METHOD FOR THE INCREASE OF WORKABILITY OF A BINDER COMPOSITION COMPRISING PORTLAND CEMENT, CALCINED CLAY, AND LIMESTONE

Abstract

A method for increasing the workability of a binder composition including calcined clay, limestone, and Portland cement. The method includes a step of adding an admixture comprising at least one PCE and at least one additive selected from the group including sugar acids, sugars, sugar alcohols, and hydroxycarboxylic acids. The invention also relates to an admixture to be used in said method and hardenable compositions, especially concrete and mortar, obtainable by the method.

Claims

1. A method for increasing the workability of a binder composition comprising calcined clay, limestone, and Portland cement, the method comprising a step of adding an admixture comprising at least one polycarboxylate ether (PCE) and at least one additive selected from the group consisting of sugar acids, sugars, sugar alcohols, and hydroxycarboxylic acids.

2. A method according to claim 1, wherein the at least one polycarboxylate ether (PCE) is one copolymer or a mixture of two or more copolymers, wherein each copolymer comprises (i) repeating units A of the general structure (I), ##STR00007## and (ii) repeating units B of the general structure (II), ##STR00008## wherein each R.sup.u independently of one another is H or a methyl group, each R.sup.v independently of one another is H or COOM, each M independently of one another is H, an alkali metal ion or an alkaline earth metal ion, m=0, 1, 2 or 3, p=0 or 1, each R.sup.1 independently of one another is —[YO].sub.n—R.sup.4, wherein Y is a C2- to C4-alkylene and R.sup.4 is H, C1- to C20-alkyl, -cyclohexyl or -alkylaryl, and n=2-350, and wherein the repeating units A and B in the copolymer have a molar ratio A:B between 10:90-90:10.

3. A method according to claim 1, wherein the binder composition comprises calcined clay (CC), limestone (L), and Portland cement (P) in the following weight ratios: P:CC is from 33:1 to 1:1, CC:L is from 10:1 to 1:50, and P:L is from 20:1 to 1:4.

4. A method according to claim 1, wherein the calcined clay is metakaolin.

5. A method according to claim 1, wherein the admixture is added to the binder composition in such an amount that a weight ratio of the at least one additive to calcined clay is in the range of 1:1,500 to 1:10.

6. A method according to claim 1, wherein the admixture is added to the binder composition in such an amount that a weight ratio of the at least one PCE to calcined clay is in the range of 1:600 to 1:50.

7. A method according to claim 1, wherein the at least one PCE and the at least one additive are added in a weight ratio of the at least one PCE to the at least one additive of 20:1 to 1:10.

8. An admixture to be used in a method according claim 1, the admixture comprising a) at least one PCE b) at least one additive selected from the group consisting of sugar acids, sugars, sugar alcohols, and hydroxycarboxylic acids.

9. An admixture according to claim 8, wherein it is a mono-component admixture.

10. An admixture according to claim 8, wherein it is a two-component admixture.

11. An admixture according to claim 8, wherein it consists of a) one PCE b) one additive selected from the group of sugar acids, sugars, sugar alcohols, and hydroxycarboxylic acids, and c) optionally water, wherein the PCE and the additive have a weight ratio of the PCE to the additive of 20:1 to 1:10.

12. A hardenable composition obtainable by a method of claim 1.

13. A hardenable composition according to claim 12, wherein it comprises a) a binder composition comprising calcined clay (CC), limestone (L), and Portland cement (P) in weight ratios of P:CC from 33:1 to 1:1, b) at least one PCE, and c) at least one additive selected from the group consisting of sugar acids, sugars, sugar alcohols, and hydroxycarboxylic acids.

14. A hardenable composition according claim 12, wherein it further comprises water in a weight ratio of water to binder composition of between 0.1-0.6.

15. A hardened body resulting from curing a hardenable composition, according to claim 14.

Description

EXAMPLES

[0194] The slump flow at different times was measured in a slump flow test according to EN 12350-8 in examples 1-4 and according to EN 12350-5 in example 5. The slump flow is thus a measure for the workability of the respective mixture. The slump flow test was performed on individual samples at defined points of time after mixing with mixing water. The respective times are given in below Tables 2 to 12. The diameter of the cone used for slump flow measurements was 37.5 mm, thus a value of 37.5 mm in the below tables 2 to 13 (examples 1-4) corresponds to a mix which has essentially no slump flow. In tables 14 and 15 (examples 5 and 6) the term “not measurable” is used in cases where essentially no slump flow could be measured.

