SU1763429A1 - Method of hard concrete mixture preparation - Google Patents

Abstract

The invention relates to the technology of building production, in particular, to the production technology of concrete mixes, and can be used in the preparation of hard and particularly hard concrete mixes in high-speed mixers for the manufacture of products and structures from them. The essence of the invention: the preparation of the mixture is carried out in three steps, first 30–40% of dry components and 20–25% of water are fed into the tank and mixed for 50–60 seconds, the second part is added with the remaining dry components and mixed 50–60 seconds, the third is added to the calculated The amount of water and the mixture is stirred for 35-45 seconds. Characteristic of concrete: RSzh 45-47 MPa, water resistance 10

Description

The invention relates to the technology of building production, to the technology of manufacturing concrete mixes, and can be used in the preparation of hard and especially hard concrete mixes in high-speed mixers for the manufacture of products and structures formed from them with immediate dismantling.

A known method of preparing a concrete mix includes activating water in a high-speed mixer, mixing sand and cement, and then mixing the resulting activated mixture with coarse aggregate in a low-grade mixer, characterized in that in order to increase the strength of concrete, in a high-speed mixer it is activated at a speed of 60-90 m (c) first sand with cement for 10–25 s, then 15–30% water by weight of cement is added and activation is continued for 35–50 s, after which the mixture is fed with the rest of the water into a low-speed mixer.

The goal is to reduce water content, increase the strength and uniformity of concrete.

Example 1. A low water capacity (VNV) was prepared by joint grinding in a ball mill to a specific surface of 3000-5000 cm2 / g of portland cement clinker, slag, gypsum stone and superplasticizer C-3, dried at 35 ° С under vacuum - cabinet. Hard concrete was prepared in a turbulent mixer by mixing dry components specified in the binder and aggregates in an amount of 30% and water in an amount of 20% of their final consumption for 50 seconds, then the rest of the dry components were injected and continued mixing for 50 seconds, after which the remaining quantity of mixing water was supplied and the mixture was finally stirred for 35 seconds.

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The resulting mixture was placed in molds, compacted with vibration and subjected to heat and moisture treatment1.

Tests of the samples showed that the compressive strength of concrete was 45.7 MPa, the intra-serial coefficient of variation of compressive strength was 4.6%, and the water tightness was W 10.

Example 2. HV B was prepared by joint grinding in a ball mill to a specific surface of 3000-5000 cm2 / g of portland cement clinker, slag, gypsum stone and C-3 superplasticizer, dried at 35 ° С in a vacuum cabinet. Hard concrete was prepared in a turbulent mixer by mixing the dry components specified in the binder and aggregates in an amount of 35% and water in an amount of 25% of their final consumption for 55 seconds, then the rest of the dry components were introduced and continued to mix for 55 then the remaining amount of mixing water was applied and the mixture was finally stirred for 40 seconds.

The resulting mixture was placed in molds, compacted with vibration and subjected to heat and moisture treatment.

Testing of the samples showed that the compressive strength of concrete was 47.0 MPa, the intra-serial coefficient of variation of compressive strength of 4.2%, the water tightness of W 10.

Example 3. VNV was prepared by joint grinding in a ball mill to a specific surface of 3000–5000 cm2 / g of portland cement clinker, slag, gypsum stone and C-3 superplasticizer, dried

at a temperature of 35 ° C in a vacuum cabinet. Hard concrete was prepared in a turbulent mixer by mixing dry components specified in the binder and aggregates in an amount of 40% and water in an amount of 30% of the final flow for 60 seconds, then the rest of the dry components were injected and continued mixing for 60 seconds, after the remainder of the mixing water was supplied and the mixture was finally stirred for 45 seconds.

The resulting mixture was placed in molds, compacted with vibration and subjected to heat and moisture treatment.

Tests of the samples showed that the compressive strength of concrete was 46.9 MPa, the intra-serial coefficient of variation of compressive strength was 4.3%, the water tightness of W 10.

Claims (1)

Invention Formula The method of preparing a rigid concrete mixture in a low water capacity (VNV), obtained by joint grinding of portland cement clinker, slag, gypsum stone and superplasticizer, by mixing the dry components of the treadmill, aggregate and water in a turbulent mixer, distinguished by the fact that In order to reduce water content, increase the strength and homogeneity of concrete, 30-40% of dry components and 20-25% of water are first mixed for 50-60 seconds, then the rest of the dry components are introduced and the mixture is mixed into e 50-60 s, and then fed with the remaining quantity of water and the mixture was finally stirred for 35-45 s. Editor A. Kulakov Tehred M. Morgenthal Order 3427 Circulation: Subscription VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, 4/5 Raushsk nab. Proofreader E. Papp