Decorative stone problems

From time immemorial, a variety of solid stone building has become a major building materials, such as the Colosseum, the pyramids of Egypt, in Beijing in 1937. The period of royal buildings in large numbers with a stone.
Stone of modern architectural projects have been a lot of use. A stone used in Construction Stone and use of the number of species directly affects the level of architectural decoration, building owners or building high-end designers in determining the decorative level, the will of the stone variety, color contrast repeated screening, to reach the the best decorative effect. However, the use of, a variety of illnesses because of damage to stone the actual decorative effect, as long as we observe these phenomena is found very much, such as: Bank of China Fuxingmen wall, the CPPCC National Committee, the Ministry of podium, Beijing the subway station walls, suburban Xizhimen, Dongzhimen the ground, and so on.
A special decorative stone ground that the Beijing Hotel, Beijing Hotel in 2000 for large-scale renovation project in 2001, the owners should be required to carry out ground disease control. In an elevator scene, we observed two stone in the black edge of each side of 5 cm, when workers use detergent to clean the black bars, we found the black can be cleaned, but also found a black stone below is dull, we spot test, ruled out the shiny stone cleaning agents the possibility of damage. Observed under a magnifying glass, dull part of the stone surface has many tiny holes, some of the dust into these holes will make the stone surface to deepen the color black. So how these small holes are formed? Through which we understand have not been before construction stone stone protection. So after the construction, extension of the cement stone of saline is absorbed into the stone surface of the four sides, and corrosion of the stone edge. Makes the shiny stone to eliminate, as far as hotels Engineering Department introduced at the hotel about 6000M2 ground stone, exist in this situation. This disease is completely resolved, can only deal with the renovation, Beijing Hotel Engineering Department in 2001, the renovation of the ground polished.
For these stone disease, we feel very shocking, has reached a point where treatment can not. It destroyed the building the appearance of the decorative effect, but also undermines the image of Beijing as an international metropolis, and Beijing's rapid development is not in harmony with the requirements of the 2008 Olympic Games far.
Decorative reasons for the formation mechanism of stone disease
Stone disease causes are varied, the reasons of their own which includes stone, stone processing during transport, stone and stone used in the construction process, the process will have a variety of diseases. In fact, as long as careful observation reveals that, in all the process of stone disease has its own characteristics.
1, such as stone processing and transportation, this period stone processing equipment and the disease is caused by improper transportation protection.
We know there is a stone processing technology called the blast, its iron ore processing is the use of compressed air driven jet in the stone surface, and make it a rough surface of the decorative effect, such as processed stone hit the surface residual pieces of iron particles in the processing after a period of time under the influence of surface water will be returned to yellow, back to rust, we have a new main building at Beijing Normal University recently wall honeycomb stone disease management project, the experience is this situation:
Beijing Normal University, the new main building roof using light steel roof, as load-bearing load is not too large, so the use of aluminum honeycomb composite stone panel of more than 2,000 M2, because the surface of stone composite panels only 3-5 mm thick, fire craft can not be used Therefore, only the stone surface blasting process. The stone from the factory to the construction site found a large area back to rust, rust manufacturers to adopt a special agent for processing stone, yellow rust removed. We also recommend that before: rust stone protection should be carried out, but our recommendations were not adopted, the removal of scaffolding to complete the acceptance period of time, a large area of ​​the stone and return rust. Because the stone is used in more than 30 meters with a floor on the building eaves, roof top for the light, not to cling to point, so rust, protective construction is extremely difficult and dangerous, but also makes the construction cost greatly increased construction time extended.
(2) stone disease and construction techniques, varieties of stone have a direct relationship. But the final analysis, the culprit is the stone disease in the salt water and cement, alkali substances. Wet Splash stone cementitious material is mainly cement. Cement containing part of the Ca +, Na +. These ion material in the cement and water to form and easy process CaOH 2, NaOH, while the cement contains a lot of salt. These substances are soluble in water, and together with water into the stone. Splash in the wet stone surface for a long period of time the color will deepen. If the day care unfavorable, will form water spots.
These substances are formed alkali salt water spots: we conducted the following experiment: Take 6 Granite divided into two groups of three comparative test; a group with pure water, soaked 24 hours after the removal, and around the back closed with plastic tape . Another group with 10% of the material and a small amount of cement, salt in water solution to soak for 24 hours after the removal, back and around the same closed with plastic tape; the specimen in the baking heat lamp, three days after the watermark while reducing , after a week immersed in pure water has been restored to the specimen surface during the drying color; and soaked with salt mixture over the stone surface is still visible watermark, two weeks after the immersion of the stone surface with a mixture to the dry recovered when the color. Repeat the same test specimen soaked in a mixture of stone found in a second drying time extension. But when we test the middle of the back and around the plastic tape will be removed, the stone will be dried within a few days, the original surface of the water spots away.
