CEMENTITIOUS BINDERS CONTAINING POZZOLANIC MATERIALS

Abstract

A cementitious composition including: a binder containing (a) 60-94%, by weight, of at least one pozzolanic material; (b) at least 0.5% calcium sulfoaluminate (CSA), by weight; (c) 1.2-11% by weight, expressed as SO.sub.3, of at least one inorganic sulfate selected from the group of sulfates consisting of a calcium sulfate hemihydrate, an anhydrous calcium sulfate, a calcium sulfate dihydrate, a sodium sulfate, and a sodium calcium sulfate; and (d) a total sulfate content of at least 3%, by weight, expressed as SO.sub.3, the cementitious composition including, at most, 3% natural lime, the cementitious composition including, at most, 10% alumina cement, the contents of the composition being calculated on a dry, aggregateless basis.

Claims

1-78. (canceled)

79. A cementitious composition comprising: a binder containing: (a) 72-94%, by weight, of ground granular blast furnace slag (GGBFS); (b) at least 0.5% calcium sulfoaluminate (CSA), by weight, said CSA having the structure 3CaO.3Al.sub.2O.sub.3.CaSO.sub.4; (c) 1.2-11% by weight, expressed as SO.sub.3, of at least one inorganic sulfate selected from the group of sulfates consisting of a calcium sulfate hemihydrate, an anhydrous calcium sulfate, a calcium sulfate dihydrate, a sodium sulfate, and a sodium calcium sulfate; and (d) a total sulfate content of at least 3%, and at most 11%, by weight, expressed as SO.sub.3; the cementitious composition comprising, at most, 3% natural lime; the cementitious composition comprising, at most, 3% alumina cement; the cementitious composition comprising, at most 5% of an Ordinary Portland Cement (OPC); the cementitious composition comprising, at most, 5% of said CSA; the contents of the composition being calculated on a dry, aggregateless basis.

80. The cementitious composition of claim 79, wherein said content of said ground granular blast furnace slag within the composition is at least 75%, by weight.

81. The cementitious composition of claim 79, wherein said content of said ground granular blast furnace slag within the composition is at least 78%, by weight.

82. The cementitious composition of claim 79, wherein said content of said ground granular blast furnace slag within the composition is at least 82%, by weight.

83. The cementitious composition of claim 79, wherein said content of said ground granular blast furnace slag within the composition is at least 84%, by weight.

84. The cementitious composition of claim 79, the cementitious composition comprising, at most, 0.2% of a polymeric resin, by weight.

85. A cementitious composition comprising: a binder containing: (a) 60-94%, by weight, of ground granular blast furnace slag (GGBFS); (b) at least 0.5% calcium sulfoaluminate (CSA), by weight, said CSA having the structure 3CaO.3Al.sub.2O.sub.3.CaSO.sub.4; (c) 1.2-11% by weight, expressed as SO.sub.3, of at least one inorganic sulfate selected from the group of sulfates consisting of a calcium sulfate hemihydrate, an anhydrous calcium sulfate, a calcium sulfate dihydrate, a sodium sulfate, and a sodium calcium sulfate; and (d) a total sulfate content of at least 3%, and at most 11%, by weight, expressed as SO.sub.3; the cementitious composition comprising, at most, 3% natural lime; the cementitious composition comprising, at most, 3% alumina cement; the cementitious composition comprising, at most 5% of an Ordinary Portland Cement (OPC); the contents of the composition being calculated on a dry, aggregateless basis.

86. The cementitious composition of claim 85, the composition comprising at least

1. 5% of said inorganic sulfate by weight, expressed as SO.sub.3.

87. The cementitious composition of claim 85, wherein a content of said calcium sulfoaluminate within the composition is at least 0.75%, and a combined content of said ground granular blast furnace slag, a material containing said CSA, and said inorganic sulfate, is at least 85% of the cementitious composition, by weight.

88. The cementitious composition of claim 85, wherein a content of said calcium sulfoaluminate (3CaO.3Al.sub.2O.sub.3.CaSO.sub.4) within the composition is at least 0.75%, wherein a combined content of said GGBFS, a material containing said calcium sulfoaluminate (3CaO.3Al.sub.2O.sub.3.CaSO.sub.4), and said inorganic sulfate, is at least 90% of the cementitious composition, by weight.