[0195] Heat flow curves were measured in an isothermal process as described in standard ASTM C1702-17. Examples were measured using an I-CAL 8000 from Calmetrix or a TAM AIR from TM Instruments. The maximum heat release (max. heat release) which is reported in the following tables is the time after which the respective heat flow curve reaches its global maximum. The time needed to reach this global maximum is a measure for the hardening speed and, for example, the strength development. A shorter time is linked to a faster hardening.

[0196] Compressive strength was measured according to DIN EN 196-1 on prisms of 40×40×160 mm after the time indicated in below tables.

[0197] Sodium gluconate, mannitol, dulcitol, sucrose, glucose, maltose, lactose, sorbitol, ascorbic acid, sodium glucuronate, lithium xylonate, citric acid, sodium citrate, triethanolamine, and triisopropanolamine were purchased from Sigma-Aldrich with 95% purity.

[0198] The following Table 1 gives an overview of other chemicals used. All chemicals were used as supplied unless otherwise noted.

TABLE-US-00001 TABLE 1 chemicals used Name Description Metakaolin Metastar 501 from Imerys kaolin Limestone Nekafill 15 from Kalkfabrik Netstal AG OPC CEM I 42.5N Gypsum CaSO.sub.4 (>99% purity) from Sigma-Aldrich Aggregates Mixture of 25 wt.-% sand (0-1 mm), 37 wt.-% gravel (1-4 mm); 38 wt.-% gravel (4-8 mm) PCE-1 Polymethacrylate (Mn = 7,000 g/mol), esterified with methoxypolyethylene glycol (Mn = 1,000 g/mol) to yield a molar ratio of carboxylic acid groups to side chains of 1.76 PCE-2 Polymethacrylate (Mn = 7,000 g/mol), esterified with a 1:3.5 mixture by weight of methoxypolyethylene glycol (Mn = 1,000 g/mol) and methoxypolyethylene glycol (Mn = 3,000 g/mol) to yield a molar ratio of carboxylic acid groups to side chains of 3 PCE-3 Copolymer of acrylic acid and methyallyl alcohol started polyethylene glycol (Mn = 2,400 g/mol) to yield a molar ratio of carboxylic acid groups to side chains of 3.6 PCE-4 Copolymer of acrylic acid and methyallyl alcohol started polyethylene glycol (Mn = 2,400 g/mol) to yield a molar ratio of carboxylic acid groups to side chains of 2.2 Caramel Caramel (color), CAS 8028-89-5 Melasse 72-76% dry substance, min. 40% total sugars 840-880 g/kg organic substances, 100-150 g/kg crude ash Vinasse Vinasse M from Manuelita S.A.

Reference Example

[0199] Reference examples Ref-1 to Ref-4 were prepared by adding the respective amounts of PCE, sodium gluconate, and water as indicated in below table 2 to the respective amount of OPC. The resulting mixture was mixed on a Heidolph propeller mixer for 2 min at 1′500 rpm. The respective testing started after these 2 minutes mixing time.

TABLE-US-00002 TABLE 2 Compositions of reference examples Ref-1 to Ref-4 (unless otherwise indicated all numbers refer to weight in grams). Ref-1 Ref-2 Ref-3 Ref-4 OPC 100 100 100 100 PCE-1 0 0.053 0 0.053 Sodium gluconate 0 0 0.025 0.025 water 46 46 46 46 Slump @ 0 min [mm] 93 95 103 124 Slump @ 30 min [mm] 93 90 86 95 Slump @ 60 min [mm] 94 89 85 98 Slump @ 90 min [mm] 75 84 85 95 Slump @ 120 min [mm] 37.5 85 84 92 Max. heat release [h] 9.74 12.29 12.77 16.11

[0200] The reference examples in table 2 show that addition of either a PCE or sodium gluconate can positively influence the initial slump flow as well as the slump life, and thus the workability, of a mix based on pure Portland cement (compare Ref-2 and Ref-3 to Ref-1). The mix is retarded by either addition, as can be seen from the time to maximum heat release of the system. The synergistical improvement of slump life observed by the concomitant addition of a PCE and sodium gluconate (Ref-4) is only small in this case and not sufficient for practical application. The retardation of the system with PCE and sodium gluconate added is increased but still acceptable for practical applications.

