The first section of rust yellow
Generally, the genesis of rust yellow can be discussed from three aspects. First, the original material (ie, the stage of stone formation), the substrate-containing rust yellow which occurs in unstable iron minerals, and the second is caused by improper handling during stone processing. Rust yellow, three, rusting pollution of the accessories after installation, the following two aspects are described one by one.
Original rust yellow
There are iron-containing minerals in the interior of marble, such as iron carbonate, iron sulfide, and ferrite minerals. This has been detailed in the previous chapters. Generally, iron-bearing minerals are more stable with ferric chloride minerals, and iron sulfide is the least. Stable, therefore, unstable iron sulfide can be said to be the most common cause of rust yellow pollution on the stone surface. In addition, although the biotite is more stable than iron sulfide, it may be oxidized and rusted under the action of acid and water for a long time. Mine (Fe2O3\Nh2O), the contaminated stone forms rust yellow, and even if the volume expands due to rust, the layer peels off, thus forming a small pit on the surface of the stone.
Rust yellow caused by improper stone processing procedures
1. When the original stone is cut by steel wire sawing, the surface of the stone may not be cleaned due to the residual steel sand. After the action of water and gas, the rust class is formed. Generally speaking, after the stone is polished and polished, the situation of the rust class usually does not occur. .
Second, the stone is pickled after being cut, and the residual acid causes the accelerated oxidation of the iron-containing mineral of the stone.
Stone hanging accessories pollution:
When the stone is installed by wet reinforcement method or dry method, the iron fittings rust and spread to the surface of the stone. Due to the rust yellow factor, the stone itself contains unstable iron-containing minerals or foreign rust. Because the moisture penetrates into the surface of the stone to cause rust yellow, therefore, reducing the moisture content of the stone can avoid the occurrence of stone rust yellow, and the preventive measures are as follows:
First, the stone is to be maintained before installation to prevent water from invading the slate, and to avoid rust yellow caused by the oxidation of iron-containing minerals and moisture and oxygen in the air.
Second, when cleaning the stone, avoid using acid-containing detergent to clean, because acidic substances are easy to dissolve iron-containing minerals. It reacts with moisture and oxygen in the air to cause rust yellow.
Third, when the stone is installed in a dry method, the stainless steel pendant should be carefully selected to prevent the pendant from spreading to the surface of the stone due to rust and forming rust yellow.
Fourth, the stone surface in the decoration, avoid the use of materials and accessories that are easy to pollute the stone, such as lamps without anti-rust treatment, air outlet wind deflector, fixed screws, etc., and the stone cutting saw wear after decoration, should be in Apply the curing agent once. To prevent rust yellow from spreading to the surface and forming pollution.
The second section of Baihua
Baihua is a phenomenon in which white powder is deposited on the surface of stone or in joints. It often occurs outdoors or where water is abundant. Such as flower benches, outdoor steps, external wall caulking and so on.
When the stone is installed by the wet construction method, the alkaline substance such as calcium hydroxide and calcium in the cement mortar is backed up and dissolved by a large amount of water to penetrate the surface of the stone or the place where the joint is not filled, and the calcium hydroxide is again combined with the air. The carbon dioxide in the acid or the SO2 sulfuric acid compound in the acid fish reacts to form calcium carbonate or calcium sulfate when the water evaporates. Calcium carbonate or calcium sulfate crystallizes to form white huahua.
Baihua, a source of moisture that is dissolved according to the alkaline matter in the cement. It can be divided into Baihua and Secondary Baihua. When the cement slurry is too high, the excess water will dissolve the calcium hydroxide or alkaline metal ions out of the stone surface or the joints are not solid. The formed Baihua is called Baihuahua because its water source comes directly from the cement mixing water. When the rainwater seeps into the cement mortar under the stone, or the groundwater dissolves under the hydroxide or alkaline metal ions, it penetrates into the water. The surface of the stone or the place where the caulking is not solid accumulates into a white semi-solid powder. The formed white yam is made by indirectly being dissolved by the external water to fill the cement alkali substance, so it is called secondary white huahua.
The measures to prevent the formation of Baihua are as follows:
First, the stone should be maintained before the installation (positive, five or six sides, depending on the project requirements), to prevent the stone from inhaling too much water, to prevent the cement from the front of the stone or the groundwater source into the cement mortar under the stone to avoid cement The alkaline metal ions of the mortar penetrate into the stone, causing Baihua.
Second, select the joint material suitable for the stone, and follow the correct construction method to construct. Good quality sealing material and correct construction method. It can prevent the occurrence of Baihua at the joint.
3. When the powder is mixed with cement mortar, use low water-ash ratio or additional water-reducing agent to reduce excess water. One can avoid the occurrence of Baihua.
4. Adding a waterproofing agent to the cement mortar can prevent the metal ions from being dissolved and oozing out of the surface of the stone to form white hua.
Fifth, the use of non-polluting aggregates, such as calcium, magnesium, sodium and other sea sand, and avoid the use of more mineral groundwater for mixing water, reduce the source of metal ions, reduce the incidence of water spots.
The third water spot
The water spot is the wet and watery surface of the stone, which causes the surface of the stone to produce an overall or partial dull phenomenon, which affects the beauty of the stone.
The causes of water spots on stone are mostly divided into two categories. The first category belongs to the absorption of neutral water. The reasons are as follows:
Since the stone is a porous material, when the rainwater and the water for cleaning the ground penetrate the front surface of the stone by capillary principle, the surface of the stone will be dull. This water spot is usually temporary, as long as it is dry, the water can naturally The play is excreted and restores the original appearance of the stone.
