"Your Majesty, this thing is almost as hard as a stone. Old Cheng's hands are shaking from the shock."

Li Shimin knew that Cheng Yaojin would not fool him, but he still picked up the hammer and smashed it a few times. The result was the same as when Cheng Yaojin did it. The cement block was not smashed, but a few dents were made on the surface.

of small pits.

"How can this thing be so hard?" Li Shimin secretly clicked his tongue.

Li Jing looked at Qin Hao with bright eyes: "Mr. Qin County, can this thing be used to build city walls?"

"Building a city wall? The hardness of cement is sufficient, but this material is afraid of weathering, and its hardness will decrease after a few decades. Moreover, if the city wall is made of cement as the main body, it will be difficult to strengthen and repair it in the future."

"Decades? It's a pity to say so." Li Jing sighed in disappointment.

Ancient city wall construction standards were based on hundreds of years. A few decades is equivalent to a lifespan reduced by half. The most terrible thing is Qin Hao's last sentence. It is difficult to reinforce. Most city walls have to be repaired before they completely collapse.

Repairing and rebuilding it every few decades would be a waste of time and money.

Li Shimin frowned when he heard this. So, isn't this cement just like chicken ribs, tasteless and a pity to throw away?

"How much does this cement cost?"

Qin Hao and Yun Ye looked at each other: "According to a rough estimate, the cost of building a three-story building, including other materials such as sand, gravel, bricks, etc., should be around five guans."

"What? Wu Guan?"

Du Ruhui and other civil servants screamed in surprise.

Li Shimin didn't know how much money it would cost to build a house among the private sector, so he could only wait for what Du Ruhui and others would say.

Sure enough, Du Ruhui came to Qin Hao excitedly.

"Mr. Qin County, Your Majesty, this matter is related to the destiny of the country, so don't talk nonsense!"

Qin Hao said calmly: "Wuguan is already a conservative estimate, and it may be even lower."

"If the cost of this thing is so low, it may indeed be used to build a city wall, but I don't know how much labor it will take to build it." Du Ruhui bowed deeply to Li Shimin.

In ancient times, corvee has always been a headache for the court and the people.

There are fewer corvees, city walls need to be repaired, palaces need to be built, and the emperor's tomb also needs to be built. We can't let the army do the repairs, right? What if there is an invasion by foreign enemies? So we can only mobilize the people to do the repairs.

However, if there are too many corvees and they are too frequent, the land will be deserted and the people will not be able to make a living. This is how Emperor Yang of the Sui Dynasty played himself to death. Otherwise, if the conquest of Goguryeo failed, the world would not be in chaos.

"If we only count the main structure, a three-story building with seven or eight strong laborers should be enough." Qin Hao remembers that when he was a child, five or six people were enough to build a house in the countryside. However, considering that in ancient times,

Without an excavator, it would definitely be more troublesome to dig the foundation, so I counted two or three more people.

Du Ruhui and other civil servants all had expressions of disbelief.

Qin Hao said unhurriedly: "The academy will break ground soon, won't we know then?"

"So, I am looking forward to your academy more and more." Li Shimin laughed.

When leaving, Li Shimin did not forget to get a few bags of freshly prepared cement from the cement workshop. Qin Hao also wrote the correct method of using cement on a piece of paper and gave it to Li Shimin.

Yun Ye looked at Li Shimin's back with a strange expression on his face.

"Senior Brother, do you think that if a thousand years later, when our generation does archeology and finds that the ancient tombs are all cement concrete structures, will they think that the people of the Tang Dynasty obtained high technology from aliens?"

"Perhaps foreigners will use this to deny our history and think that these were built by us later." When Qin Hao thought of such a scene, he felt inexplicably happy.

On the other side, after Li Shimin returned to the palace, he called the Minister of Industry over.

"I order you to build a three-story building next to the Taiji Hall. