Method to determine limit tensile strength of cement plastering compounds
FIELD: measurement equipment.
SUBSTANCE: invention relates to the field of tests of cement plastering compounds for tensile strength under static loading. Substance: the value of the limit tensile strength is defined by testing steel beams with applied plastering compound according to the scheme of the double-point bend with smooth loading by small steps and fixation of the loading step corresponding to the moment of cracking, and the value of the limit tensile strength is calculated using the formula.
EFFECT: simplified technology for testing, exclusion of the necessity to apply strain metering facilities, higher accuracy of detection of limit tensile strength and completion of tests on plaster layers with specifically small thickness from several mm to 2-3 cm.
1 tbl, 1 dwg
The invention relates to the field of testing cement plaster structures by the maximum elongation under static loading.
An important indicator for the façade plasters is the ability to perceive developing in them shrink and thermomechanical stress without cracking. The cracking of the plaster provides the aesthetic appearance of the facade and limits the ingress of moisture under the plaster, which can cause delamination of plaster layer and affect the durability of the wall.
There is a method of determining the conditional deformation of cement concrete εult(The crack resistance of concrete / Vol, Reitmanova. - M.: Energy, 1972. - P.57-59), in which this feature is calculated as the ratio of the strength of the samples tensile obtained by splitting cube or cylinder Rruskfor the dynamic modulus of elasticity EDeandetermined on samples of concrete of the same composition physical methods. Conditional maximum elongation εultdetermine from the relation εult=Rrusk/EDean.
The disadvantages of this method are the following: this method is indirect; each of the characteristics is determined with errors. In addition, when determining deformation by measuring the resistance at restiani the cleaving and dynamic modulus of elasticity tensile strength splitting R ruskusually 10-15% higher than the tensile strength Rpdetermined by direct testing of samples-eights of material on the axial extension, and dynamic modulus of elasticity higher than the static modulus of elasticity of about 20-25%. This leads to the fact that the thus obtained strain is actually more limiting elongation εultnot less than 15-20%.
Closest to the proposed a direct method for determining a deformation of concrete under tension on samples-eights (Crack resistance of concrete / Vol, Reitmanova. - M.: Energy, 1972. - P.55-56). In this method for determining definatively on samples-eights are bonded devices measure deformation (strain-gauge resistance, mechanical strain gauges), and the samples are tested for tensile strength. Based devices is the so-called zero method of measuring resistance wire sensors to ensure high accuracy of the readings. Such devices include devices series HADES-1M, AI-1, MS-3 and other
The disadvantage of this method is the difficulty of synchronizing data measuring deformation and breaking load, the following voltage.
In both the above methods are implemented test specimens of plaster composition sizes other than the real thickness of the plaster layer.
Object of the invention is the simplification of testing, eliminating the need for application of strain gauges, improving the accuracy of the determination of the maximum tensile and testing on the layers of plaster with a characteristically small in thickness from a few mm to 2-3 cm
The problem is solved in that in the method of determination of the maximum elongation of the cement plaster compounds, including testing of samples of material plaster composition tensile, according to the invention the minimum elongation shall be determined by testing samples of steel beams coated with a plaster composition according to the scheme of the two-point bending with a smooth loading of small steps and a fixation step of loading corresponding to the point of cracking, and the maximum elongation are calculated according to the formula:
where εultSh.R.the ultimate elongation of a plaster solution; P is the applied load is equal to two concentrated forces P/2, kN; and the distance from the support of balocchi to the point of application of concentrated force P/2, cm; Es- the modulus of elasticity of steel, 2·105MPa; b - width steel balocchi, cm; h - height of balocchi, see
By providing uniform loading cement plaster layer dostigaet the homogeneous stress state in the cross section of the specimen due to its alignment with the loading. Thus, technological simplicity in testing and improving the accuracy of determining the magnitude of the limiting stretch.
