The development of any empire cannot bypass the bottleneck of resources, and the most important resource bottlenecks are nothing more than four categories: food, fuel, fiber and building materials. Pen ~ fun ~ pavilion www.biquge.info

The four bottlenecks that hinder the economic growth of all empires, and each empire faces these constraints, must get rid of these four resource bottlenecks if economic growth is to be rapidly increased.

Food is the core of any empire, without food, the common people will not be able to fill their stomachs, the empire will be in turmoil, or even collapse, and the backwardness of agricultural technology will lead to extremely low productivity of food, so that a large number of people must be engaged in agricultural production in order to meet the empire's demand for food.

As a result, the empire could not spare enough manpower to carry out other work, and even, in the face of foreign invasion, it had to recruit the poorly trained agricultural population to join the army, thus destroying the development of agriculture to a certain extent and causing the loss of national strength.

After Li An invented black powder, Datang's steel output increased dozens of times, and ordinary people could use more iron farm tools for farming, thereby increasing the output of grain, and in the later gradual promotion of agricultural machinery, agricultural productivity was higher, so that many manpower could withdraw from agricultural production and transfer to the field of industrial and handicraft production.

The importance of fiber is similar to that of food, because Datang is in the temperate zone, divided into four seasons of the year, summer is better, but the winter is very cold, if there is not enough fiber, you can't make enough cotton clothes, so, the people will be frozen to death, so, in order to meet the demand for clothing, Datang must divide part of the arable land to plant mulberry leaves and flax to make silk and linen to meet the demand for clothing.

And in this way, the land where mulberry leaves and flax are planted can not grow grain, which forms a constraint on food, of course, silkworm raising and weaving require a lot of manpower, which is also very huge for the consumption of manpower, and a large amount of manpower is sucked on this.

After Li An invented various machinery, increased the output of pig iron, and produced two crops a year, he could meet the needs of less arable land and produce more grain.

Not to mention the importance of fuel, people need to eat every day, and they must use fuel to eat, firewood and charcoal have always been the most relied on fuel for ordinary people.

But the burning efficiency of firewood and charcoal is relatively low, and the amount of use is naturally relatively large, so that the people in the countryside often go up the mountain to cut firewood, which consumes a lot of manpower, and the people in the city need to spend more money, and the purchase of these firewoods consumes the same is not small, and wood is an important material for making carriages and furniture, as well as houses, and a large amount of consumption of wood will inevitably restrict the construction of furniture, carriages and houses, thereby restricting economic development.

After Li An came to Datang, he first invented honeycomb coal, and gradually became popular, which greatly saved manpower and material resources, and then invented the solar stove is even more powerful, can directly use solar energy to boil water and cook, and has no consumption of fuel, although there is not the sun every day, but most of the time of the year is sunny, which is undeniable, so that at least half of the fuel consumption can be saved, so as to solve the problem of fuel constraints.

The last big problem is the building materials, the building is the necessary facilities to maintain human habitation, and in the Tang Empire, the building is mainly wood and stone, of which wood is the mainstay.

Whether it is the use of wood or stone, it requires a lot of manpower to mine, and then it needs to be processed, the consumption of labor and natural resources is very huge, and the growth of wood takes a lot of time, excessive exploitation will lead to a large reduction of forest resources, thus causing serious soil erosion problems.

The Wei River in Guanzhong, and the Yellow River in the Central Plains are muddy rivers because of the fact that human activities are too frequent and they have cut down forests to meet their own needs, which has caused such serious consequences.

Now that Ang Lee has invented cement and concrete, it is possible to use this new material to make buildings in the future, thus freeing himself from the great destruction of forest resources.

Of course, these things that Ang Lee has invented so far can only alleviate the constraints of the four major bottlenecks on the empire's economy, and there are many aspects, and we still have to continue to work hard.

