RU2811049C1 - Raw material mixture for production of heat-resistant fibre-vermiculite-pumice concrete - Google Patents

Abstract

FIELD: construction materials.

SUBSTANCE: manufacture of heat-resistant products from fibre-vermiculite-pumice concrete. The raw material mixture for production of heat-resistant concrete includes Portland cement, expanded vermiculite, volcanic pumice, saponified wood resin, basalt fibre, and water. It contains expanded vermiculite of a fraction of 0.315–5 mm and volcanic pumice of a fraction of 0.16–0.63 mm, with the following ratio of components, wt.%: Portland cement - 22.1–22.3, expanded vermiculite of a fraction of 0.315–5 mm - 12 ,1–12.4, volcanic pumice fraction 0.16–0.63 mm - 25.9–26.9, saponified wood resin - 0.11–0.12, basalt fibre - 1.0–1.1, water - balance.

EFFECT: production of effective heat-resistant vermiculite concrete while expanding the raw material base, increasing the strength and reducing the cost of vermiculite concrete.

1 cl, 3 tbl

Description

The invention relates to the building materials industry and can be used by industrial and construction organizations for the manufacture of heat-resistant products from fiber vermiculite pumice concrete.

Known compositions of heat-resistant concrete based on Portland cement with finely ground additives using lightweight aggregates. Expanded vermiculite, perlite, expanded clay, agloporite, slag pumice and others are used as porous aggregates [1, 2].

A concrete mixture is known containing wt.%: fast-hardening Portland cement as a binder - 5.9-21.25 and silicate block - 0.1-3.75, asbestos as a filler - 10-17, vermiculite - 4-6, expanded clay – 8-12 and mixing water – 51-59 [1]. However, products of this composition are difficult to manufacture and have a high cost; the strength of the resulting products is low.

The authors [2] investigated the influence of the type of finely ground additive (cemento, fly ash, expanded clay, fireclay in the amount of 33% of the mass of cement and diatomite brick in the amount of 25% of the mass of cement) on the residual strength of expanded clay concrete after heating at a temperature of 200-1000 ^o C. Disadvantages These compositions are characterized by low residual strength after exposure to a temperature of 800 ^o C, and relatively low bending strength of expanded clay concrete.

The closest are the raw material mixtures for the production of heat-resistant vermiculite concrete with an average density of 800-850 kg/m ³ , containing Portland cement and finely ground fireclay [2]. The disadvantages of these compositions are the high cost, low strength after heating at a temperature of 105 ^o C and 800 ^o C of heat-resistant vermiculite concrete.

The purpose of the invention is to expand the raw material base, increase the bending and compressive strength after heating at temperatures of 105 ^o C and 800 ^o C, and reduce the cost of heat-resistant vermiculite concrete.

The problem is solved by using Portland cement, expanded vermiculite, volcanic pumice, basalt fiber and saponified wood resin (WRS) in a heat-resistant raw material mixture.

The binders used in the experiments were Portland cement PC500-DO produced by Belgorod Cement JSC. Pumice sand from the Psykhureyskoe deposit, fraction 0.16-0.63 mm, with a bulk density of 700 kg/m ³ was used as an active mineral additive and filler.

The chemical composition of volcanic pumice is presented in Table 1.

Table 1

Content of main components in% by weight _{SiO2 Al2O3 _ Fe2O3 _} CaO MgO Na ₂ O+K ₂ O SO ₃ p.p.p. 72.8 13.15 1.80 2.38 0.50 6.30 0.02 4.30

The filler is expanded vermiculite from the St. Petersburg mica factory, fraction 0.16-5 mm, with a bulk density of 150 kg/ ^m3 .

The granulometric composition of expanded vermiculite is given in table. 2.

table 2

Granulometric composition of vermiculite

Name of material Partial residues on sieves, % Passed through the sieve 0.16 2.5 1.25 0.63 0.315 0.16 Vermiculite 28.0 12.0 13.0 28.5 18.5 –

For dispersed reinforcement of heat-resistant vermiculite concrete, basalt fiber produced by PJSC "Ivotsteklo" brand RNB-9-1200-4s was used, the ratio of fiber length to diameter was accepted based on preliminary experiments .

