Special mineral admixture concrete and preparation method thereof

Abstract

The invention belongs to the technical field of concrete, and particularly discloses special mineral admixture concrete and a preparation method thereof. The concrete comprises the following components in parts by mass: 40-60 parts of cement, 110-120 parts of coarse aggregate, 60-65 parts of fine aggregate, 20-30 parts of a special mineral admixture, 0.8-1.2 parts of a water reducing agent and 14-16 parts of water, the special mineral admixture comprises superfine limestone powder, fluorgypsum, slaked lime, fly ash, sodium acetate and triethanolamine. The superfine limestone powder is adopted to replace the fly ash, so that the problem of insufficient supply of high-quality fly ash at present is solved, and shrinkage and cracking of the concrete can be avoided; the added fluorgypsum, slaked lime, sodium acetate and the like are beneficial to improving the early strength of the concrete, and the defect that the early index of superfine limestone powder is relatively low is avoided; and meanwhile, the defect that the superfine limestone powder is easy to agglomerate and the pH value of the slurry can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of concrete, and in particular to a special mineral admixture concrete and a preparation method thereof. Background Art

[0002] Concrete is a composite material made of cementitious materials, aggregates, water and admixtures in a certain proportion. It has the characteristics of high compressive strength, good durability and strong plasticity, and is widely used in construction, civil engineering and other fields.

[0003] With the continuous progress and development of concrete technology, in addition to the above-mentioned components, concrete at this stage often contains a large amount of admixtures. The addition of admixtures can significantly improve the strength and durability of concrete, making it better resistant to erosion and damage from the external environment and extending the service life of buildings. The significance of this role has far exceeded the significance of environmental protection and cost reduction. Secondly, it can also adjust the working performance of concrete, such as improving its fluidity, cohesion and water retention, making concrete easier to construct and pour, and improving construction efficiency and quality. In addition, admixtures can also reduce the production cost of concrete to a certain extent, because it can replace part of the cement and reduce the consumption of raw materials. Adding admixtures is an economical, environmentally friendly and effective approach.

[0004] At present, the commonly used admixtures in concrete are mainly fly ash, silica fume and mineral powder. As the most common admixture in concrete, fly ash has many excellent properties, such as low price, moderate reaction rate, and can effectively improve the durability of concrete. It has the characteristics of universality. However, there are few manufacturers that can provide high-quality fly ash, resulting in insufficient supply of high-quality fly ash, and inferior fly ash is difficult to meet the requirements of concrete. Although silica fume can improve the early strength, impermeability and wear resistance of concrete, it requires a large amount of water and is generally mixed with other admixtures. In addition, the price of silica fume is relatively high, making it difficult to apply on a large scale. Mineral powder also has disadvantages such as easy cracking and carbonization, making it difficult to replace fly ash in concrete.

[0005] Therefore, how to provide a special mineral admixture concrete and a preparation method thereof, reduce the use of fly ash, and lower the preparation cost of concrete is a difficult problem that needs to be solved urgently in this field. Summary of the invention

[0006] In view of this, the present invention provides a special mineral admixture concrete and a preparation method thereof to solve the problem of insufficient supply of existing high-quality fly ash, as well as the problems of high price and poor performance of substitutes.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A special mineral admixture concrete comprises the following components in parts by weight: 40 to 60 parts of cement, 110 to 120 parts of coarse aggregate, 60 to 65 parts of fine aggregate, 20 to 30 parts of special mineral admixture, 0.8 to 1.2 parts of water reducing agent and 14 to 16 parts of water;

[0009] The special mineral admixtures include: ultra-fine limestone powder, fluorgypsum, slaked lime, fly ash, sodium acetate and triethanolamine.

[0010] Preferably, the mass ratio of ultrafine limestone powder, fluorgypsum, slaked lime, fly ash, sodium acetate and triethanolamine in the special mineral admixture is 10:2-4:1-2:0-2:0.05-0.5:0.05-0.5.

[0011] Preferably, the particle size of the ultrafine limestone powder is 100 nm to 5 μm.

[0012] Preferably, the cement includes one or more of ordinary Portland cement, aluminate cement and sulphoaluminate cement.

[0013] Preferably, the water reducer is a polycarboxylate water reducer.

[0014] Another object of the present invention is to provide a method for preparing special mineral admixture concrete, comprising the steps of mixing cement, coarse aggregate, fine aggregate, special mineral admixture, water reducer and water to obtain special mineral admixture concrete.

[0015] It can be seen from the above technical solutions that, compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The present invention discloses a concrete containing special mineral admixtures, wherein the special mineral admixtures contain ultrafine limestone powder, fluorgypsum, slaked lime, fly ash, sodium acetate, triethanolamine and other components. The present invention adopts ultrafine limestone powder to replace fly ash, thereby solving the problem of insufficient supply of high-quality fly ash. Moreover, the ultrafine limestone powder used in the present invention will not cause a violent hydration reaction of the mineral admixture due to its too small fineness, and has lower hydration heat and adiabatic temperature rise, and the temperature rise of concrete is gentle, which can avoid shrinkage and cracking of concrete.

