CN106938896B

CN106938896B - Concrete expanding agent and preparation method and application thereof

Info

Publication number: CN106938896B
Application number: CN201710194230.XA
Authority: CN
Inventors: 武建华; 辛红芳; 王志国; 李永明; 杜景超; 武娟; 崔迎; 李智; 秦飞鹏; 穆乃亮
Original assignee: Cccc First Harbor Engineering Transportation Engineering Co ltd; CCCC First Harbor Engineering Co Ltd
Current assignee: Cccc First Harbor Engineering Transportation Engineering Co ltd; CCCC First Harbor Engineering Co Ltd
Priority date: 2017-03-28
Filing date: 2017-03-28
Publication date: 2020-05-15
Anticipated expiration: 2037-03-28
Also published as: CN106938896A

Abstract

The invention discloses a concrete expanding agent and a preparation method and application thereof, relating to the technical field of concrete, and the concrete expanding agent comprises the following raw materials in parts by weight: 6-8 parts of clay, 15-20 parts of sulfur trioxide, 26-32 parts of volcanic ash, 22-30 parts of wollastonite powder and 35-45 parts of gypsum. Through detection, the product has better adaptability to concrete strength and compensation shrinkage effect than similar products, and has better waterproof and anti-permeability effects.

Description

Concrete expanding agent and preparation method and application thereof

Technical Field

The invention relates to the technical field of concrete, in particular to a concrete expanding agent and a preparation method and application thereof.

Background

The cracks of the building are mainly caused by the drying shrinkage and temperature deformation of the concrete, the concrete can generate chemical reaction to generate crystalline compounds in the initial stage of setting and the hydration process, the volume shrinkage of the concrete can be caused because the crystalline compounds are smaller than the volume of raw materials, and the concrete cracks can be generated when the tensile stress generated by the shrinkage is larger than the tensile strength limit of a concrete member. Therefore, the shrinkage-compensating concrete is the most effective and economic technical way for solving the concrete cracking. The expanding agent for concrete is a main additive for preparing shrinkage-compensating concrete, and is widely used for self-waterproofing of underground concrete structures, seamless construction of overlong structures and large-volume concrete crack control due to excellent shrinkage-compensating performance of the expanding agent. The concrete expanding agent generates micro expansion when the concrete begins to shrink or before the concrete begins to shrink, and applies compressive stress to the concrete member to offset, weaken or balance the tensile stress caused by the shrinkage, so that the aims of minimizing the structural internal stress, preventing cracks and avoiding cracks are fulfilled.

Most of the expanding agents in the current market are ettringite expanding agents prepared by calcined kaolin, alunite, dickite, aluminum slag, calcium aluminate clinker or calcium sulphoaluminate clinker and gypsum, and have the disadvantages of low expansion energy, mismatched expansion rate with the hydration reaction rate of concrete condensation nuclei, large mixing amount, high alkali content, easy alkali-aggregate reaction and the like; the calcium oxide expanding agent taking CaO as a main component has the defects of over-high expansion speed, short expansion time, incongruity of expansion and concrete shrinkage rate, difficult storage and the like; the magnesium oxide expanding agent with MgO as the main component has the defects of too low expansion speed, too long expansion starting time behind the concrete shrinkage starting time, incapability of playing a role in cracking resistance and the like. The existing expanding agent can not meet the requirement of the concrete expansion performance in construction, and the concrete expanding agent with better performance needs to be developed.

Disclosure of Invention

In view of the above, the invention provides a concrete expanding agent which has good shrinkage compensation effect, can adapt to the strength of concrete and has waterproof and anti-permeability effects, and a preparation method and application thereof.

In order to achieve the above object, the present invention provides the following technical solutions:

a concrete expanding agent comprises the following raw materials in parts by weight: 6-8 parts of clay, 15-20 parts of sulfur trioxide, 26-32 parts of volcanic ash, 22-30 parts of wollastonite powder and 35-45 parts of gypsum.

The invention also has the following additional technical features:

preferably, the feed comprises the following raw materials in parts by weight: 7 parts of clay, 17 parts of sulfur trioxide, 30 parts of volcanic ash, 26 parts of wollastonite powder and 39 parts of gypsum.

Preferably, the feed comprises the following raw materials in parts by weight: 6 parts of clay, 18 parts of sulfur trioxide, 29 parts of volcanic ash, 29 parts of wollastonite powder and 36 parts of gypsum.

Preferably, the feed comprises the following raw materials in parts by weight: 7 parts of clay, 20 parts of sulfur trioxide, 26 parts of volcanic ash, 22 parts of wollastonite powder and 45 parts of gypsum.

Preferably, the feed comprises the following raw materials in parts by weight: 8 parts of clay, 19 parts of sulfur trioxide, 32 parts of volcanic ash, 24 parts of wollastonite powder and 40 parts of gypsum.

Preferably, the feed comprises the following raw materials in parts by weight: 7 parts of clay, 15 parts of sulfur trioxide, 31 parts of volcanic ash, 26 parts of wollastonite powder and 42 parts of gypsum.

Preferably, the feed comprises the following raw materials in parts by weight: 8 parts of clay, 17 parts of sulfur trioxide, 28 parts of volcanic ash, 25 parts of wollastonite powder and 44 parts of gypsum.

Preferably, the clay contains 22-27% of aluminum oxide, 2.2-3.4% of calcium oxide, 2.1-2.6% of magnesium oxide, 0.9-1.5% of titanium dioxide and 2-3.5% of ferric oxide by mass.