The method is performed by the following sequence of operations: prepare pre-peeled (to improve adhesion) sample in the form of a steel fatless balocchi from soft carbon steel, the lower surface of which is applied a plaster layer of constant thickness. Next, the sample is incubated under normal conditions (temperature (20±2)°C and relative humidity (90±5)%) required time. After a period of storage under normal conditions balochku placed in natural conditions (temperature (20±2)°C, humidity (55±5)%) for 24 h to remove excess moisture. Next balochku mounted on support media with a mechanical system loading, and test the circuit point-to-point bending with a smooth loading of small steps. The magnitude of the steps taken small increase of the load relative to the maximum allowable, based on the yield strength of the steel sample. After application the next step of loading the plaster layer view (if necessary with the help of a magnifying glass) on the possibility of crack formation at this stage of loading. During the test, record the amount of steps corresponding to the moment of crack formation. The loading is performed in which the limits of 0.8 to 0.9 of the load level, corresponding to the yield strength of the steel balocchi. The ultimate elongation shall be determined based on strain compatibility conditions steel and plaster layer, assuming the absence of influence of a layer on the stress-strain state of the steel balocchi. The accuracy of the method is estimated by the deformation corresponding to1/2it increments one step prior to cracking. The maximum possible error in strain Δε respectively1/2stage load. Varying degrees increment of load, it is possible to obtain the required accuracy.
The drawing shows a diagram of the testing circuit point-to-point bending with a smooth loading of small steps.
In relation to the loading scheme of the two-point bending steel balocchi cross-section b×h, length (span) l bending moment in the pure bending zone will be
where P is the applied load is equal to two concentrated forces P/2, kN; and the distance from the fulcrum to the point of application of concentrated force P/2, cm; M is the bending moment, kN·cm;
where b is the width of the steel balocchi, cm; h - height of balocchi, cm; Wsthe moment resistance of the cross-section balocchi, cm3.
Normal stress in the extreme extended hair is not balocchi
when σsthe maximum allowable voltage is made relatively low yield strength steel σy10-20%, MPa.
From the compatibility conditions of deformation in the assumption that there is no influence of a layer on the stress-strain state of the steel balocchi get
where Es- the modulus of elasticity of steel, Es=2·105MPa; εsthe ultimate elongation of the steel balocchi; εultSh.R.the ultimate elongation of the plaster equal to
The proposed method can be used when estimating the limit of elasticity solutions and research on optimizing the composition of plasters to improve their fracture toughness.
Examples of implementation of the method
The proposed method for the determination of the maximum elongation of the plaster composition is substantiated by the experimental results.
Laboratory studies were carried out for different plaster compositions: Baumit StartContact, Baumit Artoplast, Fast OK Insulation, cement-sand mortar. The proposed method of preparing pre-peeled fat-free steel balocchi (steel grade S230) of size 7×10×200 mm, on the bottom surface which cause the thing is Horny layer of constant thickness. Further, these samples incubated under normal conditions (temperature (20±2)°C and relative humidity (90±5)%) required number of days. After a period of storage under normal conditions of balocchi placed in natural conditions (temperature (20±2)°C, humidity (55±5)%) for a day to remove excess moisture, and then install them on the support of the press with a mechanical system loading (mechanical press with a capacity of 5kN P-8), and test the circuit point-to-point bending with a smooth loading of small steps. Testing for compliance conducted at the age of 14 and 28 days.
The table shows the technique of the experiment and the results of the test beams coated with a plaster composition according to the scheme of the two-point bending on the ultimate elongation (see Annex).
The method of determination of the maximum elongation of the cement plaster compounds, including testing of samples of material plaster composition tensile, characterized in that the minimum elongation shall be determined by testing of steel beams coated with a plaster composition according to the scheme of the two-point bending with a smooth loading of small steps and a fixation step of loading corresponding to the point of cracking, and the maximum elongation calculated by the formula:
SUBSTANCE: method involves measurement of hardening concrete temperature at given time moments and calculation of concrete strength over three days for hardening in standard conditions by the formula:
EFFECT: reduced labour consumption of monitoring.
1 tbl, 2 dwg
SUBSTANCE: apparatus has at least two sealed chambers with a U-shaped pipe filled with water for releasing excess pressure in the chamber, inlet and outlet gas-distributing manifolds, filters for cleaning the gas-air medium collected from the chambers and the inside of each chamber is fitted with a ventilator and a bath with a saturated salt solution for creating and maintaining given relative air humidity inside the chamber, connected to the sealed chambers through the inlet gas-distributing manifold and, installed on pipes, electromagnetic valves, a carbon dioxide gas source, an automatic gas analyser with a gas flow activator, a gas distribution switch for alternately collecting samples from the chambers and transferring the samples to the gas analyser through the gas flow activator; the gas analyser is also connected to a computer for automatic monitoring of gas concentration in the sealed chambers and feeding gas into the chambers through the electromagnetic valves.
