RU2544190C1 - Method to prepare haydite concrete mix - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: in the method to prepare a haydite concrete mix, including preparation and mixing of mixture components, mixing of the haydite concrete mix is carried out in a turbulent concrete mixer with rotor rotation frequency of at least 8 sec-1 and not more than 30 sec-1, at first 30% of required tempering water is supplied into the turbulent concrete mixer, and gradually haydite gravel is loaded with the running turbulent mixer, and mixed for 120 sec., then the required balance of water is supplied to the continuously running turbulent concrete mixer with addition of technical modified lignosulphonates and a gas forming additive PAK-3, then fly ash and cement are loaded, and the mix is mixed for 2-3 min. to produce homogeneous mix with required cone slump, at the following ratio of components, wt %: portland cement 20.00, haydite 41.50, superplasticiser LSTM 0.0312, fly ash of TPP 17.50, PAK-3 0.025, water - balance.

EFFECT: reduced process operations in production of haydite mix, increased frost resistance, heat insulation properties and reduced average density of haydite without strength reduction.

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Description

The invention relates to the building materials industry, in particular to a technology for manufacturing expanded clay concrete mixtures, resource-saving technologies for lightweight concrete.

A known method for the production of aerated concrete mixture (Patent No. 2474493, IPC В28С 5/00, publ. 02/10/2013), which includes the preparation and mixing in a mixer of Portland cement, lime with a known value of enthalpy, gypsum, water, a siliceous component, back slag, aluminum powder, measuring the temperature of the mixture in the mixer during mixing, unloading the mixture from the mixer into the mold.

The disadvantage of this method is the large number of technological operations, multicomponent mixture.

A known method of producing concrete (Patent No. 2470901, IPC С04В 40/00, С04В 28/26, С04В 111/20 publ. 12/27/2012), including the preparation of aluminosilicate binder component, dosing of aggregate and binder components, mixing, molding of products, their aging and subsequent hardening. The preparation of the aluminosilicate component includes a joint grinding in an ash ball mill and a waste ash and slag mixture for 20 minutes, molding is performed by vibration.

The disadvantage of this method is the large number of technological operations.

A known method of autoclave-free manufacturing of aerated concrete building products (Patent No. 2083535, IPC С04В 38/02, С04В 28/18, С28В 1/50 publ. 07/10/1997), which includes the preparation of concrete mix in a mortar mixer by mixing shale binder, siliceous aggregate ( quartz sand or coal ash) and water, followed by introducing a blowing agent into the concrete mixture and mixing them to obtain a gas concrete mixture, molding the products by casting the resulting gas concrete mixture into a mold, and curing the products under the action of gypsum rotermalnoy processing in the steam chamber of low pressure steam.

The disadvantage of this method is the large number of technological operations that allow to obtain aerated concrete of the required quality.

The technical result of the claimed invention is to reduce technological operations in the production of expanded clay mixture with the required technological, and in the future, operational properties of expanded clay.

The technical result is achieved by the fact that for the manufacture of expanded clay mixture, including the preparation and mixing of the mixture components in the following ratio of components, wt.%: Portland cement 20.00, expanded clay 41.50, superplasticizer LSTM 0.0312, fly ash TPP 17.50, PAK-3 0.025, water - the rest, according to the invention, use a turbulent concrete mixer with a rotor speed of at least 8 sec ^-1 and not more than 30 sec ^-1 . First, 30% of the required amount of mixing water is supplied to the turbulent concrete mixer, and expanded clay gravel is gradually loaded with the turbulent mixer operating, while the expanded clay gravel is crushed and activated for 120 seconds, then, the non-stop turbulent concrete mixer is supplied with the required remaining water with the additive modified technical lignosulfonates (hereinafter referred to as LSTM superplasticizer) and gas-forming additive PAK-3 (hereinafter PAK-3), then fly ash and Portland are loaded nt, and the mixture was stirred for 2-3 minutes to obtain a homogeneous mixture with a desired slump.

The use of a turbulent mixer with a rotor speed of at least 8 sec ^-1 and not more than 30 sec ^-1 contributes to the partial crushing of expanded clay gravel. When crushing expanded clay gravel, new surfaces of expanded clay gravel are exposed, which contain free radicals with an unsaturated valency. These free radicals actively interact with Portland cement clinker minerals to form new chemisorption compounds on the surface of expanded clay gravel grains. These new chemisorption compounds are firmly held on the surface of expanded clay gravel and on the surface of Portland cement grains, as a result of which the strength and other physical and mechanical properties of expanded clay are improved. The crushing of expanded clay for 120 seconds together with 30% of the required amount of mixing water is considered optimal.

