RU2278836C1 - Complex additive for concrete and mortars - Google Patents

Abstract

FIELD: construction engineering; manufacture of building materials.

SUBSTANCE: proposed complex additive includes calcium chloride and polyalcohols; it additionally includes sodium nitrite and water at the following ratio of components, mass-%: calcium chloride, 25-30; polyalcohols, 0.3-1.0; sodium nitrite, 12-16; the remainder being water. Proposed additive may additionally contain ligno-sulfonate in the amount of 0.2-1 mass-% or antacidin at mass ratio of antacidin to calcium chloride of 0.001-0.0015:1; glycerin is used as polyalcohol. The following ratio of components is preferable, mass-%: calcium chloride, 30; sodium nitrite, 15; glycerin, 0.35; ligno-sulfonate, 0.25; the remainder being water. As a result, gain in strength is obtained both in early and later hardening terms.

EFFECT: enhanced plasticity of concrete mix; possibility of operating at negative ambient temperatures.

5 cl, 4 tbl

Description

The invention relates to the construction and construction materials industry, in particular to the manufacture of complex additives in cement mortars and concrete to accelerate the hardening of building products and structures.

It is known to use a complex additive consisting of aluminum sulfate and calcium chloride to accelerate setting and increase strength after 1 day (A.S. SU 302320, С 04 В 21/20, publ. 1970).

Known complex additive to concrete and mortar for working at low ambient temperatures, including calcium sugar and calcium chloride with a mass ratio of calcium sugar and calcium chloride of 0.0001-0.001: 1 (Patent RU No. 2187480, IPC ⁷ C 04 B 28/02 , published on 08/20/2002).

Known additive in concrete mixture to increase the strength of concrete in the early stages of hardening, including sodium hydroxide and glycerin (Patent RU No. 2185347, IPC ⁷ C 04 B 28/02, publ. 20.07.2002).

A common disadvantage of the above complex additives is the insufficiently high speed of curing in the early stages of hardening, in addition to this, the additives are not sufficiently frost-resistant.

The closest technical solution is a comprehensive additive for concrete and mortar (Patent RU No. 2168478, IPC ⁷ 04 04 28/04, publ. 6.10.2001), including an accelerator and a plasticizer, and salts of hydrochloric and formic acids are used as an accelerator , and as a plasticizer - polyspitra. As the salt of hydrochloric acid, calcium, potassium and sodium chlorides are used.

This supplement also has the disadvantages of the above additives.

The objective of the proposed solution is to develop the optimal composition of a complex additive, leading to accelerated hardening of concrete, increase the ductility (mobility) of the concrete mixture, increase frost resistance and reduce corrosion of reinforcement.

The problem is solved using a complex additive for concrete and mortar, including calcium chloride, polyalcohols, sodium nitrite and water, in the following ratio of components, wt.%:

Calcium chloride 25-30 Polyalcohol 0.3-1.0 Sodium nitrite 12-16 Water Rest

The complex additive may contain as a plasticizer an additional lignosulfonate in an amount of 0.2-1 wt.%.

The complex additive as polyalcohols preferably contains glycerin, in the following ratio, wt.%:

Calcium chloride thirty Sodium nitrite fifteen Glycerol 0.35 Lignosulfonate 0.25 Water Rest

The complex additive may additionally contain calcium sugar in the mass ratio of calcium sugar and calcium chloride 0.001-0.0015: 1.

In the proposed complex additive, the optimal composition of the components is selected, accelerating the set of strength in both early and late hardening periods. The additional introduction of lignosulfonate can significantly increase the ductility of the concrete mixture. As polyalcohols, any known, preferably glycerin, can be used, the use of which in combination with other plasticizers makes it possible to obtain both dense and porous concrete mixtures.

The introduction of calcium sugar can increase the efficiency in the production of concrete work carried out at low ambient temperatures, and contributes to both accelerating the set of strength and increasing the strength of concrete.

Thus, the technical result achieved by adding a complex additive to concrete and mortar is to accelerate the curing in both early and late hardening periods, increase the ductility of the concrete mixture and the ability to work at low ambient temperatures.

For the preparation of complex additives, glycerin obtained in accordance with GOST 6824-95, technical calcium chloride obtained in accordance with GOST 450-77, technical powder lignosulfonate obtained in accordance with TU 54-028-00279580-97, modified granulated plasticizer lignosulfonate obtained in accordance with TU 5870 are used -001-58042865-03, sodium nitrite, obtained according to GOST 19906.