The invention also provides application of the concrete expanding agent, wherein the adding proportion of the expanding agent in concrete is 7-10% by mass of cement.

Preferably, the adding proportion of the expanding agent in the concrete is 8% by mass of the cement, the influence of the adding amount on the expansion performance and the initial setting and final setting time is large, and the optimal initial setting time is about 140min according to the actual construction condition, so that the adding amount is determined to be 8%.

The invention also provides a preparation method of the concrete expanding agent, which comprises the steps of mixing clay, sulfur trioxide, volcanic ash, wollastonite powder and gypsum, then burning for 30-60min at 1300 ℃ with the temperature of 900-.

Preferably, the gypsum is gypsum.

Preferably, the temperature is 1100 ℃.

Preferably, the time is 50 min.

Preferably, the specific surface area is 400 square meters per kg.

Compared with the prior art, the invention has the advantages that:

after clay, sulfur trioxide, volcanic ash, wollastonite powder and gypsum are mixed and calcined at the temperature of 900 ℃ and 1300 ℃, more free silicon oxide, calcium oxide, aluminum oxide, sulfur oxide, magnesium oxide molecules and the like with higher activity can be generated, the comprehensive expansion effect of various active molecules is higher than that of a single active molecule, and through detection, the adaptability and the compensation shrinkage effect of the product to the concrete strength are superior to those of similar products, and the product has better waterproof and anti-permeability effects.

Detailed Description

Some embodiments of the invention are disclosed below, and those skilled in the art can appropriately modify the process parameters to achieve the invention according to the disclosure herein. It is expressly intended that all such similar substitutes and modifications which would be obvious to one skilled in the art are deemed to be included in the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.

EXAMPLE 1 preparation of No. 1 bulking agent

70g of clay, 170g of sulfur trioxide, 300g of volcanic ash, 260g of wollastonite powder and 390g of gypsum are mixed, and then are burned for 40min at 1100 ℃, and then are ground until the specific surface area is 400 plus square meters per kg, thus obtaining the modified concrete.

Comparative example 1 is sulfur trioxide free, all else being the same as example 1.

Comparative example 2 was clay-free, and the rest was the same as example 1.

EXAMPLE 2 preparation of No. 2 bulking agent

60g of clay, 180g of sulfur trioxide, 290g of volcanic ash, 290g of wollastonite powder and 360g of gypsum are mixed, then the mixture is burned for 60min at 900 ℃, and then the mixture is ground until the specific surface area is 200 plus one square meter per kg of 600 plus square meters.

EXAMPLE 3 preparation of No. 3 swelling agent

70g of clay, 200g of sulfur trioxide, 260g of volcanic ash, 220g of wollastonite powder and 450g of gypsum are mixed, and then are burned for 50min at 1300 ℃, and then are ground until the specific surface area is 200 plus one square meter per kg of 600 plus square meters.

EXAMPLE 4 preparation of No. 4 swelling agent

80g of clay, 190g of sulfur trioxide, 320g of volcanic ash, 240g of wollastonite powder and 400g of gypsum are mixed, then the mixture is burned for 40min at 1000 ℃, and then the mixture is ground until the specific surface area is 200 plus one square meter per kg of 600 plus square meters.

EXAMPLE 5 preparation of No. 5 swelling agent

70g of clay, 150g of sulfur trioxide, 310g of volcanic ash, 260g of wollastonite powder and 420g of gypsum are mixed, and then the mixture is burned for 50min at 1100 ℃, and then the mixture is ground until the specific surface area is 200 plus one square meter per kg of 600 plus square meters.

EXAMPLE 6 preparation of No. 6 bulking agent

80g of clay, 170g of sulfur trioxide, 280g of volcanic ash, 250g of wollastonite powder and 440g of gypsum are mixed, then the mixture is burned for 50min at 1200 ℃, and then the mixture is ground until the specific surface area is 200 plus one square meter per kg of 600 plus square meters.

The concrete expanding agent prepared in the 8 embodiments is mixed into concrete according to the mass of 8% of the mixing amount of cement (32.5-grade ordinary portland cement), and the concrete expanding agent is subjected to effect detection with a commercially available calcium sulphoaluminate concrete expanding agent A with a good sales amount, the detection result is shown in table 1, and the detection result of the expanding agent in the embodiments of the invention meets the GB23439-2009 concrete expanding agent and JC474-2008 standards.

As can be seen from the detection results of the expansion rate in water and dry air, the compressive strength, the permeation height ratio and the water absorption ratio, the effective expansion rate and the waterproof and anti-permeability effects of the expanding agent are obviously superior to those of the expanding agent A sold in the market.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. The concrete expanding agent is characterized by comprising the following raw materials in parts by weight: 6-8 parts of clay, 15-20 parts of sulfur trioxide, 26-32 parts of volcanic ash, 22-30 parts of wollastonite powder and 35-45 parts of gypsum; the preparation method comprises the steps of mixing clay, sulfur trioxide, volcanic ash, wollastonite powder and gypsum, burning for 30-60min at 1300 ℃ with the temperature of 900-.

2. The concrete expanding agent as claimed in claim 1, wherein the clay contains 22-27% by mass of alumina, 2.2-3.4% by mass of calcium oxide, 2.1-2.6% by mass of magnesium oxide, 0.9-1.5% by mass of titanium dioxide, and 2-3.5% by mass of iron oxide.

3. Use of a concrete expanding agent according to claim 1 or 2, wherein the expanding agent is added to the concrete in a proportion of 7-10% by mass of cement.