Inorganic material with improved properties

Abstract

Suggested is a solid formed with Si, Al, Ca, O and at least one of Na and K, characterized in that in the .sup.27Al-MAS-NMR spectra of the solid compared to the .sup.27Al-MAS-NMR spectrum of calcium aluminate, an additional signal is present which has a chemical shift which lies between that of the main peak of calcium aluminate and that peak of calcium aluminate which is closest to the main peak in the higher field. 2.

Claims

1. A solid formed with Si, Al, Ca, O and at least one of Na and K, wherein in comparing the .sup.27Al-MAS-NMR spectrum of the solid to the .sup.27Al-MAS-NMR spectrum of calcium aluminate, an additional signal is present in the .sup.27Al-MAS-NMR spectrum of the solid, wherein the additional signal has a chemical shift which lies between that of the main peak of calcium aluminate and that peak of calcium aluminate which is closest to the main peak in the higher field, wherein on the basis of the signal areas of the three signals attributed to calcium aluminate signal and the additional signal in the .sup.27Al-MAS-NMR spectrum of the solid, the Si/Al-ratio is determined to be less than 1 and greater than 0.1, wherein a calcium aluminate signal is also present in the .sup.27Al-MAS NMR spectrum of the solid, at a chemical shift around 78 ppm, the calcium aluminate signal being at least 3 (sigma) above the noise, wherein the .sup.27Al-MAS-NMR spectrum of the solid has the additional signal and a calcium aluminate signal at a chemical shift around 78 ppm, and wherein said solid is hydrophobic throughout the volume.

2. The solid of claim 1, wherein the chemical shift of the additional signal is between 67 ppm and 57 ppm.

3. The solid of claim 1, wherein the additional signal is at least 3 (sigma) above the noise.

4. The solid of claim 1, having a band at about 960-920 cm.sup.1 in an IR spectrum.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) The invention is further explained below with reference to the attached drawing by way of example, where in the drawing shows:

(2) FIG. 1: 27A1-MAS-NMR spectrum of calcium aluminate (Almatis CA-14).

(3) FIG. 2: 27A1-MAS-NMR spectrum of the solid obtained in example 5

(4) FIG. 3: 27A1-MAS-NMR spectrum of the solid obtained in example 6

(5) FIG. 4: 27A1-MAS-NMR spectrum of the solid obtained in Example 7.

(6) FIG. 5: Kinetics of the solid formation reaction based on IR spectra; shown is the change over time of the IR absorption spectrum of a mixture of water glass and calcium aluminate activated with NaOH:

(7) FIG. 5a shows the change of the IR spectra in transmission between 650 and 2000 cm.sup.1,

(8) FIG. 5b shows the absorption between 650 and 1200 cm.sup.1. Absorptions above 1300 cm.sup.1 are caused by water. The transformation of a SiOSi bond into an AlOSi bond as the dominant bond associated with a shift from 995 to 920-960 cm.sup.1 is clearly visible.

(9) FIG. 6 Compressive strengths obtained for different Si/Al ratios (reaction with sodium silicate, NaOH, calcium aluminate and different amounts of quartz flour to achieve identical initial viscosities of the reaction mixture).

(10) FIG. 7 .sup.27A-MAS-NMR spectrum (SiAl ratio 0.875) with the maximum of the bond peak at 59.3 ppm and in the IR at 943 cm.sup.1.

(11) FIG. 8 .sup.27A-MAS-NMR spectrum (SiAl ratio 0.625) with the maximum of the bond peak at 59.1 ppm and in the IR at 940 cm.sup.1.

(12) FIG. 9 .sup.27Al-MAS-NMR spectrum (SiAl ratio 0.375) with the maximum of the bond peak at 63.4 ppm and in the IR at 943 cm.sup.1.

(13) FIG. 10 .sup.27Al-MAS-NMR spectrum (SiAl-ratio 0.125) with the maximum of the binding peak at 65.0 ppm and in IR at 952 cm.sup.1.

