Additive for hydraulically setting compositions

Abstract

The present invention relates to an additive for hydraulically setting compositions comprising a colloidally disperse preparation comprising at least one salt of a polyvalent metal cation with at least one organic phosphonate and/or phosphate compound as anion and at least one polymeric dispersant comprising anionic and/or anionogenic groups and polyether side chains. The additive is especially suitable as slump retainer and for improving early strength.

Claims

1. An additive for hydraulically setting compositions, comprising an aqueous colloidally disperse preparation comprising a) at least one salt of at least one polyvalent metal cation with at least one organic phosphonate and/or organic phosphate compound as anion, optionally in a mixture with at least one compound capable of releasing an inorganic anion selected from carbonate, oxalate, silicate, phosphate, polyphosphate, phosphite, borate, aluminate and sulphate, which forms a sparingly soluble salt with the polyvalent metal cation and b) at least one polymeric dispersant comprising anionic and/or anionogenic groups and polyether side chains, wherein the polyvalent metal cation selected from Al.sup.3+, Fe.sup.3+, Fe.sup.2+, Zn.sup.2+, Mn.sup.2+, Cu.sup.2+, Mg.sup.2+, Ca.sup.2+, Sr.sup.2+, Ba.sup.2+ and mixtures thereof, and wherein the metal cation is present in an amount corresponding to the following formula (a): $\begin{array}{cc}0.1<\frac{\underset{i}{.Math.}{z}_{K,i}*n_{K,i}}{\underset{j}{.Math.}{z}_{S,j}*n_{S,j}}<50.& \left(a\right)\end{array}$ where z.sub.K,i is the magnitude of the charge of the polyvalent metal cation, n.sub.K,i is the number of moles of the polyvalent metal cation, z.sub.S,j is the magnitude of the charge of the anionic and anionogenic group present in the polymeric dispersant, n.sub.S,j is the number of moles of the anionic and anionogenic group present in the polymeric dispersant, the indices i and j are independent of one another and are an integer greater than 0, where i is the number of different kinds of polyvalent metal cations and j is the number of different kinds of anionic and anionogenic groups present in the polymeric dispersant.

2. The additive according to claim 1, wherein the organic phosphonate or organic phosphate compound is capable of forming a sparingly soluble salt with at least one of the polyvalent metal cations.

3. The additive according to claim 1, wherein at least one polyvalent metal cation and at least one anion are present in an amount which is calculated by the following formulae: $\begin{array}{cc}0.1<\frac{\underset{i}{.Math.}{z}_{K,i}*n_{K,i}}{\underset{j}{.Math.}{z}_{S,j}*n_{S,j}}<50& \left(a\right)\\ 0<\frac{\underset{l}{.Math.}{z}_{A,l}*n_{A,l}}{\underset{l}{.Math.}{z}_{K,i}*n_{K,i}}<3& \left(b\right)\end{array}$ where Z.sub.K,i is the magnitude of the charge of the polyvalent metal cation, n.sub.K,i is the number of moles of the polyvalent metal cation, z.sub.S,j is the charge of the anionic and anionogenic groups present in the polymeric dispersant, n.sub.S,j is the number of moles of the anionic and anionogenic groups present in the polymeric dispersant, z.sub.A,l is the charge of the anion, n.sub.A,l is the number of moles of the anion, the indices i and j are independent of one another and are an integer greater than 0, i is the number of different kinds of polyvalent metal cations and j is the number of different kinds of anionic and anionogenic groups present in the polymeric dispersant, I is the number of different kinds of anions which can form a sparingly soluble salt with the metal cation.

4. The additive according to claim 1, wherein the salt comprises an anion is selected from an anion of organic phosphonates or organic phosphates having 1 to 3 phosphonic acid and/or 1 to 3 phosphoric acid groups, wherein in the phosphonates the organic radical is attached to the phosphorus atom and in the phosphates the organic radical is attached to one or two oxygen atoms of the phosphate group, wherein the organic radical is selected from a C.sub.1-C.sub.12-alkyl radical which may optionally be interrupted by a nitrogen and/or oxygen atom, C.sub.2-C.sub.4-alkenyl radical or a poly(C.sub.2-C.sub.4-alkoxy) radical having 2 to 300 alkoxy units.