EFFECT: high information value and faster determination.
SUBSTANCE: previously they make at least two samples with different water-cement ratios, thermal cycling and cyclic compression of the sample with the least water-cement ratio are alternated until proportion is disturbed between relative residual deformation and number of cycles, the ratio is calculated between relative reduction of threshold load and relative residual deformation, the concrete grade of frost resistance is determined, as well as relative residual deformation εm, corresponding to reduction of the strength limit specified by the standard for the frost resistance grade of the investigated concrete, they alternate thermal cycling and cyclic compression of other samples with higher water-cement ratios until residual deformation is achieved εm, the number of cycles required for this purpose is accepted as the grade of concrete frost resistance with higher water-cement ratio, using the produced results, they calculate parameters of the function that approximates experimental results.
EFFECT: expanded arsenal of technical facilities for detection of concrete frost resistance dependence on water-cement ratio.
SUBSTANCE: in the method including drying of a sample to permanent mass, hydraulic insulation of its side surfaces and water saturation, nonwetting of the upper end surface of the sample is provided, and a light-reflecting water impermeable coating is applied on it, and continuous even water saturation is carried out via the bottom end surface of the sample, at the same time the sample is installed onto fixed supports inside a reservoir for water saturation, the reservoir is filled with water, and even contact is provided between the lower end surface of the sample with water during the entire cycle of measurements, then with the help of laser radiation a series of holographic interferograms is registered on a non-wetted surface of the sample in process of water saturation, at the same time position, speed and acceleration of moisture movement front are determined by comparison of changes in the field of movements of the registered surface, produced according to interferograms, with the rated field of movements of a geometrically similar sample.
EFFECT: improved information value and reliability of detection.
2 cl, 1 dwg
SUBSTANCE: method is realised by fixation of an experimental concrete sample in the form of a prism between bearing plates of a test bench using a centring device, providing for central application of a compressing load in process of loading, and registration of a force and deformation of a prism in time using a dynamometer and a strain station with loading, realised through a lever system in two stages: at the first stage - stepped static loading of a sample to the required level in different shares of the crack formation load by means of laying of unit weights onto a loading platform, at the second stage - instantaneous or stepped dynamic additional loading with a weight dropping during reduction of current force in an electromagnet, the axis of the centre of gravity of which matches with the axis of the loading platform.
EFFECT: increased reliability of tests.
SUBSTANCE: method involves dipping and holding samples of the test materials at room temperature into a weakly aggressive medium - mixture of organic acids: 0.9-1.1% acetic acid, 0.9-1.1% citric acid, 0.09-0.12% oxalic acid, said acids being in ratio of 1.8:2.7:0.8-2.1:3.1:1.2. After exposure, the samples are removed and dried to constant weight and their strength characteristics are then determined.
EFFECT: high efficiency and reliability of tests.
SUBSTANCE: method includes soaking concrete, drilling concrete, detection of power spend for drilling, measurement of value and speed of drilling tool displacement with production of data in the form of curves of power, displacement, speed of the drilling tool, characterising structure and layer strength of concrete with production of digital data on each curve, besides, prior to performance of tests on this investigated section of a concrete item selected for detection of structure and strength of concrete, preliminary preparation of the concrete item surface is carried out, for this purpose the investigated section is polished, and its surface strength is determined in dry condition, then this section of the concrete item is soaked, and surface strength of concrete is identified with account of its moisture, then a drilling plant is installed on the investigated section for drilling of concrete, and by means of drilling, the layer structure and layer strength of concrete in moist condition are identified, besides, as a result of drilling, additionally a cylindrical reference concrete sample is produced, which is used for further tests during determination of strength of the reference concrete sample for compression or axial tension, at the same time readings are compared with readings produced by other previous methods, and the reference concrete sample is previously dried. Also a device of similar purpose is provided.
EFFECT: increased accuracy and reliability of analysis and monitoring.
8 cl, 10 dwg
FIELD: machine building.
