Method to determine composition of dry construction mix for concrete
SUBSTANCE: previously prepared samples with various quantity of a filler in a highly dispersed condition for a dry construction mix are placed into a hollow part of metal washers, placed on a metal plate, are compacted by any available method under permanent load of up to 5 MPa per 1 cm2 of sample surface for 10-15 seconds, then marks are applied on the surface of each sample in the form of drops of a solution of various concentration, wetting angles of samples are measured θ, a curve of dependence is built cosθ-1=f(1/σl), where σl - surface tension of the liquid, they determine the angle of inclination of this functional dependence a for each sample of different composition, the curve of dependence a is built on quantity of mix components, and by the point of break of the curve of dependence they define the optimal content of a modifier in the tested object.
EFFECT: reduced number of tests and higher accuracy of mixture composition selection.
2 cl, 2 dwg, 1 tbl
The invention relates to methods for determining the composition of the dry mix mortar for concrete filler in finely dispersed condition, which includes technological measures for measuring material properties in order to increase the strength and / or other performance characteristics of the concrete.
The optimum content of the filler in the composition of dry construction mixes for concrete is often determined experimentally.
There is a method of determining the composition of the dry mix mortar for concrete by measuring the mobility of mortar [GOST 31357-2007. A mixture of dry construction with cement binder. General specifications; GOST 5802-86. The mortars. Test methods]. In accordance with GOST 5802-86 the method includes a preliminary selection of the composition, mixing the starting components, preparation of mortar and based on the dependence of the mobility of the construction of the mortar mix and the magnitude of the depth of immersion of the standard metal cone relative to the surface of the mixture. This method is resource-demanding, less accurate and requires a large number of experimental tests.
There is a method of determining the flow of fine and coarse aggregate in the concrete mix by the values of bulk density and average protectionary and coefficient of separation of the grains of the coarse aggregate with a solution of [RU, patent 2014305, C04B 28/00, 1994]. This method relates to a method of operational control concrete mix, including the selection of the composition of the starting components, but it is very cumbersome, multi-stage, includes a large amount of experimental tests and inspections, adjustments calculations. This method is adopted for the prototype.
The task of the invention is to reduce the amount of experimental testing and improving the accuracy of the determination of the dry mixes for concrete.
Sample preparation is carried out as follows. Conducted selection and mixing of the original main components of dry building mix: aggregate (sand), binder (cement), water, and optional components: filler in fine condition, modifier, etc., In this particular case as a source of additional component was used filler in fine condition. The prepared samples with different amount of filler in fine condition for dry building mixtures are placed in a hollow part of the metal washers that are located on a metal plate, compacted by any known method under a constant load of 5 MPa on 1 cm2the sample surface for 10-15 seconds.
The determination is performed following the way. Prepare standard solutions of liquid, in this case water-alcohol solutions of ethanol of different concentrations. The sample is put a drop of wetting liquid. Parameters drops measure the contact angle of the surface θ. Formulate dependence
determine the slope of this dependenceafor each sample of different composition. Build a dependency graphafor each sample, and the breakpoint graph dependencies define the optimum filler content in the tested object.
The surface tension of the standard liquid σWinstall any known method Rehbinder, method account drops and so on [Surface phenomena and surfactants: a Handbook/ by A. A. Abramson, L. E. Bobrov, L. P. Zaichenko, etc. - L.: Chemistry, 1984, 392 S., ill.]. In our case, we used a method of hanging drops, implemented on the installation Easy Drop intended for measuring surface tension, interfacial tension between two liquids, and also for measuring the wetting angle between the liquid and the solid surface. The measurement results of the surface tension of the liquid range of water-alcohol solutions ethanol are shown in table 1.
The invention is illustrated in the drawing, where Fig.1 presents zobrazeniearly, received by highlighting on the one hand, recording the camcorder (digital photography, observation under a microscope) and transfer to a computer for determining the contact angle of the surface of the test material. In this particular case was used in the laboratory setup Easy Drop, the measuring principle of which is based on highlighting drops on one side of the lifting table. Using DSA1 software analyzes the shape of the drop and is determined by the boundary angle. Calculate the cosine of the contact angle, build a dependency graph cosθ-1=(1/σW) determine the slope of this dependenceandproduce similar measurements and calculations for all of the subjects, objects with different filler contents. According to the data obtained for different percentage content of the filler in dry mixes build functional dependence ofafor each sample, and the break point of this graph determine the optimum content of the components of the test object (Fig.2).
The contact angle of the water-alcohol solutions of different concentrations to determine the installation Easy Drop on the phase boundary.
