Cement-reduced construction composition

Abstract

A cement-reduced construction composition comprises a) a cementitious binder comprising one or more calcium silicate mineral phases and one or more calcium aluminate mineral phases, and having a Blaine surface area of at least 3800 cm.sup.2/g; b) a fine material having a Dv90 of less than 200 ?m, selected from alkali-activatable binders, rock powders and inorganic pigments, or mixtures thereof; c) optionally, an extraneous aluminate source; d) a sulfate source; and e) a polyol. The composition contains a controlled amount of available aluminate, calculated as Al(OH).sub.4.sup.?, from the calcium aluminate mineral phases plus the optional extraneous aluminate source; and the molar ratio of total available aluminate to sulfate is 0.4 to 2.0. The construction composition further comprises f) an ettringite formation controller and g) a co-retarder. The cement-reduced construction composition is a reduced carbon footprint construction composition and exhibits high early strength, high final strength, sufficient open time, high durability, and reduced shrinkage compared to ordinary Portland cement based mixes.

Claims

1. A cement-reduced construction composition comprising a) a cementitious binder comprising one or more calcium silicate mineral phases and one or more calcium aluminate mineral phases, and having a Blaine surface area of at least 3800 cm.sup.2/g, in an amount of 180 to 400 kg per m.sup.3 of a freshly mixed construction composition; b) a fine material having a Dv90 of less than 200 ?m, selected from alkali-activatable binders, rock powders and inorganic pigments, or mixtures thereof, in a total amount of 20 to 200 parts by weight, relative to 100 parts by weight of cementitious binder a); c) optionally, an extraneous aluminate source; d) a sulfate source; and e) a polyol in an amount of 0.3 to 2.5 wt.-%, relative to the amount of cementitious binder a); wherein the composition contains available aluminate, calculated as Al(OH).sub.4.sup.?, from the calcium aluminate mineral phases plus the optional extraneous aluminate source, per 100 g of cementitious binder a), in a total amount of at least 0.08 mol, if the amount of cementitious binder a) is in the range of 180 to less than 220 kg per m.sup.3 of the freshly mixed construction composition, at least 0.06 mol, if the amount of cementitious binder a) is in the range of 220 to less than 280 kg per m.sup.3 of the freshly mixed construction composition, and at least 0.05 mol, if the amount of cementitious binder a) is 280 kg or more per m.sup.3 of the freshly mixed construction composition; and the molar ratio of total available aluminate to sulfate is 0.4 to 2.0; the construction composition further comprising f) an ettringite formation controller comprising (i) glyoxylic acid, a glyoxylic acid salt and/or a glyoxylic acid derivative; and (ii) at least one of (ii-a) a borate source and (ii-b) a carbonate source, wherein the carbonate source is selected from inorganic carbonates having an aqueous solubility of 0.1 g.Math.L.sup.?1 or more at 25? C., organic carbonates, and mixtures thereof, and g) a co-retarder selected from (g-1) ?-hydroxy monocarboxylic acids and salts thereof, (g-2) phosphonic acids and salts thereof, (g-3) polycarboxylic acids and salts thereof, and mixtures thereof.

2. The composition according to claim 1, wherein the calcium silicate mineral phases and calcium aluminate mineral phases constitute at least 90 wt.-% of the cementitious binder a), and the calcium silicate mineral phases constitute at least 60 wt.-% of the cementitious binder a).

3. The composition according to claim 1, wherein the calcium aluminate mineral phases are selected from C3A, C4AF, and C12A7.

4. The composition according to claim 1, wherein the cementitious binder a) is Portland cement.

5. The composition according to claim 1, wherein the alkali-activatable binder is selected from latent hydraulic binders and pozzolanic binders.

6. The composition according to claim 1, wherein the rock powder is a silicate or carbonate rock powder.

7. The composition according to claim 1, wherein the inorganic pigment is selected from iron oxides, titanium dioxide, cobalt-chrome-aluminum-spinels, and chrome(III)-oxides.

8. The composition according to claim 1, wherein the fine material has a Dv90 of less than 150 ?m.

9. The composition according to claim 1, wherein the extraneous aluminate source c) is selected from non-calciferous aluminate sources and calciferous aluminate sources.

10. The composition according to claim 1, wherein the sulfate source d) is a calcium sulfate source.

11. The composition according to claim 1, wherein the cementitious binder a) has a Blaine surface area of at least 4500 cm.sup.2/g.

12. The composition according to claim 1, wherein the polyol, in a calcium aluminate precipitation test in which a test solution, obtained by supplementing 400 mL of a 1 wt.-% aqueous solution of the polyol with 20 mL of a 1 mol/L NaOH aqueous solution and 50 mL of a 25 mmol/L NaAlO.sub.2 aqueous solution, is titrated with a 0.5 mol/L CaCl.sub.2) aqueous solution at 20? C., inhibits precipitation of calcium aluminate up to a calcium concentration of 75 ppm.

13. The composition according to claim 12, wherein the polyol is selected from monosaccharides, oligosaccharides, water-soluble polysaccharides, compounds of general formula (P-I) or dimers or trimers of compounds of general formula (P-I): ##STR00020## wherein X is ##STR00021## wherein R is CH.sub.2OH, NH.sub.2, n is an integer from 1 to 4, m is an integer from 1 to 8.

14. The composition according to claim 1, wherein the glyoxylic acid derivative is a glyoxylic acid polymer.

15. The composition according to claim 1, wherein the glyoxylic acid, glyoxylic acid salt and/or glyoxylic acid derivative (i) is present in a total amount of 0.2 to 2 wt.-% relative to the amount of cementitious binder a).

16. The composition according to claim 1, wherein the inorganic carbonate is selected from potassium carbonate, sodium carbonate, sodium bicarbonate, lithium carbonate and magnesium carbonate; and the organic carbonate is selected from ethylene carbonate, propylene carbonate and glycerol carbonate.

17. The composition according to claim 1, wherein the carbonate source (ii-b) is present in an amount of 0.3 to 1 wt.-%, relative to the amount of cementitious binder a).

18. The composition according to claim 1, wherein the ?-hydroxy monocarboxylic acid salt is sodium gluconate.

19. The composition according to claim 1, wherein the polycarboxylic acid or a salt thereof (g-3) has a milliequivalent number of carboxyl groups of 3.0 meq/g or higher assuming all the carboxyl groups to be in unneutralized form.

20. The composition according to claim 1, wherein the polycarboxylic acid is selected from phosphonoalkyl carboxylic acids, amino carboxylic acids, and polymeric carboxylic acids.

21. The composition according to claim 1, wherein the composition additionally comprises h) at least one aggregate.

22. The composition according to claim 1, additionally comprising a dispersant.

23. The composition according to claim 22, wherein the dispersant is selected from the group of comb polymers having a carbon-containing backbone to which are attached pendant cement-anchoring groups and polyether side chains, non-ionic comb polymers having a carbon-containing backbone to which are attached pendant hydrolysable groups and polyether side chains, the hydrolysable groups upon hydrolysis releasing cement-anchoring groups, colloidally disperse preparations of polyvalent metal cations, and a polymeric dispersant which comprises anionic and/or anionogenic groups and polyether side chains, and the polyvalent metal cation is present in a superstoichiometric quantity, calculated as cation equivalents, based on the sum of the anionic and anionogenic groups of the polymeric dispersant, sulfonated melamine-formaldehyde condensates, lignosulfonates, sulfonated ketone-formaldehyde condensates, sulfonated naphthalene-formaldehyde condensates, phosphonate containing dispersants, phosphate containing dispersants, and mixtures thereof.

24. The composition according to claim 1, wherein the construction composition comprises less than 5 wt.-% of cementitious hydration products, relative to the total weight of the construction composition.

25. The composition according to claim 1 in freshly mixed form, comprising water in an amount of 120 to 225 L per m.sup.3 of the freshly mixed construction composition.

26. The composition according to claim 25, exhibiting a 3-hour compressive strength according to DIN EN 196-1 of at least 10 MPa at 20? C.

