Ultralow-carbon clinker-free cement, method for preparing same and application of ultralow-carbon clinker-free cement

Abstract

The disclosure provides an ultralow-carbon clinker-free cement, prepared from the following raw materials: granulated blast-furnace slag, gypsum and calcium oxide-based materials. The granulated blast-furnace slag accounts for 65%-95% of the total weight of the raw materials, the gypsum accounts for 4.5%-34.5% of the total weight of the raw materials, and the balance is the calcium oxide-based material. A weight percentage of calcium oxide and/or calcium hydroxide in the total weight of the raw materials is controlled to be 0.05%-0.75%. The disclosure further provides a method for preparing the ultralow-carbon clinker-free cement and application of the ultralow-carbon clinker-free cement in the preparation of concrete, mortar or cement products. The ultralow-carbon clinker-free cement of the disclosure has the advantages of high early strength, ultrahigh long-term strength, low shrinkage, carbonation resistance, low carbon emissions, etc.

Claims

1. An ultralow-carbon clinker-free cement, prepared from the following raw materials in weight percentage: 79.47%-79.82% of granulated blast-furnace slag, 20% of gypsum and the balance of calcium oxide-based material; wherein a weight percentage of free calcium oxide in the total weight of the raw materials is 0.16%; and a specific surface area of the raw materials is 500 m.sup.2/kg; and the free calcium oxide is the component in the raw materials that are not combined with acidic oxides and exist in the form of free calcium oxide and/or calcium hydroxide.

2. An ultralow-carbon clinker-free cement, prepared from the following raw materials: granulated blast-furnace slag, gypsum, cement additives and a calcium oxide-based material; wherein the granulated blast-furnace slag accounts for 33%-94% of the total weight of the raw materials, the gypsum accounts for 19.5%-20% of the total weight of the raw materials, the cement additives accounts for 0.65%-32% of the total weight of the raw materials, and the balance is the calcium oxide-based material; and a weight percentage of free calcium oxide in the total weight of the raw materials is controlled to be 0.10%-0.5%; and the free calcium oxide is the component in the raw materials that are not combined with acidic oxides and exist in the form of free calcium oxide and calcium hydroxide.

3. The ultralow-carbon clinker-free cement according to claim 2, wherein the granulated blast-furnace slag accounts for 35%-90% of the total weight of the raw materials.

4. The ultralow-carbon clinker-free cement according to claim 2, wherein the granulated blast-furnace slag accounts for 47%-80% of the total weight of the raw materials.

5. The ultralow-carbon clinker-free cement according to claim 2, wherein the granulated blast-furnace slag accounts for 54%-80% of the total weight of the raw materials.

6. The ultralow-carbon clinker-free cement according to claim 2, wherein the cement additives accounts for 0.65%-25% of the total weight of the raw materials.

7. The ultralow-carbon clinker-free cement according to claim 2, wherein the cement additives accounts for 0.65%-5% of the total weight of the raw materials.

8. The ultralow-carbon clinker-free cement according to claim 2, wherein the cement additives accounts for 10%-20% of the total weight of the raw materials.

9. The ultralow-carbon clinker-free cement according to claim 2, wherein the weight percentage of the free calcium oxide in the total weight of the raw materials is controlled to be 0.16%-0.2%.

10. An ultralow-carbon clinker-free cement, prepared from the following raw materials in weight percentage: 54%-78% of granulated blast-furnace slag, 20% of gypsum, 0.65%-5% of cement additives and the balance of calcium oxide-based material; wherein a weight percentage of free calcium oxide in the total weight of the raw materials is controlled to be 0.15%-0.16%; and a specific surface area of the raw materials is 500 m.sup.2/kg; and the free calcium oxide is the component in the raw materials that are not combined with acidic oxides and exist in the form of free calcium oxide and/or calcium hydroxide.

11. An ultralow-carbon clinker-free cement, prepared from the following raw materials in weight percentage: 54%-68% of granulated blast-furnace slag, 20% of gypsum, 10%-20% of cement additives and the balance of calcium oxide-based material; wherein a weight percentage of free calcium oxide in the total weight of the raw materials is controlled to be 0.15%-0.16%; and a specific surface area of the raw materials is 500 m.sup.2/kg; and the free calcium oxide is the component in the raw materials that are not combined with acidic oxides and exist in the form of free calcium oxide and/or calcium hydroxide.

12. An ultralow-carbon clinker-free cement, prepared from the following raw materials: granulated blast-furnace slag, gypsum, a set controlling and accelerating component and a calcium oxide-based material; wherein the granulated blast-furnace slag accounts for 63%-94% of the total weight of the raw materials, the gypsum accounts for 20% of the total weight of the raw materials, the set controlling and accelerating component accounts for 0.9%-1.95% of the total weight of the raw materials, and the balance is the calcium oxide-based material; and a weight percentage of free calcium oxide in the total weight of the raw materials is controlled to be 0.10%-0.5%; and the free calcium oxide is the component in the raw materials that are not combined with acidic oxides and exist in the form of free calcium oxide and calcium hydroxide.

13. The ultralow-carbon clinker-free cement according to claim 12, wherein the granulated blast-furnace slag accounts for 65%-90% of the total weight of the raw materials.

14. The ultralow-carbon clinker-free cement according to claim 12, wherein the granulated blast-furnace slag accounts for 77.5%-79% of the total weight of the raw materials.

15. The ultralow-carbon clinker-free cement according to claim 12, wherein the set controlling and accelerating component accounts for 1%-1.5% of the total weight of the raw materials.

16. The ultralow-carbon clinker-free cement according to claim 12, wherein the weight percentage of the free calcium oxide in the total weight of the raw materials is controlled to be 0.16%-0.2%.

17. An ultralow-carbon clinker-free cement, prepared from the following raw materials: granulated blast-furnace slag, gypsum, cement additives, a set controlling and accelerating component and a calcium oxide-based material; wherein the granulated blast-furnace slag accounts for 60%-61% of the total weight of the raw materials, the gypsum accounts for 19.5%-20% of the total weight of the raw materials, the cement additives accounts for 15%-18% of the total weight of the raw materials, and the set controlling and accelerating component accounts for 0.9%1.95%1%-1.2% of the total weight of the raw materials; and a weight percentage of free calcium oxide in the total weight of the raw materials is controlled to be 0.10%-0.5%; and the free calcium oxide is the component in the raw materials that are not combined with acidic oxides and exist in the form of free calcium oxide and calcium hydroxide.

