MODIFIED DOLOMITE POWDER, PREPARATION METHOD THEREOF AND CONCRETE

Abstract

The invention provides a modified dolomite powder, a preparation method thereof, and a concrete. The modified dolomite powder is prepared from 98% to 99% of a dolomite powder, 0.2% to 0.5% of a chaotropic agent, 0.6% to 1.0% of a dihydrogen phosphate, and 0.2% to 0.5% of a capillary filler according to the mass percentage. The chaotropic agent is one or more of sodium sulfate, potassium sulfate, and ammonium sulfate. By promoting the dissolution of the surface of the dolomite powder, participating in the hydration reaction, and filling capillary pores, the triple modification solves the problems of bleeding, strength, and durability of the dolomite powder concrete in the related art. The obtained modified dolomite powder has good solubility and high chemical activity, and the prepared concrete has high strength and compactness, low porosity, and good durability.

Claims

1. A modified dolomite powder, prepared from 98% to 99% of a dolomite powder, 0.2% to 0.5% of a chaotropic agent, 0.6% to 1.0% of a dihydrogen phosphate, and 0.2% to 0.5% of a capillary filler according to the mass percentage, wherein the chaotropic agent is one or more of sodium sulfate, potassium sulfate, and ammonium sulfate.

2. The modified dolomite powder according to claim 1, wherein a particle size of the dolomite powder is 300 mesh to 600 mesh.

3. The modified dolomite powder according to claim 2, wherein the particle size of the dolomite powder is 600 mesh.

4. The modified dolomite powder according to claim 1, wherein the dihydrogen phosphate is one or more of ammonium dihydrogen phosphate, potassium dihydrogen phosphate, and sodium dihydrogen phosphate.

5. The modified dolomite powder according to claim 1, wherein the capillary filler is one or more of polyaluminum sulfate, polyferric sulfate, and polyaluminum-ferric sulfate.

6. The modified dolomite powder according to claim 1, wherein a mass ratio of the chaotropic agent, the dihydrogen phosphate, and the capillary filler is 2:6:2.

7. A preparation method of the modified dolomite powder according to claim 1, comprising: (1) weighing a dolomite powder, a chaotropic agent, a dihydrogen phosphate, and a capillary filler according to a proportioning ratio; (2) dissolving the chaotropic agent in water into a chaotropic agent diluent; (3) spraying the chaotropic agent diluent while stirring the dolomite powder, so that the chaotropic agent is evenly dispersed among the dolomite powder; and (4) adding the dihydrogen phosphate and the capillary filler, and mixing thoroughly to obtain the modified dolomite powder.

8. The preparation method according to claim 7, wherein a mass concentration of the chaotropic agent diluent is 5% to 10%.

9. A concrete, comprising the modified dolomite powder according to claim 1, wherein an added amount of the modified dolomite powder is 15% to 30% of a cementing material.

Description

DESCRIPTION OF THE EMBODIMENTS

[0035] In order to facilitate understanding of the disclosure, the disclosure will be described more comprehensively below together with specific embodiments. However, the disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosed content of the disclosure more thorough and comprehensive.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by a person having ordinary skill in the art to which this disclosure belongs. The terms used herein in the description of the disclosure are for the purpose of describing specific embodiments only, and are not intended to limit the disclosure.

[0037] A preparation method of modified dolomite powder in the following examples and comparative examples is provided as follows: [0038] (1) According to the proportioning ratios in Table 1 below, dolomite powder, a chaotropic agent, dihydrogen phosphate, and a capillary filler are weighed. [0039] (2) The chaotropic agent is dissolved in water into a chaotropic agent diluent with a mass concentration of 5% to 10%. [0040] (3) While stirring the dolomite powder, the chaotropic agent diluent is sprayed, so that the chaotropic agent is evenly dispersed among dolomite powder. [0041] (4) The dihydrogen phosphate and the capillary filler are then added and fully mixed to obtain the modified dolomite powder.

[0042] Class II fly ash is used as Comparative Example 1.

TABLE-US-00001 TABLE 1 Raw material components and proportioning ratios of modified dolomite powder in Examples 1 to 6 and Comparative Examples 1 to 5 Dolomite Powder Class Chao- 600 500 400 300 II Fly tropic Dihydrogen Capillary No. mesh mesh mesh mesh Ash Agent Phosphate Filler Comparative — — — — 100% — — — Example 1 Comparative  100% — — — — — — — Example 2   Comparative   99% — — — —   1% — — Example 3   Comparative   97% — — — — —   3% — Example 4   Comparative   99% — — — — — —   1% Example 5 Example 1   98% — — — — 0.5% 1.0% 0.5% Example 2 98.5% — — — — 0.3% 0.9% 0.3% Example 3   99% — — — — 0.2% 0.6% 0.2% Example 4 — 99% — — — 0.2% 0.6% 0.2% Example 5 — — 99% — — 0.2% 0.6% 0.2% Example 6 — — — 99% — 0.2% 0.6% 0.2%

[0043] The components and proportioning ratios of the concrete are listed in Table 2.