Mixing the expanded clay mixture in a turbulent mixer for 2-3 minutes also has an activating effect on fly ash, which is loaded together with Portland cement after adding the necessary water residue with the addition of superplasticizer LSTM and PAK-3. Spherulites of fly ash are partially crushed, during which the surfaces of fly ash containing silica and alumina are exposed. The listed oxides actively interact with calcium hydroxide released during the hydration of tricalcium silicate with the formation of low-basic hydrosilicates and calcium hydroaluminates, which significantly improve the hydrophysical properties of expanded clay concrete.

The use of a turbulent mixer for producing claydite-concrete mix has an activating effect on Portland cement grains. Intensive mixing in a turbulent mixer activates Portland cement grains due to their partial crushing, while new surfaces of unhydrated Portland cement grains are exposed. Having free radicals, these surfaces actively enter hydration processes with the intensive formation of new hydrated compounds. The introduction of PAK-3 into the claydite-concrete mixture leads to the formation of a cement stone structure with evenly distributed pores in the form of polydisperse in size, closed, deformed into regular polyhedra with a glossy surface of the pore layer, separated by thin, but dense and identical in cross-section inter-pore partitions (Additives in concrete and mortar: educational-reference manual / LI Kastornykh. - Rostov-on-Don: Phoenix, 2007). A similar pore structure of expanded clay mixture contributes to the improvement of thermal insulation properties of expanded clay and improve the other physico-mechanical properties of the resulting expanded clay.

The use of a turbulent mixer also contributes to the activation of the blowing agent, which leads to the formation of a large pore volume in the expanded clay mixture and a decrease in the average density of the expanded clay mixture without reducing the strength of the system. Thus, the use of a turbulent mixer for the manufacture of expanded clay mixture allows to obtain expanded clay with high performance properties.

Table 1 Compositions of expanded clay mixture Components Content, wt.%: Composition No. 1 Composition No. 2 (optimal) Composition No. 3 Portland cement 15.00 20.00 23.00 Expanded clay 40.00 41.50 44.00 Fly ash CHP 21.50 17.50 15.50 Superplasticizer LSTM 0,0312 0,0312 0,0312 Gas-forming additive PAK-3 0,025 0,025 0,025 Water 23,444 20,944 17,444 The average density, kg / m ³ 1210 1000 1130 The strength of expanded clay, kg / cm ² 75 95 90 Frost resistance (F), cycle fifteen twenty twenty

The technical result claimed in the invention was achieved on expanded clay concrete samples with the following composition: Portland cement, expanded clay, fly ash of thermal power plants, PAK-3, superplasticizer LSTM in the following ratio of components, wt.%: Portland cement 20.00; expanded clay 41.50; superplasticizer LSTM 0.0312; fly ash CHP 17.50; PAK-3 0.025; water is the rest.

The dependence of the characteristics of the obtained samples prepared by various mixing methods on the mixing parameters of the expanded clay mixture are presented in table 2.

table 2 Mixing parameters in a turbulent concrete mixer. Comparative characteristics The method of preparation of the mixture No. 1 Number 2 No. 3 (optimal) Rotor speed, sec ^-1 7.0 7.5 8.0 The time of crushing and mixing expanded clay with water, sec 150 135 120 Mixing time of the mixture with ash, superplasticizer LSTM and PAK-3, min 5 four 3 The average density, kg / m ³ 1250 1150 1000 The strength of expanded clay concrete, 85 90 95 kg / cm ² Frost resistance (F), cycle fifteen twenty twenty

From table 2 it is seen that the method of preparation of the mixture with the optimal parameters is method No. 3. Comparing the characteristics of expanded clay concrete samples prepared in various ways, it can be concluded that with a decrease in the rotor speed, the average density increases and the strength decreases. Even with an increase in the time of crushing and mixing of the mixture, this dependence changes insignificantly. Therefore, the use of a concrete mixer with a rotor speed of 8 sec ^-1 and not more than 30 sec ^-1 (with a corresponding reduction in the mixing time of the claydite-concrete mixture in the framework established above) is the most effective for the claydite-concrete mixture under consideration.

Claims (1)

A method of preparing a claydite-concrete mixture, comprising preparing and mixing the components of the mixture, characterized in that the claydite-concrete mixture is mixed in a turbulent concrete mixer with a rotor speed of at least 8 sec ^-1 and not more than 30 sec ^-1 , first 30% is fed into the turbulent concrete mixer the required amount of mixing water and expanded clay gravel is gradually loaded with the turbulent mixer running and mixed for 120 seconds, then into the non-stop turbulent concrete mixture tel, carry out the supply of the required water residue with the addition of technical modified lignosulfonates and a gas-forming additive PAK-3, then fly ash and cement are loaded, and the mixture is mixed for 2-3 minutes until a homogeneous mixture with the required cone sediment is obtained, in the following ratio of components, wt.%: Portland cement 20.00, expanded clay 41.50, superplasticizer LSTM 0.0312, fly ash TPP 17.50, PAK-3 0.025, water - the rest.