Speaking of which, Zhu Daming, who came from later generations, suddenly remembered one thing, although it was not urgent, but the sooner it started, the better, this is the problem of building a city. Pen @ fun @ pavilion wWw. ｂｉｑUｇE。 There is no problem in building a city, and a nation that can build the Great Wall of China certainly has no problems that cannot be overcome in building a city, and all kinds of city defense fortifications are also striving for excellence.

However, Zhu Daming, who came from later generations, knew some better and more effective methods and materials. The method can be left out for the time being, but the sooner the material is developed, the better. This material, of course, is the cement concrete material of later generations. In fact, since the Song Dynasty, Sanhe soil has spread in the land of China, and in the Ming Dynasty, it has been widely used to build cities and pave roads.

The so-called triple soil, as the name suggests, is the soil made of three materials. It is said that it is soil, but it is not soil, but simple concrete in ancient times, similar to the so-called Roman mortar used by the Romans to build city fortifications, which plays the role of mixing and coagulating building materials such as bricks and stones.

Specifically, triad soil is composed of hydrated lime, clay and fine sand, which basically accounts for one-third of the proportion, but the proportion in actual use mainly depends on the sand content of the soil, and at the same time increase the proportion of hydrated lime, and the coagulation effect will be better.

Of course, according to the actual situation, it can also be made of slaked lime and slag, crushed stone and other grinding powder, or forty percent of hydrated lime and sixty percent of loess can also be made. The ancient Chinese city walls, especially the Great Wall built in the Ming Dynasty, were built with a combination of three-fold earth and masonry, which can be regarded as strong and durable. However, although the Sanhe soil is strong and durable, compared with the cement used in later generations, it is still far inferior, whether it is solidity, fire resistance, water insulation, or the effect of rapid condensation, it is not as good as the cement concrete of later generations.

Therefore, as soon as Zhu Daming thought of this matter, he thought about quickly building this kind of thing from the cement and concrete of later generations, once he had this thing, it would definitely be twice the result with half the effort to build a city with it, even if he learned to cast and use artillery in the future, Daming didn't have to worry about them using artillery to attack the city.

The power of the old-fashioned artillery may be useful for the old-style three-way earth-clad brick wall, but for the cement and concrete walls of later generations, its power is not worth mentioning at all. In addition, at this time, the artillery used mostly solid bullets, it was basically impossible to smash the cement and concrete city wall.

Now Yang Yingqian's military tun division, in order to build the new army camp and the residence of the new tunhu, has been in Zhuozhou and other places, digging and building more than 10 brick kilns, under the guidance of craftsmen sent by the Ministry of Industry, began to fire green bricks in large quantities, if there is cement concrete, in the future to build the new army camp siege and barracks, and even rebuild the city wall of Tongzhou and other Beijing portals, it will be faster and stronger.

Tongzhou is the east gate of Beijing, Changping is the north gate of Beijing, Fangshan is the west gate of Beijing, Gu'an is the south gate of Beijing, these cities in the past two years, must be widened and heightened and reinforced, and must be completed before the winter of the second year of Chongzhen.

Others don't know the reason, but Zhu Daming does. Because in the winter of the second year of Chongzhen in history, around the end of October, more than 100,000 Jianlu's army was about to break through from the north of the Beijing Division.

Historically, these cities fell because they were defenseless, so that the Jianyu drove straight in, and finally hit the gate of Jingshi Desheng. In this life, Zhu Daming must not make such a mistake, not only to organize and train the new army in advance, but also to build a strong city in advance, so as to leave an unforgettable lesson when the time comes.

In addition, the process of firing cement is not complicated, but it is slightly more than the triple soil, and there is a little more composition. If you want to increase the strength and hardness, you can add iron ore, crush it together, mix it, and then grind it finely, which is considered to be the raw material made of cement concrete; After being made into cement concrete, it is transported into the kiln for high temperature firing, and after firing, it becomes the clinker of cement concrete; After firing the mature material, it is mixed with an appropriate amount of gypsum, and then ground into powder.

The reason for adding gypsum is to control the rate at which the cement sets. If you want the concrete to set faster, you can add more, and if you want it to set slowly, add less. The whole process is two grinding and one burning.

The high-temperature firing here may be a little difficult for ordinary people, because it has relatively high requirements for furnace temperature, generally reaching 1,400 degrees, but for the Ministry of Industry of the Ming Dynasty, the high temperature of 1,400 degrees is not much of a problem, and the Ming Dynasty's Foshan, Guangdong, Jingdezhen, Jiangxi, including Zunhua's iron smelting industry, common kilns, can reach such a temperature. Moreover, Zunhua has a lot of iron ore, ironmaking and slag, which can completely burn higher quality cement concrete.

Zhu Daming told Li Banghua about the idea of firing Sanhe soil to obtain new concrete. He thought that Li Banghua would not understand or be surprised, but in fact Li Banghua was not surprised.

For a man who knows a lot about the military, the Sanhe soil is of course very familiar, the Ministry of Engineering is in charge of civil engineering construction, and the Sanhe soil is naturally a common and commonly used thing. But the concrete that the emperor said, of course he had never heard of it. However, the emperor said that concrete was the Sanhe soil of Westerners, and it was a common material used by Westerners to build cities, so he did not investigate the root cause.

The emperors of the Ming Dynasty, unlike the emperors of the Manchu Qing Dynasty in later generations, never rejected the progress of Western studies or science and technology, such as Xu Guangqi, Li Zhizao, Li Tianjing, Sun Yuanhua, etc., these people who admired Western science and even believed in Catholicism, not only were admitted to Jinshi, but also became high-ranking officials. Not to mention that the Emperor of the Apocalypse himself was a genius craftsman.

Li Banghua has also recently heard people talk that the current emperor is quite interested in the knowledge of Westerners, and not only sent Westerners to follow him to Trench Jingao to buy muskets and artillery, but also prepared to hire a group of Western craftsmen and technicians to go north to help build the official cannon foundry run by the imperial court. Li Banghua also thought that when these people arrived in Beijing, I was afraid that nine times out of ten they might be assigned to the Ministry of Industry for management.

Of course, the most important thing is that the emperor has made it very clear that the so-called Western concrete is indeed only on the basis of the traditional triad soil ingredients, adding a high-temperature firing process, and then adding some gypsum.

So after listening to the emperor's statement, Li Banghua quickly received the order and prepared to send people to try to make it, and after success, he built a factory in Baiye City, and then fired it on a large scale. After discussing all these things, Zhu Daming finally let Li Banghua leave, and he himself set up Kunning Palace to have dinner with the queen.