18. The ultralow-carbon clinker-free cement according to claim 17, wherein the weight percentage of the free calcium oxide in the total weight of the raw materials is controlled to be 0.16%-0.2%.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 a comparison diagram of DTA curves of hydration products of a cement of Application Example 1 and a cement of Comparative Example 2 after curing for 28 days.

DETAILED DESCRIPTION OF EMBODIMENTS

(2) The disclosure provides an ultralow-carbon clinker-free cement, prepared from the following raw materials: granulated blast-furnace slag, gypsum and a calcium oxide-based material. A weight percentage of free calcium oxide in the total weight of the obtained cement raw materials is controlled to be 0.05%-0.75%. Preferably, the weight percentage of the free calcium oxide in the total weight of the obtained cement raw materials is controlled to be 0.05%-0.7%, more preferably 0.05%-0.6%, more preferably 0.05%-0.5%, further preferably 0.10%-0.5%, most preferably 0.16%-0.2%. Further preferably, a percentage of the granulated blast-furnace slag in the total weight of the raw materials may be 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94% or 95%. Further preferably, a percentage of the gypsum in the total weight of the raw materials may be 4.5%, 5.0%, 8%, 10%, 12.5%, 15%, 18%, 20%, 22.5%, 25%, 27.5%, 30%, 32% or 34.5%. Further preferably, the content of the free calcium oxide in the total weight of the obtained cement raw materials is 0.05%, 0.08%, 0.1%, 0.12%, 0.16%, 0.18%, 0.25%, 0.28%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7% or 0.75%.

(3) The disclosure provides another ultralow-carbon clinker-free cement, prepared from the following raw materials: granulated blast-furnace slag, gypsum, cement additivesand acalcium oxide-based material. A weight percentage of free calcium oxide in the total weight of the obtained cement raw materials is 0.05%-0.75%. Preferably, the weight percentage of the free calcium oxide in the total weight of the obtained cement raw materials is 0.05%-0.7%, more preferably 0.05%-0.6%, more preferably 0.05%-0.5%, further preferably 0.10%-0.5%, most preferably 0.16%-0.2%. Further preferably, a percentage of the granulated blast-furnace slag in the total weight of the raw materials may be 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93% or 94%. Further preferably, a percentage of the gypsum in the total weight of the raw materials may be 4.5%, 5.0%, 8%, 10%, 12.5%, 15%, 18%, 20%, 22.5%, 25%, 27.5%, 30%, 32% or 34.5%. Further preferably, a percentage of the cement additives in the total weight of the raw materials may be 0.65%, 1.5%, 5.5%, 7.5%, 10.5%, 12.5%, 15.5%, 17.5%, 20.5%, 22.5%, 25.5%, 27.5%, 30.5% or 32%. Further preferably, the content of the free calcium oxide in the total weight of the obtained cement raw materials is 0.05%, 0.08%, 0.1%, 0.12%, 0.16%, 0.18%, 0.25%, 0.28%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7% or 0.75%.

(4) The disclosure provides still another ultralow-carbon clinker-free cement, prepared from the following raw materials: granulated blast-furnace slag, gypsum, a set controlling and accelerating component and a calcium oxide-based material. A weight percentage of free calcium oxide in the total weight of the obtained cement raw materials is 0.05%-0.75%. Preferably, the weight percentage of the free calcium oxide in the total weight of the obtained cement raw materials is 0.05%-0.7%, more preferably 0.05%-0.6%, more preferably 0.05%-0.5%, further preferably 0.10%-0.5%, most preferably 0.16%-0.2%. Further preferably, a percentage of the granulated blast-furnace slag in the total weight of the raw materials may be 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94% or 95%. Further preferably, a percentage of the gypsum in the total weight of the raw materials may be 4.5%, 5.0%, 8%, 10%, 12.5%, 15%, 18%, 20%, 22.5%, 25%, 27.5%, 30%, 32% or 34.5%. Further preferably, a percentage of the set controlling and accelerating component in the total weight of the raw materials may be 0.9%, 1.0%, 1.2%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9% or 1.95%. Further preferably, the weight percentage of the free calcium oxide in the total weight of the obtained cement raw materials is 0.05%, 0.08%, 0.1%, 0.12%, 0.16%, 0.18%, 0.25%, 0.28%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7% or 0.75%.

(5) The disclosure provides yet another ultralow-carbon clinker-free cement, prepared from the following raw materials: granulated blast-furnace slag, gypsum, cement additives, a set controlling and accelerating component and a calcium oxide-based material. A weight percentage of free calcium oxide in the total weight of the obtained cement raw materials is 0.05%-0.75%. Preferably, the weight percentage of the free calcium oxide in the total weight of the obtained cement raw materials is 0.05%-0.7%, more preferably 0.05%-0.6%, more preferably 0.05%-0.5%, further preferably 0.10%-0.5%, most preferably 0.16%-0.2%. Further preferably, a percentage of the granulated blast-furnace slag in the total weight of the raw materials may be 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93% or 94%. Further preferably, a percentage of the gypsum in the total weight of the raw materials may be 4.5%, 5.0%, 8%, 10%, 12.5%, 15%, 18%, 20%, 22.5%, 25%, 27.5%, 30%, 32% or 34.5%. Further preferably, a percentage of the cement additives in the total weight of the raw materials may be 0.65%, 1.5%, 5.5%, 7.5%, 10.5%, 12.5%, 15.5%, 17.5%, 20.5%, 22.5%, 25.5%, 27.5%, 30.5% or 32%. Further preferably, a percentage of the set controlling and accelerating component in the total weight of the raw materials may be 0.9%, 1.0%, 1.2%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9% or 1.95%. Further preferably, the content of the free calcium oxide in the total weight of the obtained cement raw materials is 0.05%, 0.08%, 0.1%, 0.12%, 0.16%, 0.18%, 0.25%, 0.28%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7% or 0.75%.

(6) In the ultralow-carbon clinker-free cement provided by the disclosure, the gypsum is any one or a combination of at least two of natural dihydrate gypsum, natural anhydrite, hemihydrate gypsum, a high-strength gypsum, desulfurized gypsum, phosphogypsum or fluorogypsum. Preferably, the gypsum is any one or a combination of at least two of natural dihydrate gypsum, natural anhydrite, hemihydrate gypsum and desulfurized gypsum.