Example 1

[0201] The respective binders used to prepare references Ref-1 to Ref-5 (which are not according to the present invention) as well as examples 1-1 to 1-20 (which are according to the present invention) were prepared by mixing OPC, metakaolin, limestone, and gypsum in the amounts indicated in the following table 3 in dry state at 23° C./50% r.h. on a Heidolph propeller mixer for 2 min at 1′500 rpm. A visually homogeneous powder resulted in every case.

TABLE-US-00003 TABLE 3 Composition of binders 1 to 14 (all numbers refer to mass parts) OPC Metakaolin Limestone Gypsum Binder 1 50 31.5 15 3.5 Binder 2 50 25.2 21.3 3.5 Binder 3 50 18.9 27.6 3.5 Binder 4 50 12.6 33.9 3.5 Binder 5 50 6.3 40.2 3.5 Binder 6 50 15.7 30.8 3.5 Binder 7 74.4 1.9 18.6 5.1 Binder 8 30.1 52.7 15.1 2.1 Binder 9 51.8 41.5 3.1 3.6 Binder 10 66.2 26.5 2.6 4.7 Binder 11 80.1 2.3 17.6 0 Binder 12 70.5 14.1 15.4 0 Binder 13 21.2 74.2 4.6 0

[0202] The respective amounts of PCE, sodium gluconate, and water as indicated in below tables 4-6 were then added to the type and amount of binder composition indicated in these tables. The resulting mixture was mixed on a Heidolph propeller mixer for 2 min at 1′500 rpm. The respective testing started after these 2 minutes mixing time.

[0203] The following tables 4-6 show that the initial slump flow as well as the slump life, and thus the workability, of the respective binder compositions can be significantly improved when an admixture of the present invention is used as compared to the initial slump flow and the slump life, and thus the workability, of the same binder composition but only using a PCE or only an additive (compare examples 1-1 to 1-4 with Ref-5 to Ref-7, examples 1-5 to 1-8 with Ref-8 to Ref-10, examples 1-9 to 1-12 with Ref-11 to Ref-13, examples 1-13 to 1-16 with Ref-14 to Ref-16, examples 1-17 to 1-20 with Ref-17 to Ref-19).

[0204] Tables 4-6 also show that the use of an admixture according to the present invention somewhat increases the time needed to reach the maximum heat release. However, all inventive examples 1-1 to 1-20 show an acceptable time until maximum heat release and thus also an acceptable development of compressive strength. A time of max. 20 h until the maximum heat release is reached is acceptable for the present context.

[0205] An admixture of the present invention is thus able to increase the initial slump flow and the slump life, and thus the workability, of a binder composition comprising Portland cement, calcined clay, and limestone while maintaining development of strength which is perfectly acceptable for practical applications.

TABLE-US-00004 TABLE 4 Composition of Ref-5 to Ref-10, examples 1-1 to 1-8 (unless otherwise indicated all numbers refer to weight in gram) Ref-5 Ref-6 Ref-7 1-1 1-2 1-3 1-4 Ref-8 Ref-9 Ref-10 1-5 1-6 1-7 1-8 Binder 1 100 100 100 100 100 100 100 Binder 2 100 100 100 100 100 100 100 PCE-1 0.21 0.21 0.21 0.21 0.21 0.185 0.185 0.185 0.185 0.185 Sodium 0.1 0.025 0.05 0.075 0.1 0.088 0.022 0.044 0.066 0.088 gluconate water 46 46 46 46 46 46 46 46 46 46 46 46 46 46 Slump@0 min 37.5 92 37.5 108 117 114 113 37.5 124 37.5 125 126 152 134 [mm] Slump@30 min 75 37.5 114 119 126 124 117 37.5 125 128 149 155 [mm] Slump@60 min n.m. 37.5 87 108 117 130 95 37.5 113 124 149 151 [mm] Slump@90 min 37.5 n.m. 95 112 121 74 37.5 99 116 151 151 [mm] Slump@120 37.5 n.m. 104 124 n.m. 37.5 81 102 137.5 152 min [mm] Max. heat 7.38 10.55 13.1 11.44 13.93 16.02 19.9 7.35 12.95 12.3 14.93 16.46 20.02 23.17 release [h] n.m.: not measured

