SU555066A1 - Concrete mix - Google Patents

Description

one

The invention relates to compositions of concrete mixtures and can be used for concreting in winter conditions.

A concrete mixture is known that includes a mineral in a perch, aggregates, water, and an addition of potassium carbonate (potash) 1.

Closest to the inventive mixture according to its technical essence and composition is a concrete mixture containing cement, crushed stone, sand, water, and a complex additive 2.

Such a concrete mix can harden at temperatures as low as -30 ° C. The disadvantage of this concrete mix is that it sets quickly (20-40 minutes), which makes it difficult to apply.

The aim of the invention is the acceleration of hardening at low temperatures, an increase in the setting time and the production of concretes with a finely porous structure.

This is achieved by the fact that the concrete mix contains potassium carbonate and sodium tetraborate as a complex additive in the following ratio of components, wt. %:

5-30

Cement

30-60 Rubble

Sand

15-35

Water

5-20

Potassium carbonate

0,25-4; 5 Sodium tetraborate

0.05 - 0.9

Potash, interacting with cement, forms calcite and free alkali, sodium tetraborate,

0 introduced together with the sweat goes into the metaborate with the formation of water, which is spent on alkali. Because of this, the pH of the liquid phase of the concrete mix does not increase for some time and the scooping does not occur until

5 The sodium tetraborate was completely consumed.

Adding sodium tetraborate to the concrete mixture containing potash supplemented sharply slowed down the setting and preserved the workability of the mixture for 3 hours instead of 20 minutes.

0

The method of preparation of the concrete mix is common, adopted in the tekhnolotii of concrete.

Example. Preparing a concrete mixture, including, wt.%;

Cement (portland cement) 12

53 24

9

one,

Sodium tetraborate 0.2

The draft of the cone of the concrete mixture after 60 minutes was 8.3 cm, 120 cm and 3.3 cm.

The strength of concrete samples under compression, which solidified at -20 ° C, was on the 7th day 15.8 MPa, on the 14th day 18 MPa, and on the 28th day 20.4 MPa.

Claims (2)

1. Guidelines for the use of concrete with anti-frost additives, M, NIIZHB, 1968, p. ten. 2. Chemical additives - accelerators of concrete hardening in winter conditions, M, SI, 1967, p. five.