(7) In the ultralow-carbon clinker-free cement provided by the disclosure, the calcium oxide-based material is a material mainly composed of free calcium oxide and containing 30%-80% of the free calcium oxide. For example, the content of the free calcium oxide may be ?30%, ?35%,?40%, ?45%,?50%, ?55%, ?60%, ?65%, ?70%, ?75% or ?80%. The free calcium oxide is a general term of components in the raw materials that are not combined with acidic oxides and exist in the form of free calcium oxide and/or calcium hydroxide. The content of free calcium oxide can be measured by the test method specified in Chinese Standard GB/T 176-2017. Preferably, the calcium oxide-based material is any one or a combination of at least two of quicklime, slaked lime, industrial calcium oxide, industrial calcium hydroxide, carbide slag, a calcium oxide expansive agent and an ettringite expansive agent. More preferably, the calcium oxide-based material is any one or a combination of at least two of quicklime, slaked lime and carbide slag.

(8) In the solution of the disclosure, the cement additivesis any one or a combination of at least two of fly ash, steel slag, limestone, dolomite, a pozzolanic admixture or sandstone. The introduction of the cement additives can further reduce carbon emissions of the cement of the disclosure.

(9) In the solution of the disclosure, the set controlling and accelerating component is any one or a combination of at least two selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, lithium sulfate, sodium sulfate potassium sulfate, aluminum sulfate, lithium carbonate, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, sodium silicate, lithium chloride, citric acid, sodium citrate or sodium gluconate. Preferably, the set controlling and accelerating component is any one or a combination of at least two selected from the group consisting of lithium hydroxide, sodium hydroxide, lithium sulfate, sodium sulfate, aluminum sulfate, lithium carbonate, citric acid, sodium citrate or sodium gluconate.

(10) The solutions and technical effects of the disclosure will be further explained by way of enumeration of examples below, but the solutions of the disclosure is not limited to the enumerated examples.

Example 1 to Example 11

(11) An ultralow-carbon clinker-free cement, as shown in Table 1 below, was prepared from the following raw materials in weight percentage: 78.75%-79.94% of granulated blast-furnace slag, 20% of natural dihydrate gypsum and the balance of quicklime. A content of CaO in the quicklime was 80%.

(12) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials, as shown in Table 1 below, were proportionally mixed, ground to a specific surface area of 500 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement. A weight percentage of free calcium oxide was controlled to be 0.05%-1.00%.

(13) TABLE-US-00001 TABLE 1 Weight percentage Specific of free Mix proportion of raw material (%) surface calcium Granulated area oxide blast- Natural after in raw Example furnace dihydrate grinding materials No. slag gypsum Quicklime (m.sup.2/kg) (%) 1 79.94 20.00 0.06 500 0.05 2 79.88 20.00 0.13 500 0.10 3 79.80 20.00 0.20 500 0.16 4 79.75 20.00 0.25 500 0.20 5 79.69 20.00 0.31 500 0.25 6 79.63 20.00 0.38 500 0.30 7 79.50 20.00 0.50 500 0.40 8 79.38 20.00 0.63 500 0.50 9 79.25 20.00 0.75 500 0.60 10 79.12 20.00 0.88 500 0.70 11 79.06 20.00 0.94 500 0.75

Example 12 to Example 20

(14) An ultralow-carbon clinker-free cement, as shown in Table 2 below, was prepared from the following raw materials in weight percentage: 65.30%-95.30% of granulated blast-furnace slag, 4.50%-34.50% of natural dihydrate gypsum and 0.2% of quicklime. A content of CaO in the quicklime was 80%.

(15) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials, as shown in Table 2 below, were proportionally mixed, ground to a specific surface area of 500 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement. A weight percentage of free calcium oxide was controlled to be 0.16%.

(16) TABLE-US-00002 TABLE 2 Weight percentage Specific of free Mix proportion of raw material (%) surface calcium Granulated area oxide blast- Natural after in raw Example furnace dihydrate grinding materials No. slag gypsum Quicklime (m.sup.2/kg) (%) 12 65.30 34.50 0.20 500 0.16 13 68.30 31.50 0.20 500 0.16 14 70.30 29.50 0.20 500 0.16 15 74.80 25.00 0.20 500 0.16 3 79.80 20.00 0.20 500 0.16 16 84.80 15.00 0.20 500 0.16 17 90.00 9.80 0.20 500 0.16 18 92.30 7.50 0.20 500 0.16 19 95.00 4.80 0.20 500 0.16 20 95.30 4.50 0.20 500 0.16

Example 21 to Example 25

(17) An ultralow-carbon clinker-free cement, as shown in Table 3 below, was prepared from the following raw materials in weight percentage: 79.80% of granulated blast-furnace slag, 20.00% of natural dihydrate gypsum and 0.20% of quicklime. A content of CaO in the quicklime was 80%.

(18) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials were proportionally mixed, ground to a specific surface area of 200-1200 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement. A weight percentage of free calcium oxide was controlled to be 0.16%.

(19) TABLE-US-00003 TABLE 3 Weight percentage Specific of free Mix proportion of raw material (%) surface calcium Granulated area oxide blast- Natural after in raw Example furnace dihydrate grinding materials No. slag gypsum Quicklime (m.sup.2/kg) (%) 21 79.80 20.00 0.20 200 0.16 22 79.80 20.00 0.20 300 0.16 3 79.80 20.00 0.20 500 0.16 23 79.80 20.00 0.20 700 0.16 24 79.80 20.00 0.20 1000 0.16 25 79.80 20.00 0.20 1200 0.16

Example 26 to Example 32

(20) An ultralow-carbon clinker-free cement, as shown in Table 4 below, was prepared from the following raw materials in weight percentage: 79.20%-79.82% of granulated blast-furnace slag, 20.00% of natural dihydrate gypsum and the balance of quicklime or slaked lime. A content of CaO in the quicklime was 20%-90%.

(21) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials were proportionally mixed, ground to a specific surface area of 500 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement. A weight percentage of free calcium oxide was controlled to be 0.16%.

