HU207274B - Dispersion composition of silicate powder for concrete-additives - Google Patents

Abstract

The prod. comprises max. (w/w%): 60 silica powder, 0.2-6 dispersive agent, and 0.1-1 unsatd. alcohol and/or ester

Description

The present invention relates to a silica powder dispersion composition for use as a concrete additive.

It is known that when added to concrete or mortar, silicon powder (microsilica, silica fume) produced during the production of metal silicon or ferrosilicon has a positive effect on their properties (strength, corrosion resistance, water tightness).

Such examples are listed in Hungarian Patent Application HU-202461.

Silica powder from ferro-silicon production contains 80-95% amorphous silica, has a specific surface area of 15-22 m ² / g, has a volume of 250-400 g / l and has an average particle size of 4 μ. Due to its hydraulic properties and particle size less than 100 times that of cement, it significantly increases the waterproofing, permeability and strength of the concrete, while increasing its shrinkage and cracking tendency. Therefore, its use may be limited. Its application is facilitated by the addition of various water-reducing additives, which counteract the increasing effect of silica powder on the water-cement factor, thereby eliminating the disadvantages caused by its use. The addition of silica powder thus only has a positive effect on the properties of the concrete, but does not eliminate the cumbersome handling and environmental pollution caused by the treatment of very low bulk material (transport, storage, measurement).

FR 2537127 relates to the preparation of silica powder in dispersion. The method comprises preparing a multi-component material blend using a concrete fluidizing agent with the active ingredient known as a water-reducing additive in order to achieve flow consistency to prevent gelling.

It is known from HU 196936 that aliphatic (polyhydric) alcohol with triple unsaturated bond used to prevent corrosion of the steel insert in concrete also has a plasticizing effect.

It is known from concrete technology that the effect of plasticisers and plasticizers is limited in time, and their effect is "diminishing". It is apparent from the examples herein that the viscometer torque, which is proportional to the viscosity, increases dramatically with time, i.e., the viscosity of the dispersion produced increases over time. The increase in viscosity reduces the shelf life of the material, limits its applicability, pumpability, and dosage.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an aqueous silica silica dispersion with a high silica content which is long-lasting, low viscosity, can be dispensed with conventional concrete chemical metering equipment, and allows accelerated concrete hardening and waterproofing.

A viscous viscosity stabilizing aqueous silica powder dispersion composition for use as a concrete additive system according to the present invention, which comprises dispersants other than silica powder, characterized in that 40-60% by weight of silica powder, 0.3-6.0 lignin sulfonate, sulfonated naphthalene formaldehyde condensate, formaldehyde condensate and 0.2-1.0% 2-butyn-1,4-diol, hexim-1-ol-3-one, propyl alcohol, and the like. containing their esters and the rest water.

The silica powder used has the following composition:

SiO ₂ t% 95.4 Fe ₂ O ₃ 0.6 Al ₂ O ₃ 0.35 TiO ₂ 0.07 CaO 0.4 MgO 0.56 K ₂ O 1.05 0.3 p ₂ o ₅ 0.05 MnO 0.08 C 0.7

The effect of the composition of the invention is believed to be related to the complexation of the cations in the silica powder, thereby preventing the polyvalent cations from reducing the effect of the plasticizers and fluxing agents over time and consequently increasing the viscosity.

The silica powder dispersion composition of the present invention can be prepared by adding to the mixing device the required amount of water to which the plasticizer and dispersant are added. After homogenization, the silica powder is continuously added with constant stirring. The aqueous dispersion thus prepared has a homogeneous, foam and sediment free viscosity of between 150 and 1500 mPas and a pH of 6.5 to 8.5.

The resulting dispersion is added to concrete or mortar at a rate of 6 to 30% by weight of cement on conventional metering equipment. The water content of the dispersion should be taken into account by determining the v / c factor, depending on the intended use.

/. example

Weigh 50 tr in a mixing device. water, add 1 tr. approx. 40% by weight lignin sulfonate and 0.25 tr. 20% aqueous solution of 2-butyn-1,4-diol and after stirring for 5 min. fumed silica. The homogeneous product has a viscosity of 220 mPas, pH 6.8. Addition of 15% of the dispersion thus produced to a concrete with a suitable grit structure resulted in a soil moisture consistency of 0.3 v / c.

Example 2

In the example above, 40 tr. water, 1.5 tr. 20% sulphonated melamine formaldehyde condensate (ala1

EN 207 274 Β sulfonated derivative of light condensation grade resin: Melment SKW, BASF) and 0.3 tr. hexin-1-ol-3 was added followed by 60 tr. silica powder. Viscosity 300 mPas, pH 7.2. The prepared dispersion can be mixed with 15% by weight of cement based on 5 concrete of suitable grain structure to produce shotcrete.

Example 3

By the procedure of Example 1, 50 tr. water, 0.6 tr. sulfonated naphthalene formaldehyde condensate, 0.35 tr. propalyl ester, 50 tr. a silica powder dispersion is prepared from which 30% by weight of the cement content is added to the concrete mixture to form a high strength concrete.

The additional technical effect of the composition according to the invention is illustrated by the following tables:

Table 1

Composition of concrete mixtures

concrete Preparation marking Betona- DALE kg Cement kg Water 50% dispersion of Example 1 kg 1. Benchmark 1850 300 * 180 - 2. Bowl. of 1850 270 150 60 3. Bowl. of 1850 240 120 120 4. Benchmark 1850 300 ** 180 - 5. Bowl. of 1850 270 150 60 6. Bowl. of 1850 240 120 120

Note: * 350 Kspc 20 cement

450 pc cement

Examining the composition of the concrete mixes, it can be stated that the very favorable results obtained with the use of the dispersion according to the invention can be achieved with a significant reduction of the cement content.

Table 2

Viscosity Stabilization Effect Measured by Hacke Viscometer Torque of Viscosimeter

Example Invert speed After 1 day After 7 days After 28 days After 56 days After 90 days FP2537127 description 32 4 8 11 - - Example A) 8 2 5 7 11 14 17 23 - FP2537127 description 32 8 18 17 26 - - Example B) 2 25 32 23 28 26 27 - - FP 2537127 description 32 21 57 55 - - Example C) 8 2 33 42 63 81 64 76 - - 32 53 Above 150 Above 150 Above 150 without additives 8 60 Above 150 Above 150 Above 150 2 68 Above 150 Above 150 Above 150 32 3 5 5 5 5 stabilizing Example 1 of the invention; 8 6 7 7 7 7 2 7 8 8 8 8 32 15 16 16 16 16 Invention Example 2 8 20 22 22 22 22 2 23 25 25 25 25 32 18 20 20 20 20 Example 3 of the Invention. 8 21 23 23 23 23 2 30 35 35 35 35

The viscosity of the cement mixture is favored by known plasticizers or fluxes when added at 2-6% by weight based on silica powder, but the viscosity of the cement mixture increases with time, which is disadvantageous in application. according to table.

The composition of the aqueous dispersion composition of the silica powder of the present invention not only allows a significant reduction in the viscosity of the cement mixture, but also has a constant viscosity over time and reduces the amount of additives.

Claims (1)

PATIENT PERSONALITY An aqueous silicone dispersion composition for use as a concrete additive comprising 40-60% w / w silica gel 0.3-6.0% lignin sulfonate, sulfonated naphthalene formaldehyde condensate with a sulfonated melamine-formaldehyde condensate and water, characterized in that the composition is 0.2% -1.0% by weight of 2-butin-1,4-diol, hexin-1-ol-3-one or propargyl alcohol; it contains an ester.