And because the role of cement is very huge, so Li An did not hesitate to go to the palace in person, in front of the emperor, to demonstrate the huge role of cement, so as to obtain the will to promote it throughout the country as soon as possible.

"Your Majesty, the cement will dry naturally, it will take a whole day, we will no longer wait here, just leave it to these people to watch."

Suddenly the wind rose, Li An motioned for Li Longji to return to Zichen Palace, besides, Li An still had a lot to say, to face Li Longji, in too many places such as idle people, it was not convenient to say it.

"Well, Li Shilang come with me!"

Li Longji nodded lightly and took Li An back to Zichen Palace.

"Li Shilang, there are no idle people waiting here, what do you have to say."

Li Longji hurriedly asked.

"Your Majesty, cement and concrete are extremely important to the Tang Empire, and Weichen feels that the production method of cement should be notified to all states and counties, so that all states and counties can make cement and put it into use, so that the dependence on wood can be greatly reduced."

Ang Lee opened his mouth to suggest.

"Reducing dependence on wood? Is Li Shilang going to make a house out of cement? ”

"That's right, Your Majesty, it is more advantageous to make a house out of cement than it is to make a house out of wood, and the house is stronger, less likely to be blown down by the wind, and cheaper, and more cost-effective in any case."

Li An opened his mouth to say the reason, and continued: "Your Majesty, cement has a great effect, not only can it be used to build houses, but also can be used to pave roads, build walls, build bridge piers, etc., especially paving roads, will make the road easier to walk, in case of rainy weather, there will be no silt problem, this is why Wechen wants to let every state and county build cement workshops, in the future, as long as all states and counties are paved with concrete roads, the road will become easier to walk, The transportation of goods will become much easier. ”

"Roads with concrete?"

Li Longji frowned and thought about it, now that the concrete pavement has not yet begun to be laid, Li Longji is really hard to imagine, he doesn't know what kind of effect will there be after the concrete is paved, and the houses made of cement will be strong? Can it be lived?

"Li Shilang, your proposal is very good, but I want to see the houses made of cement with my own eyes, as well as the concrete pavement, and bridge piers, as for the promotion of the whole country, this is not in a hurry."

Li Longji is still a little conservative, he feels that he must first make sure that the cement is really so good, and then he can promote it throughout the country, otherwise, once the cement is not as easy to use as Li An said, he will not be complained.

"Yes, Your Majesty, then Weichen will build a road leading to the east outside the Chunming Gate, and cross the Longshou Canal, and build a concrete bridge over the Longshou Canal, and build a concrete pavilion and a two-story concrete house on the opposite bank of the bridge, please ask Your Majesty's permission."

Li An opened his mouth and asked.

"Okay, Li Shilang just go and prepare, how long will it take? How much manpower is needed? ”

Li Longji asked.

"Your Majesty, Weichen has already prepared the materials, as long as there are a thousand craftsmen, half a month is enough."

Li An said confidently.

"Okay, then I'll wait for half a month to appreciate Li Shilang's achievements, if it's good enough, I'll consider promoting it across the country."

Li Longji seemed very happy, and continued to chat with Li Ang about various newly developed machinery and the construction of two strategic railways.

After leaving the palace, Ang Lee immediately mobilized 1,000 men and horses, using a large number of horse-drawn carriages, to transport a large amount of cement, sand and gravel made in the R&D center to the outside of Chunming Gate, and in addition, in order to prevent the construction from being disturbed, Chunming Gate was temporarily closed to anyone to pass.

After the materials were prepared, the construction began immediately, and the technical difficulty of building these things was very small, and it was nothing to Li An and the craftsmen.

However, in order to complete the construction as soon as possible, several points need to start construction at the same time, part of the road is responsible for paving, part of the bridge pier is responsible for the preparation of laying the bridge, and a small part is responsible for the construction of the pavilion and the two-story concrete building, so that the decomposition is not very manpower in each part, especially the manpower of the gazebo is only a few dozen, but it will be completed within half a month, there is no problem.