(22) TABLE-US-00004 TABLE 4 Mix proportion of raw material (%) Content of Specific Weight Source of calcium oxide CaO in surface percentage of Granulated Natural and/or calcium calcium area after free calcium Example blast-furnace dihydrate hydroxide oxide-based grinding oxide in raw No. slag gypsum Quicklime Slaked lime material (m.sup.2/kg) materials (%) 26 79.82 20.00 0.18 90% 500 0.16 3 79.80 20.00 0.20 80% 500 0.16 27 79.77 20.00 0.23 70% 500 0.16 28 79.73 20.00 0.27 60% 500 0.16 29 79.68 20.00 0.32 50% 500 0.16 30 79.60 20.00 0.40 40% 500 0.16 31 79.47 20.00 0.53 30% 500 0.16 32 79.77 20.00 0.23 70% 500 0.16

Example 33 to Example 41

(23) An ultralow-carbon clinker-free cement, as shown in Table 5 below, was prepared from the following raw materials in weight percentage: 47.80%-79.15% of granulated blast-furnace slag, 20% of natural dihydrate gypsum, 0.65%-32% of fly ash and 0.20% of quicklime. A content of CaO in the quicklime was 80%.

(24) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials were proportionally mixed, ground to a specific surface area of 500 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement. A weight percentage of free calcium oxide was controlled to be 0.16%.

(25) TABLE-US-00005 TABLE 5 Mix proportion of raw material (%) Specific Granulated Natural surface area Weight percentage of Example blast-furnace dihydrate after grinding free calcium oxide in No. slag gypsum Fly ash Quicklime (m.sup.2/kg) raw materials (%) 33 79.15 20 0.65 0.20 500 0.16 34 74.80 20 5 0.20 500 0.16 35 69.80 20 10 0.20 500 0.16 36 64.80 20 15 0.20 500 0.16 37 61.80 20 18 0.20 500 0.16 38 59.80 20 20 0.20 500 0.16 39 54.80 20 25 0.20 500 0.16 40 49.80 20 30 0.20 500 0.16 41 47.80 20 32 0.20 500 0.16

Example 42 to Example 50

(26) An ultralow-carbon clinker-free cement, as shown in Table 6 below, was prepared from the following raw materials in weight percentage: 47.80%-79.15% of granulated blast-furnace slag, 20% of natural dihydrate gypsum, 0.65%-32% of limestone powder and 0.20% of quicklime. A content of CaO in the quicklime was 80%.

(27) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials were proportionally mixed, ground to a specific surface area of 500 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement. A weight percentage of free calcium oxide was controlled to be 0.16%.

(28) TABLE-US-00006 TABLE 6 Mix proportion of raw material (%) Specific Granulated Natural surface area Weight percentage of Example blast-furnace dihydrate Limestone after grinding free calcium oxide in No. slag gypsum powder Quicklime (m.sup.2/kg) raw materials (%) 42 79.15 20 0.65 0.20 500 0.16 43 74.80 20 5 0.20 500 0.16 44 69.80 20 10 0.20 500 0.16 45 64.80 20 15 0.20 500 0.16 46 61.80 20 18 0.20 500 0.16 47 59.80 20 20 0.20 500 0.16 48 54.80 20 25 0.20 500 0.16 49 49.80 20 30 0.20 500 0.16 50 47.80 20 32 0.20 500 0.16

Example 51 to Example 55

(29) An ultralow-carbon clinker-free cement, as shown in Table 7 below, was prepared from the following raw materials in weight percentage: 61.80% of granulated blast-furnace slag, 20% of natural dihydrate gypsum, 2%-16% of fly ash, 2%-16% of limestone powder and 0.20% of quicklime. A content of CaO in the quicklime was 80%.

(30) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials were proportionally mixed, ground to a specific surface area of 500 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement. A weight percentage of free calcium oxide was controlled to be 0.16%.

(31) TABLE-US-00007 TABLE 7 Mix proportion of raw material (%) Specific Weight percentage Granulated Natural Cement additives surface area of free calcium Example blast-furnace dihydrate Limestone after grinding oxide in raw No. slag gypsum Fly ash powder Quicklime (m.sup.2/kg) materials (%) 51 61.80 20 2 16 0.2 500 0.16 52 61.80 20 6 12 0.2 500 0.16 53 61.80 20 9 9 0.2 500 0.16 54 61.80 20 12 6 0.2 500 0.16 55 61.80 20 16 2 0.2 500 0.16

Example 56 to Example 76

(32) An ultralow-carbon clinker-free cement, as shown in Table 8 below, was prepared from the following raw materials in weight percentage: 77.85%-79.80% of granulated blast-furnace slag, 20% of natural dihydrate gypsum, 0.9%-1.95% of set controlling and accelerating component and 0.20% of quicklime. A content of CaO in the quicklime was 80%.

(33) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials were proportionally mixed, ground to a specific surface area of 500 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement. A weight percentage of free calcium oxide was controlled to be 0.16%.

(34) TABLE-US-00008 TABLE 8 Mix proportion of raw material (%) Granulated blast- Natural Set controlling and accelerating component Example furnace dihydrate Sodium Lithium Aluminum Lithium Lithium Sodium No. slag gypsum hydroxide carbonate sulfate hydroxide sulfate sulfate 56 78.9 20 0.9 57 78.8 20 1 58 78.6 20 1.2 59 78.4 20 1.4 60 78.3 20 1.5 61 78 20 1.8 62 77.85 20 63 78.9 20 64 78.8 20 65 78.6 20 66 78.4 20 0.7 0.7 67 77.9 20 0.7 1.2 68 78 20 0.9 0.9 69 77.85 20 0.95 1 70 78.9 20 71 78.8 20 72 78.6 20 0.4 0.4 0.4 73 78.4 20 1 0.2 0.2 74 78.3 20 75 78 20 76 77.85 20 1 Weight percentage Specific of free surface calcium Mix proportion of raw material (%) area oxide Set controlling and accelerating component after in raw Example Potassium Citric Sodium Sodium grinding materials No. carbonate acid citrate gluconate Quicklime (m.sup.2/kg) (%) 56 0.20 500 0.16 57 0.20 500 0.16 58 0.20 500 0.16 59 0.20 500 0.16 60 0.20 500 0.16 61 0.20 500 0.16 62 1.95 0.20 500 0.16 63 0.9 0.20 500 0.16 64 1 0.20 500 0.16 65 1.2 0.20 500 0.16 66 0.20 500 0.16 67 0.20 500 0.16 68 0.20 500 0.16 69 0.20 500 0.16 70 0.4 0.5 0.20 500 0.16 71 0.5 0.5 0.20 500 0.16 72 0.20 500 0.16 73 0.20 500 0.16 74 0.5 1 0.20 500 0.16 75 1 0.8 0.20 500 0.16 76 0.95 0.20 500 0.16

Example 77 to Example 80

(35) An ultralow-carbon clinker-free cement, as shown in Table 9 below, was prepared from the following raw materials in weight percentage: 60.60% of granulated blast-furnace slag, 20% of natural dihydrate gypsum, 18% of admixture, 1.2% of set controlling and accelerating component and 0.20% of quicklime. A content of CaO in the quicklime was 80%.