(14) FIG. 11 .sup.27Al-MAS-NMR spectrum of Roman concrete (state of the art).

EXAMPLES

(15) A number of sample specimens were first prepared in accordance with the present invention in order to investigate the extent to which different mix ratios and starting materials affect the compressive strength and density of the material obtained. In addition, other properties such as the color of the obtained material and the .sup.27A-MAS-NMR spectra were investigated for some of the samples.

(16) For density determination, the volume and weight of a rectangular sample body were determined and the density was calculated as weight/volume.

(17) The compressive strength of the specimens was measured using a Zwick/Roell Z250 universal testing machine. For this purpose, the compressive forces (in N) were recorded graphically over the deformation distance. The maximum pressure reached was related to the surface area (mm) of the probe.

(18) For the recording of the NMR spectra Al-MAS-NMR spectroscopy could be performed with the following measurement parameters: 4 mm MAS BB/1 H probe in a Bruker AVANCE III 400 WB (magnetic field 9.4 T; rotational frequency 9 kHz) with a frequency of 104.3 MHz for .sup.27Al, a single pulse excitation (1 s pulse length; round trip delay 0.5 s), and a 1 M aqueous solution of AlCl.sub.3*6H.sub.2O as an external standard (0 ppm). In the figures showing NMR spectra, the chemical shift in ppm relative to external standard is plotted on the x-axis and the signal strength in arbitrary units is plotted on the y-axis.

(19) The following materials were used for examples 1 to 9: Betolin K35: potassium water glass, s=2.6; Wallner GmbH, aqueous solution with 35%. solids content Betol K5020T: potassium water glass, s=1.49; Wallner GmbH, aqueous solution with 48% solids content Protectosil WS808: water glass with propyl radical, s=0.4; Evonik; 55% solids content Secar71: calcium aluminate (Al.sub.2O.sub.3>68.5%, CaO>31.0%), Kerneos Inc. Almatis CA-14: Calcium aluminate (Al.sub.2O.sub.3=71%, CaO=28%), Almatis GmbH, Frank furt Na48/50: sodium silicate, s=2.6, Wallner GmbH, aqueous solution with 44.5% solids content Na50/52DS: sodium silicate, s=1.54, Wallner GmbH, aqueous solution with 48% solids content Na38/40: sodium silicate, s=3.4, Wallner GmbH, aqueous solution with 35.8% solids content Quartz flour: 1205-SIKRON quartz SF800
Compressive Strength and Density

(20) First, the compressive strength and density of material samples were investigated using various examples 1-4.

Example 1

(21) 100 g K35, 100 g K5020T, 36 g WS808, 50 g KOH, 64 g water) were mixed with 600 g Secar 71 and 60 g quartz flour. The mixture could be stirred for five minutes and was solid after 20 min. The density of the cured material was 2.13 g/cm, the compressive strength 179 N/mm.sup.2.

Example 2

(22) 100 g K35, 100 g K5020T, 36 g WS808, 50 g KOH, 64 g water) were mixed with 600 g Almatis CA-14 and 60 g quartz flour. The mixture could be stirred for five minutes and was solid after 20 min. The density and compressive strength of the cured material were comparable to those of Example 1.

Example 3

(23) 80 g Na 48/50, 20 g Na50/52DS, 21 g NaOH, 29 g water were mixed with 350 g Secar 71 and 4.3 g KH.sub.2PO.sub.4. The density of the cured material was 2.11 g/cm, the compressive strength 132 N/mm.sup.2.

Example 4

(24) 80 g Na 48/50, 20 g Na50/52DS, 21 g NaOH, 29 g water were mixed with 350 g Almatis CA-14 and 4.3 g KH.sub.2PO.sub.4. The density and compressive strength of the cured material were comparable to those of Example 3.

(25) It was therefore found that the compressive strength can be significantly higher than those obtained with concrete on the application date.