[0017] 2. The present invention can effectively improve the defect of easy agglomeration of ultrafine limestone powder by adding fluorgypsum. In addition, fluorgypsum is also beneficial to improving the early strength of concrete and avoiding the defect of low early indicators of ultrafine limestone powder. Quicklime and sodium acetate can provide calcium ions and sodium ions, which are beneficial to the reaction to generate CaCO3, which is beneficial to the early strength and promotes the formation of early calcium aluminate; sodium ions have a promoting effect on the stimulation of mineral admixtures. In addition, quicklime is also beneficial to adjusting the pH value of concrete slurry and improving the disadvantage of ultrafine limestone powder that causes too low pH value. Sodium acetate and triethanolamine are also beneficial to the formation of early strength; the present invention can selectively add a small amount of fly ash to improve the comprehensive performance of concrete. DETAILED DESCRIPTION

[0018] The present invention provides a special mineral admixture concrete, comprising the following components in parts by weight: 40-60 parts of cement, 110-120 parts of coarse aggregate, 60-65 parts of fine aggregate, 20-30 parts of special mineral admixture, 0.8-1.2 parts of water reducer and 14-16 parts of water; under the above-mentioned mass proportion, the addition amount of cement can be specifically 42 parts, 45 parts, 48 ​​parts, 50 parts, 52 parts, 55 parts, 58 parts; the addition amount of coarse aggregate can be specifically 112 parts, 114 parts, 115 parts, 116 parts, 118 parts; the amount of fine aggregate added can be 61 parts, 62 parts, 63 parts, 64 parts; the amount of special mineral admixture added can be 22 parts, 24 parts, 25 parts, 26 parts, 28 parts; the amount of water reducer added can be 0.85 parts, 0.9 parts, 0.95 parts, 1 parts, 1.05 parts, 1.1 parts, 1.15 parts; the amount of water added can be 14.2 parts, 14.5 parts, 14.8 parts, 15 parts, 15.2 parts, 15.5 parts, 15.8 parts.

[0019] In the present invention, the special mineral admixtures include: ultrafine limestone powder, fluorgypsum, slaked lime, fly ash, sodium acetate and triethanolamine.

[0020] In the present invention, the mass ratio of ultrafine limestone powder, fluorgypsum, slaked lime, fly ash, sodium acetate and triethanolamine in the special mineral admixture is 10:2-4:1-2:0-2:0.05-0.5:0.05-0.5, preferably 10:2.2-3.8:1.2-1.8:0.5-1.5:0.1-0.4:0.1-0.4; further preferably 10:2.5-3.5:1.4-1.6:0.8-1.2:0.2-0.3:0.2-0.3, and further preferably 10:3:1.5:1:0.25:0.25.

[0021] In the present invention, the particle size of the ultrafine limestone powder is 100nm-5μm, specifically 200nm, 500nm, 1μm, 2μm, 3μm, 4μm.

[0022] In the present invention, the cement includes one or more of ordinary Portland cement, aluminate cement and sulphoaluminate cement.

[0023] In the present invention, the water reducer is a polycarboxylate water reducer.

[0024] In the present invention, the fly ash is primary fly ash.

[0025] In the present invention, the fluorspar is a byproduct of preparing hydrogen fluoride from sulfuric acid and fluorspar.

[0026] In the present invention, the coarse aggregate is preferably one or more of granite, diabase, basalt, and limestone, and the fine aggregate is preferably one or more of quartz sand, river sand, and garnet sand; the coarse aggregate is preferably a continuously graded aggregate with a particle size of 5 to 12 mm; the fine aggregate is preferably a continuously graded sand with a particle size of 0.075 to 4.75 mm.

[0027] The present invention also provides a method for preparing special mineral admixture concrete, comprising the following steps: mixing cement, coarse aggregate, fine aggregate, special mineral admixture, water reducing agent and water to obtain special mineral admixture concrete.

[0028] In the present invention, the preparation method is preferably to first mix cement, coarse aggregate, fine aggregate and part of water, and then mix with special mineral admixture, water reducing agent and the remaining part of water to obtain special mineral admixture concrete.

[0029] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the embodiment of the present invention, the particle size of fluorgypsum is 500nm-50μm, and the particle size of slaked lime is ≤1mm.

[0031] Example 1

[0032] 20 parts of ultrafine limestone powder ground to 100-1000 nm are ground and mixed with 8 parts of fluorgypsum, 4 parts of slaked lime, 2 parts of primary fly ash, 0.2 parts of sodium acetate and 0.6 parts of triethanolamine to obtain a special mineral admixture.

[0033] Take 50 parts of ordinary Portland cement, 112 parts of limestone coarse aggregate with a particle size of 5-12 mm and continuous grade, 62 parts of quartz sand fine aggregate with a particle size of 0.075-4.75 mm and continuous grade, and mix them with 25 parts of the above-mentioned special mineral admixture, 1 part of polycarboxylic acid water reducer and 7.5 parts of water, and then mix them with the special mineral admixture concrete through curing.

