CN102092999B - Process method for chopped fiber reinforced aerated concrete - Google Patents

Abstract

The invention discloses a process method for chopped fiber reinforced aerated concrete. A process for sequentially coating resin and inorganic compound particles on a fiber surface and adding coated chopped fibers and a dispersing agent into mixed slurry of autoclaved aerated concrete before the resin is cured is adopted, so that heat resistance and alkali resistance are improved, the bonding problem of the chopped fibers and a substrate and the dispersing problem of the chopped fibers are solved, and the reinforcing function of the chopped fibers can be brought into full play during high-temperature and high-pressure curing of the autoclaved aerated concrete. The aerated concrete reinforced by the method can keep the original light and heat preservation properties, and has the advantage of high intensity. By the reinforcing method, the formula of the original aerated concrete is not required to be changed; and the method is simple and practicable.

Description

A process for chopped fiber reinforced aerated concrete

technical field

The present invention relates to the technical field of lightweight thermal insulation building materials, in particular to a reinforced autoclaved aerated concrete.

Background technique

Autoclaved aerated concrete is made of calcareous materials such as lime, siliceous materials such as silica sand, and cement and other materials as the main raw materials, mixed with water at a certain water-to-material ratio, and then foamed with a foaming agent. Products obtained by steaming under high temperature and high pressure. Autoclaved aerated concrete has a series of excellent properties: light weight, low thermal conductivity, good thermal insulation performance, can reduce the thickness of the wall and the quality of the building itself, thereby reducing the foundation size of the building and improving Improve the utilization of land and save materials. At the same time, autoclaved aerated concrete can also improve the efficiency of building construction and reduce the cost of construction. In addition, since the weight of the entire building is reduced, its ability to resist earthquakes is also improved, thereby further promoting the process of housing modernization. Therefore, the autoclaved aerated concrete block is one of the new wall material products that the country encourages the development of.

However, since the autoclaved aerated concrete contains many air bubbles, the specific gravity is small, the weight is light, and it also has the disadvantages of high brittleness, low strength, poor toughness and impact resistance. Not only does the cured autoclaved aerated concrete suffer from low strength, but the foamed molded body before steam curing has very low strength and is also prone to defects during the cutting process.

Adding fiber to cement mortar and concrete can improve its tensile strength, flexural strength and toughness. Some patents also provide such methods. Such as: Composite wallboard and manufacturing method of waste textile fiber reinforced concrete side (public number: CN1364968), manufacturing method of fiber composite reinforced concrete manhole cover (public number: CN 1401860), high performance hybrid fiber reinforced concrete (public number: CN 1686906), formulation for obtaining fiber-reinforced concrete mixture with high mechanical strength and low bulk density (publication number: CN 101309879), ultra-high-strength fiber-reinforced cement composition, ultra-high-strength fiber-reinforced mortar or concrete, and ultra-high-strength cement Additional materials (publication number: CN101160268). The fibers used in these patents include metal fibers, glass fibers, waste textile fibers, low elastic modulus fibers and the like.

Although there are already some patents on short-fiber reinforced ordinary concrete, because the preparation and molding process of aerated concrete and ordinary concrete are very different, some of the above-mentioned short fibers cannot be directly used for the reinforcement of autoclaved aerated concrete. The preparation of autoclaved aerated concrete is a process in which the foaming agent reacts with the alkaline components in the slurry to generate hydrogen. Therefore, the slurry of autoclaved aerated concrete is highly alkaline, much higher than that of concrete. In addition, autoclaved aerated concrete requires high temperature and high pressure autoclaved curing. For example, when meta-aramid fiber is used in autoclaved aerated concrete, due to the action of heat and alkali, the performance of aramid fiber deteriorates and cannot exert a good reinforcing effect. However, even if the steel fiber has undergone anti-rust treatment during use, there will be a problem that the reinforcing effect will decrease during long-term use. Asbestos fibers are also now difficult to use for reinforcement due to their cancer-causing properties. Therefore, in the process of chopped fiber reinforced aerated concrete, how to solve the problem of alkali resistance, high temperature and high pressure resistance of chopped fiber in the preparation of aerated concrete is very critical.

In the process of using chopped fiber reinforced concrete, the main reason that hinders the full reinforcement effect of chopped fiber is that the chopped fiber is easy to agglomerate and unevenly divided, especially when the fiber volume ratio and the length of the short fiber are large. This severity also increases. At present, this shortcoming is mainly overcome by processes such as spraying. When short fibers are used to reinforce autoclaved aerated concrete, the agglomeration of fibers will directly affect the formation process of air bubbles, thereby affecting the pore size and distribution of pores, as well as the strength and thermal insulation performance of autoclaved aerated concrete. Dispersion in air-entrained concrete is an especially important problem to be solved.