(26) Spectra of the Material1

(27) Solids according to the invention were then prepared using a series of material mixtures with different ratios of water glass to calcium aluminate and examined spectroscopically. For this purpose, the following waterglass-water mixtures were used in Examples 5-7: WG1: 9.92 g NaOH dissolved in 20 g water mixed with 100.2 g Na38/40. WG2: 19.98 g NaOH, dissolved in 10 g water, mixed with 100.6 g Na38/40 Almatis CA-14 was used as the calcium aluminate.

Example 5

(28) A concrete substitute was prepared from 40 g Almatis CA-14 and 19.4 g WG1; the mixture was solid and gray in color after 32 min. The density was determined to 2.21 g/cm and the compressive strength to 101.3 N/mm.sup.2. (Sample Bl)

Example 6

(29) A concrete substitute was prepared from 40 g Almatis CA-14 and 9.48 g WG1; the mixture was solid after 3-4 min and of white color. (Sample CI)

Example 7

(30) A concrete substitute was prepared from 40 g Almatis CA-14 and 28.86 g WG2; the mixture was solid after 20 min and of gray color. The density was determined to be 1.97 g/m. (Per be Dl). The .sup.27Al MAS-NMR spectra from examples 5-7 are shown in FIGS. 2-4. FIG. 1 (Pro be A) shows in comparison the .sup.27A-MAS-NMR spectrum of Almatis CA-14. This 27A1 MAS NMR spectrum shown in FIG. 1 was measured with a 4 mm MAS BB/H probe in a Bruker AVANCE III 400 WB (magnetic field 9. 4 T; rotational frequency 9 kHz) with a frequency of 104.3 MHz for Al, a single pulse excitation (1 ps pulse length; round trip delay 0.5 s), and a 1 M aqueous solution of AlCl.sub.3*6H.sub.2O as external standard (0 ppm).

(31) Reference has already been made in the introduction to literature on the interpretation of Al spectra. Taking into account the references cited above, the signals in the range from 0 to 100 ppm in FIG. can be assigned as follows Al(VI) at 11.77 ppm Al(V) at 47.19 ppm Al(IV) at 77.68 ppm (main peak)

(32) It should be mentioned that by using a different instrument and/or slightly different measurement conditions the exact appearance of the spectrum could differ somewhat from FIG. 1; however, even then the three characteristic peaks mentioned would be recognizable in the range 0-100 ppm (with AlCl.sub.3*6H.sub.2O as 0 ppm standard).

(33) The main peak at about 78 ppm is characteristic of calcium aluminate and is not found, for example, in the spectrum of tobermorite or in the spectrum of Roman concrete (see FIG. 11 from Unlocking the secrets of Al-tobermorite in Roman seawater concrete by Marie D. Jackson, Sejung R. Chae, Sean R. Mulcahy, Cagla Meral, Rae Taylor, Penghui Fi, Abdul-Hamid Emwas, Juhyuk Moon, Seyoon Yoon, Gabriele Vola, Hans-Rudolf Wenk, and Paulo J. M. Monteiro, Cement and Concrete Research, Volume 36, Issue 1, January 2006, Pages 18-29).

(34) FIGS. 2-4 show that these three signals of the calcium aluminate with approximately the same chemical shifts in ppm can also be seen in the spectra of the material according to the invention, but with different intensities. A characteristic feature of the material according to the invention, as shown in the spectra of FIGS. 2 to 4, is that in addition to these signals of the starting material calcium aluminate, a new signal appears between the signal assigned to Al(IV) and the signal assigned to Al(V), even if this signal may not be seen as a separate peak due to superposition, but as a shoulder of the Al(IV) signal on the side of the higher field. The additional signal or the added shoulder in the Al spectrum is currently explained by the fact that in the material-forming reaction new bonds are formed from Al(IV) via oxygen to Si centers by the substitution of already existing Al(IV) centers; in view of this understanding, it is considered significant for the reaction presented that energy-rich Al(IV)OAl(IV) bonds are replaced (substituted) by lower-energy Al(IV)OSi bonds. This makes the reaction exothermic in the aggregate, and so it can proceed at room temperature.