Another type of water spot that can cause stone lesions. It may cause specific damage to the stone. The cause is related to the improper construction of the stone when it is installed by wet construction or wet reinforcement. The reasons are as follows: Cement is the most commonly used bonding material for wet installation of stone. It contains a large amount of calcium oxide, aluminum oxide and iron oxide. Among them, calcium oxide accounts for about 20% of the total volume of cement products. It is easily soluble in water and is installed in wet mode. When cementing stone, if the calcium oxide in the cement is not completely water-soluble, the strongly alkaline calcium oxide will remain in the mortar filled in the stone back. If the stone is installed near the water source or the cement mortar water-cement ratio is too high during construction (It is easy to cause the calcium oxide reaction to be incomplete). Excess water dissolves the calcium hydride and penetrates to the surface of the stone by capillary principle. Then it reacts with carbon dioxide in the air to form calcium carbonate. At this time, the calcium carbonate is adsorbed due to the deliquescent. The crystal water will cause the surface of the stone to be wet and watery, causing dullness in the whole or part of the stone surface.
In general, the water surface phenomenon caused by improper construction of the above-mentioned construction materials without using a curing agent is comprehensive. That is, the water class will be evenly distributed on all surfaces of the stone. If the quality of the curing agent is not good or the construction method is not carried out according to the correct construction method, the water spot phenomenon caused by the stone maintenance project is unevenly distributed, and the alkaline water returns poorly from the curing quality. Infiltrated, causing local water spots (we measured the surface pH of the surface of the stone where water spots occurred, and found that the PH value can reach 13 or more, which is strongly alkaline). The above water spots caused by poor construction methods Except for the beauty. Stones with a small environment with a long-term alkalinity may cause damage to the quality of the stone, especially for granite with a high content of carbon dioxide. In severe cases, it will cause spalling of crystal particles. Due to the factors that cause water spots. Because the calcium hydroxide or other alkaline metal ions in the water-filled mortar are dissolved by excess water, they penetrate into the interior of the stone and gradually ooze out the surface of the stone. Further, with the carbon dioxide in the air, the water vapor should form calcium carbonate containing deliquescent ( This kind of salt will continuously absorb water from the air to form crystal water), and the surface of the stone will be wet and watery. Therefore, it is necessary to avoid the penetration of water into the interior and surface of the stone to avoid the occurrence of water spots. Thinking in two directions: First, waterproofing the stone to prevent moisture from entering the stone. Second, reducing water or waterproofing in the backfilling cement slurry, and a waterproofing layer seeps out the paddle into the slate.
The following describes the actual solution to water spot lesions in the above two directions:
First, the method of stone conservation to prevent the occurrence of alkaline water spots in stone
(1) Using a positive-type curing agent for frontal maintenance measures, so that the high-moisture water infiltrated into the stone by the back-filled mortar is blocked under the permeable layer for curing, so that the exposed alkaline moisture does not pass through the visible Stone surface, the advantage of this method is that the stone is only front-maintened, the materials used and the labor cost are lower, but the disadvantage is: the front maintenance is caused by the failure of the construction method and the improper use of the medicament, and it is not easy to remedy (after the failure of the maintenance operation) The water spots that appear are not easy to handle and are locally distributed, which is extremely unattractive).
(2) The maintenance method is to adopt the maintenance method of six sides of stone. The method is to use the back type maintenance type on the rough stone (ground and surrounding), and use the front maintenance on the smooth surface. The advantage is that the stone is well maintained and cured. The chances of failure are small. The disadvantage is that the cost of materials is high and it is generally not easy to accept.
(3) The quality and method of use of the curing agent curing agent should be used before the installation of the stone, which has a great influence on the curing effect. Therefore, it is necessary to carefully select the curing agent and use the correct construction method.
Second, the method of backfilling cement mortar waterproofing and reducing water
(1) When mixing cement mortar, use low water-cement ratio or add water reducing agent. Water reducing agent is a kind of surfactant. Adding cement concrete mixture can make cement particles disperse and cement The water bound by the slurry space grid structure is released, reducing the mixing water volume of the concrete, and promoting the full hydration of the cement, thereby increasing the density of the concrete.
(2) Adding a waterproofing agent to the cement mortar, the water repellent is a heavy resin, which can form a wrong compound with calcium or other metal ions, and can prevent metal ions from being oozing out of the water surface by a large amount of water to form water spots.
(3) Select non-polluting aggregates, such as sea sand with more calcium, magnesium and sodium ions, and avoid using groundwater with more minerals as mixing water to reduce the source of metal ions and reduce the chance of water spots.
Fourth section of the stain
Stone is a porous material. For tea, coffee, soy sauce and ink, it stays on the surface of the stone for a long time, and it will easily penetrate into the interior of the stone to cause pollution and affect the appearance of the stone. In addition, improper use of construction materials or poor work practices during construction and installation may also cause pollution. Such as residual cement powder, adhesive for adhesive tape, improper use of additives. (When using silicon to add seams, light black pollution often occurs. This kind of pollution is banded along the seam, and the width can be more than several centimeters. This is because Silicon is a small amount of unhardened in the caulking agent. The molecular weight of Silicon penetrates into the stone)
Precautions to avoid stain formation:
First, before the installation of stone, it is advisable to use curing agent first, especially in high-pollution environment, such as kitchen, dining table, etc. Pre-work maintenance work is more important. Good quality curing agent has the characteristics of water extraction and oil extraction, so it can prevent most pollution sources from infiltrating into the stone.
Second, the stone should be very careful during installation, to avoid construction workers polluting the stone with betel nut juice, tea and other pollution sources, or other construction machinery due to oil spills and stone pollution.
Third, when the stone is contaminated by betel nut juice, tea, oil, etc., it should be cleaned immediately to remove the pollution. Because the longer the pollution time, the deeper and wider the pollution, the harder it is to remove.
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