NO860350L - MENTION FOR ADDITION TO CONCRETE AND MORTEL MIXTURES AND PROCEDURE FOR THE PREPARATION OF THIS. - Google Patents

Description

The invention relates to an additive for concrete

and mortar mixtures, as specified in requirement l's preamble.

Dispersants for inorganic binders such as

for example cement or gypsum have long been known. They are used either to lower the viscosity (deliquescent) of a binder suspension at a given water-binder factor or to reduce the water requirement while maintaining the same consistency. M. R. In his book "Chemical Admixtures for Concrete" (London 1978), Rixom describes five chemically different groups of dispersants known in modern concrete technology: melamine and naphthalene-formaldehyde sulfonic acid resins, lignin sulfonates, hydroxycarboxylic acid salts and hydroxylated polymers based on polysaccharide. In addition, in West German published patent application 3144673, a further new group of dispersants is described which consists of ketone-aldehyde condensation products containing acid groups.

However, the effect of these known dispersants is different. Thus, Rixom refers to the melamine and naphthalene-formaldehyde sulfonic acid resins in general as "superfluidizers" because these have by far the greatest dispersing effect and do not lead to unwanted side effects. Also the ketone-aldehyde resins described in the West

German published patent application 3144673, due to their excellent dispersing properties, are considered the "superfluidizers". Lignin sulfonates are less effective fluidizing agents and also have the disadvantage that, even in purified, sugar-free form, they clearly delay cement hydration.

However, the person skilled in the art also knows that melamine and naphthalene formaldehyde sulfonic acid resins as well as lignin sulfonates quickly lose their good dispersing effect at a higher content of the aforementioned inorganic and organic salts in the binder suspension.

The invention therefore aims to provide an additive of the related type which causes an improved liquefaction effect, a long-lasting liquefaction effect and clearly improved early firmness. According to the invention, this task is solved by means of the features specified in the characterizing part of claim 1.

By combining with ligninsulfonates together with water-insoluble surfactants, dissolved in organic solvents, and by further adding water-insoluble resins dissolved in organic solvents, this additive is produced. Humectants that are not water-soluble, such as nonylphenol polyglycol ether with a maximum of 4 ethylene oxide groups, are not permanently dispersible

in soluble dispersants such as lignin sulphonates. They can, however, which has been demonstrated, when dissolved in organic solvents, be permanently dispersed in, for example, lignin sulphonates. With the help of such a combination alone, the dispersibility of a sulphite liquor is increased to such an extent that a 25% sulphite liquor with 3-4% nonylphenol polyglycol ether with a maximum of 4 ethylene oxide groups dissolved in toluene causes an increase in the degree of dispersion of 16-17 cm when dosed in an amount of 1% of the cement weight. The liquefying effect is a long-term effect that has not been achieved with any known dispersant to date. Still after an hour, the increase in the degree of spread still amounts to 13-14 cm. With this combination, it is achieved that, for example, ligninsulfonates can now be used as a liquefaction aid with considerably increased and longer effect.

However, such a flow aid is still not universally applicable because it delays the cement hydration considerably and is thus unsuitable for an economical building engineering advance due to the lower development of firmness, especially after 24 hours.

However, this retarding effect is, as has been shown, counteracted by the addition of water-insoluble resins dissolved in organic solvents to the sulphite liquor. The retarding effect of the sulphite liquors is reduced to the same extent as the proportion of the resin solution is increased. with a similar quantity of the resin solution, the firmness after 24 hours is not lower than the firmness of a comparative concrete without additive.

The invention is described below in more detail with help

of some examples.

Example 1

30 kg of nonylphenol polyglycol ether with no more than 4 mol of ethylene oxide and dissolved in a toluene solution is incorporated into 500 1 of a 50% sulphite leachate with vigorous stirring. The batch is then filled with water to a volume of 1000 1. From this solution, 1%, based on the cement weight, is added for the production of floating concrete, and the degree of spreading is increased from 40 cm to 57 cm. After one hour, the flowable concrete produced in this way still has a degree of spreading of 52-5 3 cm, and the compressive strength after 24 hours is 2.7 N/mm 2 compared to the compressive strength without admixture (0-concrete) which is 6.9 N/mm< 2>.

Example 2

75 1 of a toluene solution containing 18 kg of coumaronindene resin and 30 kg of nonylphenol polyglycol ether with no more than 4 mol of ethylene oxide is incorporated into 500 1 of a 50% sulphite leachate with vigorous stirring. The charge is then filled up with water to a volume of 1000 1. 1% of this solution, based on the cement weight, increases the degree of spreading from 40 cm to 57 cm. After one hour, the flowable concrete produced in this way still has a degree of spread or spread of 53 cm, and the firmness after 34 hours is 4.2 N/mm 2 compared to a firmness of 7 N/mm 2 for the O-concrete.

Example 3

9 0 1 of a toluene solution containing 36 kg of coumaronindene resin and 30 kg of nonylphenol polyglycol ether with no more than 4 mol of ethylene oxide is incorporated into 500 1 of a 50% sulphite liquor with vigorous stirring. The charge is then filled up with water to a volume of 1000 1. 1% of this solution increases the spread from 40 cm to 57 cm. After one hour, the flowable concrete produced in this way still has a spread of 53 cm. The strength after 24 hours was 6 N/mm<2>, while the strength for the O-concrete was 7.2 N/mm<2>.

Example 4

110 1 of a toluene solution containing 60 kg of terpene resin and 30 kg of nonylphenol polyglycol ether with no more than 4 mol of ethylene oxide are incorporated into 500 1 of a 50% sulphite leachate with vigorous stirring. The charge is then filled up with water to a volume of 1000 1. 1% of this solution increases the spread from 40 cm to 57 cm. After one hour, the flowable concrete produced in this way still has a spread of 52-53 cm. The firmness after 24 hours was 7.1 N/mm 2,

2

while the strength of the O-concrete was 7 N/mm.

Example 5

The additive prepared according to example 4 was in an amount of approx. 0.25%, based on cement, added to a concrete mixture within the K-l range soil moisture for the production of paving stones.

The following compressive strength values expressed in N/mm 2 were obtained:

When the concrete mixture was placed, the K-l concrete had an 8% higher density than the O mixture.

Claims (6)

1. Additive for hydraulic, inorganic binder systems, such as cements, aluminum oxide melt cements, fly ash, gypsum and the like, for liquefaction, long-term liquefaction and reduction of the delaying effect or improvement of early strength, characterized by the fact that it contains water-insoluble materials , such as resins, bituminous grades, polycondensed plasters and/or non-water-soluble surfactants which are dissolved in solvents, in an emulsifiable aqueous system. 2. Additive according to claim 1, characterized in that the emulsifiable system consists of sulfite leachate or lignosulfonates. 3. Additive according to claim 1 or 2, characterized in that the water-insoluble materials are dissolved in organic solvents. 4. Additive according to claims 1-3, characterized in that it contains dissolution mediating materials, such as polyhydric alcohols. 5. Procedure for the production of an additive for hydraulic, inorganic binder tanks, such as cements, aluminum oxide hot melt cements, fly ash, gypsum or the like, characterized in that a solution of resins, water-insoluble surfactants and possibly dissolution-mediating materials is prepared in an organic solvent and that this is emulsified in sulfite liquors or lignin sulfonates. 6. Method according to claim 5, characterized in that known per se air pore-forming materials, retarding agents, accelerating agents and sealing agents are also used.