(35) The material according to the invention can thus be described as having the three peaks of calcium aluminate in an Al-MAS-NMR spectrum in the range 0-100 ppm (using AICI3-6H.sub.2O as an external standard) and additionally a signal between the main peak and the peak nearest to the higher field, which signal can be present as a shoulder. The formation of new bonds naturally changes the relative peak heights compared to those in the spectrum of calcium aluminate.

(36) The kinetics of the solid-state formation reaction were then investigated using IR spectra, showing the change over time in the IR absorption spectrum of a mixture of water glass and calcium aluminate activated with NaOH in accordance with the invention. To show this change, several spectra recorded during the course of the reaction are superimposed in the figures. The spectra recorded later have the stronger bands.

(37) FIG. 5a shows the change of the IR spectra in transmission between 650 and 2000 cm 1, FIG. 5b shows the absorption between 650 and 1200 cm.sup.1. Absorptions above 1300 cm 1 are caused by water. The transformation of a SiOSi bond into an AlOSi bond accompanying a shift from 995 to 920-960 cm.sup.1 as dominating the bond is well seen in FIGS. 5a and 5b. Accordingly, the IR spectrum of the solid material according to the invention shows a characteristic band around 960-910 cm.sup.1. It should be mentioned that conventional geopolymers vibrate at somewhat higher wave numbers between 960-1000 cm.sup.1. It should also be mentioned that in the IR spectrum two characteristic shifts of the water bands to about 1390 cm.sup.1 and to a signal between 2800 and 3000 cm.sup.1 can also be observed, compare also FIG. 5.

(38) Aggregates of Different Grain Size

(39) It was then investigated how aggregates of different grain size affect density and compressive strength.

Example 8A and B

(40) 102 g Na38/40, 10 g NaOH, 50 g water and 925 g coarse crushed stone were mixed with 165 g Secar 71 (A) and 165 g Almatis CA14 (B), respectively. Density: 2.27 g/cm.sup.3 (A), compressive strength: 40.9 N/mm (A); density and compressive strength for (B) were comparable.

Example 9A and B

(41) 102 g Na38/40, 10 g NaOH, 18 g water were mixed with 325 g desert sand (120 pm particle size) and 180 g Secar 71 (A) or 180 g Almatis CA14 (B). Density: 2.01 g/cm.sup.3 (A), compressive strength: 37.5 N/mm (A), flexural strength: 7.8 N/mm (A); density, compressive strength and flexural strength of (B) were comparable.

(42) Carbon Dioxide Emissions

(43) It was then computationally determined, for various specimens practically manufactured according to the invention, the reduction in CO.sub.2 emissions that can be obtained in the manufacture of the material according to the invention compared to concrete.

(44) The CO.sub.2 emissions released during the production of concrete cannot be pushed below a fixed limit value, since about 2/3 of the CO.sub.2 emissions released during the production of concrete are due to the conversion of the CaCO.sub.3 to CaO. If the emission is calculated as 0.75 tons of CO.sub.2 for each ton of cement produced, or 0.354 tons of CO.sub.2 for one m of concrete of compressive strength 40 N/mm, the CO.sub.2 emissions can be compared with those released when using the mixture according to the invention, provided that it is assumed that water glass, NaOH and, to a limited extent, calcium aluminate are also produced by using solar power generated without emissions.

(45) The values given in the example formulations for the reduction of CO2 emissions now refer, on the one hand, to the CO.sub.2 emissions from the production of currently available concrete of the specified quality and, on the other hand, to the CO.sub.2 emissions from water glass, NaOH and calcium aluminate assuming exclusive use (100%) of solar electricity in the production of the required starting materials.

Example 10

(46) 6.4 g NaOH+86 g water glass Na38/40 with 36 g calcium aluminate (and 330 g construction sand) is solid after 90 min (final hardness: 41 N/mm.sup.2). The Si/AG ratio is 1/1. (Proportionate CO2 emissions, based on concrete: 20%).