To improve the rheological characteristics of the fire-retardant mixture and the physical and mechanical properties of the mortar and concrete, the surface-active air-entraining additive SDO, developed by VNIIzhelezobeton and TsNIILKHI (TU-81-05-2-78), was used.

The mixture is prepared in a forced-action mixer, in which, after supplying water with the addition of SDO, a mixture of Portland cement, basalt fiber, volcanic pumice, then expanded vermiculite, or a pre-mixed dry mixture of Portland cement, basalt fiber, volcanic pumice and expanded vermiculite is sequentially loaded. Mixing of all components is continued until a homogeneous heat-resistant fibrovermiculite-pumice-concrete raw material mixture is obtained. The duration of mixing the mixture is 1.5–2 minutes.

Forming vermiculite pumice concrete samples with dimensions were carried out on a laboratory vibration platform. The mobility of the mixture was 3-5 cm according to the immersion of the StroyTsNIL cone (GOST 5802). The samples were stored in air-dry conditions. Before testing, the samples were dried to constant weight in an oven at .

The compositions of the heat-resistant fibrovermiculite-pumice-concrete raw material mixture according to the invention and their main physical and mechanical properties are given in Table 3.

Compositions Component ratio
in the mixture, wt.% Indicators of properties of heat-resistant vermiculite concrete Portland cement vermiculite fireclay pumice FROM TO fiber water average density ρ, kg/m ³ tensile strength, MPa 0.16-0.315 mm 0.16-0.63 mm when bending when compressed heating temperature, °C 105 800 105 800 Prototype 1 33.3 15.3 14.3 – – – – 37.1 850 – – 2.9 1.2 Developed heat-resistant fiber vermiculite pumice concrete 2 22.3 12.4 – 25.9 – – – 39.4 847 2.0 1.7 3.5 2.7 3 22.3 12.4 – 25.9 – 0.12 1.1 38.18 805 3.4 3.1 4.5 3.6 4 22.1 12.1 – – 26.9 – – 38.9 855 1.9 1.3 3.5 2.6 5 22.1 12.1 – – 26.9 0.11 1.0 37.79 812 3.3 3.0 4.4 3.5

Table 3

From Table 3 it can be seen that with a lower consumption of Portland cement and approximately the same density, the developed vermiculite pumice concrete compositions have higher compressive strengths before heating and after heating at temperatures of 105 ^o C and 800 ^o C compared to the prototype. The use of basalt fibers and SDO in a vermiculite pumice concrete matrix significantly increases the bending and compressive strength after heating at temperatures of 105 ^o C and 800 ^o C, heat-resistant properties increase, and the average density of fibrovermiculite pumice concrete decreases due to the porosity of SDO. The granulometric composition of volcanic pumice (0.16-0.315 mm or 0.16-0.63 mm) does not have a noticeable effect on the average density, strength and heat-resistant properties of vermiculite pumice concrete and the composition of fiber vermiculite pumice concrete.

The cost of the developed composition of fibrovermiculite pumice concrete is significantly less than the cost of the prototype due to the replacement of expensive expanded vermiculite with volcanic pumice and a significant reduction in the consumption of Portland cement and the absence of expensive fireclay in the composition.

Information sources

1. Copyright certificate of the USSR No. 464559. IPC C04B 15/00, C04B 31/08, C04B 31/26, C04B 19/04. Concrete mixture / Tarasova A.P., Nekrasov K.D., Bakhvalova N.A., Krayukhin V.I., Zhdanova N.P.

2. Nekrasov, K. D. Lightweight heat-resistant concrete on porous aggregates [Text] / K. D. Nekrasov, M. G. Maslennikova. – M.: Stroyizdat, 1982. – 152 p.

Claims (7)

Raw mixture for the production of heat-resistant concrete, including Portland cement, expanded vermiculite, volcanic pumice, wood saponified resin, basalt fiber and water, characterized in that it contains expanded vermiculite fraction 0.315–5 mm and volcanic pumice fraction 0.16–0.63 mm , with the following ratio of components, wt.%: Portland cement 22.1–22.3 expanded vermiculite fraction 0.315–5 mm 12.1–12.4 volcanic pumice fraction 0.16–0.63 mm 25.9–26.9 saponified wood resin 0.11–0.12 basalt fiber 1.0–1.1 water the rest.