I! Pretending to Be Reborn, Director of Doomsday Hoax

Today, the Pantheon is still the largest unsupported concrete vault in the world, but also because it spans too large to be capped.

Lu Guangyuan had some longing in his eyes, and said: "As far as I know, the Pantheon adopts a centralized form covered by a dome, which represents Loma and also represents the pinnacle of dome construction technology in the world." The dome of the Pantheon is made of concrete, brick tiles, etc., and pumice is used as aggregate for concrete. Probably, bricks and tiles are used to build a few bricks along the spherical surface first, and then the concrete is poured. "However, today, perhaps something is missing, perhaps the key material, the ancient Roman concrete technology, has been lost." "

The ancient Roman concrete in the structure of the Pantheon is actually similar to modern concrete in appearance.

However, the surface of ancient Roman concrete is rougher.

However, in terms of performance,

The concrete of Ancient Rome is extremely hard, very strong, and its durability is very strong!

Take the Pantheon as an example, it has been standing for thousands of years!

It is embarrassing that modern concrete, also known as Portland cement, has a service life of up to 100 years. In fact, seven to eighty years has already reached the limit.

Lu Guangyuan was a little confused. In his eyes, the superiority of ancient Roman concrete was beyond the reach of modern Portland cement.

"Director Xu, even from the perspective of environmental protection, the carbon dioxide emissions produced by ancient Roman concrete during the manufacturing process are only one-third of that of modern concrete...

"So I really don't understand why you don't try to decompose the concrete of the Pantheon. With the current material analysis technology, it should not be difficult to understand the mystery of the ancient Roman concrete." Xu Qiu smiled.

In fact, it is hard to say that the craftsmanship of ancient Roman concrete has been lost, but it has been eliminated by social and economic changes and technological innovations.

Today's concrete is basically a coupon arch structure.

This kind of structure has a delicate load-bearing structure, a large space span, and it is convenient to open windows for lighting.

Compared with the ancient Roman concrete walls, only a bunch of small dark windows dared to be opened. I don't know how high it is.

Blindly worshiping ancient technology is actually somewhat of a secondary school taste.

Even if it is a difference machine, if Babbage is really to be reborn, and the difference machine he imagined back then is made, the calculation speed may not be as fast as the calculator used by students.

It is actually very difficult for ancient technology to play an important role today.

Because almost all ancient technologies, compared with today's technologies, can only be backward and inefficient. Otherwise, what is the point of human development for so many years?

Xu Qiu said: "However, the many advantages of the ancient Roman concrete you mentioned do exist. The contemporary reluctance to reuse the ancient Roman concrete has nothing to do with the quality, but its craftsmanship." "Technology?" Lu Guangyuan was puzzled.

Xu Qiu explained:

"First of all, you need to know the geographical location of Ancient Rome.

It is bounded by the Sabatini Volcano in the northwest and the Obano Hills in the southeast.

Although these two places are extinct volcanoes now, they were active 600,000 years ago and did not become dormant until 400,000 years ago.

However, both volcanoes were created by crustal movement, so the early eruptions were not on the ground, leaving much magma behind.

After the earth's crust changes, the magma layer rises, which causes the surface soil to be heated.

Explosive volcanic activity causes the solid rock and magma on the surface to be broken down into fine particles and ejected, forming volcanoes and craters at the same time.

After years of accumulation, the area around Ancient Rome was covered with volcanic ash several meters away. Even now, there is still a large amount of reserves.

After the volcano is formed, what flows out is magma.

After the magma is cooled, it is the basalt distributed on the surface. "

Zou Botao and Lu Guangyuan both nodded.

They still understand this knowledge.

Basalt is very hard, and without the help of modern machinery, a dozen strong men can shake a small piece in a few hours.

Xu Qiu went on to introduce, saying:

"The ancient Roman horse is not far from Dawu itself, which means that there are shallow waters near the ancient Roman horse leading to the sea, such as rivers, caves, underground water veins, etc.

Limestone is deposited in these shallow waters.

More than 20 years, volcanic eruptions, crustal deformation, etc. also caused some limestone, calcite and other minerals with calcium carbonate as the main component to be in a state of high temperature and high pressure, and then they will become marble.Therefore, under the influence of long-term deposition and natural factors, the mineral resources in the ancient Roman area are these things, basalt, marble, limestone and white pomegranate volcanic ash. "Lu Guangyuan and the others listened fascinated.

The shock in my heart was even stronger.

Xu Qiu is not only extremely talented in architecture and physics, but also understands history and paleogeography?

Xu Qiu paused for a moment, looked at Lu Guangyuan, and said solemnly: "As for the question you mentioned before, why not use ancient Roman concrete, that's the reason!

"White pomegranate volcanic ash!"

Lu Guangyuan was surprised and asked: "This kind of thing can make the performance of concrete very superior, but it is no longer produced in modern times?"

Xu Qiu shook his head and said with a smile, "On the contrary!"

The answer was beyond everyone's expectations.

Xu Qiu gave an explanation, saying:

"The main components of white pozzolan ash are silicon oxide and aluminum oxide, and the content of aluminum element is very high.

Modern concrete is mainly composed of lime and clay raw materials after high-temperature frying and burning. The main components are gypsum, tricalcium silicate, and dicalcium silicate.