(36) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials were proportionally mixed, ground to a specific surface area of 500 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement. A weight percentage of free calcium oxide was controlled to be 0.16%.

(37) TABLE-US-00009 TABLE 9 Weight percentage Mix proportion of raw material (%) Specific of free Set controlling and surface calcium Cement accelerating area oxide in Granulated Natural additives component after raw Example blast-furnace dihydrate Fly Limestone Lithium Aluminum grinding materials No. slag gypsum ash powder carbonate sulfate Quicklime (m.sup.2/kg) (%) 77 60.60 20 18 0 1.2 0 0.20 500 0.16 78 60.60 20 18 0 0.6 0.6 0.20 500 0.16 79 60.60 20 9 9 1.2 0 0.20 500 0.16 80 60.60 20 9 9 0.6 0.6 0.20 500 0.16

Application Examples 1 to 11

(38) The ultralow-carbon clinker-free cement of Example 1 to Example 11 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 10:

(39) TABLE-US-00010 TABLE 10 Application Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 1 11.0 40.6 81.2 3.3 10.2 13.8 2 16.0 45.2 83.5 4.8 11.3 14.2 3 20.2 55.3 85.5 6.1 13.8 14.5 4 22.0 53.6 83.8 6.6 13.4 14.2 5 24.1 52.5 82.1 7.2 13.1 14.0 6 26.5 51.4 80.4 8.0 12.9 13.7 7 27.4 50.3 78.7 8.2 12.6 13.4 8 25.2 49.8 71.1 7.6 12.4 13.2 9 23.6 47.7 68.5 7.1 11.9 13.0 10 20.7 47.4 65.1 6.2 11.9 12.4 11 18.8 47.0 61.6 5.6 11.8 12.3

(40) As shown in Table 10 above, in the ultralow-carbon clinker-free cement of Examples 1 to 11 of the disclosure, no Portland cement clinker was added, a proper amount of quicklime rich in free calcium oxide was directly added as the activator, and the total calcium oxide in the total amount of the raw materials was controlled within a certain range (0.05%-0.75%), so that the finally obtained cement had very excellent early strength and long-term strength. After being molded and cured for 1 day, the cement of the above examples could have a compressive strength of 11-27.4 MPa and a flexural strength of 3.3-8.2 MPa. After 3 days, the compressive strength could be above 40 MPa, and the flexural strength could be above 10 MPa. This indicated that by directly adding the quicklime containing the free calcium oxide capable of hydration reaction, proper amounts of Ca.sup.2+ and OH-were quickly released, and the quicklime quickly reacted with water, so that the granulated blast-furnace slag was quickly activated, making the cement have higher strength at the early stage. Besides, after being molded and cured for 28 days, the cement of the above examples could have a compressive strength of up to 60-85 MPa and a flexural strength of up to 12-14 MPa, indicating an ultrahigh long-term strength.

Application Examples 12 to 20

(41) The ultralow-carbon clinker-free cement of Example 12 to Example 20 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 11:

(42) TABLE-US-00011 TABLE 11 Application Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 12 15.1 40.7 61.8 4.7 10.8 11.3 13 15.8 43.1 66.7 5.5 12.4 13.1 14 16.2 44.2 68.4 4.8 11.1 11.6 15 18.2 49.8 77.0 5.5 12.4 13.1 3 20.2 55.3 85.5 6.1 13.8 14.5 16 19.2 52.5 81.2 5.8 13.1 13.8 17 18.4 49.6 77.5 5.5 12.4 13.2 18 17.2 44.5 68.9 5.2 11.1 11.7 19 16.8 43.0 65.7 5.0 10.8 11.2 20 16.3 41.5 64.7 4.9 10.4 11.0

(43) As shown in Table 11 above, the gypsum in the ultralow-carbon clinker-free cement of Examples 12 to 20 of the disclosure accounted for 4.5%-34.5% of the total weight of the raw materials, and its 1-day, 3-day and 28-day strengths increased first and then decreased with the increase of the content of the gypsum, and was optimal when the content of the gypsum was within the range of 15%-20%. Within this range, the cement had high early strength and ultrahigh long-term strength. This indicated that as long as the content of the gypsum in the raw materials was controlled at a proper level, it could bring desired early strength and long-term strength to the cement.

Application Examples 21 to 25

(44) The ultralow-carbon clinker-free cement of Example 21 to Example 25 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 12:

(45) TABLE-US-00012 TABLE 12 Application Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 21 17.5 40.3 80.1 5.3 10.1 13.6 22 18.8 48.2 85.3 5.6 12.1 14.5 3 20.2 55.3 85.5 6.1 13.8 14.5 23 22.3 56.6 85.0 6.7 14.2 14.6 24 23.9 57.0 84.8 7.2 14.3 14.5 25 25.9 56.7 80.3 7.8 14.2 14.4

(46) As shown in Table 12 above, the ultralow-carbon clinker-free cement of Examples 21 to 25 of the disclosure also had high early strength and ultrahigh long-term strength. This indicated that as long as the content of the free calcium oxide in the raw materials was controlled at a proper level, it could bring desired early strength and long-term strength to the cement. The grinding degree of the raw materials within a certain range could also affect the properties of the cement. Increasing the grinding degree of the raw materials may improve the activity of the raw materials, increase the hydration reaction speed, and significantly improve the early strength of the cement. However, when the fineness was too high, the early reaction speed was too high, resulting in a slight decrease in the long-term strength.

