LIMESTONE CALCINED CLAY CEMENT (LC3) CONSTRUCTION COMPOSITION

Abstract

A limestone calcined clay cement 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, in an amount of 180 to 400 kg per m.sup.3 of the freshly mixed construction composition; b) a supplementary cementitious material having a Dv90 of less than 200 μm, in a total amount of 50 to 100 parts by weight, relative to 100 parts by weight of cementitious binder a), the supplementary cementitious material comprising (b-1) a calcined clay material and (b-2) a carbonate rock powder in a weight ratio of (b-1) to (b-2) in the range of 0.5 to 2; 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). 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 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 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 composition; 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 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, organic carbonates, and mixtures thereof; and g) a co-retarder selected from (g-1) α-hydroxy monocarboxylic acids and salts thereof, (g-2) phosphonic acids and salts thereof, (g-3) polycarboxylic acids and salts thereof, and mixtures thereof. The limestone calcined clay cement construction composition is a reduced carbon footprint composition and exhibits high early strength, high final strength, sufficient open time and high durability. Ingredients of the construction composition are abundantly available.

Claims

1. A limestone calcined clay cement 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 the limestone calcined clay cement construction composition; b) a supplementary cementitious material having a Dv90 of less than 200 μm, in a total amount of 50 to 100 parts by weight, relative to 100 parts by weight of the cementitious binder a), the supplementary cementitious material comprising (b-1) a calcined clay material and (b-2) a carbonate rock powder in a weight ratio of (b-1) to (b-2) in the range of 0.5 to 2; 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 the cementitious binder a); wherein the composition contains available aluminate, calculated as Al(OH).sub.4, from the calcium aluminate mineral phases plus the optional extraneous aluminate source, per 100 g of the cementitious binder a), in a total amount of at least 0.08 mol, if the amount of said cementitious binder a) is in the range of 180 to less than 220 kg per m.sup.3 of the limestone calcined clay cement composition, at least 0.06 mol, if the amount of the cementitious binder a) is in the range of 220 to less than 280 kg per m.sup.3 of the limestone calcined clay cement composition, and at least 0.05 mol, if the amount of the cementitious binder a) is 280 kg or more per m.sup.3 of the limestone calcined clay cement composition; and the molar ratio of total available aluminate to sulfate is 0.4 to 2.0; the limestone calcined clay cement construction composition further comprising f) an ettringite formation controller comprising (i) at least one of glyoxylic acid, a glyoxylic acid salt 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) α-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 wherein 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 calcined clay material has a Ca(OH).sub.2 consumption according to the Chapelle test of at least 200 mg per 1 g of calcined clay material.

6. The composition according to claim 1, wherein the carbonate rock powder is selected from limestone, dolomite and mixtures thereof.

7. The composition according to claim 1, further comprising an inorganic pigment.

8. The composition according to claim 1, wherein the supplementary cementitious material b) has a Dv90 of less than 150 μm.

9. The composition according to claim 1, wherein the extraneous aluminate source c) is selected from non-calciferous aluminate sources, such as aluminum(III) salts, aluminum(III) complexes, crystalline aluminum hydroxide, amorphous aluminum hydroxide; and calciferous aluminate sources such as high alumina cement, sulfoaluminate cement or synthetic calcium aluminate mineral phases.

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 melamine-glyoxylic acid condensate, a urea-glyoxylic acid condensate, a melamine-urea-glyoxylic acid condensate and/or a polyacrylamide-glyoxylic acid condensate.

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 the 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 the cementitious binder a).

18. The composition according to claim 1, wherein the α-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.-% 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 of at least 10 MPa at 20° C.

Description

[0269] The invention is further illustrated by the appended drawing and the examples that follow.

[0270] 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

[0271] Pozzolanic Reactivity Test

[0272] A cement model paste is prepared by mixing 11.11 g of the supplementary cementitious material (SCM), 33.33 g of portlandite (lab-grade, less than 5 wt.-% of CaCO.sub.3), 60 g of deionized water, 0.24 g of potassium hydroxide (lab-grade), 1.20 g of potassium sulfate (lab-grade) and 5.56 g of calcite (lab-grade, d.sub.50 5 to 15 μm). All raw materials were preheated at 40° C. overnight before mixing.

[0273] A calorimeter was set to 40° C. followed by calibration of the heat flow channels. Then, sealed reference flasks (containing approx. 9.4 g of deionized water to match the heat capacity of the samples) were inserted into the calorimeter and the system was left to stabilize (about 2 days). The baseline heat flows (both initial and final baseline) of each 30 channel were determined for 180 min. Approximately 15 g (me) of the freshly mixed cement model paste was introduced into heated sample flasks just after the mixing.