Description

(1) The invention is further illustrated by the appended drawing and the examples that follow.

(2) FIG. 1 shows a plot of the photo current signal in mV against the time of dosage of CaCl.sub.2 in the calcium aluminate precipitation test according to one embodiment of the invention.

METHODS

(3) Testing ProcedureMini-Slump for Mortars

(4) The used procedure is analogous to DIN EN 12350-2, with the modification that a mini-slump cone (height: 15 cm, bottom width: 10 cm, top width: 5 cm) was used instead of a conventional Abrams cone. 2 L of the aqueous freshly mixed construction composition were filled into the mini-slump cone. The cone was filled completely immediately after mixing. Afterwards, the cone was placed on a flat surface, and lifted, and the slump of the mortar mix was measured. The slump of all mixes was adjusted to 11 cm by adjusting the dosage of the superplasticizer to allow for comparability.

(5) Testing ProcedureSlump for Concrete

(6) The used procedure is analogous to DIN EN 12350-2. The slump of all mixes was adjusted to 22 cm by adjusting the dosage of the superplasticizer to allow for comparability.

(7) Testing ProcedureEarly Strength Development for Mortars

(8) The adjusted mortar mixes were each filled into mortar steel prisms (16/4/4 cm), and after 3 h at a temperature of 20? C. and relative humidity of 65%, a hardened mortar prism was obtained. The hardened mortar prism was demolded and compressive strength was measured according to DIN EN 196-1.

(9) Testing ProcedureEarly Strength Development for Concretes

(10) The adjusted concrete mixes were each filled into concrete steel cubes (15/15/15 cm), and after 3 h at a temperature of 20? C. and relative humidity of 65%, a hardened concrete cube was obtained. The hardened concrete cube was demolded and compressive strength after 3 h was measured according to DIN EN 12390-3.

(11) Testing ProcedureFinal Strength Development for Concretes

(12) The adjusted concrete mixes were each filled into concrete steel cubes (15/15/15 cm), and after 3 h at a temperature of 20? C. and relative humidity of 65%, a hardened concrete cube was obtained. The hardened concrete cube was demolded and stored for 7 days at 20? C. in a water bath and further 21 days at 20? C. and relative humidity of 65% in a climate chamber. Compressive strength was measured after 28 days according to DIN EN 12390-3.

(13) Testing ProcedureSetting Time

(14) Setting time was determined with a Vicat needle according to DIN EN 480.

(15) Testing ProcedureDurability

(16) Water uptake was determined analogously to DIN 12390-9. Samples were stored in a climate chamber for 28 d and exposed to water afterwards. The water uptake over a period of 7 d was determined in % compared to the dry sample.

(17) Scaling after 28 cycles, which is indicative of freeze thaw resistance, was determined according to DIN 12390-9 (CDF test).

(18) To determine resistivity, concrete cubes hardened for 28 days as obtained above were placed in water for 2 days. Resistivity was measured via a Resipod instrument from Proceq on two opposed wet surfaces of the concrete cubes, and the average value was calculated

(19) To determine carbonation depth, concrete cubes hardened for 28 days as obtained above were stored in a carbonation chamber at 20? C., relative humidity of 65%, and an atmosphere comprising 4% of carbon dioxide for 28 days. Subsequently, the concrete cubes were split open and phenolphthalein was sprayed on the break surface. The carbonation front was determined according to DIN EN 12390-10.