5. The additive according to claim 1, wherein the anion is derived from an organic phosphonic acid or organic phosphoric acid of formula I
R.sup.A—R.sup.B—R.sup.C wherein R.sup.A is H, hydroxy, C.sub.1-C.sub.4-alkoxy, C.sub.1-C.sub.4-alkyl, phenyl, —PO.sub.3H.sub.2 or —OPO.sub.3H.sub.2; R.sup.B is C.sub.1-C.sub.4-alkylene, which is optionally substituted with hydroxy, C.sub.2-C.sub.4-Alkenylene, —(CH.sub.2).sub.x—NR.sup.D—(CH.sub.2), or —(OC.sub.zH.sub.z).sub.n—; R.sup.C is —PO.sub.3H.sub.2 or —OPO.sub.3H.sub.2; R.sup.D is —(CH.sub.2).sub.x—R.sup.C, hydroxy-C.sub.1-C.sub.4-alkyl or R.sup.E—(OC.sub.zH.sub.z).sub.n—; R.sup.E is H or C.sub.1-C.sub.4-alkyl; x is 1 or 2; y is 1 or 2; z is 1, 2, 3 or 4; and n is 1 to 100; and mixtures thereof.

6. The additive according to claim 5, wherein the anion is derived from an organic phosphonic acid or organic phosphoric acid of formula I, wherein R.sup.A is phenyl, —PO.sub.3H.sub.2 or —OPO.sub.3H.sub.2; R.sup.B is C.sub.1-C.sub.4-alkylene, which is optionally substituted with hydroxy, or —(OC.sub.zH.sub.z).sub.n—; R.sup.C is —PO.sub.3H.sub.2 or —OPO.sub.3H.sub.2; z is 2 or 3; and n is 1 to 100; and mixtures thereof.

7. The additive according to claim 1, wherein the organic phosphonate or phosphate is derived from a compound of the formula ##STR00019## and mixtures thereof.

8. The additive according to claim 1, having a pH of 8 to 13.

9. The additive according to claim 1, wherein the polymeric dispersant has, as anionic or anionogenic group, at least one structural unit of the general formulae (Ia), (Ib), (Ic) and/or (Id): ##STR00020## in which R.sup.1 is H or an unbranched or branched C.sub.1-C.sub.4-alkyl group, CH.sub.2COOH or CH.sub.2CO—X—R.sup.2; X is NH—(C.sub.nH.sub.2n) or O—(C.sub.nH.sub.2n) with n=1, 2, 3 or 4, where the nitrogen atom or the oxygen atom is bonded to the CO group or is a chemical bond; R.sup.2 is OM, PO.sub.3M.sub.2 or O-PO.sub.3M.sub.2; with the proviso that X is a chemical bond when R.sup.2 is OM; ##STR00021## in which R.sup.3 is H or an unbranched or branched C.sub.1-C.sub.4-alkyl group; n is 0, 1, 2, 3 or 4; R.sup.4 is PO.sub.3M.sub.2 or O-PO.sub.3M.sub.2; ##STR00022## in which R.sup.5 is H or an unbranched or branched C.sub.1-C.sub.4-alkyl group; Z is O or NR.sup.7; R.sup.7 is H, —(C.sub.nH.sub.2n)—OH, —(C.sub.nH.sub.2n)—PO.sub.3M.sub.2, —(C.sub.nH.sub.2n)—OPO.sub.3M.sub.2, —(C.sub.6H.sub.4)—PO.sub.3M.sub.2 or —(C.sub.6H.sub.4)—OPO.sub.3M.sub.2, and n is 1, 2, 3 or 4; ##STR00023## in which R.sup.6 is H or an unbranched or branched C.sub.1-C.sub.4-alkyl group; Q is NR.sup.7 or O; R.sup.7 is H, —(C.sub.nH.sub.2n)—OH, —(C.sub.nH.sub.2n)—PO.sub.3M.sub.2, —(C.sub.nH.sub.2n)—OPO.sub.3M.sub.2, —(C.sub.6H.sub.4)—PO.sub.3M.sub.2, or —(C.sub.6H.sub.4)—OPO.sub.3M.sub.2, n is 1, 2, 3 or 4; and where each M is independently H or one cation equivalent.