TABLE-US-00005 TABLE 5 Composition of Ref-11 to Ref-16, examples 1-9 to 1-16 (unless otherwise indicated all numbers refer to weight in gram) Ref-11 Ref-12 Ref-13 1-9 1-10 1-11 1-12 Ref-14 Ref-15 Ref-16 1-13 1-14 1-15 1-16 Binder 3 100 100 100 100 100 100 100 100 Binder 4 100 100 100 100 100 100 PCE-1 0.15 0.15 0.15 0.15 0.15 0.1 0.1 0.1 0.1 0.1 Sodium 0.071 0.018 0.036 0.053 0.071 0.048 0.012 0.024 0.036 0.048 gluconate water 46 46 46 46 46 46 46 46 46 46 46 46 46 46 Slump@0 min 37.5 120 37.5 123 134 132 140 37.5 107 37.5 115 124 128 136 [mm] Slump@30 min 110 37.5 120 133 142 151 95 37.5 97 111 121 135 [mm] Slump@60 min 84 37.5 105 130 141 152 70 37.5 81 104 116 134 [mm] Slump@90 min n.m. 37.5 88 120 135 143 n.m. 37.5 61 88 112 130 [mm] Slump@120 37.5 n.m. 106 130 148 37.5 n.m. 74 99 124 min [mm] Max. heat 7.6 12.62 12.3 14.18 16 18.33 20.87 8.11 10.98 12.0 12.17 13.53 15.04 18.83 release [h] n.m.: not measured

TABLE-US-00006 TABLE 6 Composition of Ref-17 to Ref-19, examples 1-17 to 1-20 (unless otherwise indicated all numbers refer to weight in gram) Ref-17 Ref-18 Ref-19 1-17 1-18 1-19 1-20 Binder 5 100 100 100 100 100 100 100 PCE-1 0.063 0.063 0.063 0.063 0.063 Sodium gluconate 0.03 0.008 0.015 0.023 0.03 water 46 46 46 46 46 46 46 Slump @ 0 min [mm] 37.5 123 107 123 127 130 138 Slump @ 30 min [mm] 105 65 104 113 116 126 Slump @ 60 min [mm] 91 37.5 89 100 105 121 Slump @ 90 min [mm] 75 37.5 76 89 96 113 Slump @ 120 min [mm] 72 37.5 71 82 95 107 Max. heat release [h] 8.46 10.08 11.2 11.22 11.79 12.73 13.12 n.m.: not measured

Example 2

[0206] Examples 2 shows the effector different additives.

[0207] Inventive examples 2-1 to 2-44 were prepared in the same way as examples 1-1 to 1-20 above except that different additives were used (s. tables 7-10 for details).

[0208] The following tables 7-10 show that additives according to the present invention are able to increase the initial slump flow and the especially the slump life, and thus the workability, of a binder composition according to the invention. All examples 2-1 to 2-44 can be compared to references Ref-5 to Ref-7 from Example 1.

TABLE-US-00007 TABLE 7 Composition of examples 2-1 to 2-12 (unless otherwise indicated all numbers refer to weight in gram) 2-1 2-2 2-3 2-4 2-5 2-6 2-7 2-8 2-9 2-10 2-11 2-12 Binder 1 100 100 100 100 100 100 100 100 100 100 100 100 PCE-1 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 Mannitol 0.05 0.1 0.5 Dulcitol 0.05 0.1 0.5 Sucrose 0.05 0.1 0.5 Glucose 0.05 0.1 0.5 water 46 46 46 46 46 46 46 46 46 46 46 46 Slump@0 min [mm] 124 127 90 136 131 88 119 126 141 115 116 105 Slump@30 min [mm] 102 88 64 113 107 71 115 136 146 95 106 48 Slump@60 min [mm] 61 76 37.5 85 106 59 96 130 137 37.5 78 37.5 Slump@90 min [mm] 37.5 58 37.5 88 66 79 124 126 37.5 Slump@120 min 37.5 55 65 37.5 116 119 [mm]