89. The cementitious composition of claim 85, wherein a combined content of a material containing said CSA and said inorganic sulfate within the composition is within a range of 12% to 30%, by weight, on said dry, aggregateless basis.

90. The cementitious composition of claim 85, said CSA disposed within a calcium sulfoaluminate clinker, the composition comprising at least 2.75%, by weight, of said clinker, on said dry, aggregateless basis.

91. A cementitious composition comprising: a binder containing: (a) 78-94%, by weight, of ground granular blast furnace slag (GGBFS); (b) at least 0.5% calcium sulfoaluminate (CSA), by weight, said CSA having the structure 3CaO.3Al.sub.2O.sub.3.CaSO.sub.4; (c) 1.2-11% by weight, expressed as SO.sub.3, of at least one inorganic sulfate selected from the group of sulfates consisting of a calcium sulfate hemihydrate, an anhydrous calcium sulfate, a calcium sulfate dihydrate, a sodium sulfate, and a sodium calcium sulfate; and (d) a total sulfate content of at least 3%, and at most 11%, by weight, expressed as SO.sub.3; the cementitious composition comprising, at most, 3% natural lime; the cementitious composition comprising, at most, 3% alumina cement; the cementitious composition comprising, at most 5% of an Ordinary Portland Cement (OPC); the contents of the composition being calculated on a dry, aggregateless basis.

92. The cementitious composition of claim 91, wherein a combined content of a material containing said CSA and said inorganic sulfate within the composition is within a range of 12% to 30%, by weight, on said dry, aggregateless basis.

93. The cementitious composition of claim 91, wherein said content of said ground granular blast furnace slag within the composition is at least 82%, by weight.

94. The cementitious composition of claim 91, wherein a content of said calcium sulfoaluminate (3CaO.3Al.sub.2O.sub.3.CaSO.sub.4) within the composition is at least 0.75%, wherein a combined content of said GGBFS, a material containing said calcium sulfoaluminate (3CaO.3Al.sub.2O.sub.3.CaSO.sub.4), and said inorganic sulfate, is at least 90% of the cementitious composition, by weight.

95. The cementitious composition of claim 91, wherein said inorganic sulfate predominantly includes at least one of said calcium sulfate hemihydrate, said anhydrous calcium sulfate, and said calcium sulfate dihydrate.

96. The cementitious composition of claim 91, comprising at most 3% of said Ordinary Portland Cement (OPC).

97. The cementitious composition of claim 91, comprising, at most 2% of said Ordinary Portland Cement (OPC).

98. The cementitious composition of claim 91, further comprising water, said binder and said water forming a wet cementitious mixture.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0086] The invention is herein described, by way of example only, with reference to the accompanying drawing.

[0087] The FIGURE is a bar graph plot showing the development of compressive strength of several exemplary inventive compositions versus a control composition, as a function of time.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0088] The principles and operation of the cementitious binders according to the present invention may be better understood with reference to the drawings and the accompanying description.

[0089] Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

[0090] According to M. Michel et al., the industrial development of blast-furnace slag cements such as CEM III has been hindered by their limited mechanical performance, particularly at an early age. M. Michel et al. further disclose that the mechanical performance of slag cements containing more than 70% blast-furnace slag is low with respect to that of Portland cement.

[0091] We have surprisingly discovered, however, that blended cements containing at least 60% of at least one pozzolanic material, and in many cases, at least 70%, at least 75%, at least 80%, and at least 85% pozzolans, may have advantageously high ultimate mechanical strengths. Moreover, these inventive pozzolan-based compositions may exhibit high mechanical strengths during the short term and medium term periods, and may preferably exhibit such high mechanical strengths continuously over the entire period during which the cement chemically and mechanically develops.

[0092] Thus, according to one aspect of the present invention there is provided a cementitious composition including: 60-94%, by weight, of at least one pozzolanic material; at least 0.5% calcium sulfoaluminate (CSA), by weight; 1.2-11% by weight, expressed as SO.sub.3, of at least one inorganic sulfate selected from the group of sulfates consisting of a calcium sulfate hemihydrate, an anhydrous calcium sulfate, a calcium sulfate dihydrate, a sodium sulfate, and a sodium calcium sulfate; and a total sulfate content of at least 3%, by weight, expressed as SO.sub.3, the contents of the composition being calculated on a dry, aggregateless basis. The cementitious composition is typically free of natural lime, alumina cement, and polymeric resins.