TABLE-US-00002 TABLE 2 Mixing ratios of concrete components (in kg) Modified Class Medium Stones with Water- Portland Dolomite II Fly Coarse Particle Size of reducing No. Cement Powder Ash River Sand 5 to 31.5 mm Admixture Water Mix 359 — 79 747 1032 4.35 162 Ratio 1 Mix 372  66 — 747 1032 4.35 162 Ratio 2 Mix 359  79 — 747 1032 4.35 162 Ratio 3 Mix 329 109 — 747 1032 4.35 162 Ratio 4 Mix 307 131 — 747 1032 4.35 162 Ratio 5

[0044] The concrete obtained above is tested according to GB/T 50082-2009 “Standard for test methods of long-term performance and durability of ordinary concrete” for the working performance, mechanical performance, and durability performance of each group of concrete specimens.

[0045] The composition of the Class II fly ash in Mix Ratio 1 is Comparative Example 1 in Table 1, the composition of the modified dolomite powder in Mix Ratio 3 is Examples 1 to 6 and Comparative Examples 2 to 5 in Table 1, and the performance test results are shown in Table 3.

TABLE-US-00003 TABLE 3 Concrete performance test results II Class Fly Ash Normal 28d or Modified Pressure Compressive Electric Dolomite Bleeding Strength Flux No. Powder Rate (%) (MPa) (C) Concrete 1 Comparative 0 46 1469 Example 1 Concrete 2 Comparative 32 33.7 875 Example 2 Concrete 3 Comparative 10 37.5 903 Example 3 Concrete 4 Comparative 29 39.9 1026 Example 4 Concrete 5 Comparative 22 36.8 960 Example 5 Concrete 6 Example 1 0 42.3 1347 Concrete 7 Example 2 0 43.8 1432 Concrete 8 Example 3 0 45.6 1458 Concrete 9 Example 4 0 43.1 1335 Concrete 10 Example 5 0 42.5 1289 Concrete 11 Example 6 0 41.2 1246

[0046] The modified dolomite powder prepared in Example 3 is prepared according to the Mix Ratios of 2 to 5 in Table 2, and the performance test results are shown in Table 4.

TABLE-US-00004 TABLE 4 Performance test results of the concrete prepared from the modified dolomite powder in Example 3 Normal Pressure 28d Electric Bleeding Rate Compressive Flux No. Formulation (%) Strength (MPa) (C) Concrete 12 Mix Ratio 2 0 47.2 1433 Concrete 13 Mix Ratio 3 0 45.6 1458 Concrete 14 Mix Ratio 4 0 42.0 1367 Concrete 15 Mix Ratio 5 0 40.9 1312

[0047] According to the test results in Table 3 and Table 4, it can be seen that the normal pressure bleeding rate of Concrete 2 prepared from the dolomite powder alone is 32%, which is higher than the specification requirement, and the 28d compressive strength and electric flux are also obviously low. With the addition of the modified dolomite powder, the performance indexes of the concrete are significantly optimized. Herein, the performance indexes of Concrete 6 to Concrete 8 made by adding the modified dolomite powder made of 600-mesh dolomite powder are basically comparable to those of Concrete 1 mixed with Class II fly ash alone. Further, the working performance, mechanical performance, and durability performance of Concrete 6 to Concrete 8 are good. Therefore, the modified dolomite powder in the disclosure can be used to replace Class II fly ash as a raw material for concrete. The costs of the chaotropic agent, dihydrogen phosphate, and capillary filler are low and the production process is simple, so the total costs of the modified dolomite powder are lower than the price of Class II fly ash. As such, the production costs of concrete can be greatly reduced, and comparable performance is provided.

[0048] In contrast, the performance of the obtained Concrete 3 to Concrete 5 prepared from the dolomite powder modified by a single modifier in Comparative Example 3 to Comparative Example 5 is obviously worse than that of the Concrete 6 to Concrete 8. Therefore, the modification of the dolomite powder by the chaotropic agent, dihydrogen phosphate, and capillary filler can significantly improve the working performance, mechanical performance, and durability of the concrete.

[0049] The technical features of the above-described embodiments may be combined arbitrarily. In order to simplify the description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combinations of these technical features, these combinations should be considered to be within the scope of the description in this specification.

[0050] The abovementioned embodiments only represent several embodiments of the disclosure, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for a person having ordinary skill in the art, without departing from the concept of the disclosure, several modifications and improvements can be made, which all belong to the protection scope of the disclosure. Therefore, the protection scope of the patent of the disclosure should be subject to the appended claims.