SUBSTANCE: invention relates to structural element 11 from electrically insulating material with structure made up of conductors 14a, 14b, 14c to reveal mechanical damages, say, fractures. Said structure varies its electrical properties in continuing fracture formation (arrow 20) to allow timely replacement of structural element 11. In compliance with this invention, said electrical conductor consists of particles with metal surface that stay in contact. This allows making the electric conductor that reacts to mechanical damages to increase sensitivity of aforesaid structure 14a, 14b, 14c. If said metal surface is formed solely by shell of particles and particles consist of the material of structural element 11, then it is possible to develop a conductor with matching characteristics of thermal expansion for thermally heavily-loaded structural parts, in particular, plates of heat protection shield.
EFFECT: higher sensitivity in detection of damages.
8 cl, 6 dwg
SUBSTANCE: method includes monitoring quality of finished mix, initial components of the mix, their dosing, mixing, maintenance of the specified temperature mode and registration of mix temperature at the outlet of the mixer, besides, at all stages of the technological process the spectral density of acoustic noise capacity is registered, and the mixture readiness and necessity to disconnect the mixer's drive are decided by change in density of distribution of the spectral density of capacity radiated by fractions of filler during mixing depending on extent of mixture homogeneity.
EFFECT: higher informative value and reliability of monitoring.
3 cl, 1 ex, 2 dwg
FIELD: technological processes.
SUBSTANCE: method can be used in field of road-building materials. When estimating cohesion of filling agent with mortar part of asphaltic concrete fixed is stamp-standard from three rigidly connected similar elements with lower part from filler in mortar part of examined asphaltic concrete at specified depth of metal reservoir, connected with bed, by fastening stamp-standard in rod system, moving it with respect to surface of mortar part of examined asphaltic concrete by means of thread connection, connected with rod system. After that, metal reservoir is rotated at 180° with respect to bed. Then, stretching effort is created in contact zone of each element of stamp-standard by application to each of three similar elements of stamp-standard of static rupture loading, said loading is recorded at the moment of breaking off of each of three similar element of stamp-standard, located at angle 120° with respect to each other, from mortar part of examined material, and value of tension in contact zone of each of three similar elements of stamp-standard by value of ratio of loading value to size of area of contact zone between filling agent - lower part of each of three similar elements of stamp-standard - and mortar part of asphaltic concrete.
EFFECT: increased accuracy of experimental estimation of cohesion parameter and reduced labour consumption of method realisation with application of great number of stamp-standards.
3 dwg, 1 tbl
FIELD: manufacture of building materials.
SUBSTANCE: object of invention is testing materials for use in designing compositions of artificial building conglomerates and composites as well as in optimizing compositions. Method of invention involves screen fractionation to determine average size of grains of coarse-grain fraction d1 and that of fine-grain fraction d2, ratio of grain sizes d2/d1, and value of dilution of coarse-grain fraction with fine-grain fraction in terms of formula: α = [(d1 + d2)/d1]3. If d2/d1 > 0.155, degree of compaction Y and, if d2/d1 < 0.155, degree of filling Y are found from formula Y = 2 -
EFFECT: reduced volume of laboratory tests and improved qualitative characteristics of calculated and prepared loose mixtures, for which regulation of desired properties of manufactured materials is ensured.
FIELD: manufacture of building materials.
SUBSTANCE: object of invention is testing materials for use in designing compositions of artificial building conglomerates and composites based on organic and inorganic binders. Method of invention involves screen fractionation to determine average size of grains of coarse-grain fraction d1, mm, and fine-grain fraction d2, mm, ratio of grain sizes d2/d1. Degree of compaction Y at d2/d1 > 0.155 and degree of filling Y at d2/d1 < 0.155 are determined from formula Y = 1 - d2/d1.
EFFECT: enabled determining values of degree of compaction and filling of coarse-grain fractions with fine-grain ones without experimental trials associated with preparation of loose mixtures.
FIELD: manufacture of building materials.
SUBSTANCE: object of invention is testing materials for use in designing compositions of artificial building conglomerates and any-nature composites. Method of invention comprises layer-by-layer filling of volume unit with coarse-grain and fine-grain fractions, determining average size of grains of coarse-grain fraction d1 and that of fine-grain fraction d2, d2/d1 ratio, coarse-grain and fine-grain fraction volumes V1 and V2, m3, respectively, consumed per unit mixture volume (1 m3), coarse-grain fraction free volume value Vn1, coarse-grain fraction volume mass γ1, and degree of diluting coarse-grain fraction with fine-grain fraction α calculated by formula: α = γ1/V1. When d2/d1 > 0.155, degree of compaction of coarse-grain fraction with fine-grain fraction Y is calculated using formula: V = [α(V2-1)+1]/Vn1. Invention makes it possible to determine degree of compaction of one-type fractions with other-type fractions taking into account quantitative interrelations between fraction ratios, between fraction ratios and volume of mixture being formed, between volume of mixture and coarse-grain fraction free volume value, between all them and above-indicated dilution value.
