ratio of cement, water reducing agent, foam stabilizer, early strength agent, fiber, emulsion powder, water repellent and foaming agent is 100:0.2-2.4:(0.1-3.)0:(1.0-4.0):(0.3-1.5):(0.1-5.0):(0.1-6.0):(3.0-8.0); and the water cement ratio is 0.45-0.55. The dry density of the LWFC material is 250-300kg/m<3>, the compressive strength is 0.5-1.0MPa, the heat conduction coefficient is 0.05-0.08W/m.k, the water absorption rate is 4-8%; the material can not deform and crack, is used as an inorganic incombustible lightweight heat insulating material and can replace the organic combustible heat insulating material represented by polystyrene foam; and the material can be used in the external wall exterior insulation construction of the building energy-efficient project and can also be used in the roof insulation project, the floor heating project or the occasions for preparing the composite heat insulating board and the like.

Provided is a method for manufacturing a fixed abrasive material suitable for use in CMP planarization pads from an aqueous polymer dispersion that also includes abrasive particles that involves frothing the polymer dispersion, applying the froth to a substrate, mold or carrier and curing the froth to form a fixed abrasive material having an open cell structure containing between about 5 and 85 wt % abrasive particles and a dry density of about 350 kg/m³ to 1200 kg/m³.

The invention which belongs to the field of civil engineering equipment relates to a full-automatic, digital and large frozen soil direct shear apparatus. The large frozen soil direct shear apparatus which comprises a shear box, a refrigeration system of an upper shear box, a refrigeration system of a lower shear box, a vertical servo loading and monitoring system, a horizontal servo loading and monitoring system, and a measurement and control system is to determine the shear strength of the freeze-thaw interface of the frozen soil or determine the shear strength of full frozen soil and full thawy soil. The size of a frozen soil sample in the embodiment of the invention is 305mm*305mm*200mm, static force and a layered compacting method are adopted to prepare remolded soil samples of different initial water contents and dry densities for shear tests; temperature control systems of the upper shear box and the lower shear box are adjusted to control the temperatures of soils in the shearboxes to guarantee the shear plane to be superposed with the freeze-thaw interface of the frozen soil sample. The direct shear apparatus of the present invention solves problems that the difficulty of testing the shear strength of the freeze-thaw interface is large, the shear tests of coarse grain soil are difficult and the like and provides reasonable design parameters for civil engineering and traffic engineering in cold or highly cold regions.

The object of the Electrical Density Gauge (EDG) invention is to provide a low cost, portable, non-nuclear, and rugged field-use device that measures dry density in soils that have been constructed for use as road-beds and building foundations. This data is used to ensure the quality control of the constructed foundation. The electrical properties of soil are measured at a radio frequency using probes driven into the soil. To calibrate EDG, certain algorithms of these electrical properties are related to physically measured wet densities and unit weights of water for a plurality of calibration test spots. Correlation regressions are found, that are used to convert values of the electrical properties measured at unknown field test spots into values of dry density.

The invention discloses a crack resistance type cement stabilized macadam proportioning design method based on vibration test method. The design method is implemented according to the following steps:(1) preparing framework dense graded aggregate; (2) adding cement into graded aggregate to obtain a cement stabilized macadam mixture, and adopting vibration compaction test method to determine the maximal dry density and the optimal water content of the cement stabilized macadam mixture, wherein the added cement dosage accounts for 3-5% of the graded aggregate according to mass percent; (3) adopting the cement stabilized macadam mixture in step (2) and vibration compaction test method to prepare a cement stabilized macadam cylinder test piece with the dimension being 15cm in diameter * 15cmin height; (4) carrying out an unconfined compression strength test on the cement stabilized macadam cylinder test piece which is subject to 6 days of preserving and 1 day of water soaking, and designing the cement dosage according to the result of the unconfined compression strength test. The cement stabilized macadam designed by the invention can better form a compact framework structure, featuring unlikely dissociation, the maximal dry density, the optimal water content and saving of 30-40% cement use amount, has the advantages of high strength, good crack resistance and good scour resistance, and basically solves the problems of serious crack of cement stabilized macadam which perplexes road engineering circles, at home and abroad, all the time.