[0034] Example 2

[0035] 20 parts of ultrafine limestone powder ground to 500-1500 nm are ground and mixed with 6 parts of fluorgypsum, 3 parts of slaked lime, 0.8 parts of sodium acetate and 0.5 parts of triethanolamine to obtain a special mineral admixture.

[0036] Take 52 parts of ordinary Portland cement, 110 parts of limestone coarse aggregate with a particle size of 5-12 mm and continuous grade, 64 parts of river sand fine aggregate with a particle size of 0.075-4.75 mm and continuous grade, and mix them with 8 parts of water, and then mix them with the above-mentioned 22 parts of special mineral admixtures, 1 part of polycarboxylic acid water reducer and 7 parts of water, and cure to obtain special mineral admixture concrete.

[0037] Example 3

[0038] 20 parts of ultrafine limestone powder ground to 1-5 μm are ground and mixed with 4 parts of fluorgypsum, 3 parts of slaked lime, 1 part of primary fly ash, 0.6 parts of sodium acetate and 0.6 parts of triethanolamine to obtain a special mineral admixture.

[0039] Take 60 parts of ordinary Portland cement, 120 parts of basalt coarse aggregate with a particle size of 5-12 mm and continuous grade, 64 parts of quartz sand fine aggregate with a particle size of 0.075-4.75 mm and continuous grade, and mix them with 8 parts of water, and then mix them with the above-mentioned 28 parts of special mineral admixture, 1.2 parts of polycarboxylic acid water reducer and 8 parts of water, and cure to obtain special mineral admixture concrete.

[0040] Example 4

[0041] 20 parts of ultrafine limestone powder ground to 100 nm to 2 μm are ground and mixed with 5 parts of fluorgypsum, 2 parts of slaked lime, 4 parts of primary fly ash, 0.1 parts of sodium acetate and 0.8 parts of triethanolamine to obtain a special mineral admixture.

[0042] Take 45 parts of ordinary Portland cement, 112 parts of basalt coarse aggregate with a particle size of 5-12 mm and continuous grade, 60 parts of river sand fine aggregate with a particle size of 0.075-4.75 mm and continuous grade, and mix them with 7 parts of water, and then mix them with the above-mentioned 24 parts of special mineral admixture, 0.8 parts of polycarboxylic acid water reducer and 8 parts of water, and cure to obtain special mineral admixture concrete.

[0043] Comparative Example 1

[0044] The difference between this comparative example and Example 1 is that fluorgypsum and slaked lime are not added.

[0045] Comparative Example 2

[0046] The difference between this comparative example and Example 1 is only sodium acetate and triethanolamine.

[0047] Experimental Example 1

[0048] The admixtures and concrete prepared in Examples 1 to 4 were tested for relevant properties, and the test results are shown in Table 1. Activity index: JG / T486-2015; compressive strength: GB / T 7897-2008.

[0049] Table 1 Related test results

[0050]

[0051]

[0052] It can be seen from Table 1 that the admixture obtained by the present invention has a high early activity. At 7 days, the activity index can reach 84%, which is much higher than that of Comparative Examples 1 and 2, indicating that the components in the admixture disclosed by the present invention can significantly improve the early activity of the ultrafine limestone powder, making it higher than fly ash; the ultrafine limestone powder in the present invention can fill the gaps between cement particles, participate in cement hydration in the long term, and together with the hydration products, form a gel structure, which can achieve a large replacement of fly ash. Since the admixture obtained by the present invention has high early activity and high early compressive strength, it can form strength earlier. The 28d strength can reach about 56MPa, reflecting excellent performance, indicating that other components added to the admixture of the present invention except limestone powder are also conducive to improving strength. In addition, no obvious cracks were found in the test of the embodiment of the present invention, and it has excellent anti-cracking performance.

[0053] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0054] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A special mineral admixture concrete, characterized in that: The mixture comprises the following components in parts by weight: 40 to 60 parts of cement, 110 to 120 parts of coarse aggregate, 60 to 65 parts of fine aggregate, 20 to 30 parts of special mineral admixture, 0.8 to 1.2 parts of water reducing agent and 14 to 16 parts of water; The special mineral admixtures include: ultra-fine limestone powder, fluorgypsum, slaked lime, fly ash, sodium acetate and triethanolamine.

2. A special mineral admixture concrete according to claim 1, characterized in that: The mass ratio of ultrafine limestone powder, fluorgypsum, slaked lime, fly ash, sodium acetate and triethanolamine in the special mineral admixture is 10:2-4:1-2:0-2:0.05-0.5:0.05-0.

5.

3. A special mineral admixture concrete according to claim 2, characterized in that: The particle size of the ultrafine limestone powder is 100nm-5μm.

4. A special mineral admixture concrete according to any one of claims 1 to 3, characterized in that: The cement includes one or more of ordinary Portland cement, aluminate cement and sulphoaluminate cement.

5. A special mineral admixture concrete according to claim 4, characterized in that: The water reducer is a polycarboxylate water reducer.

6. The method for preparing a special mineral admixture concrete according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: mixing cement, coarse aggregate, fine aggregate, special mineral admixture, water reducing agent and water to obtain special mineral admixture concrete.

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