[0093] The at least one pozzolanic material typically includes ground granulated blast furnace slag, which may be at least partially replaced by at least one fly ash (e.g., Type C, Type F). Other pozzolanic materials, including silica fume, metakaolin, calcined shale, calcined clay, or pumice, may at least partially replace the slag, and may be combined with the fly ash. It will be appreciated that such adjustments of the binder formulation may be made, without undue experimentation, by one of ordinary skill in the art.

[0094] It is surprising that various mechanical properties of the cement may be appreciably improved by the addition of as little as 0.5%, by weight, calcium sulfoaluminate, on a pure CSA basis. More typically, the content of the calcium sulfoaluminate within the composition may be at least 0.75%, at least 0.85%, at least 1.0%, at least 1.2%, at least 1.5%, at least 2.75%, at least 3%, at least 3.5%, at least 4.5%, or at least 5%. In some cases, the content of the calcium sulfoaluminate within the composition may be at least 5.5%, at least 6%, at least 6.5%, at least 7%, at least 7.5%, or at least 8%.

[0095] Calcium sulfoaluminate may be expensive with respect to some pozzolanic materials, gypsum, and various components of cementitious mixtures. We have found that cementitious compositions having superior mechanical and chemical properties may be achieved, while limiting the calcium sulfoaluminate content within the composition to a maximum value of 25%, 20%, 15%, 12%, 10%, 8%, 6%, or 5%, on a pure CSA basis.

[0096] Typically, the CSA is disposed within a CSA clinker. The cementitious composition of the present invention may advantageously include at least 2.75%, at least 3.5%, at least 4%, or at least 4.5%, by weight, of the CSA clinker, on a dry, aggregateless basis. More typically, the inventive cementitious composition includes at least 3.5%, at least 4%, at least 4.5%, at least 5.5%, at least 7%, at least 9%, at least 11.5%, at least 13%, at least 15%, at least 18%, at least 20%, at least 22%, at least 25%, at least 28%, or at least 32%, CSA clinker.

[0097] The clinker may advantageously contain belite. The belite content within the clinker may be at least 5%, at least 10%, at least 15%, at least 20%, at least 30%, or at least 40%, by weight. Typically, the belite content within the clinker may be within a range of 12-60%, by weight.

[0098] The weight ratio of belite to CSA, within the clinker, or within the cementitious composition, may be at least 0.2, at least 0.25, at least 0.3, at least 0.4, at least 0.5, at least 0.75, at least 1, at least 1.25, at least 1.5, or at least 1.7.

[0099] The CSA clinker used in accordance with the present invention may be devoid or substantially devoid of calcium aluminoferrite [(Ca.sub.2(Al,Fe).sub.2O.sub.5)]. The CSA clinker used in accordance with the present invention may contain less than 10%, less than 7%, less than 4%, less than 2.5%, or less than 1% calcium aluminoferrite.

[0100] The amount of iron, expressed as iron oxide, within the clinker, may be less than 7%, less than 5%, or less than 3%, and more typically, may be less than 2.8%, less than 2.5%, less than 1.5%, less than 1%, less than 0.75%, or less than 0.5%. The iron concentration in the inventive binder may be heavily dependent on the source of the various raw materials. For example, various fly ash products may contain at least several percent iron oxide. Various slag compositions may contain lesser amounts of iron oxide, e.g., at least 0.2% or at least 0.4%, but often less than 1%.

[0101] The early strength of the cement may be improved by the addition of an inorganic sulfate compound, typically anhydrite (CaSO.sub.4), gypsum (CaSO.sub.4.2H.sub.2O), hemihydrate (CaSO.sub.4./2H.sub.2O) or other sulfate sources such as glauberite (Na.sub.2Ca(SO.sub.4).sub.2) and sodium sulfate (Na.sub.2SO.sub.4). Such sulfate containing materials have been found to improve the early strength to varying extents, depending on their solubility and solubility kinetics. The total sulfate content, calculated as SO.sub.3, is at least 2.5%, by weight, including the sulfate content attributed to the calcium sulfoaluminate, to the pozzolanic material, and to any OPC or other components. More typically, the total sulfate content, calculated as SO.sub.3, may be at least 3%, at least 4%, at least 5%, at least 7%, or at least 10%, by weight.