The invention relates to the technical field of preparation of triaxial experiment samples in rock mechanics and discloses a triaxial sample preparation device for low-liquid limit silty soil and a sample preparation method. The device comprises a sample tube, a smoothening device, a vibrator and a loading device. The method comprises the following steps: sleeving a rubber diaphragm in a split cavity; gradually pouring soil sample; controlling the initial dry density through the smoothening device and the vibrator; filling carbon dioxide and air-free water from a base until saturation; and carrying out sample consolidation process according to a secondary dry density. According to the invention, the problem of producing uniform silty soil sample is solved, the split cavity integrates the functions of positioning and sealing so as to improve the dimensional precision and the sealing effect of the sample; a rubber-steel combined vibrating head is adopted to improve the vibration and densification effect; and the matching with a current triaxial apparatus is realized, which reduces the equipment investment; and through the two-stage control of the initial dry density and the secondary dry density, the density of the sample can be optionally appointed within a certain range.

The invention discloses a method for calculating the slope stability safety coefficient based on strength reduction of a humidifying condition. The method comprises the steps of testing the dry density rhod, the natural moisture content omega1, and the percentage of saturated moisture content omega2 of a slope soil body sample, testing the cohesive force c and internal friction angles of samples with different moisture contents, and calculating the volume weight gamma of the samples, wherein the formula of internal friction angles is shown in the description; drawing the relation curves of the cohesive force c and the internal friction angles respectively with the moisture content omega, and obtaining a mathematic formula of a fitting relation curve; adopting a dichotomy approximation method and considering the volume weight change, and calculating the moisture content omegaF when the slope is in critical failure; calculating the slope stability safety coefficient F. According to the method for calculating the slope stability safety coefficient based on the strength reduction of the humidifying condition, anti-shearing strength of the slope soil body is reduced based on the humidifying condition, the method better conforms to the engineering practice that the moisture content of the soil body is increased, and thus the strength is lowered due to rainfall infiltration or irrigation or the like, and the shortcoming that a prior strength reduction method is not clear in mechanical concept is overcome. When strength reduction is conducted, the adverse influence of the increase of the volume weight of the soil body on the slope stability is further considered. Therefore, the method for calculating the slope stability safety coefficient based on the strength reduction of the humidifying condition is more scientific and safer.

The invention discloses a semi-automatic multifunctional soil test sample compaction device which comprises a bracket system, a power and control system, a model forming system and a sample compaction system, wherein the bracket system comprises a base, a side column and a top plate; the lower end of the side column is fixed on the base; the top plate is fixedly arranged at the upper end of the side column; the power and control system is arranged on the base; the model forming system is arranged on the power and control system; the sample compaction system is fixedly arranged on the top plate; the corresponding model forming system and the sample compaction system are selected to be arranged on a movable sample compaction platform and the top plate; a soil sample with a certain mass is put into the gap between an inner model forming cylinder and an outer model forming cylinder (or is put into the model forming cylinder) according to the corresponding test specification; then a displacement controller is operated to control a hydraulic system, so that the movable sample compaction platform ascends to a preset height, meanwhile, a sample compaction hammer goes deep into the model forming cylinder, soil particles on each layer are layered and compacted according to the required dry density, namely a remolded hollow cylindrical sample (or a solid cylindrical sample) is obtained.

The invention provides a method for optimizing grain composition of a blasting rockfill material based on a fractal theory. The method is characterized by comprising the following steps of: establishing a function relation among the grain fractal dimension, compacted dry density and average particle size of the rockfill material, and further establishing a relation between a blasting scheme or parameter and the compacted dry density of a field rockfill material according to a correction Kuz-Ram model for forcasting the blasting fragment size distribution of a rock mass; and obtaining an optimal grain composition of a dam construction rockfill material which is easier to compact by adjusting the blasting scheme or parameter. The method can be applied to optimized design of the grain composition of the blasting rockfill material.