Invention content:

In order to solve the shortcomings of short fiber reinforced autoclaved aerated concrete in the prior art, the fiber dispersion is not good, and the fiber is not suitable for the alkalinity, high temperature and high pressure requirements of aerated concrete. The process method of fiber reinforced aerated concrete can obtain autoclaved aerated concrete with increased strength, good dispersion, alkali resistance, high temperature and high pressure resistance.

The technical solution of the present invention is: a process method for chopped fiber reinforced aerated concrete, in which resin and inorganic compound particles are sequentially coated on the surface of chopped fibers, and when the resin is not yet hardened, the coated short Cut fibers and dispersants are added to the mixed slurry of autoclaved air-entrained concrete, and are shaped, initially hardened and steam-cured according to conventional methods. The chopped fibers are para-aramid or basalt chopped fibers.

The resin is any one of polypropylene resin, epoxy-phenolic resin, epoxy resin and furan-epoxy resin.

Described epoxy resin is linear, aliphatic epoxy resin.

The inorganic compound with cation exchange capacity and adsorption is any one of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and kaolin.

The diameter of the chopped fibers is 6-12 μm and the length is 3-12 mm.

The dispersant is any one of sodium lauryl sulfate, methyl amyl alcohol, cellulose derivatives and polyacrylamide.

Beneficial effect

1. The air-entrained concrete is reinforced with para-aramid or basalt chopped fibers, which will not affect the thermal insulation performance of steamed air-entrained concrete. This is due to the high strength and toughness of aramid fiber. Choose aramid fibers with high strength, good heat resistance, acid and alkali resistance and other excellent properties, such as para-aramid fibers. The main components of basalt fiber are SiO ₂ , Al ₂ O ₃ , Fe ₂ 0 ₃ , CaO, MgO, TiO ₂ and so on. Basalt fiber has many unique advantages, such as outstanding mechanical properties, high temperature resistance, low moisture absorption, good insulation, excellent heat insulation and sound insulation performance, etc., and is more suitable for autoclaved aerated concrete. Moreover, para-aramid fibers and basalt fibers have small specific gravity, low thermal conductivity, and good heat insulation. When mixed into autoclaved aerated concrete, it will not reduce the light-weight thermal insulation properties of autoclaved aerated concrete.

2. Use dispersants for pre-dispersion treatment or directly add dispersants to the raw material complex of autoclaved aerated concrete to improve the dispersibility of chopped fibers in autoclaved aerated concrete slurry.

3. Coating resin on the fiber surface and adding interfacial active substances solves the heat and alkali resistance problems of chopped fibers and the combination of chopped fibers and matrix during the preparation of autoclaved aerated concrete, and improves the strength of autoclaved aerated concrete. The surface of the chopped basalt fiber is coated with resin to improve the alkali resistance of the chopped basalt fiber. Among polyolefin resins, the resin with polypropylene as the main component can be used as the first choice due to its low price, excellent physical and chemical properties, and high reinforcement efficiency. In addition, epoxy-phenolic resin, epoxy resin, furan epoxy resin, etc. can also be selected. Epoxy resin can choose linear or aliphatic epoxy resin. The higher the strength of the formed film, the better. In this way, the bonding strength between the resin and the concrete is higher, which is conducive to improving the reinforcing effect of the fiber on the autoclaved aerated concrete.

4. Adsorb inorganic compounds with cation exchange capacity and adsorption on the fiber surface. The inorganic compound ions act as the intermediate interface between the chopped fiber and the autoclaved air-entrained concrete, which makes it difficult for the chopped fiber to be pulled out from the autoclaved air-entrained concrete matrix, and improves the reinforcement effect of the chopped fiber.

5. The present invention mainly uses a dispersant to pre-disperse the chopped fibers or directly adds the dispersant to the raw material complex of the autoclaved aerated concrete to increase the concentration of the chopped fibers in the autoclaved aerated concrete slurry. dispersion.

6. Before the autoclaved air-entrained concrete is prepared, the chopped fibers are first coated with resin by the method proposed by the present invention. Adjust the hardening time of the resin. When the resin is not yet hardened, add the chopped fibers coated with the resin into the mixed slurry of the autoclaved aerated concrete. In the process of continuous hardening of autoclaved aerated concrete and the formation of a series of silicic acid hydrates, it is gradually combined with the matrix of autoclaved aerated concrete to improve the reinforcement effect of chopped fibers.