[0102] An excess of sulfate may deleteriously affect the ultimate strength of the cementitious composition. We have found that the total sulfate content within the composition, expressed as SO.sub.3, should be at most 15%, and more typically, no more than 11%, 10%, or 9%, by weight.

[0103] Without wishing to be limited by theory, the inventors believe that such an excess of sulfate produces, promotes, or is otherwise associated a high specific pore volume, which reduces the strength of the cementitious composition.

[0104] The inventors have found that in the production of the inventive binder, carbon dioxide emissions are reduced with respect to the production of Ordinary Portland Cements.

EXAMPLES

[0105] Reference is now made to the following examples, which together with the above description, illustrate the invention in a non-limiting fashion.

Example 1

[0106] As a control, a cementitious binder of the prior art was prepared, containing 100% Type III OPC, and weighing 450 grams. The binder was mixed with 1,350 grams of standard sand according to the EN standard 197 to produce a mixture containing 25% binder and 75% sand. The dry blend was mixed with 189 grams water and 0.7 grams Melment F10, a powdered super plasticizer based on a water-soluble sulfonated melamine polycondensate.

[0107] Sets of test cubes were prepared, one set for measuring the compressive strength at 3 hours and at 24 hours, and two sets for evaluating compressive strengths at 3, 7, 28 and 90 days.

Example 2

[0108] As a control, a cementitious binder of the prior art was prepared, containing 80% ground granulated blast furnace slag grounded (d.sub.50=3.5 ) and 15% calcium sulfate dihydrate and 5% Portland cement (CEM I 52.5). The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 189 grams water and 2.5 grams Melment F10. Sets of test cubes were prepared, one set for measuring the compressive strength at 3 hours and at 24 hours, and two sets for evaluating the compressive strength at 3, 7, 28 and 90 days.

[0109] Table 1 provides the compressive strength developed by Examples 1 and 2, as a function of time.

TABLE-US-00001 TABLE 1 1 2 Example No. Control 1 Control 2 (wt. %) OPC (CEM I 52.5) 100 5 Slag d.sub.50 = 3.5 80 Calcium Sulfate Dihydrate 15 Binder 25 25 Standard Sand 75 75 time Compressive Strength (MPa) 3 hours 0 1.25 1 day 19.2 12.5 3 days 39.8 24.2 7 days 58.1 38.0 28 days 76.0 46.9

Example 3

[0110] A cementitious binder was prepared, containing 80% ground granulated blast furnace slag (d.sub.50=3.5 ), 15% alpha calcium sulfate hemihydrate and 5% of a calcium sulfoaluminate cement or clinker having the following mineralogical composition:

TABLE-US-00002 Alite 5.2% Belite 45.7% Anhydrite 14.0% Ye' elimite 26.2% Andradite Ca.sub.3Fe.sub.2 (SO.sub.4).sub.3 6.5% Portlandite 2.2% Calcium Aluminum Iron Oxide Sulfate trace Calcium Phosphide trace
(Unless specified otherwise, this is the composition of the CSA clinker utilized in all of the Examples.) The ratio of CSA to belite in this composition was about 1.7:1.

[0111] Thus, the concentration of CSA within the cementitious binder was about 1.3% (5%26%). The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 189 grams water and 2.5 grams Melment F10.

[0112] Sets of test cubes were prepared, one set for measuring the compressive strength at 3 hours and at 24 hours, and two sets for evaluating the compressive strengths at 3, 7, 28 and 90 days.

[0113] The slags used in Example 3-17 had the following chemical composition:

TABLE-US-00003 CaO 38-45% SiO.sub.2 32-40% Al.sub.2O.sub.3 10-15% Fe.sub.2O.sub.3 0.5-1.5% MgO 6-9% TiO.sub.2 0.5-1% K.sub.2O 0.5-1% Na.sub.2O 0.2-0.5% Mn.sub.2O.sub.3 0-1.5% SO.sub.3 0.1-2% LOI (total) 0.5-3%

Example 4

[0114] A cementitious binder was prepared, containing 80% ground granulated blast furnace slag (d.sub.50=3.5 ), 15% calcium sulfate dihydrate (CaSO.sub.4.2H.sub.2O) produced by flue gas desulfurization (FGD), and 5% calcium sulfoaluminate cement. The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 189 grams water and 1.5 grams Melment F10.

[0115] Sets of test cubes were prepared, one set for measuring the compressive strength at 3 hours and at 24 hours, and two sets for evaluating the compressive strengths at 3, 7, 28 and 90 days.

