Can bricks change back to soil under natural conditions?

During the construction one year, a neatly laid brick wall was found two meters underground. Brick is that kind of big brick, which is about twice as large as modern standard brick. After textual research, it was built at the turn of Yuan and Ming Dynasties, 700 years ago. Bricks are well preserved, angular and smooth. Hardness is the same as new brick. Later, relevant experts were consulted, and they said that bricks can be preserved for a long time under closed and constant temperature conditions. For example, the bricks found at that time were buried two meters underground. The temperature difference did not change much, and it was sealed with soil and basically preserved for hundreds of years. If it has been preserved for hundreds of years, it should still be intact.

Later, the expert showed us the wall tiles he kept and the floor tiles laid by the government. It's been five or six hundred years. Only half of the city wall bricks are left, leaving only a thin layer of floor tiles. He said that under natural conditions, exposed parts, wind and sun, alternate temperature changes, the surface will be loose due to frequent thermal expansion and cold contraction. Wind and rain will remove loose parts, and new loose parts will appear, and then remove them. Over time, bricks will become dirt again. Not only bricks, but also hard stones will become soil after a long time.

Of course you can. Bricks are sintered (or cast) soil, and their hardness is not very high. In the face of time, everything on earth is fragile. However, this process is fast or slow, depending on where the bricks are.

In the surface and water environment.

Is the agate in Gobi hard? Under the long-term action of running water and sand, they will gradually be polished off all the edges and corners and eventually become sand. Bricks are much softer than agate.

Photo: Gobi agate, nicknamed "raisin".

Even if there is no sandstorm, as long as water penetrates into the tiny cracks of the brick and freezes again, the brick will expand and become brittle, and then break. Repeated freezing and thawing for hundreds of times will turn into soil.

The worst is superficial life, such as moss. After they are attached to the masonry, they will release acidic substances from the "root" part, which will make the bricks decompose layer by layer from the outside to the inside and eventually turn into soil.

Picture: Bricks covered with moss.

The situation in water is similar to that on the surface of the earth. Under the combined action of various life and natural forces, it is difficult for a brick to survive for 300 years. If maintenance is lost, even a building will collapse and disappear "soon".

Buried in the ground.

If a brick is buried underground, it will remain intact for a long time. Under the protection of soil layer, bricks are protected from air, water and life, and with luck, they may be preserved for tens of millions of years.

But it will gradually change personality. Atoms are in motion, so bricks will constantly exchange materials with things around them. We can understand this as bricks "melting" at a very slow speed in the stratum. Eventually, it will become a part of sedimentary rocks, which will slowly sink into the mantle with the movement of plates, be melted into liquid state and become a natural substance.

Photo: The Indian plate intrudes under the Eurasian plate.

If we are lucky enough, the power of the earth has never destroyed it, then when the sun helium flashes in 5 billion years, it will melt and evaporate with everything on the earth and even fall into the sun.

in short

Bricks with regular shape and uniform composition belong to "low entropy objects", while natural laws tend to be chaotic in high entropy state, and it will do everything possible to push regular objects into chaos. Therefore, unless the universe is "cold", nothing is eternal.

After strong weathering, it will eventually become soil. But if it is buried in wet soil, its strength label will increase year by year.

Of course, bricks can change back into soil under natural conditions, whether they are blue bricks or red bricks, the difference is only the length of time, because wind, rain, sunshine, heat and cold all belong to natural environments. Under the alternation of various environments, anything on the earth can turn into dust and fall to the ground to finally synthesize soil. Moreover, as a traditional building material, brick itself is made of the most common stones and clay, which will be weathered into dust particles even if it doesn't take a long time under natural conditions.

We can look at the most common situation first. Everyone knows the ancient city of Pingyao, Shanxi. Even if you haven't been there, you must have heard of it. Pingyao ancient city has a history of 2700 years. At present, if we carefully observe the periphery of the ancient city, we can clearly see that the blue bricks on the city walls have basically weathered to varying degrees, and the more they are in the dry-wet alternating zone, the more obvious the weathering is. If we take the weathering data of the blue bricks in Pingyao ancient city as a reference, we can roughly infer that in the natural environment, Pingyao ancient city has not even left weathered slag for 200,000 years.