Example 11

(47) 14 g NaOH+86 g water glass Na38/40 with 50 g calcium aluminate (and 370 g construction sand) is solid after 180 min (final hardness: 30 N/mm.sup.2). The Si/Al.sup. ratio is about 3/4 (5.7/8). (Proportionate CO.sub.2 emissions, based on concrete: 24%)

Example 12

(48) 14 g NaOH+86 g water glass Na38/40 with 50 g water and 35 g calcium aluminate (and 680 g construction sand) is solid after 24 h (final hardness: 11 N/mm.sup.2). The Si/Al-ratio is 1/1. (Proportion of CO.sub.2 emissions, based on concrete: 11%).

Example 13 (Maximum Value from FIG. 6)

(49) 30 g NaOH+32 g water glass Na38/40 and 68 g water glass Na48/50 with 70 g water and 370 g calcium aluminate (and 31 g quartz flour) is solid after 12 min (final hardness: 155 N/mm.sub.2). The Si/Al-ratio is 1/8 (proportional C02 emissions, based on concrete: 100%).

(50) In the last example in particular, it should be noted that a very high final strength was achieved and that quartz powder, i.e., a very fine aggregate, was incorporated, which typically leads to a considerable mixing energy requirement for high-performance concrete, which was not taken into account comprehensively and correctly in the lump-sum considerations. This means that considerable amounts of CO.sub.2 can be saved overall.

(51) Lipophilization

(52) It was then investigated by using different functionalizing silanes how the material can be functionalized.

(53) For this purpose, water glass, sodium hydroxide and calcium aluminate and the required amounts of water were brought into contact together with the different functionalized silanes during the preparation of the solids, and the solids obtained were then subjected to a search.

(54) It was found that the lipophilic compound octyl triethoxysilane lipophilizes the entire batch when added to the binder in a range of 0.5-3%. This makes not only the surface water repellent, but the whole stone. It is therefore possible to grind or drill without the stone losing its water-repellent properties in the corresponding areas.

(55) Even when the water glasses Rhodarsil R51T (tripotassium methylsilane triolate, a methyl siliconate) or Protektosil WS 808 (tripotassium propylsilane triolate, a propyl silicate) were added between a few % and 100% as a water glass substitute, a continuous lipophilization of the stones was achieved.

(56) Silicon Nanoparticles as Si Tetrahedral Source

(57) It was then investigated whether the material according to the invention could also be produced without water glass.

(58) In order to show that a material according to the invention can also be produced without water glass, SiO.sub.2 nanoparticles (here: Kstrosol 1540) were recombined with calcium aluminate instead of water glass. In this case, 10 g of Kstrosol mixed with 3 g of NaOH and 20 g of calcium aluminate solidified within 3 min. SiO.sub.2 nanoparticles can thus readily act as a Si tetrahedral source.

(59) Mixtures for Rapid Curing

(60) Various mixtures were used to investigate how the curing time can be shortened. 100 g K42 (Betolin K42 from Woellner), 20 g KOH, 50 g water with 55 g water and 420 g calcium aluminate. The mixture is solid after 90 sec, with a compressive strength of 123 N/mm.sup.2. 100 g K35 (Betolin K35 from Woellner), 20 g KOH, 50 g water with 55 g water and 425 g calcium aluminate, solid after 8 min, with a compressive strength of 169 N/mm.sup.2. Si/Al ratio 0.33: 100 g Na38/40 (Betol 38/40 from Woellner), 10 g NaOH, 10 g water, 250 g calcium aluminate, 125 g desert sand, solid after 12 min, with a compressive strength of 162 N/mm.sup.2.

(61) It should be emphasized that compounds with such rapid curing are already very suitable for 3D printing.

(62) Aggregates

(63) Various additives were added to formulations as described in Examples 1-13 in order to check whether a good material bond was obtained.