TABLE-US-00008 TABLE 8 Composition of examples 2-13 to 2-21 (unless otherwise indicated all numbers refer to weight in gram) 2-13 2-14 2-15 2-16 2-17 2-18 2-19 2-20 2-21 Binder 1 100 100 100 100 100 100 100 100 100 PCE-1 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 Caramel 0.05 0.1 0.5 Melasse 0.05 0.1 0.5 Vinasse 0.05 0.1 0.5 water 46 46 46 46 46 46 46 46 46 Slump@0 min [mm] 105 103 91 122 124 129 112 105 55 Slump@30 min [mm] 94 104 103 109 124 138 93 94 75 Slump@60 min [mm] 37.5 85 102 81 110 131 37.5 37.5 76 Slump@90 min [mm] 55 104 37.5 96 121 74 Slump@120 min 37.5 101 82 118 73 [mm]

TABLE-US-00009 TABLE 9 Composition of examples 2-22 to 2-33 (unless otherwise indicated all numbers refer to weight in gram) 2-22 2-23 2-24 2-25 2-26 2-27 2-28 2-29 2-30 2-31 2-32 2-33 Binder 1 100 100 100 100 100 100 100 100 100 100 100 100 PCE-1 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 Maltose 0.05 0.1 0.5 Lactose 0.05 0.1 0.5 Sorbitol 0.05 0.1 0.5 Ascorbic acid 0.05 0.1 0.5 water 46 46 46 46 46 46 46 46 46 46 46 46 Slump@0 min [mm] 116 117 106 116 117 109 135 159 76 116 82 53 Slump@30 min [mm] 98 109 83 109 98 51 114 126 95 109 98 51 Slump@60 min [mm] 61 82 68 94 99 50 80 125 75 94 99 50 Slump@90 min [mm] 46 60 61 37.5 96 37.5 53 114 76 37.5 96 37.5 Slump@120 min 37.5 60 91 37.5 94 74 91 [mm]

TABLE-US-00010 TABLE 10 Composition of examples 2-34 to 2-41 (unless otherwise indicated all numbers refer to weight in gram) 2-34 2-35 2-36 2-37 2-38 2-39 2-40 2-42 2-43 Binder 1 100 100 100 100 100 100 100 100 100 PCE-1 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 Sodium glucuronate 0.05 0.1 0.5 Lithium xylonate 0.05 0.1 Citric acid 0.05 0.1 Sodium citrate 0.05 0.1 water 46 46 46 46 46 46 46 46 46 Slump@0 min [mm] 132 141 37.5 133 142 98 75 109 76 Slump@30 min [mm] 125 135 73 115 129 95 66 97 82 Slump@60 min [mm] 110 131 100 84 127 79 65 67 78 Slump@90 min [mm] 78 130 106 37.5 121 37.5 64 37.5 60 Slump@120 min [mm] 37.5 126 104 115 37.5 37.5

TABLE-US-00011 TABLE 11 Composition of references Ref-20 to Ref-25 (unless otherwise indicated all numbers refer to weight in gram) Ref-20 Ref-21 Ref-22 Ref-23 Ref-24 Ref-25 Binder 1 100 100 100 100 100 100 PCE-1 0.21 0.21 0.21 0.21 0.21 0.21 Triethanolamine 0.05 0.1 0.5 Triisopropanolamine 0.05 0.1 0.5 water 46 46 46 46 46 46 Slump@0 min [mm] 116 114 90 117 119 120 Slump@30 min [mm] 88 90 37.5 80 66 64 Slump@60 min [mm] 37.5 37.5 37.5 37.5 37.5 Slump@90 min [mm] Slump@120 min [mm] The above references Ref-20 to Ref-25 show that the use of either triethanolamine (TEA) or triisoproanolamine (TIPA) do not improve the workability of binder compositions of the present invention to a satisfying degree (compare for example to Ref-5 and examples 1-1 to 1-4).

Example 3

[0209] Examples 3 shows the effect of different PCE.

[0210] Inventive examples 3-1 to 3-10 and references Ref-26 to Ref-28 (which are not according to the invention) were prepared in the same way as examples 1-1 to 1-20 above except that different PCE were used. Example 3-1 is identical to example 1-4.

