JPS63147065A - Method of repairing light-weight aerated concrete building - 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 A. Field of Industrial Application The present invention relates to a method for repairing a building in which a lightweight aerated concrete structural material manufactured by curing in an autoclave under high temperature and high pressure is used as the exterior.

The lightweight aerated concrete structural material (hereinafter referred to as ALC) used in prior art buildings is usually coated with a protective coating by spraying a hemline material on its surface to prevent the bare skin from being exposed.

As time passes, the cosmetic effect fades, and the ALC surface gradually begins to crack and peel, exposing the ALC surface. On the other hand, A
When LC is exposed to the atmosphere for a long period of time, the calcium component contained in the ALC undergoes a chemical reaction with carbon dioxide gas in the atmosphere and turns into calcium carbonate. By that A
The structure of LC deteriorates as it changes from alkaline to neutral and then to acidic, and tensile stress acts on it due to the so-called carbonation-induced carbonation shrinkage, which causes cracks. The same thing can also happen with other acidic gases. Buildings that have experienced such deterioration must be prevented from progressing and repaired.

Conventionally, therefore, a repair method has been adopted in which a surface hardening agent made of a solution of a water-soluble silicate compound is coated and impregnated onto the surface of the ALC exposed by removing the protective cosmetic material to protect and strengthen the surface layer. ing.

8. Problems to be Solved by the Invention According to the conventional repair method described above, spraying with ricin material can improve durability compared to cosmetic treatment; It causes a gelation phenomenon and hardens without penetrating into the interior, and even if it does penetrate, it only penetrates into an extremely shallow surface layer (within 1 to 3 mm). This phenomenon was caused by a remarkable decrease in permeability as carbonation and oxidation progressed, making it virtually impossible to repair. Therefore, AL that has become neutralized or acidified
The interior of C remains in a degraded state. In this way, it is difficult to say that a repair method in which a surface hardening agent is simply applied and impregnated onto the ALC surface has been repaired, and is only a modest improvement after all.

2. Means for Solving the Problems The present invention enables internal reinforcement that could not be achieved with the conventional repair methods described above, and its structure is such that an alkaline aqueous solution is applied to the surface of deteriorated lightweight cellular concrete. The purpose is to apply a surface treatment agent consisting of the following, allow the aqueous solution to penetrate into the interior, and further coat the surface with an inorganic surface hardening agent whose main component is a silicate-based aqueous solution.

(e) By applying a base treatment agent adjusted to be alkaline, it penetrates deep into the inside of ALC and modifies the structure of ALC itself, which has become neutral or acidic, to alkaline. alkaline components of ALC (e.g. sodium hydroxide, potassium hydroxide, etc.)
prevents the polymerization of the silicon component contained in the surface hardening agent,
Rather, it is depolymerized to prevent gelation, maintain a low viscosity solution in a penetrable state, and penetrate deep into the ALC.

EXAMPLE To explain an example of the repair method according to the present invention, first, the surface of the building is washed with water and brushed to remove the deteriorated old protective decorative material, thereby exposing the bare surface of the ALC. At this time, a base treatment agent consisting of zero-order sodium hydroxide solution, which also inspects and removes floating and peeling parts, is applied evenly and uniformly to the exposed ALC surface.

This application method includes brush application, spray application, roll application,
After applying with curtain flow coater etc., leave it for about 1 hour until the base treatment agent completely penetrates.
A surface hardening agent whose main component is a lithium silicate aqueous solution is applied thereon to cover the entire surface.

In the previous process, the alkalinity of ALC is restored not only to the surface layer but also to the inside, so the alkaline component suppresses the gelation of the surface hardening agent, and the surface hardening agent
Penetrates deep inside C. Incidentally, its depth is 10mm.
It slightly exceeds this, and reaches 15mm or more in cracked areas. Large cracks and missing parts are then filled in and repaired using polymer cement or ALC mortar, and then finished with filler or sealer and then topped up with a decorative material.

In buildings repaired in this way, the ALC eyes have been modified to be alkaline, and the surface (in the case of backfilled areas, the interface with the backfilling material) has excellent strength. It is coated with a surface hardening agent and completely refreshed to not only prevent deterioration but also strengthen it.

Next, the results of an experiment to confirm the permeability of the surface treatment agent will be illustrated.