(64) In this way, it could be confirmed that a good material bond of the compounds with the following aggregates is obtained: is obtained: Alumina, quartz flour, blue quartz flour, titanium dioxide, metakaolin, polyfill, Ceratec, Granoflour tubular gray, Granoflour yellow, concrete recycling material, fine rubber granules, coal, barium sulfate, concrete gravel, red clay gravel, mica, talc, fireclay, corundum, microsicilica, poraver in various grain sizes, namely 0.06-0.125; 0.25-0.5; 0.5-1.0; 1,0-2.0; liaver in various grains, namely 0.25-0.5; 0.5-1.0; 1,0-2.0; 2,0-4.0; wood chips; Gutex wood fiber; wood chips, expanded clay; Aeroballs; Aeropor 180; Aeroballs 0.5-0,7, Nabalox, Alfa Tab 0-0.5045; Alfa Tab 0-0.6; wollastonite Tremin 263-100, Lumiten 3108, and various types of sand, namely ultrafine sand, recycled sand 0-2 mm; desert sand from China, Dubai, Oman, Jordan and Tunisia, quartz sand from Krauchenwies in the Swabian Alb and unsifted sand from a Portuguese sand beach. Stable solids could be produced with all these materials, and these solids are sufficiently abrasion resistant for applications to be anticipated without further ado.

(65) It was examined whether the various aggregates interfere with each other or whether the material according to the invention can be used to produce a good bond. To this end, layers of material with one aggregate were cured in a mold and then further layers of material with different aggregates were cured on top to determine whether a stable material bond was produced. Thus, a first sandwich was created with material layers containing desert sand, aluminum hydroxide and brick recycling material, as well as another sandwich whose material layers included liaver, wood or concrete gravel as aggregates. These material layers proved to be stable, i.e., no separation failure occurred at the layer boundaries.

(66) As far as mineral aggregates are concerned, it was then investigated whether segregation occurs before curing when using aggregates with very different grain sizes. For this purpose, a formulation was used which had a long curing time of more than 60 minutes for the material according to the invention. Such a mixture was mixed with mineral aggregates of different grain size, poured into a column mold and placed with the mold on a vibrating table to investigate whether prolonged vibrating could provoke segregation. It was found that no segregation occurred despite the prolonged shaking.

(67) Moreover, as far as wood as an aggregate is concerned, wood chips of different wood types were combined with one and the same material mixture resulting in the material according to the invention to form a wood chipboard. In this way, stable chipboard could be produced without the need for heating under pressure. The material mixture yielding the material according to the invention was thus used as a binder. Wood chips from both hardwood and softwood species were used for various samples in order to check whether one and the same material according to the invention is in principle suitable for bonding different wood chips together, which was confirmed. No differences were found when using the same binder for different types of wood.

(68) In order to test the fire resistance, particle boards produced with the material of the invention were then flamed with a Bunsen burner. For this purpose, a water glass mixture of 102 g K35, 10 g H.sub.2O, 12 g KOH was prepared and 74 g of this mixture was mixed with 100 g calcium aluminate and 60 g wood fiber as well as 9.4 g R51T and cured in board form. It was found that after a flame treatment time, at which conventionally produced wood particle boards were already in flames, no damage was observed on the wood particle boards produced with the material according to the invention.

(69) Maximum Compressive Strengths

(70) It was then investigated how, for given starting materials, the compressive strength can be influenced by varying the Si/Al.sup. ratio.

(71) After initially establishing that particularly high compressive strengths are obtained when the Si/Al ratio is particularly small, whereas only lower compressive strengths can be obtained when the Si/Al becomes larger, i.e., less aluminum is used in relation to the silicon, the compressive strength was investigated for particularly low Si/Al ratios. By varying the mixing ratios of a material-forming compound according to the invention, it was possible to plot the compressive strength curve in FIG. 6. This shows that, if the Si/Al ratio is too low, the compressive strength decreases as before, so that the use of the expensive calcium aluminate in excess does not result in any advantages in terms of mechanical stability.
Spectra of the MaterialII

(72) The effect of varying the Si/Al.sup. ratio on the .sup.27A-MAS NMR was then investigated. For this purpose, samples of the material according to the invention were again prepared with different mixing ratios of a material-forming mixture according to the invention in such a way that samples with the desired Si/Al.sup. ratio were obtained.