10. The additive according to claim 1, wherein the polymeric dispersant has, as polyether side chain, at least one structural unit of the general formulae (IIa), (IIb), (IIc) and/or (IId): ##STR00024## in which R.sup.10, R.sup.11 and R.sup.12 are each independently H or an unbranched or branched C.sub.1-C.sub.4-alkyl group; Z is O or S; E is an unbranched or branched C.sub.1-C.sub.6-alkylene group, a cyclohexylene group, CH.sub.2-C.sub.6H.sub.10, 1,2-phenylene, 1,3-phenylene or 1,4-phenylene; G is O, NH or CO—NH; or E and G together are a chemical bond; A is C.sub.xH.sub.2x with x=2, 3, 4 or 5 or CH.sub.2CH(C.sub.6H.sub.5); n is 0, 1, 2, 3, 4 and/or 5; a is an integer from 2 to 350; R.sup.13 is H, an unbranched or branched C.sub.1-C.sub.4-alkyl group, CO—NH.sub.2 and/or COCH.sub.3; ##STR00025## in which R.sup.16, R.sup.17 and R.sup.18 are each independently H or an unbranched or branched C.sub.1-C.sub.4-alkyl group; E is an unbranched or branched C.sub.1-C.sub.6-alkylene group, a cyclohexylene group, CH.sub.2-C.sub.6H.sub.10, 1,2-phenylene, 1,3-phenylene or 1,4-phenylene, or is a chemical bond; A is C.sub.xH.sub.2x with x=2, 3, 4 or 5 or CH.sub.2CH(C.sub.6H.sub.5); n is 0, 1, 2, 3, 4 and/or 5; L is C.sub.xH.sub.2x with x=2, 3, 4 or 5 or CH.sub.2—CH(C.sub.6H.sub.5); a is an integer from 2 to 350; d is an integer from 1 to 350; R.sup.19 is H or an unbranched or branched C.sub.1-C.sub.4-alkyl group; and R.sup.20 is H or an unbranched C.sub.1-C.sub.4-alkyl group; ##STR00026## in which R.sup.21, R.sup.22 and R.sup.23 are each independently H or an unbranched or branched C.sub.1-C.sub.4-alkyl group; W is O, NR.sup.25 or N; V is 1 when W═O or NR.sup.25, and is 2 when W═N; A is C.sub.xH.sub.2x with x=2, 3, 4 or 5 or CH.sub.2CH(C.sub.6H.sub.5); a is an integer from 2 to 350; R.sup.24 is H or an unbranched or branched C.sub.1-C.sub.4-alkyl group; and R.sup.25 is H or an unbranched or branched C.sub.1-C.sub.4-alkyl group; ##STR00027## in which R.sup.6 is H or an unbranched or branched C.sub.1-C.sub.4-alkyl group; M is H or one cation equivalent; Q is NR.sup.10, N or O; V is 1 when W═O or NR.sup.10, and is 2 when W═N; R.sup.10 is H or an unbranched or branched C.sub.1-C.sub.4-alkyl group; R.sup.24 is H or an unbranched or branched C.sub.1-C.sub.4-alkyl group; A is C.sub.xH.sub.2x with x=2, 3, 4 or 5, or CH.sub.2C(C.sub.6H.sub.5)H; and a is an integer from 2 to 350.