(20) Testing ProcedureCalcium Aluminate Precipitation Test

(21) For the calcium aluminate precipitation test, an automated titration module (Titrando 905, available from Metrohm) equipped with a high performance pH-electrode (iUnitrode with Pt 1000, available from Metrohm) and a photosensor (Spectrosense 610 nm, available from Metrohm) was used. First, a solution of 400 mL of a 1 wt.-% aqueous solution of a polyol to be investigated and 20 mL of a 1 mol/L NaOH aqueous solution was equilibrated for 2 min under stirring in the automated titration module. Then, 50 mL of a 25 mmol/L NaAlO.sub.2 aqueous solution was added thereto, followed by equilibration for another 2 min, obtaining an essentially clear test solution. In a next step, the test solution is titrated with a 0.5 mol/L CaCl.sub.2 aqueous solution which is dosed with a constant rate of 2 mL/min. During the whole experiment, the temperature is hold constant at 20? C. The elapsed time to a turbidity inflection is recorded. To this end, the photo current signal in mV is plotted against the time of dosage of the CaCl.sub.2) aqueous solution. From the diagram, the onset point is determined as the intersection of the baseline tangent with a tangent to the curve after the inflection of the curve.

Examples

Reference Example: Calcium Aluminate Precipitation-Inhibiting Properties of Polyols

(22) Various polyols were assed for their precipitation-properties in the calcium aluminate precipitation test. The results are shown in the table that follows. For the control, 400 mL of bidestilled water was used instead of 400 mL of a 1 wt.-% aqueous solution of a polyol. The titration endpoint, expressed as the maximum calcium concentration (as Ca.sup.2+) before the onset of turbidity, is calculated from the elapsed time to the onset point. FIG. 1 shows a plot of the photo current signal in mV against the time of dosage of CaCl.sub.2. Curve a) of FIG. 1 shows the results in the absence of a polyol (blank). Curve b) of FIG. 1 shows the results for addition of 1% of triethanolamine. For curve b), a first tangent 1, referred to as baseline tangent, and a second tangent 2 are shown. From the baseline tangent 1 and the second tangent 2, the onset point in s may be determined as the intersection of the baseline tangent 1 with the second tangent 2.

(23) TABLE-US-00001 control (without ethylene triethanol- Polyol polyol) glycol glycerol amine erythritol Onset point [s] 42 42 64 500 686 Ca endpoint [ppm] 59 59 93 682 924

(24) All wt.-% are understood as % bwoc, i.e., as relative to the mass of cementitious binder a). Throughout the examples, retarder 7 of WO 2019/077050 was used as glyoxylic acid urea polycondensate. The total amounts of available aluminate per 100 g of the different cements employed are indicated in the tables below. The amount of available aluminate in the cementitious binder was determined by Rietveld refinement of an X-ray diffraction (XRD) powder pattern. Only the mineral phases C3A and C4AF were assessed.

(25) Mortar mixes 1 to 13 were prepared, adjusted to the same slump and their early strength development and strength after 28 days was measured. Further, concrete mixes 14 to 20 were prepared, adjusted to the same slump and their early strength development and strength after 28 days was determined.

(26) Mixing ProcedureMortar Mixes

(27) Crushed stones (2 to 5 mm) were dried in an oven at 70? C. for 50 h. Sand (0 to 4 mm) was dried for 68 h at 140? C. Afterwards, the crushed stones and sand were stored at 20? C. for at least 2 days at 65% relative humidity. A glyoxylic acid urea polycondensate, sodium gluconate, NaHCO.sub.3 and a polycarboxylate based superplasticizer (Master Suna SBS 8000, available from Master Builders Solutions Deutschland GmbH) were added to the total amount of mixing water, so as to obtain a liquid aqueous component. Subsequently, crushed stones, sand, cementitious binder, anhydrite (CAB 30, available from Lanxess) and limestone were added to a 5 L Hobbart mixer. The liquid aqueous component was added thereto and the mixture was stirred for 2 min at level 1 (107 rpm) and for further 2 min at level 2 (198 rpm) to obtain an aqueous freshly mixed construction composition.

(28) Mixing ProcedureConcrete Mixes

(29) Crushed stones (2 to 16 mm) were dried in an oven at 70? C. for 50 h. Sand (0 to 4 mm) was dried for 68 h at 140? C. Afterwards, the crushed stones and sand were stored at 20? C. for at least 2 days at 65% relative humidity. A glyoxylic acid urea polycondensate, sodium gluconate, NaHCO.sub.3 and a polycarboxylate based superplasticizer (Master Suna SBS 8000 or Master Glenium ACE 430, both available from Master Builders Solutions Deutschland GmbH) were added to the total amount of mixing water, so as to obtain a liquid aqueous component. Subsequently, crushed stones, sand, cementitious binder, anhydrite (CAB 30) and limestone were added to a 20 L Pemat mixer. The liquid aqueous component was added thereto and the mixture was stirred for 4 min at 60 rpm to obtain an aqueous freshly mixed construction composition.