EFFECT: enabled regulation of volume mass and preparation of materials with desired volume-mass characteristics.
FIELD: technologies for testing properties of materials.
SUBSTANCE: in method for determining compositions of friable bi-senary systems of expanded type with core dimensions in fractions determined by method of sieve analysis or sedimentation method, fraction volumes are determined for binary systems: V1=1/α 1, m3, V2=V1(α 1-1), m3, α 1=(1+d2/d1)3, m3, for ternary systems V1=1/α 1, m3, V2=V1((α 1-1)/ α 2), m3, V3=V2(α 2-1), m3, α 1=(1+(d2+2· d3)/d1)3, m3, α 2=(1+d3/d2)3, m3, for quaternary systems V1=1/α 1, m3, V2=V1((α 1-1)/ α 2), m3, V3=V2((α 2-1)/ α 3), m3, V4=V3(α 3-1), m3,
α 1=(1+(d2+2· d3+4· d4)/d1)3, m3, α 2=(1+(d3+2· d4)/d2)3, m3, α 3=(1+d4/d3)3, m3, for quinary systems V1=1/α 1, m3, V2=V1((α 1-1)/ α 2), m3, V3=V2((α 2-1)/ α 3), m3, V4=V3((α 3-1)/ α 4), m3, V5=V4(α 4-1), m3, α 1=(1+(d2+2· d3+4· d4+8· d5)/d1)3, m3, α 2=(1+(d3+2· d4+4· d5)/d2)3, m3, α 3=(1+(d4+2· d5)/d3)3, m3, α 4=(1+d5/d4)3, m3,for senary systems V1=1/α 1, m3, V2=V1((α 1-1)/ α 2), m3, V3=V2((α 2-1)/ α 3), m3, V4=V3((α 3-1)/ α 4) ,m3, V5=V4((α 4-1)/α 5), m3, V6=V5(α 5-1), m3, α 1=(1+(d2+2· d3+4· d4+8· d5+16· d6)/d1)3, m3,
α 2=(1+(d3+2· d4+4· d5+8· d6)/d2)3, m3, α 2=(1+(d4+2· d5+4· d6)/d3)3, m3, α 3=(1+(d5+2· d6)/d4)3 ,m3, α 4=(1+d6/d5)3, m3, where V1,V2,V3,…,V6 - fractions volumes with core sizes d1,d2,d3,…,d6,m3; α 1, α 2, α 3, ... , α 5 - volumetric coefficients of separation of cores with d1 dimension by all other cores, dimension d2 by all other cores, etc.
EFFECT: higher efficiency.
FIELD: technologies for testing properties of materials.
SUBSTANCE: in method for determining compositions of friable systems of condensed-expanded type in fractions with core sizes D1>D2>D3>D4>D5 when D2/D1,…,D5/D4 greater than 0.155 volumes of fractions VD1, VD2, VD3, VD4 having core sizes D1, D2, D3, D4 respectively, m3, are determined, as well as core material denseness, average core size, value of emptiness VeD1 of fraction with core size D1, condensation grade coefficients Y1, Y2, Y3, of fraction with core size D1 by fraction with core size D2, mixture of condensed type on basis of fraction (D1+D2) with average sizes of cores Dav.sm2 by fraction with core size D3, mixture of condensed type on basis of fractions (D1+D2+D3) with average core size Dav.sm3 by fraction with core size D4 respectively, fractions with large core sizes are used for receiving mixtures of condensed type, condensed type mixtures volumes Vsm2, Vsm3, Vsm4,are determined on basis of fractions (D1+D2), (D1+D2+D3) and (D1+D2+D3+D4) respectively, m3, emptiness value Vemp2, Vemp3, of condensed type mixtures on basis of fraction (D1+D2) and (D1+D2+D3) respectively, separation of cores in condensed type mixture is performed by fractions with lesser core sizes, separation coefficient α1, α2, α3, value is determined, for mixture cores on basis of fractions (D1+D2) with core sizes D3, mixture cores on basis of fractions (D1+D2+D3) with core sizes D4, mixture cores on basis of fractions (D1+D2+D3+D4) with core sizes D5, respectively, and compositions of friable condensed-expanded type are determined from formulae in following order: composition of condensed type binary mixture on basis of fractions (D1+D2) from formulae m3, m3m3, Y1=1-D2/D1, 1 m3 of said condensed type binary mixture Vem2=VD1+VD2=1m3 for preparation of ternary condensed-expanded type mixture, composition of which is determined from formulae composition of ternary condensed type mixture is determined on basis of fractions (D1+D2+D3) from formulae 1 m3 of said ternary condensed type mixture is used for preparation of quaternary mixture of condensed-expanded type, composition of which is determined from formulae composition of quaternary condensed type mixture is determined on basis of fractions (D1+D2+D3+D4) from formulae Ysm3=1 m3, 1 m3 of quaternary condensed type mixture is used for preparation of quinary condensed-expanded type mixture, composition of which is determined from formulae
EFFECT: higher efficiency.
