CN101492280A - Phosphate cellular concrete and process for producing its product - Google Patents

Abstract

The invention discloses a preparation method of phosphate porous concrete and its products in the technical field of construction engineering. The components and weight percentages contained in the porous concrete are: 7.5-30% of ammonium dihydrogen phosphate, 2.45-9.8% of magnesium oxide %, 60-90% of fly ash, 0.05-0.2% of setting material. Put the above materials into the mixer according to the proportion and stir evenly, add mixing water with 25-50% of the dry powder weight, stir well to form a uniform slurry, then pour the slurry into the mold for molding, demould after curing and cut into the required size lightweight concrete products. The porous concrete provided by the invention can be poured directly on site without special maintenance conditions and construction technology requirements. The porous concrete product produced by the invention has excellent performances such as rapid demoulding, high strength, high hardness, uniform distribution of pores, high temperature resistance, no deformation, no shrinkage and good durability.

Description

Phosphate porous concrete and its preparation method

technical field

The invention relates to a method for preparing concrete and its products in the technical field of construction engineering, in particular to a method for preparing phosphate porous concrete and its products.

Background technique

Porous concrete, as a lightweight, thermal insulation material, has been paid attention to in recent years with the advancement of building energy-saving technology. Porous concrete refers to those concretes that contain a large number of uniformly distributed closed pores with a diameter of less than 2 mm. At present, there are two main types of porous concrete: one is foam concrete, and the other is air-entrained concrete. Foamed concrete is a porous lightweight material that is hardened after mixing cement or slurry made of mixed materials and water with foam made of foaming agent. Air-entrained concrete is made by using chemical methods to generate gas in the mud. The methods for generating gas include adding metal powder, reacting with acid to generate hydrogen or carbon dioxide, and adding water to calcium carbonate to generate acetylene. These two types of traditional porous materials usually have very low strength, usually less than 1 MPa, and can only be used for some partition wall filling materials, and there are defects such as relatively large drying shrinkage.

After searching the literature of the prior art, it is found that in recent years, researchers have carried out a lot of research work in this area and developed a variety of high-performance porous concrete. Such as Chinese patent publication number: CN03104729.7, patent name: a high-strength lightweight concrete and its manufacturing method, the patent uses composite cementitious materials and a variety of additives and fiber composite method to prepare a strength of 15-30MPa high-strength porous concrete. Another example is the Chinese patent publication number: CN200810021256.5, patent name: high-performance aerated concrete and its production method. This patent proposes to use fly ash, lime, cement, desulfurized gypsum and aluminum powder paste as raw materials, and adopts a special process High-performance porous concrete with low shrinkage is prepared. In addition, Chinese patent publication number: CN 200610085717.6, patent name: a kind of air-entrained concrete, this patent reduces the cost by using a certain proportion of hydrogen peroxide liquid as a beating agent and an air-generating agent to replace aluminum powder. However, from the current various types of porous concrete, the cementitious materials used are basically Portland cement, and at the same time, specific air-entraining agents or air-entraining agents are used to achieve porosity inside the concrete, so to a certain extent The cost of porous concrete is increased; in terms of performance, there are defects such as relatively large shrinkage rate, low early strength and deviation in durability.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies of the prior art, to provide a phosphate porous concrete and its preparation method, which can be used in factories to produce lightweight porous concrete products, and can also be used to form thermal insulation wallboards by direct pouring at the construction site , roof insulation panels, etc. The porous concrete has high early strength, flat and hard surface, no shrinkage, no deformation, waterproof, high temperature resistance, uniform distribution of internal pores and closed and non-connected with each other.

The present invention is achieved through the following technical solutions:

The phosphate porous concrete involved in the present invention comprises components and weight percentages as follows:

Ammonium dihydrogen phosphate 7.5-30%

Magnesium Oxide Powder 2.45-9.8%

Fly ash 60-90%

Setting material 0.05-0.2%

The present invention is formed by mixing uniformly in bags according to the above ratio. The invention mainly utilizes the rapid chemical reaction of the ammonium dihydrogen phosphate, magnesium oxide and fly ash to produce fine air bubbles that are evenly distributed inside the concrete.

The ammonium dihydrogen phosphate is a powder crystal, and its particle size is preferably less than 100um.

The magnesium oxide is perburned magnesium oxide, its purity is greater than 80%, and its particle size ranges from 2um to 100um.

The fly ash powder can be selected from one of Class II fly ash, Class III fly ash and high-calcium fly ash, all of which are existing mature products.

The coagulation adjusting material can be selected from boric acid, borax, citric acid, preferably borax powder.

The preparation method of the phosphate porous concrete and its products involved in the present invention is specifically: weigh the required ammonium dihydrogen phosphate, magnesium oxide powder, fly ash and coagulation adjusting material according to the above ratio, fully stir in the mixer, The product is formed and bagged. When used at the construction site, according to the strength and apparent density of the prepared porous concrete, add mixing water with a dry powder weight of 25-50%, fully stir to form a uniform slurry, and then pour the slurry into the mold for molding, and release the mold after curing and lightweight concrete products cut to size.