The surface tension of the water-alcohol solutions determined by the method of hanging drops. The tests were empirically selected physical parameters of the droplets, the diameter of the capillary ,821 mm Table 1 presents the results obtained values of the surface tension of water-ethanol solutions σW. All experiments were conducted at 22±1°C.
|№ p/p||Water content,%vol.||(σWof ±0.02)×103N/m|
According to the obtained values build a graph of functional dependencies
This dependence is described by the equation of the straight line. Determine the slope of this functional dependenceand.
Similar experimental tests are conducted for all test objects with different content of fill who I am. Sample preparation is carried out analogously.
According to the data obtained for different percentage content of the filler in a dry building mix build dependencyafor each sample, and the break point of this graph determine the optimum content of the components of the test object.
The application of the method of determining the optimal composition of dry construction mixes for concrete filler in fine condition allows to obtain such a mixture, which increases the strength of the samples and / or other performance characteristics of the concrete, without the need for multiple, material-intensive and time-consuming experimental tests.
1. The method of determining the composition of the dry mixes for concrete, including the selection of the composition and mixing the starting components of the mixture, characterized in that the surface of the test object put labels liquid drops, measure the angles of wetting the samples θ, build a graph of functional dependencies
cosθ-1=f(1/σW), where σW- the surface tension of the liquid, determine the slope of this dependenceandbuild a dependency graphandthe number of mixture components, and the break point of this graph determine the optimum content of the components of the test object.
2. The method according to p. 1, characterized in that the when asked liquids used are water-alcohol solutions of different concentrations.
FIELD: test equipment.
SUBSTANCE: at the first stage they determine process mode of manufacturing of ceramic items providing for required operability reserve. Using the produced operability reserve and knowing the suggested time, during which ceramic items must preserve strength parameters, they assess the permissible rated speed of produced reserves consumption. At the second stage, modelling conditions of real operation by means of reproduction of accelerated cyclic variations of temperature with simultaneous impact of possible mechanical factors, they determine actual speed of consumption of the same reserves. Received results of rated permissible speed and actual speed produced for imitation of operation conditions are compared, and results are produced, making it possible to judge on ceramic items.
EFFECT: possibility to determine durability of ceramic items with regard to certain conditions of use.
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
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: nanocomposite material contains, wt %: mineral binder 83.7-83.9, mineral filler 2.1-2.3, fraction of carbon nanoparticles 0.00002, distilled water 13.79998-14.19998.
EFFECT: improvement of material characteristics, providing protection from neutron radiation flows, provision of technological mobility of working mixture in the process of pouring construction elements.
SUBSTANCE: decorative facing material includes, wt %: ground sheet glass 75.0-77.0; ground tuff 8.0-10.0; borax 10.0-13.0; ground talc 3.0-4.0. Frost resistance of the material makes at least 25 cycles. Components are dosed in required quantities. Sheet glass (broken glass) previously ground to powdered condition is mixed with borax and tuff and talc ground to powder condition. The produced mass is laid into detachable metal moulds, compacted and sintered at 800-870°C.
EFFECT: increased frost resistance of produced material.
SUBSTANCE: raw material mixture for obtaining artificial rock contains, wt %: Portland cement 26-30; quartz sand 47.3-55.85; water 16-20; fibrous metalloceramics 2.0-2.5; technical lignosulfonate LST 0.15-0.2.
EFFECT: increased strength.
SUBSTANCE: charge for obtaining a decorative-facing material includes, wt %: milled glass 50.0-55.0; milled tuff 20.0-25.0; liquid glass 10.0-15.0; clay 10.0-15.0.
EFFECT: increased frost resistance of the materials.
SUBSTANCE: invention relates to preparations used for increasing water resistance of concrete, namely to elaboration of novel concrete-colmating (imperforating concrete pores) composition. In basic version composition represents mixture of salts, formed by metals from the group: sodium, potassium, calcium, aluminium, and acids from the group: nitric, formic, sulfuric, carbonic, with the following ion ratio (ion weight in composition, g)/(100 g of composition): sodium 5.6-32, calcium 0.4-17.2, potassium 1.5-27.2, aluminium 0.5-7.6, nitrate 4.1-62.1, formiate 0.6-29.7, sulfate 10.3-54.7, carbonate 1.1-29.7, as well as complex-forming additives (such as, for instance, carbamide, nitryltriacetic acid, imino-N,N-diacetic-N-methylene phosphonic acid; glycin-N,N-di(methylene phosphonic) acid, iminodi(methylene phosphonic) acid; diaminopropanol- N,N,N',N'-tetraacetic acid; 2-hydroxypropylene diamine- N,N,N',N'-tetra(methylene phosphonic) acid; 2,3-dihydrobutylene-1,4-diamine- N,N,N',N'-tetra(methylene phosphonic) acid; 2,3-dihydroxybutylene-1,4-diamine- N,N,N',N'-tetraacetic acid; nitryl-tri(methylene phosphonic) acid; 1-hydroxyethylene diphosphonic acid; ethylenediamin- N,N,N',N'- tetra(methylene phosphonic) acid; ethylenediamine-N,N,N',N'- tetraacetic acid; in amount not more than 20% of colmating composition weight.
