SU1379293A1 - Method of preparing concrete mix - Google Patents

Abstract

The invention relates to methods for preparing concrete mixes and may find application in the building materials industry. It allows to increase the degree of plasticization of concrete mixtures on high-aluminate cements. By jointly grinding 3-10% of the cement with a 10-30% aqueous solution of the superplasticizer additive, a plasticizing cement seed is prepared, 20-50% of which is mixed with the remaining cement and aggregates, and the mixture is then mixed with water and 10-40% solution The additives are added for 1-3 minutes and the remaining amounts of the cement seed and the additive solution are introduced in succession. The spread of the cone of the resulting fine-grained concrete mix is 190-195 mm. 3 tab. (L with so OE

Description

The invention relates to methods for preparing concrete mixes and may find application in industry. These materials are material.

The aim of the invention is to noBbiuyenie the degree of plasticization of concrete mixtures on high aluminate cements

Use 1 linozemic cement and Talum high-aluminate cement. Chemical and mineralogical compositions of cements are given in Table. one.

Use lT fine-grained concrete of cement: sand 1: 3 (by weight) at water / water / cement ratio O, A.

As additives, i-iit superplasticizers are used: C-3 (naphthalene-formaldehyde type) and MFLS (melam-1P1 formaldehyde-type), causing in the Ts1 norms on the content of P1 (H, cements have a strong liquefying effect. Additives are used in the form of aqueous solutions 30% • coneHTpanHVi, injected in the amount of 0.5 and 0.75% by weight of cement (dry matter basis).

G1 p and m 1. A 30% HC1D solution of the additive superplasticizer C-3 is prepared, taken at the rate of 0.5% i) T mass) of cement.

Aluminum cement, taken in the amount of 3% of the total mass of cement

If the temperature rises above 20 ° C, the plasticizing effect is reduced.

The plasticizing effect is determined on a shaking table. The results of the determinations are given in table. 3,

Then make 9 samples - beams of 40x40x160 mm in size for each plasticization method and for each variant. Compaction of the solutions is carried out on a standard vibrating table. The hardening of the samples of the solution is carried out in the chamber of normal humidity. Strength tests are made at the age of 3, 7 and 28 days for bending, and then the halves of the beams are tested for compression. The results of the strength tests show that the decrease in R w-jr and R. during all test periods (3, 7, and 28 days), the formulations prepared according to the proposed method were not observed (as compared with the known methods).

At the age of 28 days, the strength characteristics of the beam samples exceed the control figures for the compared

R

Chzg

by 8-10%, R

on

ways: 10-15%.

Absolute indicators of the strength of the solutions prepared by the proposed method (in particular, according to example 4), at the age of 28 days: R „jr 8.3 MPa, R 62.4 Sha.

As follows from the results, compare

40

subjected to joint grinding with the plant tests of several methods of the additive C-3, taken in the amount of 10% of the total weight of the additive. At the same time prepare a plasticizing cement seed with a water-cement ratio of 0.05. Then, 20% of the seed is mixed with the remaining cement and aggregates (1st stage).

After that, the mixture obtained is closed with water and a solution of the additive, 113ЯTYM in the amount of 10% of the total May-45 additive (2nd stage), and incubated for 1 minute.

At the 3rd stage of mixing, the remaining amount (80%) of the cement-plasticizing seed is introduced into the mixture, at the 4th stage - the remaining amount (80%) of the additive solution.

Similar examples 2-5 implementation of the proposed method is reduced

Bon plasticization of compositions based on two high-aluminate cements, the proposed method using the two most common and effective types of additives - naphthalene- and melamine-type dehydrate superplators - gives an increase in plasticization of its effect by more than 30%.

Claims (1)

Invention Formula The method of preparation of the concrete mix; including the mixing of cement, aggregates, water and a 30% aqueous solution of the additive superplasticizer, which is introduced into the mixture in parts, in order to increase the degree us in tab. 2 (there are also examples of the plasticization of concrete mixtures in holes 6 and 7 with extreme parameters of the method). The optimum temperature for preparing a concrete mix is 10–20 ° C. For soy-aluminate cements, preliminarily, by joint grinding 3–10% of cement with an aqueous solution of the additive of superplasticizer in quantity several tests Bon plasticization of compositions based on two high aluminate cements, the proposed method using the two most common and effective types of additives - superplasticizers naphthalene and melamine - type, gives an increase in plasticization of its effect by more than 30%. Invention Formula The method of preparation of the concrete mix; including the mixing of cement, aggregates, water and a 30% aqueous solution of the additive superplasticizer, which is introduced into the mixture in parts, in order to increase the degree co-aluminate cements, preliminarily, by joint grinding of 3–10% cement with an aqueous solution of an additive of a superplasticizer in an amount of 10–30% by weight of the additive, a plasticizing cement seed is prepared, 20–50% of which is mixed with the remaining cement and aggregates, after which the mixture is obtained are A1.0, CaO SiO, Fe, 0j Chemical composition 45 38 9 8 Mineralogical CaO-L, Oj (CA) 88 5СаО-ЗА1,0, (С5Аз) 8 CaO 2A1.0 ,, (SA,) 4 2CaO Al, 0j-SiO, () - , 1379293 node and 10-40% solution of the additive, incubated for 1-3 minutes and the remaining amounts of cement seed and mortar are introduced sequentially supplements. Table 1 TaOlica 2 Continued) table 2. Continued table. 3