SU624896A1 - Concrete mix preparing method - Google Patents

Description

The invention relates to methods for the preparation of concrete mixtures and can be used in the manufacture of monolithic and precast concrete products and structures, monolithing nodes and joints where concrete with improved technological and physico-mechanical properties is required.

There is a known method of preparing concrete by mixing in the ground, fillers and mixing water, vibroactiv- days after the mixture is kept for a time corresponding to the duration of the first stage of the process of structure formation 1J.

The disadvantage of the known method is the duration of the technological cycle due to the long (up to 6O minutes) duration of the first stage of the process of formation of strings.

The aim of the invention is to increase the strength of concrete and shorten the production cycle.

To do this, when preparing a concrete mix by mixing into a live,

aggregates and mixing water and mechanical activation of the mixture after it has been aged, corresponding to the duration of the first stage of the process of formation, into the water of the NIN gate, preliminarily glycerin is introduced in an amount of 0.05-0.30% by weight of cement.

The introduction of glycerol in the specified amount of plasticizes the concrete mix to significantly improve workability, or gives the opportunity to reduce the water-cement ratio. In addition, the duration of the first stage of the process of structure formation is shortened and the mechanical activation takes place after 20-30 minutes, after which the rate of hardening of the concrete increases. All these factors significantly reduce the technological; concrete preparation cycle.

Claims (1)

Example. A concrete mix containing kg / m is prepared: cement-405, peCoK-40O, cinder-1314, and water - 166. Preliminary, into the mixing water inlet | t in the amount of 0.6 kg (0.15% by weight of cement). The introduction of glycerol reduces the amount of mixing water by 9% while maintaining the same workability. The duration of the first structure formation stage for the mixture is 20 JMKH. 20 minutes after mixing, the mixture is vibrated, then the molded samples are steamed. The table gives comparative data on the strength of concrete obtained by known and proposed methods. Known Proposed 272 The strength of concrete of the same composition, containing 0.15% glycerol, subjected to that vibration immediately after mixing 64 mixture, is 262 and 362 kgf / cm after steaming and after 28 days, respectively. The invention makes it possible to increase the strength of concrete both in the early and in the later periods of hardening, to increase the formwork turnover and shorten the technological cycle. Formula of the invention The method of preparing a concrete mix, consisting in mixing in a binder, aggregates and mixing water, mechanically activating the mixture after extracting it with a corresponding duration of the first stage of the structure formation process, characterized in that, in order to increase the strength of the concrete and the reduction of the technological cycle, the mixing water Glycerin is introduced in the amount of 0.05-0.3% of the weight of cement. Sources of information taken into account in the examination: 1. USSR Author's Certificate No. 310877, cl. From 04 to 7/38, 1969.