11. The additive according to claim 1, wherein the polymeric dispersant is a polycondensation product comprising structural units (III) and (IV): ##STR00028## in which T is a substituted or unsubstituted phenyl or substituted or unsubstituted naphthyl radical, wherein the phenyl or naphthyl is substituted by 1 or 2 C.sub.1-C.sub.4-alkyl or hydroxyl or 2 C.sub.1-C.sub.4-alkoxy groups, or a unsubstituted heteroaromatic radical having 5 to 10 ring atoms, of which 1 or 2 atoms are heteroatoms selected from N, O and S; n is 1 or 2; B is N, NH or O, with the proviso that n is 2 when B is N and the proviso that n is I when B is NH or O; A is C.sub.xH.sub.2x with x=2, 3, 4 or 5 or CH.sub.2CH(C.sub.6H.sub.5); a is an integer from 1 to 300 R.sup.25 is H, a branched or unbranched C.sub.1- to C.sub.10-alkyl radical, C.sub.5- to C.sub.8-cycloalkyl radical, aryl radical or heteroaryl radical having 5 to 10 ring atoms, of which 1 or 2 ring atoms are heteroatoms selected from N, O and S; where the structural unit (IV) is selected from the structural units (IVa) and (IVb): ##STR00029## in which D is a substituted or unsubstituted phenyl or substituted or unsubstituted naphthyl radical, wherein the phenyl or naphthyl is substituted by 1 or 2 C.sub.1-C.sub.4-alkyl or hydroxyl or 2 C.sub.1-C.sub.4-alkoxy groups, or a unsubstituted heteroaromatic radical having 5 to 10 ring atoms, of which 1 or 2 ring atoms are heteroatoms selected from N, O and S; E is N, NH or 0, with the proviso that m is 2 when E is N and the proviso that m is 1 when E is NH or 0; A is CH.sub.2H.sub.2x with x=2, 3, 4 or 5 or CH.sub.2CH(C.sub.6H.sub.5); b is an integer from 1 to 300; M is independently H or one cation equivalent; and m is 1 or 2; ##STR00030## in which V is a substituted or unsubstituted phenyl or substituted or unsubstituted naphthyl radical, wherein the substituted phenyl or naphthyl is substituted by one or two radicals selected from R.sup.8, OH, OR.sup.8, (CO)R.sup.8, COOM, COOR.sup.8, SO.sub.3R and NO.sub.2; R.sup.7 is COOM, OCH.sub.2COOM, SO.sub.3M or OPO.sub.3M.sub.2; M is H or one cation equivalent; and R.sup.8 is C.sub.1-C.sub.4-alkyl, phenyl, naphthyl, phenyl-C.sub.1-C.sub.4-alkyl or C.sub.1-C.sub.4-alkylphenyl.

12. The additive according to claim 1, additionally comprising calcium silicate hydrate.

13. The additive according to claim 12, wherein the calcium silicate hydrate is obtained by reacting a water-soluble calcium source with a water-soluble silicate source in the presence of a polymeric dispersant.

14. The additive according to claim 1, wherein the additive is dried to form a solid, optionally in powder form.

15. A process for producing the additive for hydraulically setting compositions according to claim 1, wherein the salt of the polyvalent metal cation is precipitated with at least one organic phosphate or phosphonate compound as anion in the presence of the polymeric dispersant, in order to obtain an aqueous colloidally disperse preparation of the salt, or wherein a freshly precipitated salt of the polyvalent metal cation is dispersed in the presence of the polymeric dispersant in order to obtain an aqueous colloidally disperse formulation of the salt, and the aqueous colloidally disperse preparation obtained is optionally dried.

16. A method comprising adding the additive for hydraulically setting compositions according to claim 1 as a slump retainer or for improving early strength in water-containing building material mixtures comprising a hydraulic binder.

17. A building material mixture comprising an additive according to claim 1 and a binder selected from (portland) cement, slag sand, fly ash, silica dust, metakaolin, natural pozzolans, burnt oil shale and calcium aluminate cement and mixtures thereof.

18. The additive according to claim 1, having a pH of 11 to 13.

19. The additive according to claim 1, having a pH of >11.5 to 13.

Description

EXAMPLES

(1) Gel Permeation Chromatography

(2) The sample preparation for the determination of molar mass was effected by dissolving polymer solution in the GPC buffer, such that the polymer concentration in the GPC buffer is 0.5% by weight. Thereafter, this solution was filtered through a syringe filter having a polyethersulphone membrane and pore size 0.45 μm. The injection volume of this filtrate was 50-100 μl.

(3) The molecular weights were determined on a Waters Alliance 2690 GPC instrument with UV detector (Waters 2487) and RI detector (Waters 2410). Columns: Shodex SB-G Guard Column for SB-800 HQ series Shodex OHpak SB 804HQ and 802.5HQ (PHM gel, 8×300 mm, pH 4.0 to 7.5) Eluent: 0.05 M aqueous ammonium formate/methanol mixture=80:20 (parts by volume) Flow rate: 0.5 ml/min Temperature: 50° C. Injection: 50 to 100 μl Detection: RI and UV

(4) The molecular weights of the polymers were determined relative to polyethylene glycol standards from PSS Polymer Standards Service GmbH. The molecular weight distribution curves of the polyethylene glycol standards were determined by means of light scattering. The masses of the polyethylene glycol standards were 682 000, 164 000, 114 000, 57 100, 40 000, 26 100, 22 100, 12 300, 6240, 3120, 2010, 970, 430, 194, 106 g/mol.

