RU2583965C1 - Composition of fibre concrete - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to composition of fibre concrete, used for making precast and monolithic building structures. Concrete mixture, which contains portland cement, microsilica, plasticiser, fibrous filler, sand and water, contains as a plasticiser hyperplasticiser Stachement 2061/151.2, polypropylene fibre as fibrous filler with length of 18 mm and diameter 20 mcm, coarse sand with fineness modulus M_K=2.5÷3.0 in non-fraction form with following ratio of components, wt%: portland cement 19.00-22.00, microsilica 1.50-2.50, plasticiser 0.15-0.60, polypropylene fibre 0.02-0.15, sand 65.00-75.00, water - balance.

EFFECT: obtaining fibre concrete with high compression strength, frost resistance and water impermeability at minimal consumption of cement, as well as low cost of composition as a whole.

1 cl, 1 tbl

Description

 The invention relates to compositions of fiber-reinforced concrete mixtures used for the manufacture of prefabricated and monolithic building structures and products with high performance characteristics.

Known fiber concrete mixture, including cement, aggregate and hardener - steel wire [US Pat. No. 2420472. The Russian Federation. Fiber-concrete mix / Perfilov V.A .; Patentee Perfilov V.A. - Publ. 06/10/2011. - Access mode: http://www1.fips.ru]. The disadvantages of the mixture are the use of special equipment and the time required to prepare a modifying additive, the use of crushed stone of two fractions.

The closest is the composition of the fiber-reinforced concrete mixture containing Portland cement, basalt fiber, plasticizer, sand and water [US Pat. No. 2423331. The Russian Federation. Fiber-concrete mix / Borovskikh I.V., Khozin V.G., Morozov N.M .; patent holder Fiber-concrete hatches limited liability company (LLC FBL). - Publ. 07/10/2011. - Access mode: http://www1.fips.ru], adopted as a prototype.

The main disadvantages of the mixture are the use of expensive fractionated sand, high consumption of cement and basalt fiber, the lack of data on water resistance, the plasticizers used have different technical properties.

The technical task of the claimed invention is to obtain fiber-reinforced concrete with high compressive strength, frost resistance and water resistance with minimal cement consumption, as well as reducing the cost of the composition as a whole.

The technical result is achieved by the fact that the rational selection and consumption of components of the fiber-reinforced concrete mixture provide increased compressive strength, increased frost resistance and water resistance

fiber concrete, and a decrease in the amount of cement and the use of large unfractionated sand leads to a decrease in its cost.

In FIG. 1 shows information confirming the positive effect of the claimed invention.

The claimed fiber-reinforced concrete mixture contains Portland cement, silica fume, plasticizer, fibrous filler, sand and water. Stachement 2061 / 151.2 hyperplasticizer was used as a plasticizer, fibrous filler — polypropylene fiber 18 mm long and 20 microns in diameter, coarse sand with a coarse modulus M _K = 2.5 ÷ 3.0 was introduced into the mixture in unfractionated form. The ratio of components in fiber-reinforced concrete mixture is selected as follows, wt. %:

Portland cement 19.00-22.00 Silica fume 1,50-2,50 Plasticizer 0.15-0.60 Polypropylene fiber 0.02-0.15 Sand 65.00-75.00 Water rest

For the preparation of fiber-reinforced concrete mixture were used:

- Portland cement CEM I 42.5N CJSC Belgorodsky cement, GOST 31108-2003, GOST 30515-97;

- silica fume MKU-85 OJSC Kuznetsk Ferroalloys, Novokuznetsk, TU 5743-048-02495332-96 with the following chemical composition, wt. %: SiO ₂ 93.8; H ₂ O 0.1; Na ₂ O 0.68; K ₂ O 1,6; CaO 0.41; SiO ₃ 0.41; loss on ignition 1.6;

- Stachement 2061 / 151.2 hyperplasticizer, EN 934-2: 2001, GOST 24211-2008 - a liquid additive based on polycarboxylates and a moderator manufactured by STACHEMA Bratislava a.s., Bratislava, Slovak Republic;

- polypropylene fiber with a length of 18 mm and a diameter of 20 microns, TU 2272-001-90345062-2012, TU 5458-001-82255741-2008;

- Unfractionated coarse sand M _K = 2.5 ÷ 3.0, GOST 8736-93.

When using silica fume in the composition of knitting and coarse unfractionated sand, the density of the mixture increases, the strength increases and the porosity of the cement stone decreases and the cement consumption is reduced. Hyperplasticizer allows you to increase the water-reducing effect, improve the rheological and technological properties of the mixture. With a uniform distribution over the volume, the polypropylene fiber has the greatest effect on the concrete matrix as a reinforcement of the “cement stone - aggregate” contact zone. Optimization of the consumption of components in the composition of fiber-reinforced concrete mix allows to obtain fiber-reinforced concrete with high operational quality indicators.

The fiber-reinforced concrete mixture was prepared as follows: Portland cement was pre-mixed with silica fume, then the binder was poured together with sand into a paddle concrete mixer and mixed for 30 s until a homogeneous mass was obtained. After that, water with the plasticizer dissolved in it was added to the dry mixture to obtain the required mobility and mixed for 60 s. Then the polypropylene fiber was added without preliminary preparation to the finished mixture and mixed for another 60 s. Compaction of the mixture was carried out on a laboratory vibrating table. Fiber-concrete mixture hardening took place under normal conditions; testing of fiber-reinforced concrete samples for compressive strength, frost resistance and water resistance was carried out on the 28th day in accordance with GOST 10180-2012, GOST 10060-2012, GOST 12730.5-84.

The proposed rational compositions of fiber-reinforced concrete mixtures, as well as strength and operational properties of the obtained fiber-reinforced concrete in comparison with the prototype are shown in the tables. When using unfractionated coarse sand with a particle size modulus M _K = 2.5 ÷ 3.0, at low consumption of polypropylene fiber 0.02-0.15% and dosages of plasticizer 0.15-0.60%, high compressive strength is achieved, its frost resistance and water resistance increase. At

an increase in mobility (up to OK = 23 cm) of the fiber-reinforced concrete mix, the quality indicators change slightly.

A comparison of the test results of the claimed solution (optimal compositions of fiber-reinforced concrete mixture 1-3) and the prototype shows that the compressive strength is less by 12%, frost resistance is 1.7 times higher while saving cement and silica fume 1.5 times and reducing fiber consumption by 10 up to 30 times by weight.

four

FIBER CONCRETE MIX

Claims (1)

Fiber-concrete mixture containing Portland cement, silica fume, plasticizer, fibrous filler, sand and water, characterized in that it contains Stachement 2061 / 151.2 hyperplasticizer as a plasticizer, polypropylene fiber 18 mm long and 20 microns in diameter, coarse sand with a module size M _K = 2.5 ÷ 3.0 in unfractionated form with the following ratio of components, wt. %:
Portland cement 19.00-22.00 Silica fume 1,50-2,50 Plasticizer 0.15-0.60 Polypropylene fiber 0.02-0.15 Sand 65.00-75.00 Water rest

Images