RU2132828C1 - Concrete mix for hydroinsulation and method of preparing concrete mix for hydroinsulation - Google Patents

Abstract

FIELD: building industry, more particularly hydroinsulation of tunnels, foundations various subsurface structures, manufacture of hydroinsulating coatings for walls, overhead covers and floors. SUBSTANCE: concrete mix comprises, binder, water, polymeric additives as water-soluble epoxy diethylene glycol and triethylene glycol resins and polyethylene polyamine hardener and further comprises industrial lignosulfonate plasticizer, ratio of components being as follows (wt %) based on binder weight: diethylene glycol or triethylene glycol resins, 0.8-1.4; polyethylene polyamine, 0.075-0.225; and industrial lignosulfonate, 0.01-0.25. Mixture is prepared as follows. Binder, fillers and plasticizer are mixed with 65-70% of the required amount of water. Remaining water containing resin additive and hardener is then added, and the whole is stirred. EFFECT: higher quality and greater service life of hydroinsulation due to reduced water absorption, high water impermeability, high adhesion with surface to be protected and high placability of the concrete mix. 3 cl, 1 tbl

Description

 The invention relates to the field of construction, namely the production of building materials used for waterproofing tunnels, foundations, various underground structures, for example, in the construction of the subway, as well as the production of waterproofing coatings of walls, floors and floors.

 It is known that in order to ensure waterproofing properties, various additives, for example polymers, are introduced into concrete mixtures.

 Known concrete mixture containing a mineral binder, aggregates, water and a polymer additive - melamine urea formaldehyde resin (AS USSR N 438625, B.I. N 29, 1974). Such an additive increases the density of concrete, but reduces the speed of curing in the initial stages of hardening of the mixture.

 Known mortar for waterproofing coatings containing Portland cement, ashes of thermal power plants, sand, a plasticizing additive and water (AS USSR N 537972, B.I. N 45, 1976). Chloroprene latex and sodium aluminate are used as a plasticizer in this solution to accelerate hardening of the coating and increase crack resistance.

 It is known to use water-soluble resins (aliphatic epoxy, polyamine and urea) as an additive for the preparation of concretes for various purposes, which improve some characteristics of concrete: mobility, density, ductility, water resistance. Resin 89 increases the corrosion resistance of cement stone in acidic environments, reduces the development of chemical and physical suffusion, and increases water resistance ("Concrete and reinforced concrete", N 7, 1977, p. 12-13).

 Water-soluble resins are introduced with mixing water in the traditional technology for the preparation of concrete mixtures ("Concrete and reinforced concrete", N 10, 1981, S. 16-18).

 Closest to the claimed is a concrete mixture containing cement, aggregates, water and polymer additives in the form of water-soluble epoxy resins of diethylene glycol or triethylene glycol in the amount of 1.5-2.5% by weight of cement (A.S. USSR N 184691, B.I. . N 15, 1966).

 The mixture has sufficient ductility due to the large amount (1.5-2.5% by weight of cement) of the additive. But such a large content of water-soluble epoxy resins leads to a significant increase in the cost of structures, and reduces the rate of curing in the early stages of hardening of the mixture.

 A known method of preparing waterproof concrete or mortar by mixing cement, aggregates and water with a polymer additive previously introduced into it in the form of a water-soluble polyamide resin in an amount of 1.5-2.5% by weight of cement with a hardener polyethylene polyamine (A.S. USSR N 187595 B.I. N 20, 1966).

 There is a method of preparing waterproof concrete or mortar by mixing cement, aggregates and water with polymer additives previously introduced into it — water-soluble epoxy resins with hardener (A.S. USSR N 184691, B.I. N 15, 1966). The method provides an increase in the degree of water tightness and deformability of concrete.

 Closest to the claimed is a method of preparing a concrete mixture by mixing cement and aggregate with mixing water and a sulfonated condensation product of melamine and formaldehyde. At the same time, sulfite-yeast mash is introduced into 50-90% of the water and the mixture of cement and aggregates is closed with this water, after which the remainder of the water is introduced with the condensation product of melamine and formaldehyde (A.S. USSR N 737383, B.I. N 20 , 1980). The mixture obtained in this way has sufficient workability and viability, but does not have the necessary waterproofing properties and adhesive properties with the treated surface.

 The invention solves the problem of improving the quality, durability and frost resistance of waterproofing at the same time due to reduced water absorption, high water resistance, high adhesion to the protected surface and the required workability of the concrete mixture.

This is achieved by the fact that the concrete mixture contains a binder, aggregates, water, polymer additives in the form of water-soluble epoxy resins of diethylene glycol or triethylene glycol and a hardener of polyethylene polyamine with an additionally introduced plasticizer - technical lignosulfonate - in the following ratio of ingredients,% of the weight of the binder:
Diethylene glycol or triethylene glycol resins - 0.8 - 1.4
Polyethylene polyamine - 0.075 - 0.225
Technical lignosulfonate - 0.1 - 0.25
The problem is also solved by the fact that the binder, fillers and plasticizer are shut off with two-thirds of the required amount of water, then the remaining water is added with the resin and hardener added beforehand, after which everything is mixed.