Example 5

[0116] A cementitious binder was prepared, containing 80% ground granulated blast furnace slag (d.sub.50=3.5 ), 15% anhydrous calcium sulfate (CaSO.sub.4, or anhydrite), and 5% calcium sulfoaluminate cement (CSA clinker). The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 189 grams water and 1.8 grams Melment F10.

[0117] Sets of test cubes were prepared, one set for measuring the compressive strength at 3 hours and at 24 hours, and two sets for evaluating the compressive strengths at 3, 7, 28 and 90 days.

[0118] Table 2 provides the compressive strength developed by Examples 3-5, as a function of time.

Example 6

[0119] A cementitious binder was prepared, containing 80% ground granulated blast furnace slag (d.sub.50=13 ), 15% alpha calcium sulfate hemihydrate and 5% calcium sulfoaluminate cement. The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 189 grams water and 2.5 grams Melment F10. Sets of test cubes were prepared, one set for measuring the compressive strength at 3 hours and at 24 hours, and two sets for evaluating the compressive strengths at 3, 7, 28 and 90 days.

[0120] Table 3 provides the compressive strength developed by Examples 3 and 6, as a function of time.

TABLE-US-00004 TABLE 2 Example No. 3 4 5 (wt. %) Slag d.sub.50 = 3.5 80 80 80 Alpha 15 Hemihydrate Dihydrate 15 Anhydrite 15 CSA clinker 5 5 5 Binder 25 25 25 Standard Sand 75 75 75 time Compressive Strength (MPa) 3 Hours 1.85 0 0.4 1 day 3 1.6 1.2 3 days 9.5 33 24 7 days 54 40 36 28 days 79 56 51 90 days 85 61 69

TABLE-US-00005 TABLE 3 Example No. 3 6 (wt. %) Slag (d.sub.50 = 3.5 ) 80 Slag (d.sub.50 = 13 ) 80 Alpha Hemihydrate 15 15 CSA clinker 5 5 Binder 25 25 Standard Sand 75 75 time Compressive Str. (MPa) 3 Hours 1.85 1.9 1 day 3.1 3.2 3 days 9.5 20.5 7 days 53.7 55.1 28 days 79 77.4 90 days 85.4 81.2

Example 7

[0121] A cementitious binder was prepared, containing 75% ground granulated blast furnace slag (d.sub.50=3.5 ) 15% alpha calcium sulfate hemihydrate, and 10% calcium sulfoaluminate cement. The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 189 grams water and 2.4 grams Melment F10.

[0122] Sets of test cubes were prepared, one set for measuring the compressive strength at 3 hours and at 24 hours, and two sets for evaluating the compressive strengths at 3, 7, 28 and 90 days.

Example 8

[0123] A cementitious binder was prepared, containing 70% ground granulated blast furnace slag (d.sub.50=3.5 ) 15% alpha calcium sulfate hemihydrate, and 15% calcium sulfoaluminate cement. The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 189 grams water and 2.4 grams Melment F10.

[0124] Sets of test cubes were prepared, one set for measuring the compressive strength at 3 hours and at 24 hours, and two sets for evaluating the compressive strengths at 3, 7, 28 and 90 days.

Example 9

[0125] A cementitious binder was prepared, containing 65% ground granulated blast furnace slag (d.sub.50=3.5 ) 15% alpha calcium sulfate hemihydrate, and 20% calcium sulfoaluminate cement. The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 189 grams water and 4.0 grams Melment F10.

[0126] Sets of test cubes were prepared, one set for measuring the compressive strength at 3 hours and at 24 hours, and two sets for evaluating the compressive strengths at 3, 7, 28 and 90 days.

[0127] Table 4 provides the compressive strength developed by Examples 3, and 7-9, as a function of time.

TABLE-US-00006 TABLE 4 Example No. 3 7 8 9 (wt. %) Slag (d.sub.50 = 3.5 ) 80 75 70 65 Calcium Sulfate 15 15 15 15 Hemihydrate CSA clinker 5 10 15 20 Binder 25 25 25 25 Standard Sand 75 75 75 75 time Compressive Strength (MPa) 3 hours 1.85 3.1 4.53 5.75 1 day 3.1 6 8.7 11.1 3 days 9.5 21.6 14.3 13.4 7 days 53.7 52.6 48.2 56.5 28 days 79 77.8 87.4 90.2 90 days 85.4 83.2 90.4 99.1

[0128] The FIGURE is a comparative bar graph plot showing, from left to right, the development of compressive strength of Examples 2 (a control sample containing 80% GGBFS), 3, 7, 8, and 9, as a function of time. Measurements of the compressive strength were taken at 3 hours, 1 day, 3 days, 7 days, 28 days (wet and dry) and 90 days (wet and dry).