(30) TABLE-US-00002 TABLE 1 Mortar mixes. Mortar mix # 1 2 3 4 5 6 CEM I 52,5 R [kg/m.sup.3] 275 275 275 275 276 276 Sand (0 to 4 mm) [kg/m.sup.3] 1349 1317 1354 1352 1343 1344 Crushed stones (2 to 5 mm) [kg/m.sup.3] 300 294 302 301 299 300 Available aluminate from CEM I 0.092 .sup.[2] 0.092 .sup.[2] 0.092 .sup.[2] 0.092 .sup.[2] 0.092 .sup.[2] 0.084 .sup.[3] 52,5 R (mol/100 g cement) Blaine surface area [cm.sup.2/g] 5000 5000 5000 5000 5000 4800 Fly ash 275 275 0 0 0 0 (Dv90: 94 ?m) [kg/m.sup.3] Limestone powder (Dv90: 26 ?m) 0 0 275 275 276 276 [kg/m.sup.3] Water [L/m.sup.3] 158 173 173 173 183 183 Anhydrite (CAB 30) [wt.- %] 15 15 15 15 15 15 Amorphous Al(OH).sub.3 [wt.- %] 0 0 0 3 0 0 Molar ratio of total available 0.61 0.61 0.61 0.72 0.61 0.60 aluminate to sulfate Master Suna SBS 8000 [wt .- %] .sup.[1] 0.38 0.25 0.28 0.33 0.3 0.3 Glycerol [wt.- %] 1.5 2 2 1.5 2 2 Glyoxylic acid urea polycondensate 1 1 1 1 1 0.67 [wt.- %] .sup.[1] NaHCO.sub.3 [wt.- %] 0.37 0.5 0.5 0.75 0.5 0.5 Sodium gluconate [wt.- %] 0.077 0.077 0.077 0.1 0.077 0.077 Setting time [min] 30 30 30 20 65 95 Compressive strength after 16 14 14 17.5 15 10 3 h [MPa] Mortar mix # 7 8 9 10 11 12 13* CEM I 52,5 R [kg/m.sup.3] 276 276 386 386 386 386 386 Sand (0 to 4 mm) [kg/m.sup.3] 1345 1343 1337 1337 1341 1339 1337 Crushed stones (2 to 5 mm) [kg/m.sup.3] 300 299 298 298 299 298 298 Available aluminate (mol/100 g 0.075 .sup.[4] 0.067 .sup.[5] 0.092 .sup.[2] 0.084 .sup.[3] 0.075 .sup.[4] 0.067 .sup.[5] 0.022 .sup.[6] cement) Blaine surface area [cm.sup.2/g] 4500 5200 5000 4800 4500 5200 3900 Fly ash 0 0 0 0 0 0 0 (Dv90: 94 ?m) [kg/m.sup.3] Limestone powder (Dv90: 26 ?m) 276 276 166 166 166 166 166 [kg/m.sup.3] Water [L/m.sup.3] 183 183 183 183 183 183 183 Anhydrite (CAB 30) [wt.- %] 15 15 15 15 15 15 15 Molar ratio of total available 0.53 0.48 0.61 0.60 0.53 0.48 0.17 aluminate to sulfate Master Suna SBS 8000 [wt.- %] .sup.[1] 0.3 0.3 0.2 0.2 0.2 0.2 0.2 Glycerol [wt.- %] 2 2 2 2 2 2 2 Glyoxylic acid urea polycondensate 1 1 0.67 0.67 0.67 0.67 0.67 [wt.- %] .sup.[1] NaHCO.sub.3 [wt.- %] 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Sodium gluconate [wt.- %] 0.077 0.077 0.077 0.077 0.077 0.077 0.077 Setting time [min] 110 150 50 40 75 145 105 Compressive strength after 6 5 24 20 16 4 0 3 h [MPa] *comparative example .sup.[1] dosage calculated as active substance .sup.[2] Karlstadt CEM I 52,5 R .sup.[3] Couvrot CEM I 52,5 R .sup.[4] Burglengenfeld CEM I 52,5 R .sup.[5] Spenner CEM I 52,5 R .sup.[6] Aalborg White CEM I 52,5 R