In the preparation method of the present invention, the slurry can be directly poured into the roof floor of the building, and becomes a lightweight porous concrete roof insulation board after solidification.

In the preparation method of the present invention, the slurry can be poured into the concrete slab mold on which the steel supports have been placed, and demolded after curing to form a lightweight porous concrete wall panel prefabricated part.

Compared with the prior art, the technical solution of the present invention breaks the limitation that porous lightweight concrete can only be produced and poured in factories and requires specific production equipment and process requirements, and can be poured and constructed under any conditions and environments, and the form of the product This can include blocks, prefabricated wall panels, roof insulation panels and more. The porous lightweight concrete of the present invention has excellent properties such as fast demoulding (the demoulding time can be completed within 30 minutes), high strength, high hardness, uniform pore distribution, high temperature resistance, no deformation, no shrinkage and good durability.

Detailed ways

The embodiments of the present invention are described in detail below: the present embodiment is implemented under the premise of the technical solution of the present invention, and detailed implementation and specific operation process are provided, but the protection scope of the present invention is not limited to the following implementation example.

Example 1

Weigh 7.5% of ammonium dihydrogen phosphate, 2.45% of magnesium oxide, 90% of grade III fly ash, and 0.05% of borax by mass ratio, put them into a mixer and stir them fully, add 30% of the dry powder weight and stir for 2 minutes to form a uniform Flowing slurry, pour the uniform slurry into the mold to form, after 30 minutes of curing, demould and cut into the required size. Then place it at room temperature for curing for 3 days to make a lightweight porous concrete block. The ^lightweight concrete block is measured according to the standard of GB/T11968-1997 "Autoclaved Aerated Concrete Block". The coefficient is 0.17W/m·k. Comply with relevant standards.

Example 2

Take by weight 30% of ammonium dihydrogen phosphate, 9.8% of magnesium oxide, 60% of grade III fly ash, and 1.2% of boric acid, put them into a mixer and stir fully, add 45% of the dry powder weight and stir for 3 minutes to form a uniform Flowing slurry, the slurry is directly poured into the roof floor of the building, and after curing, it becomes a lightweight concrete roof insulation board. After testing, it meets the industry standard requirements for light weight, strength and heat transfer coefficient.

Example 3

Weigh 18.75% of ammonium dihydrogen phosphate, 6.125% of magnesium oxide, 75% of grade III fly ash, and 0.125% of borax by mass ratio, put them into a mixer and stir fully, add 25% of the dry powder weight and stir for 2 minutes to form a uniform The flowing slurry is directly poured into the concrete mold with the steel support placed, and it is cured and demoulded in 35 minutes to make a lightweight concrete wall panel prefabricated part. After testing, it meets the standard light weight and strength of GB 15762-1995 "Autoclaved Aerated Concrete Slab".

Example 4

Take by weight 15% of ammonium dihydrogen phosphate, 4.9% of magnesium oxide, 80% of grade III fly ash, and 0.1% of borax, put them into a mixer and stir fully, add 50% of the dry powder weight and stir for 3 minutes to form a uniform Flowing slurry, pour the uniform slurry into the mold to form, after 45 minutes of curing, demould and cut into the required size. Then place it at room temperature for curing for 3 days to make a lightweight porous concrete block. The ^lightweight concrete block is measured according to the standard of GB/T11968-1997 "Autoclaved Aerated Concrete Block". The coefficient is 0.08W/m·k, in line with relevant standards.

Claims (9)

1. A phosphate porous concrete, characterized in that the components contained and their percentages by weight are: 7.5-30% ammonium dihydrogen phosphate, 2.45-9.8% magnesium oxide, 60-90% fly ash, and setting-adjusting material 0.05-0.2%. 2. The phosphate porous concrete as claimed in claim 1, characterized in that said ammonium dihydrogen phosphate is a powdery crystal with a particle size of less than 100um. 3. The phosphate porous concrete as claimed in claim 1, characterized in that the magnesium oxide is perburned magnesium oxide, the purity of which is greater than 80%, and the particle size ranges from 2um to 100um. 4. The phosphate porous concrete according to claim 1, characterized in that said fly ash powder is selected from one of class II fly ash, class III fly ash and high calcium fly ash. 5. The phosphate porous concrete as claimed in claim 1, characterized in that, said coagulation adjusting material is selected from one of boric acid, borax and citric acid. 6. The phosphate porous concrete according to claim 5, characterized in that borax powder is selected as the coagulation adjusting material. 7. A method for preparing a phosphate porous concrete product as claimed in claim 1, characterized in that, the porous concrete material is put into a mixer and stirred evenly, adding mixing water with 25% to 50% of dry powder weight, fully Stir to form a uniform slurry, then pour the slurry into the mold for molding, demould after curing and cut into lightweight concrete products of required size. 8. The method for preparing phosphate porous concrete products as claimed in claim 6, wherein said slurry is poured directly into the roof floor of the building, and becomes a lightweight porous concrete roof insulation board after curing. 9. The method for preparing phosphate porous concrete products as claimed in claim 6, characterized in that the slurry is poured into the concrete slab mold with steel supports placed therein, and after curing, it is demoulded to form a lightweight porous concrete wall Board prefabs.