(5) Polymer Synthesis

(6) The comb polymer P1 is based on the monomers maleic acid, acrylic acid and vinyloxybutyl polyethylene glycol—5800. The molar ratio of acrylic acid to maleic acid is 7. Mw=40 000 g/mol and was determined via GPC. The solids content is 45% by weight. The synthesis is described, for example, in EP0894811. The charge density is 0.93 μeq/g.

(7) Polymer P2

(8) A 1 l jacketed reactor with thermometer, reflux condenser and a connection for second feeds was initially charged with 500 g of water, 350 g of vinyloxybutyl polyethylene glycol (VOBPEG 3000) (116.7 mmol), 0.01 g of FeSO.sub.4, 1, 55 g of mercaptoethanol and 3.5 g of Brüggolit FF06 (sulphinic acid-based reducing agent; Briggemann KG).

(9) Subsequently, 25.48 g of acrylic acid (99%, 350.0 mmol) and 1.8 g of 50% H.sub.2O.sub.2 were added. After 20 minutes, the polymer solution is neutralized with 69 g of 20% NaOH. The solids content is 41.0%. The molecular weight is 37 500 g/mol. The charge density is 0.897 μeq/g.

(10) Illustrative Calculation of Charge Density:

(11) $\underset{j}{.Math.}{z}_{S,j}\times n_{S,j}\mathrm{in}\mathrm{mmol}\mathrm{per}\mathrm{gram}\mathrm{polymer}=\frac{\begin{array}{c}n\left(\mathrm{mol}\mathrm{number}\mathrm{of}\mathrm{weight}\mathrm{portion}\mathrm{of}\mathrm{acid}\mathrm{monomers}\mathrm{in}\mathrm{mmol}\right).Math.\\ \mathrm{charge}\mathrm{of}\mathrm{acid}\mathrm{monomer}\end{array}}{\begin{array}{c}m\left(\mathrm{mass}\mathrm{of}\mathrm{polymer}\mathrm{solution}\mathrm{in}g\right).Math.\\ \mathrm{solids}\mathrm{content}\mathrm{of}\mathrm{the}\mathrm{polymer}\mathrm{solution}\mathrm{in}\%\end{array}}$

(12) Example Calculation for Polymer P2 (for Starting Weights See Polymer Synthesis)

(13) $\underset{j}{.Math.}{z}_{S,j}\times n_{S,j}=\frac{\left(350\mathrm{mmol}\right).Math.1}{\left(951\text{.}3g.Math.41.0\%\text{/}100\right)}=0\text{.}897\mathrm{mmol}\text{/}g$

(14) Illustrative calculation of formula (a) with reference to example Al:

(15) The corresponding masses are taken from Table 2, Composition of the additives: Mass of polymer P1 7.4 g and mass of calcium nitrate 1.5 g.

(16) Therefore:

(17) $n_K=1.5g\text{/}164g\text{/}\mathrm{mol}=9.2\mathrm{mmol},n_S=7.4g.Math.0.93\mathrm{mmol}\text{/}g=6.88\mathrm{mmol}$$\mathrm{and}$$\frac{\underset{i}{.Math.}{z}_{K,i}\times n_{K,i}}{\underset{j}{.Math.}{z}_{S,j}\times n_{S,j}}=\frac{9.2\mathrm{mmol}.Math.2}{6.88\mathrm{mmol}.Math.1}=2.68$

(18) TABLE-US-00001 TABLE 1 % Physical data of the polymers P1 P2 Σ.sub.jz.sub.S, j × n.sub.S, j in mmol 0.93 0.897 per gram of polymer

(19) Examples for Preparation of the Additives According to the Invention

(20) Phosphonate and phosphate compounds used as anion were derived from the following compounds:

(21) ##STR00018##

(22) Preparation of Additives A1 to A9 and Comparative Additives C1 and C2:

(23) The aqueous solutions of the comb polymers are mixed by stirring with the metal cation salts according to the invention, the anion compounds according to the invention or the anions for C1 and C2, and optionally a base or acid to adjust the pH. The mixing is conducted in a 1 l jacketed glass reactor with paddle stirrer at 300 rpm, at a controlled temperature of 20° C. The sequence of addition is stated in the table by a code of letters. P represents the aqueous solution of the comb polymer, K represents the metal cation salt according to the invention, A represents the anion compound according to the invention, and B and S respectively represent base and acid. A code of PKAB means, for example, that the polymer P is initially charged, then the metal cation salt A is added. This is followed by the addition of the anion compound A and the addition of the base B. The amounts are always based on the solids contents. The final pH of the resulting suspensions is likewise stated.