An aerated composite material produced from carbonatable calcium silicate compositions (carbonation cured AAC) that has a compressive strength equivalent to autoclaved aerated concrete (ordinary AAC) at substantially the same density and a process of production of the same are provided. The composite material of the present invention comprises: a plurality of bonding elements, each including a core comprising calcium silicate, a first layer which partially or fully surrounds the core and is rich in SiO₂, and a second layer which partially or fully surrounds the first layer and is rich in CaCO₃; a plurality of filler particles having their particle sizes ranging from 0.1 μm to 1000 μm; and a plurality of voids; wherein the plurality of bonding elements and plurality of filler particles together form a bonding matrix and are substantially evenly dispersed in the matrix and bonded together, the plurality of voids are bubble-shaped and/or interconnected channels, a pore volume with a radius of 0.004 μm to 10.0 μm in the plurality of voids is 0.30 ml/composite material 1 g or less, and a estimated compressive strength expressed by the following formula (1): estimated compressive strength (absolute dry density=0.50)=compressive strength×(0.50÷absolute dry density)² is 2.0 N/mm² or greater.

The invention discloses a chemical foaming method for preparing foamed concrete, which belongs to the technical field of building thermal insulation materials. The raw material composition and weight percentage of foam concrete are: cement 20-80wt%, ore powder 1-5wt%, fly ash 5-30wt%, foaming agent 1-6wt%, water 10-70wt%, modifier 0.2- 1.5wt%, fiber 0.2-1wt%, auxiliary material 1-8wt%. Its preparation method is to pour water into the container first, then put a certain amount of cement, ore powder, fly ash, and additives into the water, stir evenly with a stirrer, pour in foaming agent to mix and stir, and then quickly transfer After leaving the mixer, the foaming is completed within 30 minutes, and the strength is reached after 24 hours, and the formed foam concrete is obtained after 28 days of curing. The foamed concrete obtained by the invention has good water resistance, low thermal conductivity, low dry density, high strength, strong durability, simple formula and convenient construction; it can partially replace polystyrene board, extruded plastic board and rubber powder in the external wall insulation system Polystyrene particles and other organic insulation materials.

The invention discloses a sandy soil microbe solidification method and apparatus. The solidification method comprises steps of first, preparing high concentration bacteria liquid, second, compounding cementation medium solution, third, injecting the high concentration bacteria liquid and cementation medium solution into sandy oil, and fourth, nursing the sandy soil and molding the same. In the high concentration bacteria liquid preparation step, Pasteur spore sarcina is transplanted into an ammonium salt-yeast base nutrient solution; the PH value of the nutrient solution is adjusted to be about 8.0 to 9.0; the nutrient solution is vibratingly water-bathed for 30 to 40 hours at the temperature of 30 DEG C; then high concentration bacteria liquid with concentration of 0.8 to 1.2x107cells/ml is centrifugally achieved; the cementation medium solution comprises urea-calcium chloride, ammonium chloride, sodium bicarbonate and ammonium salt-yeast base nutrient solution; in the third step, the sandy soil is manufactured into samples with various dry density; two ends of each sample are respectively provided with a plastic block; the external side of the sample is covered with latex film; 15mL high concentration bacteria liquid and 50 to 100mL cementation medium solution are successively injected into the sandy oil via a peristaltic pump; and the samples are placed and nursed in environment with temperature ranging from 22 to 20 DEG C and relative humidity of 95%. With action of microbe solidification, unconfined compression strength can be obviously improved for the sandy soil.

The invention discloses a method for preparing a road (bottom) base material cylindrical test piece simulating on-site rolling effect. The vibration compaction test method is adopted to determine the maximum dry density rhodmax and the optimal moisture content wo and the vibration method is adopted to prepare the cylindrical test piece. The operation process of the method corresponds to the on-site practical construction process. The maximum dry density and the optimal moisture content of the tested (bottom) base material and the prepared test piece coincide with the on-site practical rolling effect. The test result of the performance of the test piece is objective and real; and the method has good repeatability. Steps of measuring the moisture content of dried aggregates and moisture content of dried test samples, a step of interlayer broom-finish treatment, a step of flattening the surface of the samples and the like are saved; the material feeding process is simplified; and the working efficiency is improved. The method has the advantages of simple operation, reliable result and good repeatability.

