JPH07165477A - Molded article of porous open-cell concrete and production of composite material of the same concrete - Google Patents

Abstract

PURPOSE:To obtain a lightweight molded article of porous open-cell concrete having excellent acoustic absorptivity, strength, etc., by successively mixing a cement slurry having a specific composition with foams and a quick setting slurry and hardening the mixture by steam curing at normal temperature under normal pressure. CONSTITUTION:A water reducing agent (e.g. naphthalene-based water reducing agent), a setting retarder (e.g. sodium citrate) and a strength development promoter (e.g. potassium carbonate) are dissolved in water. Then the aqueous solution is mixed with a hydraulic substance (e.g. ordinary cement) and a hydration promoter (e.g. slaked lime) and kneaded to give a cement slurry. Then foams are introduced into the cement slurry to give a foamed slurry, which is further blended with a quick-setting slurry prepared by blending a quick- setting hydraulic substance (e.g. alumina cement) with water to give a porous base slurry. Then the base slurry is hardened by steam curing at a normal temperature under high pressure to give a molded article of porous open-cell concrete having <=0.4 bulk specific gravity without using an autoclave.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a porous cellular concrete molding having excellent sound absorption and heat insulation and a method for producing a concrete composite using the same.

[0002]

2. Description of the Related Art In order to improve the performance of concrete products used for sound absorption and heat insulation, natural or artificial lightweight aggregates are used and a large amount of air bubbles are mixed therein. , Recently, extreme weight reduction has been promoted.

However, as the weight is reduced, the amount of the lightweight aggregate and the amount of air bubbles are increased and the strength is lowered, so that the cracks are more likely to be generated or broken. In order to improve this, conventionally, means such as reforming by autoclave (high temperature and high pressure steam curing) is performed after normal pressure steam curing.

[0004]

However, the strength to be increased cannot be obtained as expected even by the above modification. Therefore, measures are taken to prevent the damage by reducing the member size. Moreover, the autoclave treatment performed for reforming requires a large amount of cost and troublesome work.

Further, it has been proposed to use the above-mentioned lightweight concrete compact as a composite set with ordinary concrete or the like, but due to damage of the lightweight concrete at the time of handling or insufficient adhesion due to defective setting, etc. Separation and dropout may occur.Furthermore, due to the difference in thermal expansion coefficient and drying shrinkage between lightweight concrete and other materials in autoclave, peeling of both materials and cracking of lightweight concrete are likely to occur. However, the size of the product is limited due to the capacity of the autoclave.

The present invention solves the above problems and makes it possible to develop strength of a molded porous porous cellular concrete excellent in sound absorption and heat insulation by normal temperature and normal pressure steam curing without undergoing an autoclave process, which is economical. The present invention is intended to provide a new method which is capable of producing large-sized products having high properties.

[0007]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that the composition and temperature of the base slurry containing cement as a main material are It is an important condition for the formation of open cells in the base material slurry, and it was also found that a good quality porous cellular concrete product can be obtained using this base material slurry without subjecting it to an autoclave treatment. Was formed.

That is, in the method for producing a porous continuous cell concrete molding according to claim 1, a hydraulic substance and a hydration reaction accelerator are added to an aqueous solution in which a water reducing agent, a set retarder and a strength development accelerator are dissolved in water. The mixture is kneaded to form a cement slurry, and bubbles are mixed into the cement slurry to form a cell slurry. Furthermore, the cell slurry is added and mixed with a quick-setting slurry obtained by mixing a quick-setting hydraulic substance and water to form a porous slurry. The base material slurry is prepared by hardening the base material slurry by steam curing at room temperature and normal pressure.

According to a second aspect of the present invention, in the method for producing a porous open-celled concrete composite, the lightweight cellular concrete 2, the lightweight concrete 3 or the ordinary concrete 4 is cast on the mold 1 and the porous cellular material is placed thereon. It is characterized in that the base material slurry 5 is cast and integrally cured by steam curing at room temperature and atmospheric pressure.

Further, in the method for producing a porous continuous cell concrete composite according to a third aspect, a steel frame 6 is used as a mold, and the porous cell substrate slurry 5 is cast into the mold to cure at room temperature and atmospheric pressure. It is characterized in that it is cured and integrated by means of.

The method for producing a porous, open-celled concrete molded body of the present invention comprises a step of obtaining a cement slurry (primary slurry) containing a hydraulic material as a main material, and a step of mixing bubbles into the cement slurry to form a cell slurry (secondary slurry). (Slurry), a step of converting the air bubble slurry into a porous base material slurry, and a step of hardening the base material slurry by normal temperature and pressure steam curing.

First, in the first step of obtaining a cement slurry, 0.5 to 4.0 parts by weight of a water reducing agent (naphthalene type or melamine type) and 0.4 to 1.4 parts by weight of a setting retarder (sodium citrate) are added to 75 to 95 parts by weight of water. , Strength-enhancing agent (potassium carbonate) 0.2-0.5 parts by weight in an aqueous solution, cement (normal cement, early strength cement) 100-1 as hydraulic substance
50 parts by weight, slab fine powder 90-140 parts by weight, hydration reaction accelerator (slaked lime and anhydrous gypsum) 7.5-20 parts by weight,
Knead for 90 to 120 seconds.

