SU675022A1 - Method of preparing concrete mix - Google Patents

Description

The invention relates to building materials technology. There are known methods for preparing a concrete mix, including the preliminary mixing of a portion of cement with water 1. There are also known methods for preparing a concrete mix, including step-by-step mixing of the components (2. The disadvantage of such methods is that when preparing concrete mixes, including additives, such as alkali metal sulphates, an increased consumption of water is required to obtain a homogeneous composition, and an increase in the water content of the concrete mix leads to a decrease in strength of concrete. The aim of the invention is to reduce water demand and increase the strength of concrete. This is achieved by the fact that in the process of preparing a concrete mix, including step-by-step mixing of components, pre-mixing with water 20-7 solid components are applied, then the additive is added and the mixture is continued to mix until it reaches its original consistency, after which the remaining solid components are added followed by luffing the mixture until homogeneous. mixed at the initial stage with water is determined experimentally from the condition that when the additive is added the mixture thickens slightly, i.e. its awn stirring and reduction of the original consistency. The method is carried out as follows. Take part of the solid components of the concrete mix (in the gnaw, aggregates) in the amount of 20-70% and mix with water. Water is taken in an amount intended for the entire batch. In the process of mixing, the additive is added to the mixture, and then the remaining part of the solid components. A distinctive feature of the proposed method is that it provides for three-stage mixing in the following sequence: 1) mixing part of the solid components with water; 2) mixing the plastic mixture with a supplement; 3) adding the rest. Tschayatzh solid components and re ;; I 111Ivania to obtain a homogeneous

composition.

P ROME and p. The tests are conducted on a concrete mix of the following composition, kg:

Grand Slag1200

White Portland cement600 Additive (magnesium sulphate) 12.

The amount of water is selected on the basis of giving the mixture a predetermined consistency (the spread of the standard cone is 205 mm) /

The mixture is prepared in three ways: 1) simultaneous displacement of all components; 2) pre-mixing of cement, water and additives with half the filler required for the mix and the subsequent introduction into the concrete mix 6 part of the filler; 3) pre-mixing with water 50% of the solid components, added-ie additives, mixing of the solid components and subsequent mixing to obtain a single composition. The amount of water required to obtain equipotent mixtures is, in the first case, 65% rt of the weight of cement, in the second - 59%, in

the third is 54%. After 2V days, concrete samples have strength, respectively: 1-194 kg / cm. 2-223 kg / cm; 3-250 kg / cm.,

It follows from the above data that three-stage mixing of the concrete mix (method 3) allows to reduce the water demand and increase the strength of the concrete .;

Claims (1)

Invention Formula A method for preparing a concrete mix, which includes step-by-step mixing of the components, is distinguished by, and with, I: TO, with the aim of reducing water consumption. and increasing the strength of concrete, pre-mixing with water is subjected to 20-70% of the solid components, then the additive is added and the mixture is continued to be stirred until the original consistency is reached, after which the remaining solid components are added, followed by mixing to a uniform state. Sources of information taken into account in the examination 1, For the application number 2315461 / 29-33, cl. C 04 B 15/00, 01.20.76. 2, USSR Author's Certificate No. 482414, cl. From 04 To 15/02, 1973.