The mobility, stiffness and bulk density of the concrete mixture, strength and frost resistance of concrete were determined in accordance with the requirements of GOST 10181-81 "Concrete mixtures. Test methods", GOST 10181-78 "Concretes. Methods for determining the compressive and tensile strength", GOST 10860- 76 "Concrete. Methods for determination of frost resistance." Tables 1-4 present data on the composition of the additive in the tests performed, confirming the obtained technical result.

The complex additive is given the code name "Benotech PMP-1".

The concrete mixture is prepared according to the following method: cement and aggregates are introduced into the mixer and intensively mixed, a complex additive is added to the resulting dry mixture in an amount of 0.5 to 5% by weight of the cement and the mixture is mixed until a homogeneous mass. Then, concrete products are prepared according to the standard method for manufacturing laboratory-type samples.

For the preparation of the concrete mixture, cement was used - PC400, manufacturer of Iskitmcement OJSC; sand with M _cr. = 2.15, pollution 1.2% - manufacturer AOZT "North-Krivodanovsky quarry"; crushed stone-diabase, fractions of 5-20 mm - manufacturer of OJSC "Stone quarry" p. Gorny.

From the data presented in tables 1-4, it is seen that the proposed additive is highly effective in concrete work carried out at low ambient temperatures. The use of additives contributes both to accelerating the set of strength and increasing the strength of concrete. This increases the protective properties of concrete in relation to steel reinforcement. Corrosion is absent.

Table 1
The composition of the additive "Benotech PMP-1" No. p / p Calcium Chloride, wt.% Sodium nitrite, wt.% Polyalcohols, wt.% Lignosulfonate, wt.% Calcium sugar, wt.% Water, wt.% Glycerol Pentaerythritol one 30,0 15.0 0.35 - 0.25 - 54,4 2 30,0 16,0 0,305 - - - 53,695 3 25.0 12.0 - 1,0 1,0 0,03 60.97 four 30,0 15.0 0.35 - - 0.45 54,20 5 (prototype) 66.0 Formic acid salt - 100 - 24.0 - - -

Table 4
The effectiveness of the additive "Benotech PMP-1" in concrete №№p / p Consumption of materials per 1 m ³ concrete The density of the concrete mixture, kg / m ³ Cone draft, cm C / in Compressive Strength, MPa Cement kg Sand kg Crushed stone, kg Water, l Additive,% by weight of cement 1 day 28 days Concretes (composition of additive No. 3 from table 1) one 450 705 1000 180 - 2375 4.0 2,5 12.9 48,2 2 450 705 1000 160 0.5 2375 3.0 2,8 19,4 51.7 3 450 705 1000 151 1,0 2375 2,5 2.98 19.5 52,2 four 450 705 1000 144 1,5 2375 4.0 3,1 22.6 51.7 5 (prototype) 450 705 1000 144 3.0 2375 4.0 3,1 15.9 49.5 Mortar Pk3 (8-12 cm) (composition of additive No. 4 from table 1) one 350 1250 - 240 - 2075 10.0 1.46 2,4 19.6 2 350 1250 - 149 0.5 2075 9.0 2,35 3.6 23.1 3 350 1250 - 142 1,0 2075 8.0 2.46 4.0 22.8 four 350 1250 - 140 1,5 2075 8.5 2,5 4.6 24.8 5 (prototype) 350 1250 - 140 3.0 2075 8.0 2,5 2,5 20,0

Claims (5)

1. A comprehensive additive for concrete and mortar, including calcium chloride, polyalcohols, characterized in that it additionally contains sodium nitrite and water in the following ratio, wt.%: Calcium chloride 25-30 Polyalcohol 0.3-1.0 Sodium nitrite 12-16 Water Rest 2. The complex additive according to claim 1, characterized in that it additionally contains lignosulfonate in an amount of 0.2-1 wt.%. 3. The complex additive according to claim 2, characterized in that it contains glycerol as polyalcohols. 4. The complex additive according to claim 3, characterized in that it has the following ratio of components, wt.%: Calcium chloride thirty Sodium nitrite fifteen Glycerol 0.35 Lignosulfonate 0.25 Water Rest 5. The complex additive according to claim 1, characterized in that it further comprises calcium sugar in a mass ratio of calcium sugar and calcium chloride of 0.001-0.0015: 1.