In the subsequent second step, bubbles generated by putting a foaming liquid consisting of 12 to 17 parts by weight of water and 40 to 46 parts by weight of a foaming agent in a bubbler are mixed into the cement slurry to obtain 60 to 90 parts by weight. Knead for 2 seconds to obtain a foam slurry.

Next, as a third step, the above-mentioned aerated slurry is mixed with a quick-setting hydraulic substance (alumina cement) 15.5 to 25.5.
Add a mixture of 12 to 17 parts by weight of water and 16 to
Knead at a temperature of 20 ° C for 15 to 20 seconds to obtain a porous base material slurry.

In the final fourth step, the above-mentioned base material slurry is put into a mold and allowed to stand for 10 to 15 minutes for coagulation, then normal temperature and pressure steam curing is carried out to cure it, and it is taken out from the mold. As a result, it is possible to obtain a porous concrete molded body in which air bubbles having a bulk specific gravity of 0.4 or less are communicated.

[0016]

EXAMPLES Next, the present invention will be specifically described with reference to examples.

Example 1 A base material slurry having the composition shown in Table 1 was poured into a mold at a temperature of 19 ° C., the surface was leveled, and the mixture was allowed to stand at a temperature of 20 ° C. for 3 to 5 hours, and then 55 After normal temperature and atmospheric pressure steam curing for 5 hours at a temperature of ℃, the mold was removed, and a molded product of porous open-cell concrete having a bulk specific gravity of 0.4 was obtained.

[0018]

[Table 1]

Table 2 shows a comparison between the sound absorption coefficient and the compressive strength of the test piece molded according to Example 1 and the autoclaved conventional test piece.

[0020]

[Table 2]

As shown in Table 2, the porous, open-celled concrete molded body according to the present invention has a performance in which the sound absorption coefficient and the compression strength are almost the same as those of the conventional molded body subjected to the autoclave treatment. Recognize.

Example 2 As shown in FIG. 1, a lightweight cellular concrete 2 having a specific gravity of 1.5
, And lightweight concrete 3 with a specific gravity of 1.8 and ordinary concrete 4 with a specific gravity of 2.4 are respectively placed in the formwork 1,
The surface was roughly finished, and after 30 to 40 minutes, the base material slurry 5 shown in Table 1 was cast on the upper surface of each uncured concrete 2, 3 and 4 to smooth the surface, and then Example 1 After performing room temperature and atmospheric pressure steam curing by the method described in 1. and integral curing, form 1
And remove each concrete 2, as shown in Figure 2.
A monolithically polymerized composite of porous and open-cell concrete made of 3, 4 and the base material slurry 5 was obtained.

Example 3 As shown in FIG. 3, a base material slurry 5 was cast in a steel frame 6, and normal temperature and atmospheric pressure steam curing was carried out in the same manner as in Example 2 to prepare the steel frame 6 and the base material. Slurry 5
An integrally bonded composite of porous and open-cell concrete was obtained.

[0024]

As described above, the porous, open-cell concrete molding according to the present invention has the same strength and sound absorbing effect as the conventional sound absorbing material that has been subjected to the autoclave treatment. Since it is manufactured by adopting normal temperature and pressure steam curing that does not rely on an autoclave,
This simplifies the manufacturing process and reduces the cost, and it is possible to provide a large-sized product without being restricted by the size of the product unlike the autoclave.

Further, by adopting the normal pressure steam curing, a composite body which is strongly integrally polymerized by simultaneous molding of the base slurry of the present invention and each other concrete and a composite body excellent in adhesion to a steel frame are It can be provided easily and inexpensively without being restricted by.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a process of driving a form of a porous open-cell concrete composite according to the present invention.

FIG. 2 is a perspective view showing an example of the same porous open-cell concrete composite body.

FIG. 3 is a perspective view showing an example of a porous open-celled concrete composite body integrated with a steel frame.

[Explanation of symbols]

 1 Formwork 2 Lightweight cellular concrete 3 Lightweight concrete 4 Normal concrete 5 Base material slurry 6 Steel frame

Claims (3)

[Claims] 1. A cement slurry is prepared by kneading a hydraulic substance and a hydration reaction accelerator into an aqueous solution prepared by dissolving a water reducing agent, a set retarder and a strength development accelerator in water, and mixing air bubbles in the cement slurry. To form a porous slurry, and to this porous slurry, a quick-setting slurry obtained by mixing a quick-setting hydraulic substance and water is added and mixed to form a porous base material slurry, and this base-material slurry is subjected to normal temperature and atmospheric pressure steam curing. A method for producing a porous, open-cell concrete molding having a bulk specific gravity of 0.4 or less, which is characterized by being cured by. 2. A lightweight cellular concrete, lightweight concrete or ordinary concrete is placed on the formwork, and then,
A method for producing a porous, open-cell concrete composite, comprising pouring the above-mentioned porous cellular base material slurry and integrally curing it by normal temperature and atmospheric pressure steam curing. 3. A porous continuous cellular concrete, characterized in that a steel frame is used as a mold and the porous cellular base material slurry is poured into the mold and cured by room temperature and normal pressure steam curing to be integrated. Method for producing composite.