RU1784614C - Method for preparing concrete mix - Google Patents

Abstract

The invention relates to the building materials industry and can be used in the preparation of concrete mixtures using fly ash, flotation products of ash and other fine waste. The aim of the invention is to increase the strength and uniformity of concrete. SUMMARY OF THE INVENTION: 45-55% of the mixing water is used to prepare the fly ash, then a cement slurry is prepared with the remaining water, after which all components are finally mixed. 1 tab.

Description

The invention relates to the building materials industry and can be used in the preparation of concrete mixtures using fly ash, flotation products of fly ash and other fine waste.

 The closest to the solution in technical essence and achieved effect is a method of preparing a concrete mixture, including the preparation of sludge fly ash in the ratio of ash: water 60: 40% and subsequent mixing of the sludge with other components of the concrete mixture.

The disadvantage is the low strength of concrete due to the heterogeneity of the concrete mixture.

The purpose of the invention is to increase the strength and uniformity of concrete.

 The goal is achieved in that when implementing the method of preparing the concrete mixture, including the preparation of sludge fly ash, 45-55% of the mixing water is used, the cement mortar with the remaining water is separately prepared, after which all components are finally mixed.

Example. For the preparation of sludge fly ash using fly ash of the following composition: SiOz 55.60; A120s 2.70; Re203 1.76; CaO 22.09; MDO 10.67; POZ 0.03; TUz 0.96; K20 4.92; NaaO 0.06; p.p.p. 0.95.

T-66 flotation reagent according to T2 38.103243-79, a by-product of dimethyl-dioxane production, widely used in flotation processes and as an additive in concrete, was used as a surfactant.

The composition of the mixture, parts by weight: cement 1; fly ash 0.344; sand 2.75; crushed stone 4.82, water 0.68; Surfactant 0.001.

The concrete mixture is prepared as follows.

Take 45-55% of the mixing water, mix it with a surfactant (T-66) until the latter is completely dissolved and then, within 20 seconds, with

with

with

J s

О Oh

fly ash. At the same time, in a forced-action concrete mixer, a cement mortar was prepared for 1.0-2.5 minutes using the remaining mixing water - 55-45%. Then, the fly ash was introduced into the resulting solution and the remaining components of the concrete mixture — sand, crushed stone — carried out the final stirring for 0-1.5 minutes. The mobility of the concrete mixture was determined according to GOST 10181.81.

To prepare the concrete mix, crushed granite fractions of 5-20 mm are used (GOST 10268-80. 8267-82), river sand quartz Mkr 1.53 (GOST 10268-80, 8763-77), fly ash dispersion of 3500 cm2 / g (GOST 258-18-83), Portland cement of the Balakleevsky combine, water (GOST 23772-79).

To determine the strength of concrete, cube samples of 100 x 100 x 100 mm in size were prepared by the proposed and known methods. Heat treatment was carried out according to the regime of (2 + (3 + 8 + 3) hours. The isothermal process was carried out at a temperature of 80-85 ° C. The compressive strength was determined according to GOST 10180-78. The samples were tested after steaming (after cooling) and after 28 days of storage at a temperature of 20 ± 2 ° C humidity 95%.

The test results are shown in the table.

The test results allow us to draw the following conclusions: the mobility of the concrete mix prepared by the proposed method significantly increased, while the strength increased by 17.6-20% due to the increase in uniformity with stirring.

The economic effect of introducing the proposed method was 0.78 rub / m3.

Claims (1)

SUMMARY OF THE INVENTION A method for preparing a concrete mixture, comprising mixing fly ash with a portion of mixing water and adding a surfactant, followed by mixing the resulting ash slurry with cement, the rest of the water and aggregate, characterized in that to increase the strength of the concrete, the ash is mixed with 45-55 $ of mixing water, the cement is mixed with the rest of the mixing water, after which fly ash is introduced into the resulting cement solution and the resulting mixtures are finally mixed with aggregate.