The stone is sturdy and durable, and it has gradually entered the homes of thousands of people. However, everyone thinks that the stone will be decorated once and for all, but I do not know the damage to the stone caused by dust, exhaust gas, acid rain, freezing and other pollutants in the daily living environment. If the stone is not cleaned, it will greatly reduce the decorative effect and service life of the stone.

The main reasons for stone lesions are: one is the chemical reaction between some material components inside the stone and the substances in the atmosphere; the second is caused by the increasingly serious air pollution; the third is caused by the improper construction method of the stone during installation.

Therefore, prevention (protective treatment) and treatment (cleaning and coloring) of stone lesions become essential. The prevention of stone lesions is mainly solved by protective treatment of stone materials, while the treatment of stone lesions requires cleaning and coloring methods.

Stone protection: Protect the stone by applying a protective agent to prevent or delay the occurrence of pollution, fading and even damage of the stone.

Stone cleaning: Physical or chemical methods to clean the surface of the stone or shallow surface pollution, is one of the main methods of stone disease treatment.

Stone coloring: use physical or chemical methods to add color or color to the stone to eliminate the natural color difference of the stone, or to restore the color of the stone that has produced discolored lesions.

Stone protection, cleaning and coloring technology are interrelated, mutually infiltrated, and complement each other, all in order to prevent or eliminate stone lesions, and is an indispensable part of stone conservation technology.

The following are the formation and treatment of common stone lesions

First, the rust spots of stone lesions

Formation comes from two aspects: First, the natural reaction is generated. Because the material inside the stone contains hematite and pyrite, these iron minerals are exposed to the air to be oxidized to form ferric oxide (rust), which is exuded through the pores of the stone; the second is because the stone is being mined. In the process of processing, transportation, installation, use, etc., it is inevitable to be exposed to iron articles. The residue of these iron articles is applied to the surface of the stone and is oxidized to form rust pollution. The key to preventing rust is that the stone must be waterproofed before installation to prevent the iron mineral inside the stone from being oxidized and oozing out of the stone surface. After installation, the stone must be thoroughly cleaned to prevent the stone from being rusted by external pollution.

In the construction method, dry hanging method should be used as much as possible, especially for stone such as American white linen, which is more prone to rust spots. It should avoid the use of wet construction method. If necessary, it can be used for all-round rust removal and waterproof treatment before installation. . To deal with the existing rust marks, the main products at home and abroad are rust removers. The ideal rust remover should have two conditions: firstly, the stone material after rust removal will not rust again; secondly, the rust remover itself does not corrode Stone does not affect the gloss of the stone surface. However, since the rust remover is acidic, it is necessary to carry out an experiment before derusting the marble (calcium stone), and it is necessary to dilute with water. After descaling, thoroughly clean with water, and then use protective agent to protect the stone, so that the stone has a waterproof function to prevent the occurrence of other diseases in the future and the trouble caused by chemical corrosion.

Second, the stone lesions are not dry

The main reason for the formation is caused by the influence of cement mortar in the wet construction method. Because the composition of cement contains 1% to 2% of sodium hydroxide. Because of its strong adsorption to moisture, when the ambient temperature is higher than 35 degrees in a humid atmosphere, a corrosive sodium carbonate solution is formed immediately. Crystal water often changes due to changes in temperature, but it is never scarce, which creates a phenomenon of wet marks. The prevention method is mainly to protect the stone material, so that the stone material has water repellency, thereby blocking the contact between the water in the air and the stone or cement internal material, and reducing the chemical reaction conditions; secondly, the cement construction and installation materials should be avoided as much as possible. Finally, we must do a good job of joint filling and drainage works. There are no effective methods at home and abroad to deal with the wet marks that have already appeared. The main remedy is to use a resin injection method to deepen the color of the part where no wet marks appear, thereby adjusting the chromatic aberration between the two.

3. Salt crystallization of stone lesions

This phenomenon is mainly caused by the reaction of a strongly alkaline cement with an acidic solution in the atmosphere. After the sodium carbonate solution oozes out to the surface of the stone through the pores of the stone, it immediately neutralizes with the moisture containing carbonic acid to form a salt solution. After the water in the solution is dried, salt crystallization is formed. It will appear in large areas when dissolved in water. Prevention should first avoid the use of wet construction methods, and secondly use protective agents to make the stone waterproof. And do a good job in the joint filling project. The method of dealing with salt crystallization is relatively simple. First, brush off the white powder on the surface of the stone with a brush, then thoroughly clean the residue with a large amount of water, and finally protect it or polish it with a polishing agent with waterproof properties on the surface of the stone.

Fourth, the limestone erosion of stone lesions

This phenomenon arises from the fact that the lime solution that has not been carbonated penetrates into the surface of the outer wall, and quickly reacts with carbon dioxide in the atmosphere to form calcium carbonate which is not easily hydrolyzed, and becomes a permanent coating layer.

This phenomenon mainly occurs at the seam of the stone. In the treatment of lime ablation, the calcium carbonate is first dissolved in an acidic solution, and then the stone is thoroughly washed with water, and finally, a water-repellent resin is injected to block the re-exudation of the lime solution.

Five, frost damage

This kind of phenomenon is mainly caused by cold ice formed by the pores and cracks inside the stone. Because the volumetric expansion rate of liquid water after freezing is about 10%, this will cause a lot of pressure on the inside of the stone to burst the stone. Some porous stones are more prone to such situations. The precautionary measure is to waterproof the stone to reduce the water content inside the stone.

6. The growth of bryophytes

The phenomenon mainly occurs in the interior of the stone where the moisture and organic matter content is high, which causes the stone to change color and reduce the strength and service life of the stone. Precautionary measures must first do a drainage project to avoid accumulation of water; plus the application of protective agents, so that the stone has good waterproof energy. For the moss that has appeared, it should be removed with tools first, and then cleaned with a professional cleaning agent. It is best to protect the stone, waterproof and improve the original drainage facilities.

Seven, chemical corrosion

This is due to the fact that industrial waste gas and the exhaust gas emitted by automobiles increase the content of sulfur dioxide and sulfur trioxide in the air. Dissolved in water to form an acidic solution, which can easily dissolve calcium carbonate in stone, causing chemical corrosion. Prevention is to prevent the waterproofing of the stone before construction and prevent these harmful solutions from entering the stone. In summary, the causes of these problems are all caused by the free entry and exit of harmful ionic solutions through the pores of the stone. In this process, water becomes the carrier of these harmful substances and plays a major role in the chemical reaction of harmful substances. Therefore, the protective treatment of the stone is mainly waterproof treatment.

Concerned about surprises

Label: Common stone lesions and maintenance management

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