The invention provides an earth and stone material grading optimization determining method which comprises the following steps of: changing granularity fractal dimension of earth and stone materials for the earth and stone materials with particle distribution meeting fractal distribution characteristics; preparing a grading earth and stone material sample with different particle size distribution functions; establishing a function relationship of extreme value dry density, modulus of compression, shearing strength and grading granularity fractal dimension through a field or indoor test; and regulating the granularity fractal dimension to obtain earth and stone material grading with a better filling relationship, easier compactness, higher modulus and strength. The earth and stone material grading optimization determining method can be used for a particle grading optimization design of rockfill materials and natural sand gravel materials.

The invention proposes a bituminous mixture proportion design method based on tightest state. The method includes that: (1) three parameters for evaluating the tightness of mixture mineral aggregate are determined, including the voidage of mineral aggregate , the voidage of coarse mineral aggregate and the mixture mineral aggregate dry density; (2) the relevance of the three parameters are demonstrated, the secondary curvature model is adopted for analysis to determine the extreme values of the corresponding parameter curvatures as the tightest state of the mixture; (3) the oilstone ratios corresponding to the extreme values of the parameters are selected, namely the oilstone ratios corresponding to the maximums of the voidage of mineral aggregate VMA and the voidage of coarse mineral aggregate VCA, and the oilstone ratio corresponding to the maximum of mineral aggregate dry density, and the oilstone ratios correspond to the tightest state of the mixture; (4) for reducing error, the average value of the three oilstone ratios is used as the design oilstone ratio. The invention is applicable to coarse aggregate gap-graded bituminous mixture and ensures the bituminous mixture designed by the invention to have good road performance.

The invention discloses an experimental method for measuring maximum dry density of a road base material, which comprises the following steps: filling a mixture into a test die, fixing the test die on a vibration gauge, and vibrating and compacting the test die for 100 to 120 seconds; calculating the dry density of the sample, repeating the experiment for five times to obtain five groups of blended water contents and dry densities of the sample, and drawing a relation curve of the water contents and the dry densities, wherein the horizontal coordinate is the blended water content, the longitudinal coordinate is the dry density, the dry density corresponding to a peak value of the curve is the maximum dry density and the corresponding water content is the optimal water content; and parameters of the vibration gauge are configured as follows: 30+/-2Hz of vibration frequency, 7.6+/-0.2kN of exciting force, 1.4+/-0.2mm of nominal amplitude, 3.0+/-0.4kN of working weight, 1.2+/-0.2kN of loading system, and 1.8+/-0.2kN of unloading system. The method has the advantages of simple and convenient operation, reliable result and good repeatability.

The heat insulating foamed polystyrene particle mortar used in building engineering consists of portland cement 40-45 wt%, flyash 3-6 wt%, fine silica powder 0-3 wt%, foamed polystyrene particle 1.3-2.8 wt%, polypropylene fiber 0.1-0.2 wt%, quartzite 42-47 wt% and water-thinned silane/siloxane emulsion 5-8 wt%. The present invention has light bulk weight, dry density 300-480 kg/cu m; good heat insulating and sound isolating performance, and heat conducting coefficient 0.07-0.13 W/m.k. The present invention utilizes partial flyash to replace cement and the product has no environment pollution.

The invention discloses a construction method for compacting a high loess-filled embankment by combining vibration roller compaction with dynamic compaction, and the specific construction method comprises the following steps: spreading out silt till the height of 0.4m and adopting a 50T vibratory roller to roll 10 times at the traveling speed of 3km/h; adopting a 3000kN.m-energy level dynamic compactor to perform point compaction at intervals of 4m when a body to be filled and built is filled and built in layers to the height of 6m; using a high-precision water level gauge to measure the average settlement of the filled and built body after completing one-time ramming and stopping ramming when the single-time average settlement is less than or equal to 0.05m; and continuously repeating the operation till the body is filled and built to the design scale height. By adopting the construction method, the problem that impact reinforcement can not be performed on the basis of the vibration roller compaction due to the limited space is solved, the loess collapsibility can be eliminated, the cost is simultaneously saved, the construction period is shorted, the degree of compaction of the filled and built body can be improved to 0.996 to the maximum extent, the dry density can be improved to 1.93g/cm<3> to the maximum extent, the characteristic value of bearing capacity of a foundation can achieve 350kPa and the post-construction differential settlement of the high embankment can be better controlled.