[0274] The heat release is recorded over the course of 7 days. The cumulative heat (“Heat”) is calculated from 1.2 hours after the beginning of the calorimetry test onwards. The total heat release (“H.sub.rescaled”) is reported in J/(g SCM) as follows:

[00002]$H_{\mathrm{rescaled}}=\frac{\mathrm{Heat}}{\left(m_p\times 0.0997\right)},$

[0275] wherein Heat is the cumulative heat in Joule and m.sub.p is the mass of the cement model paste in gram. 0.0997 is the weight fraction of the supplementary cementitious material in the paste sample.

[0276] Testing Procedure—Mini-Slump

[0277] 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.

[0278] Testing Procedure—Early Strength Development

[0279] 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.

[0280] Testing Procedure—Setting Time

[0281] Setting time was determined with a Vicat needle according to DIN EN 480.

[0282] Calcium Aluminate Precipitation Test

[0283] 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

[0284] The invention is illustrated by the following examples shown in the tables below.

Reference Example: Calcium Aluminate Precipitation-Inhibiting Properties of Polyols

[0285] 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.

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

[0286] 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. Karlstadt CEM I 52.5 R (0.092 mol available aluminate per 100 g) and Mergelstetten CEM I 52.5 R (0.084 mol available aluminate per 100 g) cements were used. 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. Supplementary cementitious materials according to Table 1 were used.

[0287] Mortar mixes 1 to 8 were prepared according to Table 2, adjusted to the same slump and their early strength development was measured.

[0288] Mixing Procedure—Mortar Mixes

[0289] 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.

TABLE-US-00002 TABLE 1 Supplementary cementitious materials. Blaine surface area BET Grain size Dv90 Al.sub.2O.sub.3* [cm.sup.2/g] [m.sup.2/g] [μm] [μm] [wt.-%] Calcined clay 1 7489 4.11 0.3 to 60 34 21.7 obtained from Liapor Calcined clay 2 9250 27.8 0.6 to 80 51 14.1 obtained from Arginotec Limestone powder 6250 n.d.** 0.25 to 130 23 0.17 *as determined by XRF in solid state **n.d. = not determined

TABLE-US-00003 TABLE 2 Mortar mixes. Mortar mix # 1* 2* 3 4 5 6 7 8 CEM | 52.5 R [kg/m.sup.3] 276 276 276 276 276 276 276 276 Sand (0 to 4 mm) [kg/m.sup.3] 1344 1344 1338 1338 1338 1338 1332 1332 Crushed stones (2 to 5 mm) 300 300 298 298 298 298 297 297 [kg/m.sup.3] Available aluminate 0.092 0.084 0.092 0.092 0.084 0.084 0.092 0.084 (mol/100 g cement) Blaine surface area [cm.sup.2/g] 5000 4800 5000 5000 4800 4800 5000 4000 Calcined clay 1 [kg/m.sup.3] 0 0 0 138 0 138 207 207 Calcined clay 2 [kg/m.sup.3] 0 0 138 0 138 0 0 0 Limestone powder [kg/m.sup.3] 276 276 138 138 138 138 69 69 Water [L/m.sup.3] 183 183 183 183 183 183 183 183 Anhydrite (CAB 30) [kg/m.sup.3] 41 41 41 41 41 41 41 41 Molar ratio of total available 0.61 0.60 0.61 0.61 0.60 0.60 0.61 0.61 aluminate to sulfate (cement) Master Suna SBS 8000 [wt .-%] .sup.[1] 0.3 0.3 0.9 0.45 0.9 0.4 0.50 0.45 Glycerol [wt.-%] 2 2 2 2 2 2 2 2 Glyoxylic acid urea 1 0.67 2 1.2 0.67 0.67 1.2 1.2 polycondensate [wt.-%] .sup.[1] NaHCO.sub.3 [wt.-%] 0.5 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 0.077 Setting time [min] 40 55 45 40 45 15 30 45 Comp. strength after 3 h [MPa] 13.3 8.5 14.8 17.0 7.8 12.4 19.7 14.4 Comp. strength after 24 h [MPa] 17.0 29.9 18.4 21.1 22.7 23.6 27.8 24.5 Comp. strength after 7 d [MPa] 69.7 60.3 68.7 76.9 60.2 72.9 n.d.** n.d. *comparative example **n.d. = not determined .sup.[1] dosage calculated as active substance

[0290] The inventive mixes show rapid strength development once setting commences. Hence, the open time largely corresponds to the setting time.