When these chemicals hit water, they form calcium silicate, a type of silicate.

When the pozzolan volcanic ash and lime are mixed with water, regular calcium acid is formed, which is a calcium aluminum silicate that can strengthen the interface area and the durability of the cemented matrix! "

"Calcium aluminum silicate?"

Composed of three elements?

Lu Guangyuan and Zou Baitao looked at each other, and they both saw the confusion in each other's eyes.

"Director Xu, as far as I know, if metal elements are added, the hardness and elasticity should be improved?" Zou Botao asked.

Doesn't this just improve performance?

Xu Qiu smiled and shook his head, and said: "Old Zou's words are correct, its essence is still silicate, and with the addition of aluminum elements, the hardness and elasticity of concrete can be improved. concrete

Reasons to be more durable and stronger than contemporary Portland cement.

"But here lies the fatal flaw!

"With the addition of aluminum, the solidification period of ancient Roman concrete is 180 days!"

Lu Guangyuan was stunned: "180 days?!"

For modern concrete, the solidification time is about 28 days, not more than one month.

And the concrete in ancient Rome, it takes more than half a year just to solidify?

Xu Qiu said: "So do you understand that, in order to increase the performance by one to two times, and add six times the cost and construction period, this is not suitable for modern construction.

"What's more, now is an extraordinary period, and there are only ten months before the sun goes out...

"Ancient Roman concrete is indeed harder, more durable, and more elastic, but its ability to resist cold is not even as good as today's ordinary concrete.

"Our time is running out!"

Xu Qiu was silent for a moment, then said: "Of course, in fact, the advantages of ancient Roman concrete no longer exist in today's world.

"The most valuable point of the ancient Roman concrete back then was its durability and low carbon.

However, cities today generally do not need cultural relics that can stand for thousands of years. For urban development, most buildings will be demolished after about 80 years.

Unless it is a monument with a special meaning, a landmark building, etc., no one will choose ancient Roman concrete.

As for low carbon.

Ancient Rome concrete uses less lime, so the output of carbon dioxide is also less, which is the root cause of low carbon.

However, with today's science and technology, recycled aggregate concrete has long been produced. Simply put, it is to make aggregates from discarded concrete slag and recast concrete.The cost of this kind of concrete is lower than that of ancient Roman concrete, and the low carbon level even exceeds that of ancient Roman concrete.

The construction period is consistent with that of common Portland cement, which is less than one month.

Even, the concrete science community, already has eco-cement, which is similar to recycled aggregate concrete and is also made from municipal waste.

However, fly ash is added to the mortar of ecological cement. This substance can absorb carbon dioxide in the air. It is not only low-carbon, but can even absorb carbon! 々〃! "Xu Qiu shook his head lightly.

Ancient, in most cases, means backwardness and elimination.

Ancient Roman concrete and Babbage's difference engine are already outcasts of the times.

Its glorious era has passed 200 years ago, even thousands of years ago.

It is not the difference machine that becomes the mechanical technology tree.

Instead, the Nuclear Difference Engine.

"Let Professor Yan Yan come to see me, the cold concrete of Longguo is about to come out." Xu Qiu said.

From the field of machinery to the field of construction, the miracles of the Dragon Kingdom are constantly being staged.

At this moment, Dragon Kingdom Tiandu, Shenlong Construction Engineering Group.

Looking at a small test piece in front of him, Yan Yan was so excited beyond words.

After Xu Qiu's guidance, the concrete developed by Yan Yan's team has reached an unprecedented level of strength, and has unparalleled cold resistance.

This kind of concrete can be used normally in the environment of minus [-] degrees to minus [-] degrees.

The extreme ambient temperature reached minus [-] degrees.

The concrete can even be moved to the poles to build houses if you want!

"What is the greatest material in human history? It is concrete!" Yan Yan squeezed this small test piece excitedly.

An engineer with dust on his face said: "Yes, residential buildings on small islands, skyscrapers, cross-sea bridges, and expressways, there is no place where concrete is not used!" Yan Yan said: "Concrete already has more than 9000 It is estimated that even the first batch of craftsmen at that time would not have guessed that with a history of [-] years, today, this kind of concrete can actually become a material that can face the Little Ice Age!" Back then, it was concrete that gave birth to the huge ancient theater, the Colosseum, Bathrooms and sewers all over the city etc.

only,

People at that time didn't know the principle of concrete, they just mixed natural materials with each other, and the quality was not stable.

With the decline of ancient Rome, without the natural volcanic ash of Pompeii volcano, this technology was gradually lost.

until modern times,

With the blessing of science, scientists began to gradually improve the firing process of cement, and summed up the law of concrete proportion and strength.

later

Water-reducing and antifreeze agents were also born one after another.

In fact, Longguo's concrete research has long been at the forefront of the world.

In 2016 alone, 84 high-rise buildings over 200 meters were built in Longguo. Behind this architectural miracle is the blowout development of super high-rise building concrete technology in Longguo.Yan Yan once participated in the discussion of concrete quality in various scientific research institutes and construction units, and made suggestions.

The rapid development of Longguo infrastructure can be said to be based on concrete technology.