Many people may not understand the weathering mechanism in the natural environment. In fact, there are many kinds of weathering, physical weathering, chemical weathering and even biological weathering. Generally speaking, the weathering of rocks and bricks is carried out under the alternation of physical and chemical modes. Physical weathering is well understood, that is, in the process of frequent thermal expansion and cold contraction, the components of the brick body are constantly released under pressure, which eventually leads to the disintegration of particles, and then peeled off with the wind under the blessing of wind to complete physical weathering.

Chemical weathering mainly depends on salinity. Most rock materials in the world are more easily weathered in saline-alkali environment, because with the participation of salt molecules, material molecules are more easily dissolved. When dissolved to a certain extent, the structural stability of substance molecules is destroyed and solid particles are produced. Under the action of wind, the particles are stripped and scattered, forming soil. Back to the ancient city of Pingyao mentioned earlier, the more places capillary water can reach, the more serious the weathering will be, because capillary water will carry salt molecules in the process of infiltration along the wall, and the specific location is 1-3m above the ground.

Finally, it is said that life can be reincarnated. In fact, the reincarnation here does not mean the reincarnation of the soul, but the reincarnation of the body, because after the death of life, the body tissue does not disappear, but continues to exist on the earth in another way. Over time, these substances will recombine into cells and further transform into life, which can be regarded as reincarnation.

Generally, red bricks fired by clay will begin to weather and peel off after more than 40 years under natural conditions, but will not weather and peel off after 40 years.

Most red bricks are fired from clay. After the wind, rain, sun and rain in the natural environment, and the temperature difference changes in spring, summer, autumn and winter, the internal structure of red brick expands with heat and contracts with cold. Especially in winter and summer, when the hot and cold temperatures are the fiercest, it will be weathered and peeled off, and it will become fine sand, return to nature and completely become soil.

The weathering of red bricks is particularly prominent on the positive side, and the weathering time on the negative side is very long. The red brick buried deep in the soil is isolated from the air for about 4 degrees all the year round, and will not be weathered even in 100 years, which shows that the explosion of the sun can accelerate the weathering process.

Therefore, many people will brush a layer of cement on the wall after the new house is built to protect the wall from direct sunlight and increase the service life of the red brick wall.

In my hometown of northwest Hubei, the walls of the old red brick houses with big tile houses built in the 1980s were made of red bricks fired in the 1970s, and some were made of red bricks fired in the 1980s. Red bricks in the 1970s have been weathered and peeled off seriously for nearly 50 years.

If the red brick is watered manually once a day, it will gradually weather and peel off at most 10 years.

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As long as enough time is given, not to mention bricks, even behemoths such as buildings and tanks can be decomposed by nature, and finally dust returns to dust and soil returns to the embrace of nature.

In nature, the process of decomposing an object takes different time, which depends on temperature, humidity, air exposure and microbial enrichment. The process of decomposing an object is a complex process with both physical and chemical effects. Under the action of external force, on the one hand, the interaction between the constituent molecules of the object is broken; On the other hand, some macromolecules such as organic compounds and complexes are decomposed into small molecules or carbon dioxide and water. But the proportion of physical and chemical processes is related to the composition of the object itself. For example, rocks in polymer state are mainly decomposed by physical changes, while animal carcasses, plant branches and leaves, etc.

In fact, from the perspective of brick making, it was originally made of clay, especially clay, and the main components of clay are silica, alumina, iron oxide, some crystal hydrates, liquid water, some humus and so on. The main working procedures of brick burning include digging, setting, air drying and roasting. In this process, crystal hydrate and liquid water lose water molecules due to high temperature. Silica reacts chemically with some metal oxides to form silicates, some substances undergo crystal repolymerization, and the rest organic substances undergo a combustion-like reaction, leaving organic substances and discharging carbon dioxide and water, which is also the main process of clay polymerization into bricks. There is no great necessity for the constituent substances. The main losses are water and organic matter, and most of the rest are re-polymerization.

In the natural state, after a long period of weathering, rain erosion and microbial growth, bricks will first crack into small pieces, and then these small pieces will be further decomposed under the action of solar radiation, wind and rain erosion and microorganisms, especially in acidic environment, and finally return to the soil in the form of fine powdery substances, and the returned substances have the same composition and structure as the soil. In a sense, bricks only change the soil of "packaging", but only

Let's start with the conclusion: yes.