Detailed ways:

A process method for chopped fiber reinforced aerated concrete, which can improve the dispersibility, alkali resistance, high temperature and high pressure resistance of chopped fibers in autoclaved aerated concrete, adopt resin and have cation exchange capacity and adsorption The inorganic compound is used to coat the chopped fibers sequentially. When the resin is not hardened, the coated chopped fibers and dispersant are added to the mixed slurry of the autoclaved aerated concrete, and the molding and initial curing are carried out according to the conventional method. hardening and steam curing;

The chopped fibers are para-aramid fibers or basalt chopped fibers.

The resin is any one of polypropylene resin, epoxy-phenolic resin, epoxy resin and furan-epoxy resin. Described epoxy resin is linear, aliphatic epoxy resin. The epoxy resin can be selected from CYD-128, E42, E44 and other grades of epoxy resin produced by Baling Petrochemical. The furan-epoxy resin can be YJ furan resin and HF9200 furan epoxy-epoxy resin produced by Wuxi Jiunai Anticorrosion Material Co., Ltd. Epoxy-phenolic resin can choose F-51 phenolic epoxy resin F-44 phenolic epoxy resin produced by Wuxi Jiunai Anticorrosion Material Co., Ltd., F-44-80 and F-53 phenolic epoxy resin produced by Jiangsu Sanmu Company .

Before the autoclaved air-entrained concrete is prepared, the chopped fibers are firstly coated with resin by the method proposed by the invention. Adjust the hardening time of the resin. When the resin is not yet hardened, add the chopped fibers coated with the resin into the mixed slurry of the autoclaved aerated concrete. In the process of continuous hardening of autoclaved aerated concrete and the formation of a series of silicic acid hydrates, it is gradually closely combined with the autoclaved aerated concrete matrix.

The inorganic compound with cation exchange capacity and adsorption is any one of silicon dioxide, aluminum oxide, zirconium oxide, titanium oxide, and kaolin. The inorganic compound particles can be mixed with the resin to form a mixture and then coated on the surface of the fiber, or can be evenly coated on the surface of the fiber when the resin has not hardened after coating the surface of the fiber.

The diameter of the chopped fibers is 6-12 μm and the length is 3-12 mm.

The key in the preparation process of autoclaved aerated concrete reinforced with chopped basalt fibers is to disperse the chopped basalt fibers as uniformly as possible in the slurry of autoclaved aerated concrete. If the chopped fibers cannot be uniformly dispersed in the autoclaved aerated concrete slurry, it will directly affect the mechanical properties and thermal insulation properties of the autoclaved aerated concrete. The present invention mainly uses a dispersant to pre-disperse the chopped fibers or directly adds the dispersant to the raw material complex of the autoclaved aerated concrete to improve the dispersibility of the chopped fibers in the autoclaved aerated concrete slurry . The dispersant can be selected from any one of sodium lauryl sulfate, methyl amyl alcohol, cellulose derivatives, and polyacrylamide.

Comparative example 1:

Weigh 544 grams of fly ash, 96 grams of cement, 128 grams of lime, 32 grams of gypsum, 1.92 grams of admixture, 560 grams of water, and 0.064 grams of foam stabilizer. After mixing evenly, it is cast into shape, and after 4 hours of pre-curing, it is then cured by autoclaving to obtain autoclaved aerated concrete. Test its flexural strength and compressive strength.

Example 1:

Weigh 8.08 grams of chopped basalt fibers with a diameter of 9 μm and a length of 3 mm. Coating polypropylene resin and kaolin on the surface of chopped basalt fiber in turn. The autoclaved aerated concrete slurry was prepared by weighing the same autoclaved aerated concrete raw material as in Comparative Example 1. Add uncured chopped basalt fibers into the slurry, then add 8 grams of dispersant (sodium lauryl sulfate), stir evenly and then pour into a mold. After 4 hours of pre-curing, autoclave curing to obtain autoclaved Aerated Concrete. The same physical and mechanical properties as in Comparative Example 1 were tested.

Example 2:

Weigh 8.08 grams of chopped basalt fibers with a diameter of 9 μm and a length of 6 mm. The raw material weight, preparation method and process are the same as in Example 1 to prepare autoclaved aerated concrete. The same physical and mechanical properties as in Comparative Example 1 were tested.