Example 10

[0129] A cementitious binder was prepared, containing 75% ground granulated blast furnace slag (d.sub.50=3.5 ), 15% anhydrous calcium sulfate (anhydrite), and 10% calcium sulfoaluminate cement. The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 189 grams water and 5.0 grams Melment F10.

[0130] Sets of test cubes were prepared, one set for measuring the compressive strength at 3 hours and at 24 hours, and two sets for evaluating the compressive strengths at 3, 7, 28 and 90 days.

[0131] Table 5 provides the compressive strength developed by Example 10, as a function of time.

TABLE-US-00007 TABLE 5 Compressive Strength time (MPa) 3 hours 2.2 1 day 5.2 3 days 7 7 days 35 28 days 65 90 days 87

Example 11

[0132] A cementitious binder was prepared, containing 20% ground granulated blast furnace slag (d.sub.50=4.5 ) 60% fly ash type F, 15% alpha calcium sulfate hemihydrate, and 5% calcium sulfoaluminate clinker. The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 212 grams water.

[0133] The fly ash type F used in Example 11, and in Examples 12-17 below, had the following chemical composition:

TABLE-US-00008 CaO 2.98% SiO.sub.2 56.84% Al.sub.2O.sub.3 22.31% Fe.sub.2O.sub.3 7.44% MgO 1.74% TiO.sub.2 0.97% K.sub.2O 1.56% Na.sub.2O 1.23% P.sub.2O.sub.5 0.4% Mn.sub.2O.sub.3 0.06% SO.sub.3 0.52%

[0134] Test cubes were prepared for measuring the compressive strength at 3 hours and at 24 hours, and at 2, 7, 28 and 90 days.

[0135] Table 6 provides the compressive strength developed by Example 11, as a function of time.

Example 12

[0136] A cementitious binder was prepared, containing 40% ground granulated blast furnace slag (d.sub.50=4.5 ) 40% fly ash type F, 15% alpha calcium sulfate hemihydrate, and 5% calcium sulfoaluminate cement. The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 212 grams water.

[0137] Test cubes were prepared for measuring the compressive strength at 3 hours and at 24 hours, and at 2, 7, 28 and 90 days.

[0138] Table 6 provides the compressive strength developed by Example 12, as a function of time.

Example 13

[0139] A cementitious binder was prepared, containing 60% ground granulated blast furnace slag (d.sub.50=4.5 ) 20% fly ash type F, 15% alpha calcium sulfate hemihydrate, and 5% calcium sulfoaluminate cement. The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 212 grams water.

[0140] Test cubes were prepared for measuring the compressive strength at 3 hours and at 24 hours, and at 2, 7, 28 and 90 days.

[0141] Table 6 provides the compressive strength developed by Example 13, as a function of time.

Example 14

[0142] A cementitious binder was prepared, containing 65% fly ash type F, 15% alpha calcium sulfate hemihydrate, and 20% calcium sulfoaluminate cement. The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 212 grams water.

[0143] Test cubes were prepared for measuring the compressive strength at 3 hours and at 24 hours, and at 2, 7, 28 and 90 days.

[0144] Table 7 provides the compressive strength developed by Example 14, as a function of time.

TABLE-US-00009 TABLE 6 Example No. 11 12 13 (wt. %) Slag (d.sub.50 = 4.5 ) 20 40 60 Fly Ash type F 60 40 20 Alpha Hemihydrate 15 15 15 CSA clinker 5 5 5 Binder 25 25 25 Standard Sand 75 75 75 time Compressive Strength (MPa) 3 hours 0.8 1 1.1 1 day 1.5 2 2.3 3 days 3.3 12.4 17.2 7 days 25.4 38.7 45.4 28 days 39.4 53.5 62.2

Example 15

[0145] A cementitious binder was prepared, containing 15% ground granulated blast furnace slag (d.sub.50=4.5 ), 50% Fly Ash type F, 15% alpha calcium sulfate hemihydrate, and 20% calcium sulfoaluminate cement. The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 212 grams water.