EFFECT: extension of arsenal of preparations, used to increase concrete water resistance.
5 cl, 3 tbl
SUBSTANCE: in the method to manufacture wood concrete items with production of a base on their surface for plastering, providing for preparation and dosing of a hydraulic binder, ground cane stems, water, mixing of components, moulding of items with vibration, hardening, moulding with vibration is carried out so that cane stems cut into sections with length of 4-6 cm are located near the surface of the items, with one end staying in the mix, and with the other one - protruding outside and forming a base for application of plaster.
EFFECT: higher convenience of plaster application onto surface of items.
SUBSTANCE: additive comprises the following components, wt %: microorganisms of Leuconostoc mesenteroides type cultivated on a synthetic nutrient medium 0.5-2.7; microquartz 97.3-99.5.
EFFECT: increased mobility of a construction mix and concrete strength.
SUBSTANCE: invention relates to the industry of building materials and can be used in manufacturing products in civil and industrial construction, monolithic construction and for erection of special-purpose structures. The high-strength light concrete made from a concrete mixture contains portland cement, filler, a plasticiser, water, a mineral part consisting of microsilica with average particle size of 0.01-1 mcm, rock flour - a product of grinding quartz sand with specific surface area of 700-800 m2/kg and quartz sand with grain size of 0.16-0.63 mm, with the following ratio of components, wt %: portland cement 33.8-53.0, microsilica 4.77-13.8, rock flour 1.5-11.9, quartz sand 5.1…32.2 , microspheres 4.3-19.27, plasticiser 0.3-0.48, water - the balance.
EFFECT: obtaining concrete with high specific strength.
SUBSTANCE: invention relates to method of manufacturing fast setting light-weight cementing composition with improved compressive strength for building products such as panels. Method of obtaining light-weight cementing mixture, which has improved compressive strength and resistance to water, includes mixing water, cementing reacting powder, alkali metal salt of citric acid as set accelerator and light-weight filling agent, where weight ratio of water to reacting powder constitutes approximately 0.17-0.35:1.0, reacting powder includes 75-100 wt % of sol dust, which contains at least 50 wt % of fly ash of class C and 0-25 wt % of hydraulic cement and/or gypsum, setting of cementing mixture being achieved within from 4 to 6 minutes of composition mixing without addition of set retarder. Invention also deals with composition for obtaining light-weight cement panel.
EFFECT: obtaining light-weight cementing mixture, which has improved compressive strength and stability.
10 cl, 9 dwg, 9 tbl
SUBSTANCE: invention relates to a mixture of at least one polyol and at least one cyclohexane polycarboxylic acid derivative for reducing or minimising the dust emission when handling pulverulent construction chemical products, a method for preparing pulverulent construction chemical products and hydraulically setting materials containing the mixture according to the invention. The invention is developed in subclaims.
EFFECT: high efficiency of dust removal.
FIELD: transport building, in particular concrete block for lining of highway constructions, preferably headings.
SUBSTANCE: claimed block is formed from concrete mixture containing (kg/m3 concrete mixture): cement - 300-370; granite chip of grade 5-10 mm and 10-20 mm in ratio of 1:1.8-2.35, respectively, - 1100-1210; quartz sand of grade from 0.16 to 5 mm containing the next total knocking (mass %) 2.5 mm - 3.2-6.0; 1.2 mm - 12.8-16.2; 0.6 mm - 35.8-54.1; 0.3 mm - 70.4-89.3; 0.16 mm - 100 - 650-750; granite sand from screening with particle size up to 5 mm - 60-75; milled quartz sand with specific surface of 2200-3500 cm2/g as filler - 30-100; water - 125-143.3; and superplasticizer - 0.8-1.0 % calculated as cement mass.
EFFECT: block of improved strength, freeze-resistance, water impermeability, and crack resistance.