(73) Table 1 lists the amounts of NaOH, water glass Na38/40 and calcium aluminate used to produce the samples with the desired Si/Al.sup. ratios. Furthermore, except for waiting times and compressive strength after five and 21 days, respectively, data for these specimens are tabulated in Table 1:

(74) TABLE-US-00001 TABLE 1 Data of different mix designs with curing times and compressive strengths, measured after 5 and 21 days, respectively. Si/Al NaOH Na38/40 Ca-aluminate Curing time N/mm.sup.2 0.125 14.2 g 86 g 286 g 5 min 57 (5 days) 0.156 20.0 g 100 g + 10 g H.sub.2O 268 g 17 min 77 (21 days) 0.231 10.0 g 100 g + 10 g H.sub.2O 180 g 20 min 60 (21 days) 0.375 14.2 g 86 g 96 g 100 min 75 (5 days) 0.625 14.2 g 86 g 58 g 140 min 32 (5 days) 0.875 9.1 g 91 g 44 g 50 min 47 (5 days)

(75) The .sup.27Al-MAS NMR spectra recorded on these samples are shown in FIGS. 7-10. Note the slightly different scaling of the X-axis in some cases.

(76) These spectra show that the new binder or the novel solid-state material can not only be identified per se by .sup.27A-MAS-NMR, but furthermore that further relevant information can be obtained from the spectrum. Important conclusions can be drawn from the strengths of the signals at the respective peaks or from the area values of the signals by comparing the strengths or area values of different signals.

(77) Thus, the ratio of the area value of the signal at 65 ppm, i.e., the actual bond signal from the OSiOAlO bonds, to the area value of the signal at 78 ppm, i.e., the signal from the OAlO bonds, runs from 0if only OAlO bonds are present in the calcium aluminateto over 10. The value in the upper signal ratio range close to 10 is limited by the detectability of the signal at 78 ppm, because for Si/Al ratios close to 1 the signal at 78 ppm will be very small and possibly even close to zero, because the calcium aluminate will react off almost completely at this Si/Al ratio. However, NMR instruments today are generally very good. It is therefore possible with today's NMR instruments to set a noise ratio of 3s (sigma) as the detection limit for the 78 ppm signal, and despite this sharp criterion for clear detectability of the 78 ppm signal in a material according to the invention even if, even if it was generated with a ratio of Si/Al almost equal to 1, at which practically all calcium aluminate should have been reacted, still unreacted calcium aluminate should be found in an amount sufficient for spectral recognition, for example in insufficiently mixed regions.

(78) With this in mind, the peak areas for the three signals to be attributed to the calcium aluminate and for the additional signal were determined. If the peak area of the individual signals is normalized to the total area in the spectrum, values are obtained as listed in Table 2. Per se, the considered signals of the calcium aluminate at the values 78 ppm, 47.2 ppm and 11 ppm together with the additional signal should account for 100% of the total area; however, the peak area values deviate from this somewhat in some cases, which can be attributed to effects such as noise, inaccuracies in the calculation due to the superposition of curves, etc. Nevertheless, it is clear that the signal component of the signal around 65 ppm increases significantly with the Si/Al ratio. It should be noted that the signal at 47.2 ppm, which can be attributed to a five-coordinate aluminum, plays no role in the reaction.