FIELD: technologies for testing properties of materials.
SUBSTANCE: in method for determining compositions of bi-senary friable filled-separated type systems in fractions with core sizes d1>d2>…>d6 when d2/d1,…,d6/d5 less than 0.155 volumetric mass and denseness of core material is determined as well as emptiness value, empty spaces fill grade coefficient, volumetric separation coefficient, and fraction volumes are determined from formulae for binary systems V1=1 m3/α 1, m3,
V2=V1(У1·Ve1 + α 1-1), m3, Y1=1-d2/d1, α 1=(1+d2/d1)3, Ve1=1-γ 1/ρ 1, for ternary systems V1=1 m3/α 1, m3, V2=V1((Y· Ve1+α 1-1)/α 2), m3, V3=V2(Y· Ve2+α 2-1), m3, y1=1-d2/d1,y2=1-d3/d2, α 1=1-d2/d1, α 2 =(1+(d2 + 2· d3)/d2)3, Ve1=1- γ 1/ρ 1 Ve2=1-γ 2/ρ 2, for quaternary systems V1=1m3/α 1, m3, V2=V1((Y1Ve1+α 1-1)/α 2), m3, V3 =V2((Y1Ve2+α 2-1)/α 3), m3, V4=V3(Y3 Ve3+α 3-1), m3, у1=1-d2/d1, y2=1-d3/d2, y3=1-d3/d3, α 1=(1+(d2+2· d3+4· d4)/d1)3, α 2=(1+(d3+2d4)/d2)3, α 3=(1+d4/d3)3, Ve1=1-γ 1/ρ 1,Ve2=1-γ 2/ρ 2, Ve3=1-γ 3/ρ 3, for quinary systems V1=1m3/α 1, m3, V2=V1((Y1Ve1+α 1,-1)/α 2), m3, V3=V2((Y2Ve2+α 2-1)/ α 3), mз, V4=V3((Y3Ye3+α 3-1)/α 4), m3, V5=V4(V4Ve4+α 4-l), m3, У1=1-d2/d1, y2=1-d3/d2, y3=1-d4/d3, y4=1-d5/d4, α 1=(1+(d2+2· d3+4· d4+8· d5)/d1)3, α 2=(1+(d3+· 2· d4+4· d5)/d2)3, α 3=(1+(d4+2· d5)/d3)3, α 4=(1+d5/d4)3, Ve1=1-γ l/ρ 1, Ve2=1-γ 2/ρ 2, Ve3=1-γ 3/ρ 3, Ve4=1-γ 4/ρ 4, for senary friable systems V1=1 m3/α 1, m3, V2=V1((Y1Ve1+α 1-1)/α 2), m3,V3 =V2((Y2Ye2+α 2-1)/α 3), m3, Y4=Y3((Y3Ye3+α 3-1)/ α 4), m3, V5=V4((Y4Ve4+α 4-1)/α 5), m3, V6=V5(Y5Ve5+α 5-1), m3, Y1=1-d2/d1, Y2=1-d3/d2, Y3=1-d4/d3, Y4=1-d5/d4, Y5=1-d6/d5, α 1=(1+(d2+2· d3+4· d4+8· d5)/d1)3, α 2=(1+(d3+2· d4+4· d5)/d2)3, α 3=(1+(d4+2· d5)/d3)3, α 4=(1+d5/d4)3, α 5=(1+(d6/d5)3, Ve1=1-γ 1/ρ 1, Ve2=1-γ 2/ρ 2, Ve3=1-γ 3/ρ 3, Ve4=1-γ 4/ρ 4, Ve5=1-γ 5/ρ 5, where V1, V2, V3, V4, V5, V6 - volumes of fractions with cores sizes, respectively, d1, d2, d3, d4, d5, d6, m3; Y1, Y2, Y3, Y4, Y5 - coefficients for large core size fractions' empty spaces fill grade with fractions having lesser core sizes, dimensionless quantities; 0<Y<1; α1, α2, α3, α4, α5 - volumetric separation coefficients for fractions with large core sizes by all fractions with lesser core sizes, dimensionless quantities, in binary systems 1<α<8; Ve1, Ve2, Ve3, Ve4, Ve5 - values of fractions emptiness with core sizes, respectively, d1, d2, d3, d4, d5, dimensionless quantities (relation of emptiness' volume to fraction volume), ρ1, ρ2, ρ3, ρ4, ρ5 - denseness of cores material, kg/m3, γ1, γ2, γ3, γ4, γ5 - volumetric share of cores material, kg/m3.