(24) The Composition of the Additives is Compiled in Table 2 Below:

(25) TABLE-US-00002 TABLE 2 Composition of additives A1-A9 and comparative additives C1 and C2 Additive No. Polymer Metal salt Anion comp. Base/ acid pH Sequence Water (% by wt.) Polymer (% by wt.) Metal salt (% by wt.) Anion comp. (% by wt.) Base/ acid (% by wt.) $\frac{\underset{i}{.Math.}{z}_{K,i}*n_{K,i}}{\underset{j}{.Math.}{z}_{S,j}*n_{S,j}}$ $\frac{\underset{l}{.Math.}{z}_{A,l}\times n_{A,l}}{\underset{j}{.Math.}{z}_{K,i}\times n_{K,i}}$ Al P1 Ca(NO.sub.3).sub.2 HEDP NaOH 12.4 PKAB 90.6 7.4 1.5 0.3 0.2 2.68 0.2 A2 P1 Ca(NO.sub.3).sub.2 HEDP NaOH 12.5 PKAB 90.2 7.2 1.5 0.6 0.4 2.68 0.48 A3 P1 Ca(NO.sub.3).sub.2 HEDP NaOH 12 PBAK 72.9 20.2 4.1 1.5 1.2 2.68 0.40 A4 P1 Ca(NO.sub.3).sub.2 PEP NaOH 12.5 PKAB 72.3 20.1 4.1 1.8 1.7 2.68 0.33 A5 P1 Fe(NO.sub.3).sub.3 × HEMPA NH.sub.4OH 6 PKAB 69.4 20.8 7.8 1.0 1.1 3.00 0.27 9H.sub.2O A6 P1 Fe(NO.sub.3).sub.3 × ATMP NH.sub.4OH 6 PKAB 69.5 20.7 7.8 0.9 1.2 3.0 0.40 9H.sub.2O A7 P1 Ba(OH).sub.2 HEDP HNO.sub.3 12.5 PKAS 70.4 20.8 4.4 1.6 2.8 2.68 0.4 A8 P1 Ba(OH).sub.2 ATMP HNO.sub.3 12.5 PKAS 70.3 22.2 4.8 1.3 1.4 2.68 0.6 A9 P2 Ca(NO.sub.3).sub.2 HEDP NaOH 12.5 PKAB 71.7 22.7 3.2 1.7 0.7 2.0 0.6 Cl P1 Ca(NO.sub.3).sub.2 H.sub.3PO.sub.4 NaOH 11 PKAB 72.5 21.0 4.3 0.9 1.3 2.68 0.52 C2 P2 Ca(NO.sub.3).sub.2 NaAlO.sub.2 NaOH 10 PAKB 72.9 23.0 3.2 0.5 0.4 2.00 0.15

(26) Preparation of the Inventive Additive A10 and Comparative Additives C3 and C4:

(27) Additive A2 was mixed with a calcium silicate hydrate suspension (C—S—H or CSH) in a solids ratio of 1:1. A pH of 11.9 was established.

(28) The preparation of the calcium silicate hydrate suspension is described in WO2010/026155A1 (accelerator example 5, table on page 40).

(29) Additives C3 and C4 serve as comparative examples for additives according to WO 2014/013077 in a mixture with C—S—H (prepared according to WO 2010/026155). Additive C3 is additive C1 additionally containing CSH in a solids ratio of 1:1. In the case of C3, a pH of 11.4 was established. Additive C4 is additive C2 additionally containing CSH in a solids ratio of 1:1. In the case of C4, a pH of 11.6 was established.

(30) Preparation of the Inventive Additive A11:

(31) Additive A4 was mixed with the same calcium silicate hydrate suspension (prepared according to WO 2010/026155) as in A10 in a solids ratio of 1:1. A pH of 12 was established.

(32) Application Tests

(33) Mortar Tests

(34) The mortar tests used were standard mortar tests according to DIN EN 1015-3 with Bernburg CEM I 42.5 R (w/c 0.42). The weight ratio of sand to cement was 2.2 to 1. A mixture of 70% by weight of standard sand (Normensand GmbH, D-59247 Beckum) and 30% by weight of quartz sand was used. Before the testing in a mortar, the additive samples were defoamed with 1% by weight of triisobutyl phosphate, based on the additive solids content.

