UA125046U - A METHOD OF MANUFACTURING SELF-STRESSED FIBROBETON - Google Patents

Abstract

A method of manufacturing a self-tensile fiber concrete involves mixing expanded cement consisting of Portland cement, metacoalin and gypsum (Matoushek cement) with water, basalt fiber and sand, forming the product and keeping it in a humid environment. Phosphogypsum is used as gypsum, which is pre-neutralized and dried. Extensive cement is produced by compatible grinding of Portland cement, metakaolin and phosphogypsum in the presence of a polycarboxylate type superplasticizer additive. The resulting binder is made of a concrete mixture with the introduction of steel g-shaped fiber with flattened ends. The curing of the product is carried out for 4-5 hours in the form at a temperature of 20 ± 2 ° C with subsequent heat treatment.

Description

The useful model belongs to the building materials industry and can be used at enterprises for the manufacture of products and structures using fiber concrete based on expansive cements.

There is a known method of manufacturing gypsum-aluminous expanded cement (GGRC), which includes joint grinding of alumina clinker - 7095 with natural dihydrate gypsum - Z0 95 to a fineness corresponding to the residue on the Me008 sieve less than 10 95. |Runova R.F., Dvorkin L.Y. , Dworkin

O.L., Nosovsky Yu.L. Binders: Textbook. - K.: Osnova, 2012. - P. 317). The shortcoming of this method is the short period of time for the start of longing: not earlier than 10 minutes.

There is also a known method of manufacturing expanded tension cement (SC), which includes the combined grinding of portland cement, alumina cement and gypsum to a specific surface of 3000-4500 g/cm2g with their percentage ratio by mass within the range: 70:16:14-64:20: 16 with a possible addition of lime up to 5 95. |Runova R.F., Dvorkin L.Y., Dvorkin O.L., Nosovsky Yu.L. Binders: Textbook. - K.: Osnova, 2012. - P. 318). The disadvantage of this method is a relatively short period of time for the start of hardening of the expansive tension cement: no earlier than 30 minutes.

A known method of manufacturing expanded cement (Matoushek's cement), which includes the combined grinding of Portland cement - 65 9o, metakaolin - 22 95 and dihydrate gypsum - 13 95 | Dworkin

L.Y., Lushnikova N.V., Runova R.F., Troyan V.V. Metakaolin in construction mortars and concretes:

Monograph - KNUBA Publishing House, 2007. - P. 21). The disadvantage of this method is a short time for the start of hardening and the need for hardening in water.

Also known since 1918 (France, H. Alfsen) is the method of manufacturing structures from fiber concrete - reinforcing concrete with steel fibers, which is characterized by high impact strength, shear and tensile strength, frost resistance and waterproofing, crack resistance, increases the bending strength of concrete, reduces the time installation of reinforcement, increases the vibration resistance of concrete |Dvorkin L.Y., Babych E.M., Zhitkovsky V.V. etc. High-strength fast-hardening concretes and fiber concretes: monograph. - Rivne: NUVHP, 2017. - P. 155-164).

The use of such fiber concrete cannot create tension in the fiber and reinforcement in the products.

The closest analogue to the proposed one is the method of manufacturing cement-sand stressed fiber concrete, which includes mixing Matoushek’s expanded cement with water and polycarboxylate plasticizer and 5 95 by mass of cement basalt fibers (fibers)

With a length of 25 mm with sand in a ratio of 1:11 by mass, product formation and hardening in a humid environment (|Belomesova, K.Yu. Cement-sand mortar, reinforced with basalt fiber / K.Yu. Belomesova, V.V. Tur / / Innovations in concrete production, construction production and training of engineering personnel: a collection of articles on materials

International scientific and technical conference dedicated to the 100th anniversary of the birth

I.N. Akhverdova and S.S. Ataeva, Minsk, June 9-10, 2016: in 2 hours / "Belarusian National Technical University; ed.: Z.I. Batyanovsky, V.V. Babytsky. - Minsk, 2016. - Part 1. - C 34-9.

The disadvantage of this method is the need for increased consumption of cement in the recommended composition of stressed fiber concrete.

The purpose of the useful model is to obtain self-tensioning fiber concrete products on Matoushek's expanded cement with increased bending strength under normal conditions and after steaming, saving steel reinforcement, effective utilization of phosphogypsum.

The task is solved by the fact that in the method of manufacturing self-tensioning fiber concrete, which includes mixing expanded cement, which consists of Portland cement (PC)-71 9o, metakaolin (MK)-14 905 and gypsum (GC)-15 95 (Matoushek cement) with water , basalt fiber and sand, forming the product and keeping it in a humid environment, according to a useful model, phosphogypsum is used as plaster, which is pre-neutralized 5-6 96 cement by weight and dried at a temperature of 70-80 "C, and expansive cement is obtained by compatible by grinding Portland cement, metakaolin and phosphogypsum (FG), respectively in mass percentages: PC:MK:FG-70:16:14-64:20:116 in the presence of a polycarboxylate type superplasticizer additive in the amount of 0.3-0.5 95 by mass binder, on the obtained binder, a concrete mixture is made with the introduction of steel g-shaped fiber with flattened ends in the amount of 140-150 kg/m" with a water-binder ratio of V/Vzh-0.4-0.5, and the product is kept for 4-5 hours in the form of temperature of 2022 "C with subsequent heat treatment.