Application Examples 26 to 32

(47) The ultralow-carbon clinker-free cement of Example 26 to Example 32 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 13:

(48) TABLE-US-00013 TABLE 13 Application Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 26 21.7 56.9 85.0 6.5 14.2 14.5 3 20.2 55.3 85.5 6.1 13.8 14.5 27 20.0 54.7 84.6 6.0 13.7 14.4 28 19.8 54.2 84.8 5.9 13.5 14.4 29 19.6 53.7 84.0 5.9 13.4 14.3 30 19.4 53.1 84.2 5.8 13.3 14.3 31 19.0 52.6 84.3 5.7 13.1 14.3 32 21.3 56.2 84.5 6.4 14.1 14.4

(49) As shown in Table 13 above, the ultralow-carbon clinker-free cement of Examples 26 to 32 of the disclosure also had high early strength and ultrahigh long-term strength. This indicated that as long as the content of the free calcium oxide in the raw materials was controlled at a proper level, it could bring desired early strength and long-term strength to the cement. The purity and type of the calcium oxide-based material could vary according to the actual situation.

Application Examples 33 to 41

(50) The ultralow-carbon clinker-free cement of Example 33 to Example 41 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 14:

(51) TABLE-US-00014 TABLE 14 Application Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 33 19.2 52.5 81.2 5.8 13.1 13.8 34 18.2 49.8 77.0 5.5 12.4 13.1 35 17.2 47.0 72.7 5.2 11.8 12.4 36 16.8 45.9 71.0 5.0 11.5 12.1 37 16.2 44.2 76.4 4.8 11.1 13.0 38 15.8 43.1 66.7 4.7 10.8 12.0 39 15.4 42.0 65.0 4.6 10.5 11.7 40 15.2 41.5 64.1 4.5 10.4 11.5 41 14.1 38.7 59.9 4.2 9.7 11.2

Application Examples 42 to 49

(52) The ultralow-carbon clinker-free cement of Example 42 to Example 49 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 15:

(53) TABLE-US-00015 TABLE 15 Application Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 42 20.8 56.5 83.8 6.2 13.0 14.5 43 21.1 56.8 80.4 6.3 12.7 14.2 44 21.5 57.0 77.0 6.5 12.5 14.0 45 22.0 57.2 75.2 6.6 12.3 13.8 46 22.2 58.1 71.8 6.7 12.2 13.7 47 21.2 57.7 71.0 6.4 12.0 13.3 48 20.2 56.9 70.1 6.1 11.9 12.9 49 18.9 55.1 67.5 5.7 11.5 12.7 50 17.5 53.1 61.6 5.3 10.5 12.3

Application Examples 51 to 55

(54) The ultralow-carbon clinker-free cement of Example 51 to Example 55 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 16:

(55) TABLE-US-00016 TABLE 16 Application Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 51 21.6 57.1 80.1 6.5 13.6 14.3 52 20.3 56.6 78.2 6.1 13.3 14.2 53 19.3 55.1 77.2 5.8 13.1 13.8 54 19 50 76.8 5.7 12.5 13.1 55 18.6 46.9 75.1 5.6 11.7 12.8

(56) As shown in Tables 13 to 16 above, the ultralow-carbon clinker-free cement of Examples 26 to 54 of the disclosure also had high early strength and ultrahigh long-term strength. This indicated that as long as the content of the free calcium oxide in the raw materials was controlled at a proper level, it could bring desired early strength and long-term strength to the cement. A certain amount of cement additives could also be added to the raw materials to further reduce the carbon emissions of the cement of the disclosure.

Application Examples 56 to 76

(57) The ultralow-carbon clinker-free cement of Examples 56 to 76 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 17:

(58) TABLE-US-00017 TABLE 17 Application Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 56 30.20 56.20 85.30 9.06 14.05 14.50 57 29.10 58.30 85.00 8.73 14.58 14.45 58 26.10 60.60 84.70 10.50 17.97 18.90 59 31.20 60.10 80.20 9.36 15.03 13.63 60 28.70 53.33 80.47 8.61 13.33 13.68 61 25.10 51.51 79.62 7.53 12.88 13.54 62 28.90 50.30 76.30 8.67 12.57 12.97 63 20.10 57.40 91.60 6.03 14.35 15.11 64 19.90 58.10 92.30 5.97 14.53 15.23 65 20.50 59.60 93.20 6.15 14.90 15.38 66 31.70 59.00 80.60 9.51 14.75 14.70 67 30.50 58.29 81.20 10.20 17.70 19.19 68 32.10 58.90 83.88 9.63 13.80 14.26 69 31.60 60.70 79.50 9.48 13.10 14.20 70 31.20 62.10 92.50 9.20 14.10 14.70 71 20.10 56.40 94.30 7.50 14.50 15.00 72 34.60 60.10 87.10 9.15 18.66 19.98 73 32.10 59.20 85.10 8.70 14.20 15.20 74 33.40 58.60 92.00 8.90 13.70 15.00 75 20.10 60.10 91.90 6.60 13.50 15.80 76 27.90 54.00 91.00 7.80 13.20 15.10

Application Examples 77 to 80

(59) The ultralow-carbon clinker-free cement of Examples 77 to 80 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 18:

(60) TABLE-US-00018 TABLE 18 Application Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 77 18.2 50.2 74.4 5.4 11.6 12.6 78 18.8 55.2 82.0 7.1 15.1 16.4 79 21.5 52.1 80.1 6.5 13.0 13.6 80 22.1 54.2 83.1 7.2 15.0 16.8

(61) As shown in Tables 17 to 18 above, the ultralow-carbon clinker-free cement of Examples 56 to 80 of the disclosure also had high early strength and ultrahigh long-term strength. This indicated that as long as the content of the free calcium oxide in the raw materials was controlled at a proper level, it could bring desired early strength and long-term strength to the cement. A certain amount of cement additives could also be added to the raw materials to further reduce the carbon emissions of the cement of the disclosure, and a certain amount of set controlling and accelerating component could also be added to the raw materials to further increase the early strength of the cement.