The invention discloses a nondestructive testing method for the compaction quality of a rock-soil filled foundation. The nondestructive testing method comprises the following steps of: acquiring wave speed data of surface waves of the rock-soil filled foundation; calculating the macroscopic shear wave speed of a rock-soil mixed material; calculating the shear wave speed of fine grained soil in a rock-soil mixed material; calculating the dry density of the fine grained soil in the rock-soil mixed material to obtain characterization compactness; calculating the compaction quality of the fine grained soil according to the characterization compactness and a standard characterization compactness value; and the like. According to the nondestructive testing method for the compaction quality of the rock-soil filled foundation, which is provided by the invention, reasonable evaluation for the compaction quality of the rock-soil filled foundation is realized by testing the compactness of the fine grained soil; by means of the shear waves and the surface waves as test means, the integral compaction condition of the lower part of the foundation can be reflected and the problem of poor representativeness of a measuring point in a traditional method is avoided; in addition, the nondestructive testing method has the advantages of high detection precision, high speed, low cost and no damage to the foundation, thus the nondestructive testing method is a detection technology which can adapt to modern construction of civil engineering and has a broad application prospect.

The invention provides a preparation method for a lightweight gypsum-based fireproof door core board. The preparation method employs alpha-hemihydrate gypsum, a cement foaming agent, a short fiber, gridding cloth and a water reducer as raw materials. The fireproof door core board prepared in the invention has dry density of 300 to 450 kg/m<3>, oven dry compressive strength of no less than 1.0 MPa, oven dry rupture strength of no less than 0.5 MPa and combustion performance according with the fire-resistance rating A1 prescribed in Building Material and Product Combustion Performance Rating GB8624-2006; the preparation method for the fireproof door core board has the advantages of low comprehensive cost, simple production process, environment friendliness and no pollution, enables long fire endurance time of the fireproof door core board to be obtained and effectively overcomes the problems of complex production process for a vermiculite fireproof door core board and moisture absorption and returning of halogen and frost of a magnesium oxychloride cement fireproof door core board.

The invention discloses a red mud porous material. In order to solve the problem of discharge of red mud, the invention adopts a synthetic technology of chemically bonded ceramics and a chemically entraining technology; and according to the invention, the porous material is prepared from red mud serving as a part of raw material of a synthetic material, as well as solid water glass, slags, coal ash, a foam stabilizer, water and a foamer. The porous material has the advantages of uniform aperture, light weight, good insulating property, low water absorption, high strength, high percentage of close area, environment-friendliness, high solid waste utilization rate and the like, and the percentage of close area of the prepared red mud porous material is over 95%, the dry density is 450-700kg/<m3>, the heat conducting coefficient can be lower than 0.13w/mk and the fire protection ability can reach 4 hours, so that the material can be widely applied to aspects such as chemical engineering, heating and heat insulating, building energy conservation, indoor sound isolation and noise barriers for expressways.

The invention provides a method suitable for measuring the extreme dry density of naturally-graded coarse particles on an earth and rockfill dam construction field. The method for measuring the extreme dry density of a naturally-graded coarse particle dam construction material comprises the following steps of: measuring the extreme dry density of the naturally-graded coarse particle dam construction material on the basis of the vibrating compaction energy delivering mechanism of a heavy-duty vibrating roller and paving and rolling testing on the dam construction field; and calculating relative density according to a designed dry density. On the basis of the input energy mechanism of a field vibration rolled real dam body, the extreme dry density of the naturally-graded coarse particle dam construction material is calculated under a given construction rolling condition, so that the compaction characteristic of the naturally-graded coarse particle dam construction material is controlled by using a relative density index. A practicable method for controlling the field compaction quality of an earth and rockfill dam is provided.