When an L-shaped steel fiber with flattened ends is introduced in the amount of 140-150 kg/m3, it is arbitrarily oriented in three planes during the formation of the product, which leads to a decrease in the ratio of compressive strength to bending strength to Ist/Izg-3.8-4 ,2 after hardening of self-stressing fiber concrete, both under normal hardening conditions and after (516) steaming.

In addition, with the simultaneous grinding of Portland cement, metakaolin, phosphogypsum neutralized with cement and polycarboxylate plasticizer, the particles of the plasticizer cover the grains of the expanded cement components, which significantly reduces their water consumption and leads to a delay in the beginning of cement hardening up to 40-60 minutes, which in turn allows construction work to be carried out with mortars and concretes based on it.

The amount of cement 5-695 by mass of dry phosphogypsum is necessary and sufficient for its neutralization, and the amount of 0.3-0.595 by mass of binder dry polycarboxylate plasticizer satisfies the rheological properties of expansive cement in a mixture with aggregates. Drying phosphogypsum from 5-6 96 cement at a temperature of 70-80 C makes it possible to obtain dry calcium sulfate dihydrate, which is sufficient for Matoushek cement.

The method is carried out as follows.

Phosphogypsum is mixed with 5-6 95 by mass of PC-I-500 type cement and loaded into runners of wet grinding and grinding the mixture for 25-30 minutes, bringing it to a humidity of about 20-2590. At the same time, conditions are created for cement hydration and neutralization phosphogypsum as a result of the formation of calcium hydroxide, which actively reacts with acid residues contained in phosphogypsum. After that, the homogenized mixture of phosphogypsum and cement is dried at a mixture temperature of 70-80 "C for 1.5-2 hours to a residual moisture content of 0.5-1.0 96 and loaded into a ball mill together with Portland cement of the PC-I-500 type, metakaolin and 0.3-0.5 95 plasticizers of KDITS PP "Termit" in Rneve from the mass of the binder and ground to a specific surface of 4000-4500 cm/g.

To obtain expanded cement, the following mass ratios of components are used: portland cement-70...64 96, metakaolin-16...20 95, phosphogypsum neutralized with cement-14...16 95, dry polycarboxylate plasticizer KDiIC - 0.3-0.595 from masses of binder.

Preparation of self-tensioning fiber concrete from expanded cement is carried out by mixing it with sand of the composition Vzh:P-1:3...1:4 with water at a water-binding ratio

V/Vzh-0.4...0.5 and g-shaped fiber with flattened ends in the amount of 140-150 kg/m? before forming the product.

The table shows the comparative values of the ratios of the compressive strength limits to the limits

On the flexural strength of self-tensioning sand fiber concretes on Matoushek expanded cement with basalt fiber and expanded cement based on jointly ground Portland cement of the PC-I-500 type, metakaolin, neutralized with phosphogypsum cement and polycarboxylate plasticizer of the KDIiC type with 150 kg/m of steel g-shaped fiber with with flattened ends.

Table of sand fiber concrete bending at the age of 28 days of normal hardening - Ist/Izg

Self-stressed| PC: MK: "GKA 71:14:15, fiber concrete according to Polycarboxylate prototype with plasticizer - 0.5 95; 4.9...5.0

Basalt VzhPe1:3; fiber Fiber - 35 kg/m3

PC: MK: FG-70:16:14,

Self-stressing)| Polycarboxylate fiber concrete with plasticizer-0.5 905; 3.8...42 similar fiber |VzhP-1:3;

Fiber - 150 kg/m3

According to the table, the ratio of compressive strength to flexural strength - Yst/Izg, the proposed self-tensioning fiber concrete on expanded cement with neutralized phosphogypsum cement and g-shaped fiber is 13-15 95 better than this indicator according to the prototype.

The useful model can be used in the manufacturing technology of thin-walled reinforced concrete products from prestressed fiber concrete on expanded binders with the use of man-made waste - phosphogypsum, which will improve their technical properties and reduce the cost of the products.

Claims (1)

USEFUL MODEL FORMULA The method of manufacturing self-tensioning fiber concrete, which includes mixing expanded cement, which consists of Portland cement (PC)-71 95, metakaolin (MC)-14 9o and gypsum (GC)- 15 95 (Matoushek's cement) with water, basalt fiber and sand, forming the product and keeping it in a humid environment, which differs in that phosphogypsum is used as plaster, which is pre-neutralized 5-6b9o of cement by weight and dried at a temperature of 70-80 " C, and expansive cement is obtained by the combined grinding of Portland cement, metakaolin and phosphogypsum (FG), respectively, in mass percentages: PC:MK:FG-70:16:14-64:20:16 in the presence of a polycarboxylate-type superplasticizer additive in the amount of 0.3 -0.5 95 from the mass of the binder, on the obtained binder, a concrete mixture is made with the introduction of steel g- similar fiber with flattened ends in the amount of 140-150 kg/m" with a water-binder ratio V/Vzh-0.4-0.5, and the product is aged for 4-5 hours in a mold at a temperature of 20522 7C with subsequent heat treatment.