(31) TABLE-US-00003 TABLE 2 Concrete mixes. Concrete mix # 14 15 16 17 18* 19* CEM I 52,5 R [kg/m.sup.3] 200 200 280 280 400 400 Sand (0 to 4 mm) [kg/m.sup.3] 941 941 936 936 895 783 Crushed stones (2 to 16 mm) 939 939 934 934 892 781 [kg/m.sup.3] Available aluminate (mol/100 g 0.092 .sup.[2] 0.084 .sup.[3] 0.084 .sup.[3] 0.075 .sup.[4] 0.092 .sup.[2] 0.092 .sup.[2] cement) Blaine surface area [cm.sup.2/g] 5000 4800 4800 4500 5000 5000 Limestone powder (Dv90: 26 ?m) 200 200 120 120 50 50 [kg/m.sup.3] Water [L/m.sup.3] 126 126 126 126 160 252 Ratio of water/cementitious binder 0.63 0.63 0.45 0.45 0.4 0.63 Anhydrite (CAB 30) [wt.- %] 15 15 15 15 0 0 Molar ratio of total available 0.61 0.60 0.60 0.53 2.02 2.02 aluminate to sulfate Master Suna SBS 8000 [wt.- %] .sup.[1] 0.4 0.3 0.3 0.24 0 0 Master Glenium ACE 430 [wt.- %] .sup.[1] 0 0 0 0 0.22 0 Glycerol [wt.- %] 2 2 2 2 0 0 Glyoxylic acid urea polycondensate 1 0.66 0.66 0.66 0 0 [wt.- %] .sup.[1] NaHCO.sub.3 [wt.- %] 0.5 0.5 0.5 0.5 0 0 Sodium gluconate [wt.- %] 0.077 0.077 0.077 0.077 0 0 Compressive strength after 3 h 15 10 20 16 0 0 [MPa] Compressive strength after 28 d 92 80 97 101 94 53 [MPa] Setting time [min] 30 50 40 75 >120 >120 Concrete mix # 20* 21* 22 23 24 25 CEM I 52,5 R [kg/m.sup.3] 400 180 220 280 320 180 Sand (0 to 4 mm) [kg/m.sup.3] 783 967 965 963 961 967 Crushed stones (2 to 16 mm) 781 909 908 905 904 910 [kg/m.sup.3] Available aluminate (mol/100 g 0.084 .sup.[3] 0.064 .sup.[7] 0.064 .sup.[7] 0.064 .sup.[7] 0.064 .sup.[7] 0.092 .sup.[2] cement) Blaine surface area [cm.sup.2/g] 4800 5200 5200 5200 5200 5000 Limestone powder (Dv90: 26 ?m) 50 220 180 120 80 220 [kg/m.sup.3] Water [L/m.sup.3] 252 126 126 126 126 126 Ratio of water/cementitious binder 0.63 0.70 0.58 0.45 0.40 0.70 Anhydrite (CAB 30) [wt.- %] 0 15 15 15 15 15 Molar ratio of total available 2.08 0.47 0.47 0.47 0.47 0.61 aluminate to sulfate Master Suna SBS 8000 [wt.- %] .sup.[1] 0 0.3 0.3 0.3 0.3 0.3 Master Glenium ACE 430 [wt.- %] .sup.[1] 0 0 0 0 0 0 Glycerol [wt.- %] 0 2 2 2 2 2 Glyoxylic acid urea polycondensate 0 0.66 0.66 0.66 0.66 0.66 [wt.- %] .sup.[1] NaHCO.sub.3 [wt.- %] 0 0.5 0.5 0.5 0.5 0.5 Sodium gluconate [wt.- %] 0 0.077 0.077 0.077 0.077 0.077 Compressive strength after 3 h 0 5 6 9 11 11 [MPa] Compressive strength after 28 d 52 64 74 87 96 70 [MPa] Setting time [min] >120 45 40 50 75 5 Concrete mix # 26 27 28 29 30* 31 32 CEM I 52,5 R [kg/m.sup.3] 180 200 200 280 .sup.