To understand this problem, we must first understand how soil becomes bricks. And how is the soil formed?

Knowing these two questions, it is easy to answer this question.

1. How did the soil become bricks?

The bricks used in our building are divided into baking-free bricks and sintered bricks according to whether they are sintered or not.

The problem in the topic is sintered brick, or "clay brick". This kind of brick takes clay as the main raw material and is finally made by mud treatment, molding, drying and roasting.

The main chemical components of clay are silica, alumina, ferric oxide and crystal water, and alumina may contain a small amount of alkali metal and alkaline earth metal oxides.

The picture shows the Quaternary clay in Estonia. Source: Wikipedia.

When the roasting temperature is controlled between 900 1 100, the organic water in the soil will disappear and undergo a chemical reaction, mainly producing ferric oxide (Fe2O3), or red Fe2O3 will be reduced to cyan ferrous oxide (FeO). These are the main components of red bricks and blue bricks respectively.

The picture shows a red brick.

The picture shows the blue brick.

2. How is the soil formed?

The formation process of soil and its influencing factors are very complicated, so I will briefly summarize them here.

The first step is weathering. Weathering causes rocks to break and structures to become loose. We call this kind of thing "soil parent material", which is the source that determines the composition of soil materials.

Secondly, through the role of various natural factors. Including climate, soil parent material, vegetation (biology), topography and time. Soil is formed under the joint action of the above five soil-forming factors.

Bricks can become soil.

So to solve the above two problems, the last one is easy.

The composition difference between soil and brick is mainly in organic matter, water and some inorganic substances that change at high temperature. Not two completely different substances.

After weathering, bricks can become soil again under the action of climate, soil parent material, vegetation (biology), topography and time.

Stone cried: that's because you don't understand the ruthlessness of weathering! Even I will turn into sand sooner or later, let alone a brick! Alas, what comes from dust will eventually return to dust. Who can stand the test of time?

Brick is an artificial small block material for human building, which is mainly divided into sintered brick (clay brick) and non-sintered brick (lime sand brick, fly ash brick, etc. ). Clay brick is made of clay (including shale, coal gangue and other powders) as the main raw material, which is processed, shaped, dried and roasted. Modern bricks have gradually developed from clay as the main raw material to the use of industrial wastes such as coal gangue and fly ash, and at the same time from solid to porous hollow, from sintering to non-sintering.

Bricks, like stones, are easily influenced by natural factors such as wind, water and frost in nature. Physical weathering will break bricks into small pieces. It can be achieved by wind and rain peeling, freeze-thaw cycle, wear, root swelling and dry-wet cycle. When the temperature changes rapidly, bricks will expand or crack. Frozen meltwater expands when it freezes. If moisture seeps into the cracks of bricks before winter, it will freeze and separate the bricks. When the wind blows, it will pick up sand and silt and blow the bricks to pieces.

Like freezing and thawing, the roots of trees grow bigger every year. These roots can separate bricks. Chemicals always react in the environment, leading to chemical weathering. The main chemical reactions include carbonization, dissolution, hydration, hydrolysis and redox reaction. All these reactions are related to water. Carbonic acid is saturated. Water reacts with carbon dioxide to produce carbonic acid, which can dissolve bricks.

Limestone and high-salt bricks are soluble in water. The water carried away the ions. Minerals in bricks will react with water and surrounding acids. Hydrogen atoms have replaced other cations. Brick water synthesizes clay. Redox water and brick particles react with oxygen. This causes minerals and materials to rust and turn red. Chemical weathering is more common if the weather is hot and humid. If the weather is dry, physical weathering is more prominent.

Your question is very interesting. Let me say something else through your place.

Last time I went hiking, a man pointed to a stone egg in the mud wall on the mountain road and asked me a question. He said, "Look, those stones have been buried in the soil for many years. Will they change? "

I said "yes". They will grow, otherwise there is no difference in size. Small stones will grow into big stones, and particles will grow into small stones, so there is a saying that no one can grow into a useful person.

So, your question is simple. [Smiles]