SU816991A1 - Method of producing concrete mix - Google Patents

Description

(54) METHOD FOR PREPARING CONCRETE. MIXTURES

... ... This invention relates to the manufacture of building products made of mineral based substances. There is a known method for preparing a concrete mixture by mixing portland cement aggregate, water, and ligosulfonate additives treated with nitric acid. The addition of sulfite-alcohol bards is treated with a 8 .12% solution of nitric acid and introduced into the concrete mixture in volume of 0.1-0.2% by weight of cement 1. The disadvantage of the known method is in the slow initial hardening of the concrete mix. . .), The core of the invention is the acceleration of concrete hardening. The goal is achieved by the fact that in the method of preparation of concrete mixes by mixing portland cement, aggregate, water and the addition of leagues of nosulfonates treated with nitric acid, the addition of lignosulfonates is treated with 30-100% nitric acid (U) and the weight ratio of the lignosulfonate to nitric acid from 3 to 0 5 and injected into the concrete mixture in the amount of 0.0015-0.2% by weight of cement 272 hours after treatment with nitric acid. The efficiency of the accelerating effect of the additive increases with an increase in the content of alita in the cement and with a decrease in the content of aluminate from the surface. With the introduction of an additive in the amount of O ,, 03-0.2% by weight of cement, the acceleration of concrete hardening is achieved while simultaneously reducing the water demand of the concrete mix; expense of the plasticizing effect of the additive. The optimal amount of additive reduces the water demand of slow-moving concrete mixes by 10-14% while maintaining the desired mobility of the mixture. . Example 1. Belgorod Portland cement (M-500), sand of the Academic quarry with a fraction of 50, 14 mm and water is used to prepare a cement-sand mixture with a ratio of cement weight to sand weight 1: 3 and water-cement ratio W / C - 0 / 3-5. Along with the mixing water, an additive is added to the cement-sand mixture with sulfite-alcohol stillage treated with 30% HNOj solution, with a weight ratio of lignosulfonates (PRS) to nitric acid 1.0 and 0.5. From the prepared cement-sand mixtures using vibrating compaction, balancing specimens with a size of 4x4x16 cm are formed, which are then steamed at modes 2 -3 3 3, 2, 5 and 2 3 - + - 6ЧС by subsequent cooling in an open steaming chamber. On the following day, the specimens are molded and tested for compression. The test results are shown in Table. li

Example 2. A concrete mix of the following composition is made from Voskresensk cement (M-400), sand, rubble,

Cement480

Sand with Mkr.2,87 740 Crushed stone fraction of 10-20 mm. 1026 The amount of water in the mixture is 178 l, W / C 0.37, the hardness of the concrete mix - 71 s. Concrete mix is prepared

with the addition of sulphite yeast brew (RRT), treated with 100% HNOj with a weight ratio of RRT to azbtic acid from 10 to 0.3. Prepared concrete mixes using vibrating compaction form cubic samples 10x10x10 cm in size, some of which hardened under normal temperature and humidity conditions, and another part was subjected to steaming for 2 + 2 + 5 hours with cooling in an open chamber. At the age of one day, the samples are molded and tested for compression. The test results are shown in Table. 2

Making concrete by the proposed method allows to shorten the cycle of heat treatment of products, to accelerate the hardening of solid concrete, to increase its strength, density, or, while maintaining normalized strength, to reduce cement consumption.

Table 1

According to the proposed method

Table 2.

Claims (2)

Claim A method of preparing a concrete mixture by mixing Portland cement, aggregate, water and an additive of lignosulfonates treated with nitric acid, characterized in that, in order to increase the strength of concrete, an addition of lignosulfonates is processed with 30-100% nitric acid VNIIPI Order 1192/29 12 Air-210 moist toy (with a weight ratio of ligno. Sulfonates to nitric acid from 3 to 0.5) and injected into the concrete mixture In an amount of 0.0015-0.2% by weight of cement 272 hours after treatment with nitric acid.