[0211] The following table 12 shows that POE of different structure and when combined with an additive of the present invention are able to increase the initial slump flow and the especially the slump life, and thus the workability, of a binder composition according to the invention. None of the POE works in the same way without addition of the additive (see references Ref-26 to Ref-28).

TABLE-US-00012 TABLE 12 Composition of Ref-26 to Ref-28, examples 3-1 to 3-10 (unless otherwise indicated all numbers refer to weight in gram) 3-1 Ref-26 3-2 3-3 3-4 Ref-27 3-5 3-6 3-7 Ref-28 3-8 3-9 3-10 Binder 1 100 100 100 100 100 100 100 100 100 100 100 100 100 PCE-1 0.21 PCE-2 0.181 0.181 0.181 0.181 PCE-3 0.142 0.142 0.142 0.142 PCE-4 0.194 0.194 0.194 0.194 Sodium gluconate 0.1 0.05 0.1 0.2 0.05 0.1 0.2 0.05 0.1 0.2 water 46 46 46 46 46 46 46 46 46 46 46 46 46 Slump @ 0 min [mm] 113 107 138 162 112 86 125 128 37.5 80 104 90 48 Slump @ 30 min [mm] 124 n.m. 111 162 144 n.m. 106 159 123 n.m. 102 118 92 Slump @ 60 min [mm] 130 n.m. 155 153 n.m. 157 136 62 116 100 Slump @ 90 min [mm] 121 148 156 151 143 37.5 110 102 Slump @ 120 min [mm] 124 125 155 145 146 86 104 n.m.: not measured

Example 4

[0212] Example 4 shows the effect of different dosage of PCE at fixed dosages of sodium gluconate.

[0213] Inventive examples 4-1 to 4-20 were prepared in the same way as examples 1-1 to 1-20 above except that the dosages of PCE and sodium gluconate as indicated in below table 13 were used.

[0214] The following table 13 shows that the initial slump flow as well as the slump life, and thus the workability, of the respective binder compositions can be significantly improved when an admixture of the present invention is used if compared to reference compositions without the PCE and/or without the additive (compare to references Ref-5 to Ref-19 from Example 1).

[0215] Similar to the results from Example 1, the results in table 13 show that the use of an admixture according to the present invention somewhat increases the time needed to reach the maximum heat release. However, all inventive examples 4-1 to 4-20 show an acceptable time until maximum heat release and thus also an acceptable development of compressive strength.

[0216] An admixture of the present invention is thus able to increase the initial slump flow and the slump life, and thus the workability, of a binder composition comprising Portland cement, calcined clay, and limestone while maintaining development of strength which is perfectly acceptable for practical applications.

TABLE-US-00013 TABLE 13 Composition of examples 4-1 to 4-20 (unless otherwise indicated all numbers refer to weight in gram) 4-1 4-2 4-3 4-4 4-5 4-6 4-7 4-8 Binder 1 100 100 100 100 Binder 2 100 100 100 100 PCE-1 0.053 0.105 0.158 0.21 0.046 0.093 0.139 0.185 Sodium gluconate 0.1 0.1 0.1 0.1 0.09 0.09 0.09 0.09 water 46 46 46 46 46 46 46 46 Slump @ 0 min [mm] 37.5 37.5 37.5 113 37.5 60 98 134 Slump @ 30 min [mm] 37.5 37.5 37.5 124 37.5 69 115 155 Slump @ 60 min [mm] 37.5 37.5 37.5 130 37.5 68 125 151 Slump @ 90 min [mm] 37.5 37.5 37.5 121 37.5 65 119 151 Slump @ 120 min [mm] 37.5 37.5 37.5 124 37.5 62 117 152 Max. heat release [h] 13.6 14.9 16.9 20 13.6 15.9 18.9 23.2 4-9 4-10 4-11 4-12 4-13 4-14 4-15 4-16 Binder 3 100 100 100 100 Binder 4 100 100 100 100 PCE-1 0.038 0.075 0.113 0.15 0.025 0.05 0.075 0.1 Sodium gluconate 0.071 0.071 0.071 0.071 0.048 0.048 0.048 0.048 water 46 46 46 46 46 46 46 46 Slump @ 0 min [mm] 37.5 80 127 140 55 71 109 136 Slump @ 30 min [mm] 37.5 76 132 151 37.5 64 100 135 Slump @ 60 min [mm] 37.5 76 131 152 37.5 64 98 134 Slump @ 90 min [mm] 37.5 72 133 143 37.5 37.5 95 130 Slump @ 120 min [mm] 37.5 37.5 131 148 37.5 37.5 84 124 Max. heat release [h] 12.8 16.2 19.9 20.9 12.6 13.5 14.8 18.8 4-17 4-18 4-19 4-20 Binder 5 100 100 100 100 PCE-1 0.016 0.032 0.047 0.063 Sodium gluconate 0.03 0.03 0.03 0.03 water 46 46 46 46 Slump @ 0 min [mm] 113 121 126 138 Slump @ 30 min [mm] 75 89 92 108 Slump @ 60 min [mm] 66 74 78 94 Slump @ 90 min [mm] 37.5 37.5 62 73 Slump @ 120 min [mm] 37.5 37.5 37.5 63 Max. heat release [h] 11.4 11.7 12.4 13.1