These phenomena and test results tell us that such a process: the construction of stone wet cement in the cement in the less salt and curing of the material, together with water into the stone, and extended the gap to reach stone natural stone surface, water will be evaporated in the air, some of the CaOH 2, NaOH, CaCo3, Na2Co3 be left in the stone. Pores in the stone will be left a lot of salt, these substances will slowly clogging the pores of stone, the stone inside the water can not evaporate through the porous stone, together with routine maintenance may not be law, so they water spots form. When we remove the stone back of the adhesive material, the stone inside the water will evaporate from the back, which could lead to stone water spots disappear.
Cement in the saline substances into the stone, the stone will stimulate the formation of iron oxide Fe203, which is what we usually see the stone back to yellow.
3 stone in daily use problems are also often seen. Many high-rise buildings are decorated with a hanging wall stone wall, hanging stone is to overcome one of the advantages linked to the wet stone, return to base, back to rust, white and Chinese and other shortcomings. Therefore, many construction unit that is not necessary for stone protection. Here are some data I can find some problems:
People in the Marco Polo Bridge in Beijing to study the stone lions found during the past 50 years, the degree of weathering of the surface of the stone lions far ahead of 7-8 years of weathering. Bridge some of the lions are now weathering serious, some not see the outline of a lion.
Beijing Environmental Protection Bureau issued in 2002 and mentioned in the report of the atmosphere below the weather in 2002 two in total 162 days from the sulfur dioxide and suspended particulate matter pollution accounted for 95%.
Thus, the modern industrial production of sulfur dioxide and dust particles of pollution is still very serious. The existence of such pollution, the danger is hanging stone for long-term, it will accelerate the weathering of the stone surface, so that stone color, texture changes, but should attract attention.
Stone disease prevention
Stone disease can be prevented, by brushing stone repellant to stone disease prevention purposes. Stone protective agent can effectively avoid or reduce the production of a variety of stone disease, prevent water spots, Bai Hua, from the alkali, rust, etc. from stone disease. How to properly use and use of protective stone stone Protectant is the key.
We advocate such a principle: a scientific, rational choice and the correct use of protective agent protective agent is indispensable.
How to achieve this principle, first of all should be aware of the classification of protective agent. Combined with the specific requirements of our project, we repellant divided into: 1, waterproof; 2, and pollution prevention; 3, anti-oil type; 4, the back of the type; 5, the other type.
Stone Stone repellant selection should be based sources of pollution to the specific characteristics and the use of options. For example: Building wall hanging stone, because stone used in the ground a few meters away from the first hundred meters, usually man-made pollution is very small, there may be contamination of natural dust, rain. Especially once the rain will make the stone into the stone to produce water spots, rust, over time will affect the building's appearance. This feature combined with the choice of protective agent when we should use water-based repellant, waterproof protective agent is characterized by excellent waterproof effect and lower price. In the edge of a pool, bathroom countertops, large surface areas can choose type of protectant, such as the construction of protective agent in the wet did not generally prohibit the use of special instructions in the stone back.
Another example is the building's lobby and the staff often move around and people can come into contact with the stone, its main sources are coffee, tea, cola, and various fruit juices, in the construction when there will be ink and other contaminants, combined with the characteristics of pollution sources, We recommend protective agent should use anti-fouling protective agent, its price is higher than the waterproof, protective agent in the overall price is moderate.
Anti-oil repellant properties of oil is a very good protective agent, it can use the kitchen table, dining on the ground as well as other parts of the stone more on oil, its price is higher than the price of the two protective agent.
The back of the protective agent, in the construction area after construction because the formation of opaque film, make the stone texture, color affected, it is mainly used in stone on the back and around. Construction of wet stone and it will not reduce the strength of cement mortar paste. At the same time, it can close the empty dark stone surface crack, the water and alkali in the cement, salt within the stone can not be penetrated, to prevent water spots resulting from the construction stone, efflorescence, pan rust, wet paste which is indispensable in stone repellant.
The use of protective agent is a very important part, should be taken seriously, on the one hand the stone used is not a monolithic protective agent, it is subject to construction, stone varieties, stone water content, so the construction of the protective agent, should be strictly instructions in accordance with the requirements of protective agent to do the other construction workers should also be careful not leak seriously uneven brush or brushing only from scrupulous in all aspects, in order to maximize the role of protective agent.
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