(62) In the process of proposing the disclosure, the inventors not only obtained the desired ultralow-carbon clinker-free cement through the experiments of the above examples, but also verified the degradation of the properties of the cement caused by raw materials in other mix proportions through a larger number of experiments. Only representative comparative examples are selected below for illustration:

Comparative Example 1

(63) An ultralow-carbon clinker-free cement, as shown in Table 19 below, was prepared from the following raw materials in weight percentage: 80% of granulated blast-furnace slag and 20% of natural dihydrate gypsum.

(64) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials were proportionally mixed, ground to a specific surface area of 500 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement.

(65) TABLE-US-00019 TABLE 19 Weight percentage Specific of free Mix proportion of raw material (%) surface calcium Granulated area oxide blast- Natural after in raw Comparative furnace dihydrate grinding materials Example No. slag gypsum Quicklime (m.sup.2/kg) (%) 1 80 20 0 500 0

Comparative Example 2

(66) An ultralow-carbon clinker-free cement, as shown in Table 20 below, was prepared from the following raw materials in weight percentage: 77.50% of granulated blast-furnace slag, 20% of natural dihydrate gypsum and 2.5% of quicklime. A content of CaO in the quicklime was 80%.

(67) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials were proportionally mixed, ground to a specific surface area of 500 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement. A weight percentage of free calcium oxide was controlled to be 2%.

(68) TABLE-US-00020 TABLE 20 Weight percentage Specific of free Mix proportion of raw material (%) surface calcium Granulated area oxide blast- Natural after in raw Comparative furnace dihydrate grinding materials Example No. slag gypsum Quicklime (m.sup.2/kg) (%) 2 77.50 20 2.50 500 2

Comparative Example 3

(69) An ultralow-carbon clinker-free cement, as shown in Table 21 below, was prepared from the following raw materials in weight percentage: 59.80% of granulated blast-furnace slag, 40% of natural dihydrate gypsum and 0.2% of quicklime. A content of CaO in the quicklime was 80%.

(70) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials were proportionally mixed, ground to a specific surface area of 500 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement. A weight percentage of free calcium oxide was controlled to be 0.16%.

(71) TABLE-US-00021 TABLE 21 Weight percentage Specific of free Mix proportion of raw material (%) surface calcium Granulated area oxide blast- Natural after in raw Comparative furnace dihydrate grinding materials Example No. slag gypsum Quicklime (m.sup.2/kg) (%) 3 59.80 40.00 0.20 500 0.16

Comparative Example 4

(72) An ultralow-carbon clinker-free cement, as shown in Table 22 below, was prepared from the following raw materials in weight percentage: 96.80% of granulated blast-furnace slag, 3% of natural dihydrate gypsum and 0.2% of quicklime. A content of CaO in the quicklime was 80%.

(73) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials were proportionally mixed, ground to a specific surface area of 500 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement. A weight percentage of free calcium oxide was controlled to be 0.16%.

(74) TABLE-US-00022 TABLE 22 Weight percentage Specific of free Mix proportion of raw material (%) surface calcium Granulated area oxide blast- Natural after in raw Comparative furnace dihydrate grinding materials Example No. slag gypsum Quicklime (m.sup.2/kg) (%) 4 96.80 3 0.20 500 0.16

Comparative Example 5

(75) An ultralow-carbon clinker-free cement, as shown in Table 23 below, was prepared from the following raw materials in weight percentage: 79.80% of granulated blast-furnace slag, 20% of natural dihydrate gypsum and 0.2% of quicklime. A content of CaO in the quicklime was 80%.

(76) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials were proportionally mixed, ground to a specific surface area of 100 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement. A weight percentage of free calcium oxide was controlled to be 0.16%.

(77) TABLE-US-00023 TABLE 23 Weight percentage Specific of free Mix proportion of raw material (%) surface calcium Granulated area oxide blast- Natural after in raw Comparative furnace dihydrate grinding materials Example No. slag gypsum Quicklime (m.sup.2/kg) (%) 6 79.80 20 0.20 1400 0.16

Comparative Example 6

(78) An ultralow-carbon clinker-free cement, as shown in Table 24 below, was prepared from the following raw materials in weight percentage: 79.80% of granulated blast-furnace slag, 20% of natural dihydrate gypsum and 0.2% of quicklime. A content of CaO in the quicklime was 80%.

(79) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials were proportionally mixed, ground to a specific surface area of 1400 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement. A weight percentage of free calcium oxide was controlled to be 0.16%.

(80) TABLE-US-00024 TABLE 24 Weight percentage Specific of free Mix proportion of raw material (%) surface calcium Granulated area oxide blast- Natural after in raw Comparative furnace dihydrate grinding materials Example No. slag gypsum Quicklime (m.sup.2/kg) (%) 5 79.80 20 0.20 100 0.16

Comparative Example 7

(81) An ultralow-carbon clinker-free cement, as shown in Table 25 below, was prepared from the following raw materials in weight percentage: 39.80% of granulated blast-furnace slag, 20% of natural dihydrate gypsum, 40% of fly ash and 0.2% of quicklime. A content of CaO in the quicklime was 80%.

(82) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials were proportionally mixed, ground to a specific surface area of 500 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement. A weight percentage of free calcium oxide was controlled to be 0.16%.

(83) TABLE-US-00025 TABLE 25 Mix proportion of raw material (%) Specific Weight percentage Granulated Natural Cement additives surface area of free calcium Comparative blast-furnace dihydrate Fly Limestone after grinding oxide in raw Example No. slag gypsum ash powder Quicklime (m.sup.2/kg) materials (%) 7 39.80 20 40 0 0.2 500 0.16

Comparative Example 8

(84) An ultralow-carbon clinker-free cement, as shown in Table 26 below, was prepared from the following raw materials in weight percentage: 76.80% of granulated blast-furnace slag, 20% of natural dihydrate gypsum, 3% of Sodium hydroxide and 0.2% of quicklime. A content of CaO in the quicklime was 80%.

(85) A method for preparing the ultralow-carbon clinker-free cement included: all the raw materials were proportionally mixed, ground to a specific surface area of 500 m.sup.2/kg, and mixed uniformly, thereby obtaining the ultralow-carbon clinker-free cement. A weight percentage of free calcium oxide was controlled to be 0.16%.