[0146] Test cubes were prepared for measuring the compressive strength at 3 hours and at 24 hours, and at 2, 7, 28 and 90 days.

[0147] Table 7 provides the compressive strength developed by Example 15, as a function of time.

Example 16

[0148] A cementitious binder was prepared, containing 30% ground granulated blast furnace slag (d.sub.50=4.5 ), 35% Fly Ash type F, 15% alpha calcium sulfate hemihydrate, and 20% calcium sulfoaluminate cement. The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 212 grams water.

[0149] Test cubes were prepared for measuring the compressive strength at 3 hours and at 24 hours, and at 2, 7, 28 and 90 days.

[0150] Table 7 provides the compressive strength developed by Example 16, as a function of time.

Example 17

[0151] A cementitious binder was prepared, containing 50% ground granulated blast furnace slag (d.sub.50=4.5 ), 15% Fly Ash type F, 15% alpha calcium sulfate hemihydrate, and 20% calcium sulfoaluminate cement. The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 212 grams water.

[0152] Test cubes were prepared for measuring the compressive strength at 3 hours and at 24 hours, and at 2, 7, 28 and 90 days.

[0153] Table 7 provides the compressive strength developed by Example 17, as a function of time.

TABLE-US-00010 TABLE 7 Example No. 14 15 16 17 (wt. %) Slag (d.sub.50 = 4.5 ) 15 30 50 Fly Ash type F 65 50 35 15 Alpha Hemihydrate 15 15 15 15 CSA clinker 20 20 20 20 Binder 25 25 25 25 Standard Sand 75 75 75 75 time Compressive Strength (MPa) 3 hours 2.5 2.3 2.6 2.9 1 day 5.3 5.6 6.2 6.6 3 days 7.1 10.1 16.6 20.4 7 days 18.8 32.6 46.3 53.3 28 days 27.7 49.4 60.5 70.2

Example 18

[0154] A cementitious binder was prepared, containing 32.5% ground granulated blast furnace slag (d.sub.50=5 ), 32.5% Fly Ash type F, 15% anhydrous calcium sulfate (anhydrite), and 20% calcium sulfoaluminate cement. The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 216 grams water.

[0155] The slag used had the following chemical composition, based on a standard XRF characterization:

TABLE-US-00011 CaO 42.0% SiO.sub.2 32.2% Al.sub.2O.sub.3 14.2% Fe.sub.2O.sub.3 0.6% MgO 6.5% TiO.sub.2 0.5% K.sub.2O 0.29% Na.sub.2O 0.16% P.sub.2O.sub.5 0.00% Mn.sub.2O.sub.3 0.29% SO.sub.3 1.8%

[0156] Test cubes were prepared for measuring the compressive strength at 3 hours and at 24 hours, and at 2, 7, 28 and 90 days.

[0157] Table 8 provides the compressive strength developed by Example 18, as a function of time.

Example 19

[0158] A cementitious binder was prepared, containing 40% ground granulated blast furnace slag (d.sub.50=5 ), 40% Fly Ash type F, 15% anhydrous calcium sulfate (anhydrite), and 5% calcium sulfoaluminate cement. The binder, weighing 450 grams, was mixed with 1,350 grams of sand, as in Example 1, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 216 grams water.

[0159] The slag used had the following chemical composition, based on a standard XRF characterization:

TABLE-US-00012 CaO 41.2% SiO.sub.2 35.9% Al.sub.2O.sub.3 10.6% Fe.sub.2O.sub.3 0.6% MgO 7.7% TiO.sub.2 0.6% K.sub.2O 0.35% Na.sub.2O 0% P.sub.2O.sub.5 0.01% Mn.sub.2O.sub.3 0.42% SO.sub.3 1.5%

[0160] Test cubes were prepared for measuring the compressive strength at 3 hours and at 24 hours, and at 2, 7, 28 and 90 days.

[0161] Table 8 provides the compressive strength developed by Example 19, as a function of time.

Example 20

[0162] A cementitious binder was prepared, containing 75% ground granulated blast furnace slag (d.sub.50=3.6 ), 10% anhydrous calcium sulfate (anhydrite) and 15% of a calcium sulfoaluminate cement or clinker (Alipre #1, Italy) having the following mineralogical composition: 18% belite, 60% Ye'elimite, and 9% of a calcium sulfate. Thus, the ratio of CSA to belite in this CSA clinker was about 3.3:1.