EFFECT: higher efficiency, broader range of functional capabilities.
FIELD: technologies for testing properties of materials.
SUBSTANCE: in method for determining compositions of friable condensed-filled-separated type systems in fractions with sizes of cores D1>D2>…>Dn-1>Dn when D2/D1, D3D2,…,Dn/Dn-1 greater than 0.155, d1>d2>…>dn-1>dn when d2/d1, d3/d2,…,dn/dn-1 less than 0.155, where Dn>d1, cores material denseness is determined, as well as volumetric mass, emptiness value and average fraction cores size, compaction level value is calculated, composition of mixture of condensed type is determined on basis of fractions with core sizes D, emptiness value and average cores size of said mixture, value of grade of filling of empty spaces of mixture with fractions with core sizes d is calculated, value of separation level of condensed mixture by fractions with core sizes d is calculated, and compositions of friable systems of condensed-filled-separate type are determined from formulae in following order: , m3, where Vmx - volume of mixture of condensed type on basis of fractions with core sizes D, m3; α - coefficient for condensed type mixture separation by fractions with core sizes d; Vd - volume of fraction with sizes of cores d, m3; Y - level of filling of empty spaces of compacted type by cores of fractions with sizes d, limits of value measurement being 0<Y≤1; Vemp - condensed type mixture emptiness value - relation of empty spaces volume to mixture volume, Dav.mx2 - average size of cores in a mixture.
EFFECT: higher precision, lower laboriousness.
FIELD: nondestructive testing.
SUBSTANCE: method comprises drilling hole in concrete, securing anchor device inside the hole, and pulling out the anchor with applying destroying force. The strength of concreter is determined form the formula , where N is the destroying force, D is the diameter of the specimen, m, and d is the diameter of the hole, m.
EFFECT: enhanced accuracy of determining.
1 dwg, 1 ex
SUBSTANCE: method comprises securing anchor device connected with the instrument in the concrete, applying breaking load, and determining the strength form the breaking load. The concrete is provided with hole and ring groove coaxial to the hole. The depth of the groove is equal to the height of the specimen. The anchor device is then secured in the hole and breaking force is applied by pressing the anchor device until the specimen is spalled. The strength is determined from the formula where N is the breaking load, in N, h is the height of the specimen, in m, D is the diameter of the specimen, in m, and d is the diameter of the hole.
EFFECT: decreased labor consumption.
1 dwg, 1 ex
FIELD: building, particularly to perform nondestructive testing of structure concrete strength.
SUBSTANCE: method involves drilling bore-hole in concrete body; cutting annular groove in concrete body coaxial to bore-hole; arranging metal cylindrical ferrule in annular groove, wherein cylindrical ferrule has dimension comparable with that of sample; securing anchoring head in bore-hole and pressing anchoring head into concrete body up to sample destruction. Concrete strength is determined from the following formula: R = (N·10-6)/2πdh, where R is concrete strength, MPa, N - destructive force, H, h is sample height, m.
EFFECT: possibility to determine physical and mechanical concrete characteristics directly in structure body.