(86) TABLE-US-00026 TABLE 26 Mix proportion of raw material (%) Set controlling Specific Weight percentage Granulated Natural and accelerating surface area of free calcium Comparative blast-furnace dihydrate component after grinding oxide in raw Example No. slag gypsum Sodium hydroxide Quicklime (m.sup.2/kg) materials (%) 8 76.80 20 3 0.2 500 0.16

Application Comparative Example 1

(87) The ultralow-carbon clinker-free cement of Comparative Example 1 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 28:

(88) TABLE-US-00027 TABLE 28 Application Comparative Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 1 0.0 5.6 11.7 0.0 1.4 2.0

(89) In the ultralow-carbon clinker-free cement in this application comparative example, due to the lack of the calcium oxide alkaline activator in the raw materials, the granulated blast-furnace slag was not activated, and the cement had almost no strength at the stage and extremely poor long-term strength.

Application Comparative Example 2

(90) The ultralow-carbon clinker-free cement of Comparative Example 2 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 29:

(91) TABLE-US-00028 TABLE 29 Application Comparative Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 2 14.1 33.2 34.2 4.2 8.3 8.0

(92) In this application comparative example, the ultralow-carbon clinker-free cement of Comparative Example 2 was used. The addition of excessive quicklime to the raw materials made too much calcium oxide involved in the hydration reaction. On the one hand, the excessive calcium oxide caused too much alkali in the pore solution, which hindered the formation of ettringite, resulting in the reduction of ettringite production and strength of the system (by comparing DTA curves of hydration products in the hardened cements of Application Example 1 and this application comparative example of the disclosure after curing for 28 days, the inventors found that the peak height of ettringite in this application comparative example was obviously lower than that in Application Example 1, indicating that the ettringite production in this application comparative example was obviously less than that in Application Example 1; the comparison of the DTA curves of the hydration products is shown in FIG. 1). On the other hand, the excessive free calcium oxide may react with the alumina gel and the ettringite to generate monosulfate type calcium sulfoaluminate hydrate that was low in strength, easily carbonated and less resistant to corrosion. Moreover, this reaction may cause a reduction in the volume of the product, resulting in a loose hardened body with increased porosity. This reaction may also consume the alumina gel capable of gelling, resulting in an insufficient amount of colloidal in the system to bond other substances. Thus, the strength of the cement was significantly reduced, and the generated monosulfate type calcium sulfoaluminate hydrate was easily carbonated, making the cement easily carbonated and corroded. The finally obtained cement was significantly improved as compared with the cement of Application Comparative Example 1, but had worse early strength and long-term strength as compared with the cement of the application examples of the disclosure.

Application Comparative Example 3

(93) The ultralow-carbon clinker-free cement of Comparative Example 3 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 30:

(94) TABLE-US-00029 TABLE 30 Application Comparative Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 3 8.2 25.3 36.1 2.5 6.3 6.1

(95) In this application comparative example, the amount of the granulated blast-furnace slag added to the ultralow-carbon clinker-free cement was too low, and relatively, the amount of the gypsum added was too high, which led to the surplus of gypsum exhibiting large-size rod-shaped crystals in the system, resulting in the looseness or even cracking of the system. Therefore, the obtained cement could not gain desired early strength and long-term strength.

Application Comparative Example 4

(96) The ultralow-carbon clinker-free cement of Comparative Example 4 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 31:

(97) TABLE-US-00030 TABLE 31 Application Comparative Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 4 8.1 22.1 34.2 2.4 5.5 5.8

(98) In this application comparative example, the amount of the granulated blast-furnace slag added to the ultralow-carbon clinker-free cement was too high, and the amount of the gypsum raw material added was too low, which led to the reduction in reactants required for producing ettringite, resulting in the reduction in the main hydration product, i.e., ettringite. Therefore, the obtained cement could not gain desired early strength and long-term strength.

Application Comparative Example 5

(99) The ultralow-carbon clinker-free cement of Comparative Example 5 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 32:

(100) TABLE-US-00031 TABLE 32 Application Comparative Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 5 2.5 35.0 75.8 0.8 8.8 12.9

(101) In this application comparative example, the raw materials of the ultralow-carbon clinker-free cement were not ground sufficiently, making it difficult for the gypsum and the quicklime to quickly break the vitreous structure of the slag and activate the slag. Therefore, the obtained cement could not gain desired early strength and long-term strength.

Application Comparative Example 6

(102) The ultralow-carbon clinker-free cement of Comparative Example 6 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 33:

(103) TABLE-US-00032 TABLE 33 Application Comparative Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 6 20.6 50.1 70.6 6.2 13.5 13.5

(104) In this application comparative example, the raw materials of the ultralow-carbon clinker-free cement was ground excessively, which made the treatment cost high and the production of the hydration product such as ettringite too fast, resulting in more pores and lower compactness inside the hardened cement. Therefore, the obtained cement could not gain desired early strength and long-term strength.

Application Comparative Example 7

(105) The ultralow-carbon clinker-free cement of Comparative Example 7 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 34:

(106) TABLE-US-00033 TABLE 34 Application Comparative Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 7 9.1 25.1 35.2 2.7 6.3 6.0

(107) In this application comparative example, the amount of the fly ash with low activity in the raw materials of the ultralow-carbon clinker-free cement was too high, and the content of the slag with higher activity was relatively low. Therefore, the obtained cement could not gain desired early strength and long-term strength.

Application Comparative Example 8

(108) The ultralow-carbon clinker-free cement of Comparative Example 8 and water were mixed in a water-to-binder ratio of 0.4 according to Chapter 7.2 in GB 1346 to prepare a neat paste. The net paste was molded according to Chapter 7 in GB/T 17671, cured to 1 day, 3 days and 28 days according to Chapter 8 in GB/T 17671, and tested for its compressive strength and flexural strength according to Chapter 9 in GB/T 17671. The test results are shown in Table 35:

(109) TABLE-US-00034 TABLE 35 Application Comparative Compressive strength (MPa) Flexural strength (MPa) Example No. 1 d 3 d 28 d 1 d 3 d 28 d 8 14.80 43.20 37.94 4.50 9.80 8.20

(110) In this application comparative example, the amount of the set controlling and accelerating component sodium hydroxide added in the raw materials of the ultralow-carbon clinker-free cement was too high, which caused a high preparation cost and too much alkali in the system due to the excessive sodium hydroxide, hindering the formation of the main hydration product, i.e., ettringite. Therefore, the obtained cement could not gain desired early strength and long-term strength.