As for the experimental method, as shown in Fig. 1 a and b,
A film of silicone agent 2 was applied to the outer circumferential side of an AI, C test piece l with csX 5 cm and a height of 10 cm to completely seal the surrounding area, leaving the bottom surface exposed and using this as a test solution of the base treatment agent. The penetration depth was measured by immersing the sample into the beaker 4 containing the sample.

As sample solution 3 of the surface treatment agent, commercially available Na0H (sodium hydroxide), Ca (OH)2 (calcium hydroxide) are used.
, LiOH (lithium hydroxide), KOH (potassium hydroxide), and Na2C03 (sodium carbonate) aqueous solutions were used. Following this experiment, to test the permeability of the surface hardening agent, we immersed it in a sample solution of the surface treatment agent and naturally dried it at room temperature. The penetration depth was also measured by penetrating into a hardening agent solution.

In parallel with these experiments, data on tap water and lithium silicate alone were also obtained under the same conditions and are listed together with the above data.

From these results, although there are slight differences in the penetration depth of the surface treatment agent and surface hardening agent depending on the type of surface treatment agent and pH, it is clear that the penetration depth of the surface treatment agent and surface hardening agent differs slightly depending on the type of surface treatment agent and the pH. All hardener penetration depths are 9.5
It can be confirmed that tap water penetrates to a depth of 9 cm or more. Similar good results were obtained when a silicate-based aqueous solution other than silica lithium was used as the surface hardening agent, even if the pH of the surface treatment agent was too high.

On the other hand, it was also confirmed that good results are not necessarily obtained even if the temperature is too low. The coated foil was applied to both the base treated state and the base treated state with sodium hydroxide, and the strength of the surfaced foil was examined.

From this result, it was confirmed that when the base was treated with sodium hydroxide, the adhesive strength was more than double that of the untreated and water treated cases, and the untreated and water treated cases ensured sufficient adhesive strength. Based on this fact, high adhesion strength can be achieved by alkali treatment.

It has been found that the coating effect is also increased in comparison. Therefore, even if tap water is used as a surface treatment agent, the penetration depth of the surface hardening agent is barely satisfactory, but practicality cannot be expected due to insufficient adhesive strength.

The purpose of the surface treatment agent used in the present invention is to restore alkalinity to neutral or acidified ALC, thereby allowing the surface hardening agent to penetrate deep into the surface. A solution containing a compound, its carbonate, or both, with a pH of 8.5 to 1.
It was also confirmed that particularly good results were obtained when the ratio was adjusted within the range of 4.0.

However, in the present invention, the surface treatment agent is not limited to alkaline earth metal hydroxides, carbonates thereof, or a mixture of both, but is alkaline and is applied to surfaces coated after surface treatment with the surface treatment agent. It is also possible to use a material that has the effect of penetrating the hardening agent to a depth that is practically required. The surface treatment agent is not limited to lithium silicate as long as it has a silicate-based liquid as a main component, and the amount of surface hardening agent applied, the drying time of the surface treatment agent, etc. are determined according to the implementation conditions. You may change it as appropriate.

G. Effect According to the present invention, the surface treatment agent penetrates into the inside of the deteriorated ALC to restore alkalinity and restore the strength of the ALC itself, and also promotes the penetration of the surface hardening agent into the inside to strengthen it from the surface to the inside. Furthermore, the strong adhesion of the surface hardening agent provides long-term protection from the atmosphere. As a result, the tissue is rejuvenated, not only recovering sufficient strength but also being strengthened, the surface is thoroughly protected, and strength and durability that exceed its original performance are demonstrated, which has great practical benefits.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are explanatory diagrams of the penetration experiment apparatus. l...ALC test piece, 2...silicon material, 3...
Reagent for surface treatment agent, 4... Beaker Patent applicant Onoda NLC Co., Ltd. @Figure 1

Claims (1)

[Scope of Claims] 1. A surface treatment agent made of an alkaline aqueous solution is applied to the surface of deteriorated lightweight cellular concrete, and this aqueous solution is allowed to penetrate into the interior, and the surface is further treated with an inorganic surface mainly composed of a silicate-based aqueous solution. A method for renovating lightweight aerated concrete structures, characterized by coating them with a hardening agent. 2. The method for repairing a lightweight cellular concrete building according to claim 1, wherein the surface treatment agent is an aqueous solution containing an alkaline earth metal hydroxide or carbonate, or both.