Example 5

[0217] Example 5 shows the effect of the addition of an admixture of the present invention to a mortar composition based on a binder comprising ordinary Portland cement, metakaolin, limestone, and gypsum.

[0218] Inventive examples 5-1 to 5-10 and references Ref-29 to Ref-36 (which are not according to the present invention) were prepared by mixing binder, PCE, sodium gluconate, limestone and aggregates in the amounts as given in below table 14 for 1 minute at 23° C./50% r.h. on a Heidolph propeller mixer at 1′500 rpm. A visually homogeneous powder resulted in every case. An amount of water was added to achieve a water to binder ratio (w/b) of 0.5 in every case. Mixing was then continued for 3 minutes on a Heidolph propeller mixer at 1′500 rpm.

[0219] Measurements were performed as indicated above.

TABLE-US-00014 TABLE 14 Composition of examples 5-1 to 5-10 and Ref-29 to Ref-36 (unless otherwise indicated all numbers refer to weight in gram) Ref-29 5-1 Ref-30 5-2 Ref-31 5-3 Ref-32 5-4 5-5 Ref-33 Binder 1 100 100 100 100 100 100 100 100 100 100 PCE-1 0.18 0.18 0.24 0.24 0.27 0.27 0.3 0.3 0.3 0.48 Sodium gluconate 0.2 0.125 0.1 0.075 0.1 Limestone 18.8 18.8 18.8 18.8 18.8 18.8 18.8 18.8 18.8 18.8 Aggregates 400 400 400 400 400 400 400 400 400 400 Water 50 50 50 50 50 50 50 50 50 50 Slump @ 0 min [mm] 122 143 160 216 180 241 227 256 238 268 Slump @ 30 min [mm] n.m. 160 132 228 146 245 180 232 245 256 Slump @ 60 min [mm] 162 n.m. 220 n.m. 232 n.m. 206 238 250 Slump @ 90 min [mm] 150 213 218 154 240 231 Slump @ 120 min [mm] 144 Compressive strength 11.2 6.4 8 9.1 6.7 8.3 @ 1 d [MPa] Compressive strength 20.2 17.5 19.1 20.9 18.6 18.9 @ 2 d [MPa] Ref-34 5-6 5-7 5-8 Ref-35 5-9 5-10 Ref-36 Binder 6 100 100 100 100 100 100 100 100 PCE-1 0.18 0.18 0.18 0.18 0.24 0.24 0.24 0.3 Sodium gluconate 0.04 0.075 0.15 0.025 0.05 Limestone 18.8 18.8 18.8 18.8 18.8 18.8 18.8 18.8 Aggregates 400 400 400 400 400 400 400 400 water 50 50 50 50 50 50 50 50 Slump @ 0 min 216 258 254 258 255 260 268 216 [mm] Slump @ 30 min 195 253 248 242 233 255 260 268 [mm] Slump @ 60 min 163 232 236 240 197 230 251 256 [mm] Slump @ 90 min 142 213 224 235 166 205 238 248 [mm] Slump @ 120 min n.m. 228 151 154 240 [mm] Compressive 10 9.5 7.8 8 8.8 strength @ 1 d [MPa] Compressive 18.8 19.1 17.8 17.1 18.4 strength @ 2 d [MPa] n.m.: not measurable

