RU2276660C2 - Complex additive for concretes and cement mortars - Google Patents

Abstract

FIELD: manufacture of building materials.

SUBSTANCE: invention relates to composition of complex additive for concretes, cement mortars, and dry mixes to improve vitality concrete mix, molding properties of concrete mixes, and to reduce corrosion of construction carcass. Additive 3-20% lignosulfonates, 40-87% fireclay, and (additionally) 10-40% clay containing montmorillonite, said fireclay being preferably kaolin clay and said montmorillonite-containing clay being bentonite clay.

EFFECT: improved functional properties of additive, increased waterproofness, frost resistance, strength of concretes and cement mortars.

3 cl, 3 tbl

Description

The invention relates to active ingredients and compositions of complex additives for concrete, cement mortars, dry mixes and can be used in the construction materials industry.

Complex additives are known to increase the ductility, frost resistance, water tightness and strength of concrete mixtures, for example the additive “Superplasticizer S-3”, which includes sodium salts of the condensation product of naphthalene sulfonic acid and formaldehyde. The use of this additive increases the fluidity of concrete mixtures and cement mortars. The disadvantage of this additive is its high cost.

Also known is "Complex additive in concrete mixture" [description of the invention to the Copyright certificate No. 1551688, IPC ⁵ - C 04 V 24/18, publ. 03/23/90. Bull. No. 11], including technical lignosulfonates. The disadvantage of the additive is the complexity of production, insufficient increase in water resistance.

The closest analogue to the proposed additive is a complex additive in concrete and cement mortar, including Portland cement clinker, superplasticizer S-3 and PlastIL containing refractory clay and technical lignosulfonates (RF patent No. 2177459, publ. 27.12.2004, p.4).

The aim of the invention is to improve the functional properties of the proposed integrated additives for concrete and cement mortars and reduce its cost.

This goal is achieved in that the complex additive for concrete and cement mortars, including technical lignosulfonates and refractory clay, additionally contains clay containing montmorillonite, for example, bentonite, in the following ratio, wt.%:

Technical lignosulfonates 3 ÷ 20 Refractory clay 40 ÷ 87 Clay containing montmorillonite 10 ÷ 40

Most preferred is the use of koolin clay as a refractory clay, and bentonite clay as a clay containing montmorillonite.

A complex additive is prepared by mixing the components, while the refractory and bentonite clays are pre-crushed.

The technical properties of the additive are due to the combination of properties of its components. Lignosulfonate reduces the amount of mixing water and increases the fluidity of the mixture. Bentonite clay increases the water resistance and cohesion of the mixture. Refractory kaolin clay increases vitality, non-separability, density of the mixture, strengthens the properties of the additive. As a result, such a composition of materials can improve the properties of concrete and cement mortars.

Examples of complex additives with different percentages of ingredients: sodium lignosulfonate, refractory clay and clay containing montmorillonite are shown in Table 1.

Table 1 Component The ratio of the components of the additive, wt.%, In the examples one 2 3 four 5 Sodium Lignosulfonate 3 6 12 16 twenty Refractory clay 87 78 65 52 40 Clay containing montmorillonite 10 16 23 32 40

Examples of complex additives with different percentages of ingredients: sodium lignosulfonate, clay refractory koalinovy and clay containing montmorillonite, bentonite are shown in Table 2.

table 2 Component The ratio of the components of the additive, wt.%, In the examples 6 7 8 9 10 Sodium Lignosulfonate 3 6 12 16 twenty Refractory clay koalinovaya 87 78 65 52 40 Clay containing montmorillonite, bentonite 10 16 23 32 40

Examples of changes in the technical characteristics of concrete depending on the ratios of the ingredients that make up the complex additives are shown in Table 3.

Table 3 Example Concrete specifications Water Resistant (W) Frost resistance (cycles) Strength (Rb), MPa The decrease in the amount of cement,% Mobility (OK) one four one hundred 23 6 P2 2 four one hundred twenty 6 P2 3 four one hundred 24 6 P2 four four one hundred twenty 6 P2 5 four one hundred twenty 6 P2 6 10 200 25 7 P2 7 10 200 25 7 P2 8 12 200 thirty 8 P3 9 12 200 34.5 9 P3 10 12 200 thirty 8 P4 Superplasticizer. S-3 8 200 34.5 9 P4 No additives 2 fifty fifteen - P1

The tests were carried out on concrete mixtures of the following composition, wt.%: Portland cement (slag Portland) M 500-20; quartz sand M _R = 2.0-25; granite crushed stone with a particle size of 5-20 mm - 55; with a ratio of water / cement = 0.35.

Additives with different component ratios were introduced into the concrete mixture either in the form of a suspension pre-mixed in water in an amount of 1.5% relative to the mass of cement, or in dry form before the water was supplied to the mixture. The mixing time in the concrete was 1 ÷ 3 minutes.

The proposed additive is mainly used for concrete with high water and frost resistance requirements, for example, in industry - for prefabricated building structures, sedimentation tanks, silos of thin-walled and densely reinforced structures, in hydraulic engineering - for prefabricated elements of bridges, dams, locks, adits, embankments, etc. .P. In addition, the use of the proposed complex additives increases the viability of the concrete mixture, the compressive strength of concrete, improves the molding properties of concrete mixtures, reduces the corrosion of reinforcement structures.

Claims (3)

1. A comprehensive additive for concrete and cement mortars, including technical lignosulfonates and refractory clay, characterized in that it additionally contains clay containing montmorillonite, in the following ratio, wt.%: Technical lignosulfonates 3-20 Fire-clay 40-87 Clay containing montmorillonite 10-40 2. The complex additive according to claim 1, characterized in that as a refractory clay it contains kaolin clay. 3. The complex additive according to claim 1, characterized in that as the clay containing montmorillonite, it contains bentonite clay.