JPS63215577A - Lightweight foamed concrete - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to lightweight cellular concrete mainly used as a building material.

[Background of the invention]

This type of lightweight cellular concrete is made by kneading silicic raw materials such as silica sand and silica stone, calcareous raw materials such as lime and cement, and water to form a slurry, and then foaming it by adding a foaming agent or foaming agent to the slurry. After that, it is poured into a mold of a predetermined shape and cured by heating. Although such lightweight cellular concrete is lightweight, it has low strength and is brittle, so it has the disadvantage that it is easily damaged by external forces received during manufacturing, transportation of the product, or construction.

[Conventional technology]

Conventionally, lightweight cellular concrete has been provided in which carbon fibers are further added as a reinforcing agent to a raw material slurry mixture mainly composed of silicic raw materials and calcareous raw materials, and the concrete is molded and cured.

[Problem that the invention seeks to solve]

However, since carbon fibers have a smooth surface, their bonding properties with the matrix made of silicic raw materials and calcareous raw materials are weak and sufficient entanglement cannot be expected, so the reinforcing effect of carbon fibers is not satisfactory, and carbon fibers However, this method has the problem that it leads to an increase in the cost of lightweight aerated concrete, which is expensive.

[Means for Solving the Problems] ' The present invention, as a means to solve the above-mentioned conventional problems, adds wood pulp fibers to a raw material slurry mixture mainly composed of silicic raw materials and calcareous raw materials. The object of the present invention is to provide lightweight cellular concrete that can be obtained by adding it in a proportion of 7% by weight or less based on the solid content and molding and curing it.

The silicic raw material used in the lightweight cellular concrete of the present invention is a material containing silicic acid such as silica sand and silica stone, and the calcareous raw material is a material containing calcareous material such as lime and cement.

The wood pulp fibers added when producing the lightweight cellular concrete of the present invention are made from softwood, hardwood, waste paper, etc., and include mechanical pulp, chemical pulp, ground wood pulp,
Chemi-ground pulp, sulfite pulp, alkaline pulp,
Sulfate pulp, semi-chemical pulp, neutral sulfite semi-chemical pulp, acidic sulfite semi-chemical pulp,
It includes any type of pulp such as kraft semi-chemical pulp, saran pulp, unsalted pulp, cass pulp, etc.

In the present invention, the ratio of the siliceous raw material to the calcareous raw material is usually about 1:0.3 to 1:1.5 by weight, and the amount of wood pulp fiber added is 7% based on the total solid content of the raw material slurry.
It is preferably 0.5 to 2% by weight or less.

Water is added to the above raw material mixture to make a slurry with a solid content of 30 to 60% by weight, and a foaming agent such as aluminum powder, zeolite adsorbent, etc. and/or surfactant, foaming agent such as protein derivative, or If desired, add a small amount of a cell stabilizer such as methylcellulose or starch, foam and/or foam, pour into a prescribed mold, heat to harden if desired, and further heat cure to completely harden. go to Heat curing conditions are usually 50-90°C5
It is 1 to 7 hours. If desired, curing may be performed by steam heating in an autoclave.The curing conditions in this case are usually an autoclave internal pressure of 1 to 10 kg1d (gauge pressure) and a temperature of about 100 to 180°C. Finally, drying is performed at a temperature of 60 to 140°C for about 2 to 8 hours to obtain lightweight cellular concrete. [Operation] The above slurry is hardened by a calcium silicate reaction between the silicic raw material and the calcareous raw material.・Wood nolp fibers contain substances that inhibit the above-mentioned curing reaction. However, if the content of wood pulp fibers is 7% by weight or less, the curing reaction will be carried out smoothly without being inhibited. Since the surface of wood pulp fibers is rough, it can be expected to have a high degree of bonding with the matrix composed of silicic raw materials and calcareous raw materials, and to be highly entangled.

〔Effect of the invention〕

Therefore, in the present invention, @Keikai foam concrete is provided which has high mechanical strength relative to its specific gravity and is inexpensive.

Example 1 A raw material slurry obtained by kneading a mixture of 50 parts by weight of silica sand, 401 parts of Portland cement, and 10 parts by weight of quicklime with 45 parts by weight of water was mixed with pressed wood pulp fibers shown in Table 1. Add in the indicated amount and stir thoroughly to make the mixture uniform. 0 Add a diluted solution prepared by diluting the protein-based foaming agent stock solution to 15 times in advance to the wood pulp fiber mixed raw material slurry obtained in this way. Add about 0.5-100 times the foaming agent in terms of solid content, and stir and mix until uniform. The above-mentioned foamed slurry is poured into a mold having a predetermined shape, the surface is smoothed, and the slurry is heated to about 80° C. for 5 hours to be cured to obtain a molded body. The obtained molded body was removed from the mold and autoclaved at 180'C for 15 hours.

It is then dried at 100°C for 3 hours.

Table 1 shows the physical properties of the lightweight cellular concrete molded body thus obtained.

Table 1 It is clear from Table 1 that the bending strength and compressive strength of the molded product obtained by adding only 0.5% by weight of wood pulp fibers are significantly improved, but a comparative example in which carbon fibers were mixed is shown. No significant improvement was observed in either bending strength or compressive strength.

Example 2 45 parts by weight of silica sand, 35 parts by weight of Portland cement, 10 parts by weight of alumina cement, 0.5 parts by weight of soda carbonate,
50 parts by weight of water are added to a mixture of 0.5 parts by weight of sodium citrate and 3 parts by weight of gypsum and kneaded to obtain a raw material slurry. A lightweight cellular concrete molded body is obtained by the same process as in Example 1 using a wood pulp fiber mixed raw material slurry which has been uniformly heated by adding lii quantity of waste paper pulp to the raw material slurry.

However, in the case of this example, the molded body within the mold is hardened to the extent that it can be removed from the mold in one hour.

The physical properties of the lightweight aerated concrete thus obtained are: specific gravity 0.53, bending strength 25 kg/d, and compressive strength 61.
It was kqld.

Claims (1)

[Claims] Lightweight cellular concrete obtained by adding wood pulp fibers to a raw material slurry mixture mainly composed of silicic raw materials and calcareous raw materials at a ratio of 7% by weight or less based on the total solid content of the raw material slurry, and molding and curing the mixture.