[9] 280 .sup.[10] 200 200 Sand (0 to 4 mm) [kg/m.sup.3] 966 965 965 963 963 941 941 Crushed stones (2 to 16 mm) 909 908 908 905 905 939 939 [kg/m.sup.3] Available aluminate (mol/100 g 0.092 .sup.[8] 0.092 .sup.[8] 0.092 .sup.[2] 0.050 .sup.[9] 0.036 .sup.[10] 0.092 .sup.[2] 0.084 .sup.[3] cement) Blaine surface area [cm.sup.2/g] 3800 3800 5000 4719 4290 5000 4800 Limestone powder (Dv90: 26 ?m) 220 200 200 120 120 200 200 [kg/m.sup.3] Water [L/m.sup.3] 126 126 126 126 126 126 126 Ratio of water/cementitious binder 0.70 0.63 0.63 0.45 0.45 0.63 0.63 Anhydrite (CAB 30) [wt.- %] 15 15 5 15 15 15 15 Molar ratio of total available 0.61 0.61 1.11 0.76 0.57 0.61 0.60 aluminate to sulfate Master Suna SBS 8000 [wt.- %] .sup.[1] 0.3 0.3 0.3 0.3 0.3 0.4 0.3 Master Glenium ACE 430 [wt.- %] .sup.[1] 0 0 0 0 0 0 0 Glycerol [wt.- %] 2 2 2 2 2 2 2 Glyoxylic acid urea polycondensate 0.66 0.66 0.66 0.66 0.66 1 0.66 [wt.- %] .sup.[1] NaHCO.sub.3 [wt.- %] 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Sodium gluconate [wt.- %] 0.077 0.077 0.077 0.077 0.077 0 0 Citric acid [wt.- %] 0 0 0 0 0 0.077 0.077 Compressive strength after 3 h 10 13 5 7 4 12 8 [MPa] Compressive strength after 28 d 60 65 73 86 81 69 70 [MPa] Setting time [min] 7 8 7 40 25 4 7 *comparative example .sup.[1] dosage calculated as active substance .sup.[2] Karlstadt CEM I 52,5 R .sup.[3] Couvrot CEM I 52,5 R .sup.[4] Burglengenfeld CEM I 52,5 R .sup.[7] Milke CEM I 52,5 R .sup.[8] Karlstadt CEM I 52,5 N .sup.[9] 186 kg/m.sup.3 Milke CEM I 52,5 R + 94 kg/m.sup.3 Aalborg White CEM I 52,5 R .sup.[10] 94 kg/m.sup.3 Milke CEM I 52,5 R + 186 kg/m.sup.3 Aalborg White CEM I 52,5 R

(32) The inventive mixes show rapid strength development once setting commences. Hence, the open time largely corresponds to the setting time.

(33) For selected concrete mixes, durability tests were performed.

(34) TABLE-US-00004 TABLE 3 Durability tests at a ratio of water/cementitious binder of 0.63. Concrete mix # 14 15 19* 20* Water uptake after 28 days [%] 0.52 0.9 1.01 1.40 Scaling after 28 cycles [g/m.sup.2] 2645 2590 5420 4948 Resistivity [k?cm] 8.3 8.3 2.2 5.2 Carbonation depth [mm] 4 5 8 5 *comparative example

(35) It is evident that concrete mixes 14 and 15 according to the invention exhibit superior water uptake and scaling than comparative mixes 19 and 20, as well as a higher resistivity and comparable or favorably reduced carbonation depth.