Example 3:

Weigh 8.08 grams of chopped basalt fibers with a diameter of 9 μm and a length of 12 mm. The raw material weight, preparation method and process are the same as in Example 1 to prepare autoclaved aerated concrete. The same physical and mechanical properties as in Comparative Example 1 were tested.

Example 4:

Weigh 2.02 grams of chopped basalt fibers with a diameter of 9 μm and a length of 3 mm. The raw material weight, preparation method and process are the same as in Example 1 to prepare autoclaved aerated concrete. The same physical and mechanical properties as in Comparative Example 1 were tested.

Example 5:

Weigh 4.04 grams of chopped basalt fibers with a diameter of 9 μm and a length of 3 mm. The raw material weight, preparation method and process are the same as in Example 1 to prepare autoclaved aerated concrete. The same physical and mechanical properties as in Comparative Example 1 were tested.

Embodiment 6:

Weigh 12.12 grams of chopped basalt fibers with a diameter of 9 μm and a length of 3 mm. The raw material weight, preparation method and process are the same as in Example 1 to prepare autoclaved aerated concrete. The same physical and mechanical properties as in Comparative Example 1 were tested.

The test result of the intensity of above embodiment is shown in Table 1

Table 1 Invention embodiment and intensity

Note: 1. The meaning of D9L3 means that the diameter of chopped basalt fiber is 9 μm and the length is 3 mm. Others are similar to this meaning.

It can be seen from the above table that when the length of chopped fibers is relatively short, the dispersion is relatively better, and when the amount of fibers is relatively increased, the reinforcement effect will be better.

Embodiment 7:

Weigh 8.08 grams of chopped para-aramid fibers with a diameter of 9 μm and a length of 3 mm. The epoxy phenolic resin is coated on the surface of the chopped fiber, and when the resin is not hardened, the silicon dioxide is coated on the surface of the chopped para-aramid fiber. Add 8 grams of dispersant (methyl amyl alcohol) to the autoclaved aerated concrete slurry, add the short-cut para-aramid fiber that has not been cured by the resin into the slurry, stir evenly, and cast it according to the conventional method. After 4 hours and After curing, autoclave curing is carried out to obtain autoclaved aerated concrete.

Embodiment 8:

Weigh 8.08 grams of chopped basalt fibers with a diameter of 9 μm and a length of 3 mm. The furan-epoxy resin is coated on the surface of the chopped basalt fiber, and aluminum oxide is coated on the surface of the chopped basalt fiber when the resin is not hardened. Add the uncured chopped basalt fiber and 8 grams of dispersant (sodium cellulose) into the slurry and stir evenly, then cast it according to the conventional method. After 4 hours and curing, then autoclave curing to obtain autoclaved gas concrete.

Embodiment 9:

Weigh 8.08 grams of chopped basalt fibers with a diameter of 9 μm and a length of 3 mm. Coat epoxy resin and zirconia on the surface of chopped basalt fiber in turn. When the resin is not yet hardened, add the uncured chopped basalt fiber and 8 grams of dispersant (polyacrylamide) into the slurry and stir evenly It is poured and formed according to the conventional method, and after 4 hours of curing, it is then cured by autoclaving to obtain autoclaved aerated concrete.

Claims (5)

1. one kind is used for the process method that chopped strand strengthens gas concrete; It is characterized in that; At chopped strand surface application of resin successively, inorganic compound particles; And when resin is still unhardened, chopped strand after the coating processing and dispersion agent are added in the mixed slurry of steam-pressing aero-concrete, by ordinary method moulding, first foster the sclerosis and steam-cured processing;

Described chopped strand is p-aramid fiber or basalt chopped fiber; Described inorganic compound particles is any one in silicon-dioxide, aluminium sesquioxide, zirconium white, titanium oxide, the kaolin.

2. the process method that is used for chopped strand enhancing gas concrete as claimed in claim 1 is characterized in that described resin is any one in acrylic resin, epoxy-phenolic resin, epoxy resin, the furans-epoxy resin.

3. the process method that is used for chopped strand enhancing gas concrete as claimed in claim 2 is characterized in that described epoxy resin is linear, aliphatic epoxy resin.

4. the process method that is used for chopped strand enhancing gas concrete as claimed in claim 1 is characterized in that the diameter of described chopped strand is 6～12 μ m, length 3～12mm.

5. the process method that is used for chopped strand enhancing gas concrete as claimed in claim 1 is characterized in that described dispersion agent is any one in sodium lauryl sulphate, methyl amyl alcohol, derivatived cellulose, the SEPIGEL 305.