RU1813760C - Concrete mix - Google Patents

Abstract

The invention relates to concrete mixtures and may find application in the technology of building materials. The aim of the invention is to increase the accuracy and frost resistance of concrete. The concrete mixture contains, wt.%: Cement 9.98-12.56, quartz sand 25.53-26.45, granite crushed stone fractions 5-10 mm 16.09-16.66 and fractions 10-20 mm 37.53 -38.88; water the rest. Moreover, the sand has the following fractional composition, wt.%: 5.0-2.5 mm 23.2-29.2; 2.5-1.2 mm 7.5-10.00; 1.25-0.63 mm 18-19.5; 0.62-0.315 mm 34.0-35.5; 0.315-0.14 mm 8.2-13.3; less than 0.14 mm rest. The strength of the resulting concrete is 21.3-22.5 MPa, and the grade for frost resistance is 240-260. 2 tab.

Description

The invention relates to concrete mixtures and may find application in the technology of building materials.

The aim of the invention is to increase the strength and frost resistance of concrete.

The goal is achieved in that the concrete mixture, including cement, quartz sand fractions, mm; 5.0-2.5, 2.5-1.25, 1.25-0.63, 0.63-0.315, 0.315-0.14 and less than 0.14 mm, crushed granite fractions, mm: 10- 20 and 5-10, and water, contains quartz sand in the following ratio of these fractions, wt.%: 5.0-2.5 mm 23.2-29.2, 2.5-1.2 mm, 7.5 -10.0 1.25-0.63 mm, 18-19.5, 0.63-0.315 mm, 34.0-35.5, 0.315-0.14 mm, 8.2-13.3, less than 0, 14 mm the rest in the following ratio of components, wt.%: Cement 9.98-12.56, quartz sand 25.53-26.45, granite crushed stone fractions 5-10 mm 16.09-16.66, fractions 10-20 mm 37.53-38.88, the rest is water.

Example. In the preparation of concrete mixtures, the following materials were used: granite crushed stone of fractions 5-10 and ID-20 mm quartz sand of the following particle size distribution, wt.%: 2.5-5.0 mm, 23.2-29.5, 1.25- 2.5 mm, 7.5-10.0, 0.64-1.25 mm 19.5-18.0 0.315-0.63, 35.5-34.0, 0.14-0.315, 13, 3-8.2, less than 0.14 1.0-0.3.

Portland cement M400 of the Akhangeran plant was used as the baking agent. Examples of concrete mixes are given in table. 1.

Concrete mixtures were prepared as follows.

A dosed amount of crushed stone fractions of 5-10 and 10-20 mm was mixed in a concrete mixer for 30 s. Next, the required amount of sand was introduced into the working mixer and mixed for more than 30 s. In the prepared gravel and sand mixture

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ABOUT

the required composition was injected with the required amount of cement and the dry mixture was mixed for 30 s.

After this time, mixing water was poured into the running mixer for 15 seconds and the whole mixture was mixed for another 74 seconds.

After the concrete mix was prepared with a specific composition, samples were taken to determine the volume of air involved using a volume meter.

From the prepared concrete mixtures, samples were formed - cubes measuring 10 x 10 x 10 cm, which hardened for 28 days under normal humidity conditions.

Tests of samples for strength, frost resistance were carried out according to standard methods. The test results of the concrete mix and concrete are presented in table. 2.

From the table. 2 it follows that the resulting concrete mixtures according to the invention have advantages: with the saving of cement, the compressive strength of concrete

2-7%, and frost resistance is 20-31% higher than the corresponding values of the prototype.

Formula A from Breteni

Concrete mixture including cement, quartz sand fractions, mm: 5.0-2.5; 2.5-1.25; 1.25-0.63; 0.63-0.315; 0.315-0.14 and less than 0.14, crushed granite fractions 10-20

0 and 5-10 mm and water, characterized in that, in order to increase the strength and frost resistance of concrete, it contains quartz sand in the following ratio of these fractions, wt.%: 5.0-2.5 mm - 23.2- 29.2;

5 2.5-1.25 mm - 7.5-10.0; 1.25-0.63 mm 18.0-19.5; 0.63-0.315 mm - 34.0-35.5; 0.315-0.14 mm - 8.2-13.2; less than 0.14 mm - the rest, in the following ratio of components, wt.%:

0 Cement

Quartz sand Granite crushed stone fractions 5-10 mm fractions 10-20 mm

5 water

9.98-12.56 25.53-26.45

16.09-16.66 37.53-38.88 Else

Table 1

Table 2