[0220] It can be seen from the above table 14, that the addition of an admixture of the present invention to a binder of the present invention leads to a better workability, especially a higher slump flow, as compared to the same composition but only comprising a POE. At the same time, the compressive strength of inventive examples as measured after 1 d and after 2 d is at the same level as the compressive strength of the respective references. Thus, retardation of the curing is acceptable for practical applications. It can furthermore be seen from the results of table 14 that the effect of an admixture of the present invention on a binder composition of the present invention is similar as an increase in the dosage of POE. This the method of the present invention is also a way of reducing the dosage of POE in a binder composition of the present invention.

Example 6

[0221] Example 6 shows the effect of an admixture of the present invention on binders comprising calcined clay, limestone, and Portland cement in different ratio.

[0222] Examples 6-1 to 6-14 and references Ref37 to Ref43 were prepared and measured in the same way as examples 1-1 to 1-20 above. The following table 15 shows the type of binder used, dosage of the admixture and measured slump flow values after different times as well as maximum heat release time. The dosage of the respective admixture used was set to achieve an initial slump of appr. 140 mm. Examples 6-1 to 6-14 are according to the present invention, examples Ref37 to Ref43 are comparative examples and not according to the present invention.

TABLE-US-00015 TABLE 15 Composition of examples 6-1 to 6-14 and Ref37 to Ref43 (unless otherwise indicated all numbers refer to weight in gram) Ref37 6-1 6-2 Ref38 6-3 6-4 Ref39 6-5 6-6 Binder 7 100 100 100 Binder 8 100 100 100 Binder 9 100 100 100 PCE-1 0.033 0.026 0.029 0.141 0.1 0.131 0.132 0.093 0.109 Sodium gluconate 0.013 0.007 0.046 0.031 0.045 0.026 water 46 46 46 46 46 46 46 46 46 Slump @ 0 min [mm] 139 137 140 143 142 143 143 140 140 Slump @ 30 min [mm] 132 131 125 136 151 150 152 143 143 Slump @ 60 min [mm] 126 123 124 126 153 148 164 140 140 Slump @ 90 min [mm] 130 117 124 95 156 149 152 141 141 Slump @ 120 min [mm] 129 120 122 n.m. 154 146 148 141 141 Max. heat release [h] 13.11 17.24 14.76 12.16 34.36 16.68 18.89 33.3 23.56 Ref40 6-7 6-8 Ref41 6-9 6-10 Ref42 6-11 6-12 Ref43 6-13 6-14 Binder 10 100 100 100 Binder 11 100 100 100 Binder 12 100 100 100 Binder 13 100 100 100 PCE-1 0.087 0.067 0.082 0.041 0.028 0.034 0.059 0.05 0.097 4.035 2.80 3.32 Sodium gluconate 0.032 0.02 0.013 0.008 0.002 0.023 1.33 0.79 water 46 46 46 46 46 46 46 46 46 46 46 46 Slump @ 0 min [mm] 137 139 144 143 140 137 142 138 138 n.m. n.m. n.m. Slump @ 30 min [mm] 138 147 120 139 131 128 137 132 146 n.m. n.m. n.m. Slump @ 60 min [mm] 135 131 120 135 133 124 132 134 144 n.m. n.m. n.m. Slump @ 90 min [mm] 135 133 123 136 134 124 145 133 146 n.m. n.m. n.m. Slump @ 120 min [mm] 135 131 123 131 129 130 132 133 145 n.m. n.m. n.m. Max. heat release [h] 16.54 30.16 24.2 15.35 18.71 17.31 14.75 38.4 18.4 n.m. n.m. n.m. n.m.: not measurable

[0223] It can be seen from the above table 15 that only in some cases an improvement of slump life was achievable when using an admixture of the present invention as compared to the use of only POE (6-3 and 6-4 as compared to Ref38, 6-12 as compared to Ref42). It has to be noted that in case of examples 6-3, 6-4, and 6-12 an additional fluidification (increase in slump flow) over time was observed which is undesirable.