(35) Mixing Operation

(36) Cement was introduced into the initial charge of water. This defines the time 0 s. This was followed by stirring at level 1 for 30 s. Then the sand was added and the mixture was stirred at level 1 (140 rpm) for a further 30 s and at level 2 (285 rpm) for a further 30 s. Then the stirring was stopped for 90 s. Within this time interval, the additive was added as an aqueous preparation. The water added with the additive here was subtracted correspondingly from the amount of mixing water. Finally, the mixture was stirred at level 2 for another 60 s. After the total mixing time, which was thus 4 minutes, the first slump was determined.

(37) The slump was determined by shaking the flow table, according to the above-mentioned DIN method, by raising and dropping (knocking) it 15 times. The diameter of the mortar cake after the knocking is referred to as the slump. Delta refers to the difference in the slump for the additive in question after 30 min compared to the slump after 4 min.

(38) The mortar mixtures produced are used to make prisms to determine flexural and compressive strength according to DIN EN 196-1.

(39) The dosages stated are based on the solids content of the additives used.

(40) The results for additives A1 to A9 and comparative additives C1 and C2 are compiled in Table 3, and the results for additives A10 and A11 and comparative additives C3 and C4 in Table 4.

(41) TABLE-US-00003 TABLE 3 Mortar results, Bernburg cement, w/c 0.42 Additive Dosage Slump (cm) Delta (cm) no. (%) 4 min 10 30 60 90 (30 min − 4 P1 0.105 25.4 20.5 18.2 −7.2 P2 0.11 23.0 21.1 19.1 −3.9 A1 0.25 24.9 26.1 28.5 28.7 26.7 +3.6 A2 0.23 21.9 23.4 25.4 25.7 25.7 +3.5 A3 0.3 25.5 24.5 24.5 24.8 24.0 −1.0 A4 0.3 20.8 21.0 22.1 22.6 22.0 +1.3 A5 0.2 24.9 25.2 24.3 23.7 22.1 −0.6 A6 0.2 24.7 25.2 24.8 23.7 22.0 +0.1 A7 0.22 29.6 28.6 27.8 26.9 24.8 −1.8 A8 0.17 28.2 27.3 25.3 22.9 20.6 −2.9 A9 0.19 23.5 23.4 23.6 23.4 22.6 +0.1 C1 0.22 24.5 26.4 26.7 25.8 25.5 +2.2 C2 0.22 21.2 22.6 23.8 23.6 23.7 +2.6

(42) TABLE-US-00004 TABLE 4 Strength after 12 h Additive Dosage Slump (cm) Delta Flexural strength Compressive strength no. (%) 4 min 10 min 30 min 60 min 90 min 120 min (30 min) (MPa) (MPa) A10 0.40 24.5 24.9 24.2 23.1 21.7 20.1 −0.3 2.044 7.228 A11 0.40 25.5 25.2 22.6 20.9 19.5 −2.9 2.210 8.528 C3 0.60 20.9 21.7 22.2 21.5 19.7 17.2 +1.3 2.051 6.825 C4 0.40 25.7 25.3 23.7 23.6 22.1 20.6 −2.0 1.613 5.278

(43) As the mortar results show, the additives according to the invention have excellent retention of consistency. In addition, the early strength of the additives according to the invention is improved; see the 12 h strength for the inventive additives A10 and A11.

(44) In a further experiment, additives A12 and A13 as well as C5 were prepared using the components given above for additives A2, A4 and C1 but without addition of calcium silicate hydrate. Mortar mixtures were prepared as described above which were used for the preparation of prisms for determining the compressive strength after 7d in accordance with DIN EN 196-1. The results are given in table 5 below.

(45) TABLE-US-00005 TABLE 5 Slump (cm) Additive Dosage CS 60 90 Nr. (%) bwoc (MPa) 5 min 10 min 30 min min min A12 0.12 47.9 25 25.1 24.2 23.8 23.9 A13 0.14 50.0 25.3 25.8 26.1 25.5 25.8 C5 0.12 32.6 21.7 22.6 23.8 25.1 26 CS = compressive strength bwoc = by weight of cement

(46) As can be seen, the additives A12 and A13 of the invention provide, as compared to additive C5, for an increased slump retention combined with an increased compressive strength after 7d. Thus, the additives of the invention have the advantage that the mortar remains workable for a longer period of time and that the formwork can already be removed after 7 days so that the construction can be continued at an early time.