 The use of water-soluble epoxy resins of diethylene glycol or triethylene glycol promotes plasticization of the mixture and provides high water resistance and high adhesion of the mixture to the protected surface. The resin content of more than 1.4% by weight of the binder enhances the plasticizing effect, but leads to a significant slowdown in the hardening of the solution. The resin content of less than 0.8% by weight of the binder does not allow to obtain durable concrete with high rates of water resistance and adhesion to the protected surface.

 The hardener content of polyethylene polyamine more than 0.225% by weight of the binder reduces the efficiency of the additive, and also increases the cost of the material. When the content of polyethylene polyamine is less than 0.075% by weight of the binder, the potential of the resins is not fully utilized.

 The presence in the mixture of technical lignosulfonate (LST) increases the ductility of the concrete mixture and helps to accelerate its hardening in the early stages. The content of LST less than 0.1% of the weight of the binder is ineffective, and more than 0.25% slows down the curing of concrete. In addition to plasticizing concrete, the introduction of LFB in an amount of 0.1-0.15% helps to accelerate the hydration processes and increase early strength.

 Mixing the concrete mixture with water with a complex of additives previously dissolved in it leads to clumping and does not provide the required plasticity of the mixture due to the interaction of technical lignosulfonate with polymers, and also slows down the curing in the early stages.

 From the point of view of the physicochemical processes taking place in the concrete mixture, the introduction of only two-thirds of the mixing water into the dry mixture of binder, aggregates and LFB helps to intensify the process of binder hydration, which means a decrease in the induction period and accelerate the curing. In addition, the rheology of the mixture improves: homogenization, preliminary plasticization, preparation for the perception of polymer additives.

 For the introduction of a polymer additive, 1/3 of the amount of mixing water is necessary and sufficient. The dissolution of resins in precisely this amount of water contributes to their qualitative averaging in the concrete mixture and increases the plasticity of the mixture without slowing down the hydration processes during concrete hardening.

 Preparation of the mixture is carried out directly at the place of waterproofing.

 The required amount of mixing water is divided into two parts - one twice as large as the other. Most of the water (two-thirds) mix the dry mixture of binder, aggregates and plasticizer. The resulting mass is thoroughly mixed for 5-10 minutes. Premixed resin and hardener are introduced into a smaller part of the water (one third). Then both parts (solution and polymer additive) are combined and thoroughly mixed. The mass must be uniform.

 Thus prepared concrete mixture with a water-cement ratio W / C = 0.42-0.45 has high mobility and can be applied to the prepared surface manually or by means of pneumatic concrete.

 Example.

 Six concrete mixtures were prepared with C: P: B = 570: 1100: 256 (1: 1.93: 0.45), differing in the content of additives.

 The test results are shown in the table.

 As can be seen from the table, the introduction of a mixture of resin in an amount of 0.8-1.4 (mixture 3-6) leads to a significant increase in water resistance.

 The introduction of a plasticizer LST in an amount of 0.1-0.25 together with the resin improves ductility and workability (mixtures 3, 4, 5), ensuring stability of water resistance and increasing strength, and allows changing the mobility to use various methods of applying materials to the treated surface ( pneumatic injection, manually, shotcrete).

 The introduction into the mixture of plasticizer - technical lignosulfonate - in dry form allows you to pre-cook the semi-finished product - dry waterproofing mortar or concrete mixes.

 Thus, the concrete mixture of the specified composition, prepared by the specified method, has both high workability, high adhesion to the surface to be protected and high water resistance. These qualities provide frost resistance, durability, improving the quality of waterproofing without increasing costs.

Claims (1)

1. A concrete mixture for waterproofing containing a binder, aggregates, water and a polymer additive in the form of water-soluble epoxy resins of diethylene glycol or triethylene glycol and a hardener of polyethylene polyamine, characterized in that the mixture additionally contains a plasticizer - technical lignosulfonate in the following ratio of additive ingredients,% by weight in weight
Diethylene glycol or triethylene glycol resins - 0.8 - 1.4
Polyethylene polyamine - 0.075 - 0.225
Technical lignosulfonate - 0.1 - 0.25
2. A method of preparing a concrete mixture for waterproofing, comprising mixing the dry binder and aggregate mixture 65 to 70% of the required amount of mixing water, dissolving the additive in the rest of the water and then introducing it into the mixed mixture, characterized in that the mixing of the dry binder and aggregate mixture is carried out if there is a plasticizer in this mixture - technical lignosulfonate, and as an additive when dissolved in the rest of the water, a polymer additive in the form of water-soluble epoxy diethylene glycol is used ring or triethylene glycol resins and hardener polyethylene polyamine.

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