The work of paving the road is very simple, because this section of the road has long been stepped on by pedestrians coming and going, and there is no longer a need to compact the road surface, and it is enough to lay gravel directly on the road surface, and after laying the gravel, sprinkle the mixture of sand and cement on it, but do not add water, use tools to compact, and the last step can lay the mixed concrete.

Because the gravel in the concrete is too heavy, it is difficult to mix with a shovel, and it is difficult to mix evenly, so Li An has already asked the craftsmen to build a drum mixer, and it is driven by a steam engine, of course, due to time constraints, only two machines have been built so far, but it is enough for laying a short section of road.

Before laying the first concrete road, Ang Lee fully considered various situations, such as the thermal expansion and contraction of concrete, the strength of the road surface, and whether the foundation was stable.

For the foundation, Li An is confident that there will be no problems, the strength of the concrete has also been tested, as long as the craftsman is careful to construct, there will not be too much of a problem, and in order to resist thermal expansion and contraction, the road crack problem may be caused, Li An adopts the method of surface embossing, leaving a gap every five steps, so that the cracks on the road surface can be greatly reduced, and the beauty and practicality of the road can be guaranteed.

The craftsmen in charge of the construction paved each section of the road in full accordance with Li An's requirements, from the beginning of laying gravel to the final gap, all in strict accordance with the requirements, and did not dare to violate the slightest violation.

The construction of the bridge pier is not very difficult, first use the pre-made concrete pillars into the silt, and enclose a circular area, and then pour concrete into this area, so as to form a solid bridge pier, and in order to increase the strength, Li An used a long iron rod to act as a steel bar, the effect is naturally better than nothing.

After all three piers were solidified, the steel-concrete deck was laid and was quickly completed.

The concrete gazebo is a small project, and it is the fastest to complete, but it takes a lot of time to do some decoration.

The two-story concrete house, which used more than 100 people, made progress relatively quickly, but it was the last to be completed.

The two-storey house is not large, the first floor has only five houses, including a stairwell, and the second floor is even less, with only three rooms, with a large terrace on one side to stand on and enjoy the scenery in the distance.

After all this was completed, Li An personally inspected it, expressed satisfaction with the construction results of the craftsmen, and only after a day of drying did he report to Li Longji, and asked Li Longji and the ministers to come to visit to test the use of cement and concrete, and finally promote it throughout Datang.

Li Longji rode on foot, under the protection of a large number of guards, set off from Daming Palace, marched along the Jiacheng, and finally arrived at Chunming Gate.

At the moment when the Chunming Gate opened, the Tang Emperor Li Longji walked out of the city gate with the civil and military officials of the court, and saw the roads, bridges, pavilions and houses built by Li An.

They were impressed by something that had never been seen before, the roads were smooth and hard, the bridges were atmospheric and thick, and the pavilions and houses also gave a sturdy feel.

On both sides of the road, two rows of soldiers of the Yulin Army were lined up to ensure the personal safety of the emperor and the ministers, and farther away, there were also a large number of soldiers and horses to maintain order and prevent idle people from entering here.

Li Longji walked in the front, and Li An accompanied him, half a body slower than Li Longji.

"It's good, the road is smooth, it looks sturdy, what is the horizontal line on it for, and what are the ravines for?"

Li Longji felt very solid when he walked on the concrete pavement, but he felt very curious when he saw the horizontal lines and ravines on the pavement.

"Your Majesty, this is to prevent cracks on the road surface, if there are no these things, it won't be long before there will be many cracks on the road surface, which will affect the normal use of the road surface."

Li An hurriedly opened his mouth to explain, telling Li Longji the role of cracks and ravines on the road.

"Li Shilang, why is there a long yellow line drawn in the middle of this road, does it also play an important role?"

"That's right! Why draw a yellow line in the middle of a good road surface. ”

One minister spotted a yellow line in the middle of the road and questioned it, which resonated with several ministers.