(79) TABLE-US-00002 TABLE 2 Peak area values in percent of each of the .sup.27Al signals Signal at Si/Al 78 ppm 65 ppm 47.2 ppm 11 ppm 65 ppm/78 ppm 0 80.8% 0.0% 6.7% 12.5% 0 0.125 40.1% 17.6% 3.1% 39.2% 0.4 0.156 25.1% 30.6% 3.1% 34.5% 1.2 0.231 21.6% 38.8% 3.1% 36.5% 1.8 0.375 7.40% 49.5% 3.1% 40.0% 6.7 0.625 7.58% 56.2% 3.1% 33.1% 7.4 0.875 11.7% 62.0% 3.1% 23.2% 5.3

(80) In a corresponding manner, the peak heights of the individual signals in the Al-MAS NMR can be determined instead of the area values. The corresponding, relative signal heights are listed in Tab. 3, again using relative normalization. Again, the signal at 47.2 ppm, which can be assigned to a fivefold coordinated aluminum, plays no role in the reaction.

(81) TABLE-US-00003 TABLE 3 Peak height values (in percent) of the individual .sup.27Al signals Signal at Si/Al 78 ppm 65 ppm 47.2 ppm 11 ppm 65 ppm/78 ppm 0 80.8% 0.0% 6.7% 12.5% 0 0.125 40.0% 12.5% 3.5% 44.0% 0.31 0.156 33.9% 25.5% 3.5% 37.1% 0.75 0.231 40.6% 19.8% 3.5% 36.1% 0.49 0.375 15.5% 26.8% 3.5% 54.2% 1.7 0.625 16.8% 40.4% 3.5% 39.3% 2.4 0.875 35.3% 38.6% 3.5% 22.6% 1.1
Exemplary Compositions at Range Limits

(82) Mixtures were then defined against the background of the experiments which lead to the formation of material with very large or very small Si/Al ratios; for comparison, a reaction mixture was also defined which gives a material with intermediate Si/Al ratios. These mixtures are intended to indicate only exemplary reaction mixtures for the range limits, without being self-limiting. As an example, the reaction mixtures of Table 4 are suggested. As far as a mixture to obtain a material just below the Si/Al ratio of 12:12 is concerned, the calcium aluminate content will then be slightly lowered and the water glass content slightly increased.

(83) TABLE-US-00004 TABLE 4 Limits of the range of the test results Si/Al ratio 1:12 8:12 12:12 Calcium aluminate 70.2% 35.0% 26.3% Water glass (solid) 5.10% 19.9% 22.0% NaOH (solid) 2.34% 9.10% 4.70% Water 22.4% 36.0% 47.0%

(84) The inert content can be up to 80%. The above weight-percentage ratios thus drop to a maximum of 1/5 of the above values when related to the weight of a building element provided with aggregates. The proportion of calcium aluminate in the total massecuite required for the production of building elements of a given mass thus does not fall below the value of 5.26%, even for such a high inert material content.

(85) With regard to KOH and potassium silicate, the values for caustic soda and water glass are at most a factor of 56/40=1.4 above those of sodium hydroxide solution and sodium silicate. The inert material content can be increased up to 80%. The percentage ratios listed above thus drop to a maximum of 1/5 of the above values. Thus, the calcium aluminate content of no mixture falls below the value of 5.26%.

(86) Thus, described above, among others, but not exclusively, was a mixture containing Si, Al, Ca, O and at least one of Na and K, which in the .sup.27A-MAS-NMR spectrum exhibits in addition to the .sup.27A-MAS-NMR spectrum of calcium aluminate a signal with a chemical shift which lies between that of the main peak of calcium aluminate and that peak of calcium aluminate which is closest to the main peak in the higher field. The solid can be used, among other things, as a construction material with aggregates, as a coating, as an adhesive for bonding second construction elements, for sanitary ceramic elements, for high-temperature applications, for repairing existing structures, especially for underwater repair, for the construction and/or repair of structures, especially when high compressive strengths are required or chemically aggressive conditions occur. It can be produced by contacting water glass, sodium and/or potassium hydroxide, calcium aluminate, one or more aggregates and, if necessary, additionally water, in particular seawater, even at temperatures below 0 C. without heating.