[0163] The content of CaO, SiO.sub.2, Al.sub.2O.sub.3, and SO.sub.3 in the composition is provided in Table 9 hereinbelow. Also provided are the concentrations of these components in the other CSA clinkers referenced herein.

TABLE-US-00013 TABLE 8 Example No. 18 19 (wt. %) Slag (d.sub.50 = 4.5 ) 32.5 40 Fly Ash type F 32.5 40 Anhydrite 15 15 CSA clinker 20 5 Binder 25 25 Standard Sand 75 75 time Compressive Strength (MPa) 3 hours 1.81 0.39 1 day 4.63 1.46 3 days 16.26 9.91 7 days 46 27.03 28 days 59.4 37.08

TABLE-US-00014 TABLE 9 Chemical composition CaO SiO.sub.2 Al.sub.2O.sub.3 SO.sub.3 CSA clinkerExample 3 49.08 14.18 16.27 14.07 CSA clinkerExample 20 39-43 7.5 31-43 12.5-17.5 CSA Binder-III (Tangshan Polar Bear 41.65 6.95 34.52 8.46 Building Materials Co., LTD., China)

[0164] Thus, the concentration of CSA within the cementitious binder was about 2.7% (15%18%). The binder, weighing 900 grams, was mixed with 2,700 grams of sand, to produce a mixture containing 25% binder and 75% sand. To the mixture were added 378 grams water and 5 grams Melment F10.

[0165] Test cubes were prepared for measuring the compressive strength at 3 hours and at 24 hours, and at 2, 7, 28 and 90 days.

[0166] Table 10 provides the compressive strength developed by Example 20, as a function of time.

Examples 21-22

[0167] Example 20 was repeated, with 0.28 grams and 0.87 grams of citric acid being added in Example 21 and Example 22, respectively.

[0168] Test cubes were prepared for measuring the compressive strength at 3 hours and at 24 hours, and at 2, 7, 28 and 90 days.

[0169] The compressive strength developed by Examples 21 and 22, as a function of time, are provided in Table 10.

TABLE-US-00015 TABLE 10 Example No. 20 21 22 (wt. %) fine Italian slag 75 75 75 (D50 = 3.6 m) Anhydrite 10 10 10 CSA (Alipre #1) 15 15 15 F10 MELMENT (g) 5 5 5 citric acid (g) 0 0.28 0.87 Water cc 378 378 378 water/cement ratio 0.42 0.42 0.42 time Compressive Strength-MPa 3 hours 3.1 1.95 0.94 1 day 7 4.3 9.13 3 days 10.5 8.3 14.1 7 days 15.07 11.77 19.42 28 days dry 28.8 36 44.1 90 days dry 53.6 65.8 63.6

[0170] In the specification and in the claims section that follows, the term ordinary Portland cement (OPC), when used in the general sense, is meant to refer to various Portland cements recognized by those of skill in the art to be considered Ordinary Portland Cement, and is specifically meant to include white ordinary Portland cement (WOPC).

[0171] As used herein in the specification and in the claims section that follows, the term calcium sulfoaluminate, or CSA, used as a complete expression, refers to the chemical species calcium sulfoaluminate. A predominant form of calcium sulfoaluminate may be represented by 3CaO.3Al.sub.2O.sub.3.CaSO.sub.4. The term calcium sulfoaluminate is meant to refer to both natural (e.g., ye'elimite) and synthetic calcium sulfoaluminates.

[0172] As used herein in the specification and in the claims section that follows, the term calcium sulfoaluminate cement, calcium sulfoaluminate clinker or abbreviations thereof (such as CSA clinker), refer to a cement or clinker containing the chemical species calcium sulfoaluminate.

[0173] As used herein in the specification and in the claims section that follows, the term material containing calcium sulfoaluminate, or material containing CSA, refers to a CSA clinker, a CSA-based ore containing ye'elimite, or to pure or substantially pure CSA.

[0174] As used herein in the specification and in the claims section that follows, the term percent, or %, refers to percent by weight, unless specifically indicated otherwise.

[0175] Similarly, the term ratio, as used herein in the specification and in the claims section that follows, refers to a weight ratio, unless specifically indicated otherwise.

[0176] It will be appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

[0177] Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.