SU1629285A1 - Raw mix for preparing light-weight concrete - Google Patents

Abstract

The invention relates to the building materials industry and can be used to make lightweight concrete. To reduce the density and thermal conductivity, the raw mix for making lightweight concrete includes Portland cement, perlite porous aggregate of a fraction of 5-10 mm, 2.5-5 mm, volcanic slag in the form of sand, and additionally contains perlite porous aggregate of a fraction of 10-20 mm, 1.2 -2.5 mm and fine ground tuff in the following ratio of components, wt.%: Portland cement 20.0-26.0; perlite porous aggregate of the fraction 1.2-2.5 mm 3.0-17.0; perlite porous aggregate fraction 2.5-5 mm 3.0-7.0; perlite porous aggregate of fraction 5-10 mm 5.0-7.0; perlite porous aggregate of fraction 10-20 mm 7.0-9.0; fine ground tuff 3.0-7.0; volcanic slag 11.0-38.0; water the rest. Achievement of the goal is ensured by the presence of perlite aggregate of different fractions and the ratio of components, which results in lightweight concrete fused structure with a density of 770-860 kg / m3, strength of 7.5-10 MPa and thermal conductivity 0.17-0.22 W / (m &;deg; C), which is 1.5-2 times better than the same indicators of lightweight concrete of known composition, which cannot be obtained with a density below 870 kg / m3. 5 tab.

Description

The invention relates to the building materials industry, in particular to raw mix compositions for the manufacture of lightweight concrete.

The purpose of the invention is to reduce the density and thermal conductivity.

Raw mix for making lightweight concrete contains Portland cement, perlite porous aggregate of fractions 1.2-2.5 mm, 2.5-5 mm, 5-10 mm, 10-20 mm, volcanic slag, fine tuff, water in the following ratio of components , wt.%:

20.0-26.0

Portland cement

Perlite porous

aggregate:

fractions 1.2-2.5 mm

fractions 2.5-5 mm

fractions 5-10 mm

fractions 10-20 mm

Volcanic slag

Fine tuff

Water

The chemical composition of the samples of the raw mix, the raw materials of which use volcanic slag and

3.0-17.0

3.0-7.0

5.0-7.0

7.0-9.0

11.0-38.0

3.0-7.0

Rest

Os

N3 O Yu 00

ate

the rock of the Karmrashenskoye deposit of the Armenian SSR, with a fraction of not more than 2.5 mm being used, is given in Table. one.

As fine tuff, stone processing waste with a particle size of 0.0-0.14 mm and a specific surface area of 1500-2000 cm2 / g is used, the chemical composition of the sample is given in Table. 2

The technology for preparing the raw mix of lightweight concrete consists in the fact that the cement, fine and coarse aggregate are mixed together dry for 1 minute, and then the mixing water is introduced and the final mixing is carried out in 4-5 minutes. After the concrete mixture is placed in the molds, it is compacted by vibration. Then it is steamed by pre-exposure for 4 hours, isothermally heated for 3 hours at 95 ° C, and cooled for 3 hours. Samples are stored under normal conditions at 25 ± 3 ° C with a relative humidity of 90%. The obtained samples are tested according to GOST.

Specific examples of the raw mix of the proposed composition and control examples to substantiate the limits of the contents of the components are given in table. 3

The properties of the raw material mixture of the proposed composition as compared with the known are given in Table. four,

Through the use of a perlite aggregate of different fractions and the ratio of the components of the mixture, lightweight concrete with a continuous structure with high strength and low density and thermal conductivity is obtained,

This reduces the consumption of cement (20.0-26.0 wt.%) Compared with the known (27.0-48.0 May.%).

In tab. 5 shows the properties of concrete of known composition.

The comparison shows that the material of the prototype with a density of 870 kg / m has a strength of 5.4 MPa and thermal conductivity of 0.32 W / (m 0 C), and for the prototype it is impossible to obtain a material with a density below 870 kg / m3. The proposed composition with a density of 860 kg / m has a strength of 10 MPa (increase by 2 times), and thermal conductivity of 0.22 W / (m ° C) (a decrease of 1.4 times).

Thus, for the proposed composition with a ensuring strength of 5 MPa at the level of the prototype, the density is reduced to 660 kg / m3, and the thermal conductivity is 0.17 W / (m ° C) (example 2).

Claims (1)

A raw material mixture for the manufacture of lightweight concrete, including Portland cement, perlite porous aggregate of the 2.5-10 mm, 5-10 mm fraction, volcanic slag, and water, which in order to reduce the density and thermal conductivity, it also contains perlite porous aggregate fraction 1.2-2.5 mm, 10-20 mm and fine tuff in the following ratio, wt.%: Portland cement Perlite porous aggregate fraction of 1.2-2.5 mm Perlite porous aggregate fraction 2.5-5 mm Perlite porous aggregate fraction 5-10 mm Perlite porous aggregate fraction 10-20 mm Volcanic cleat Tuffled Water 45 table 2 Table 3 Table 4 Table 5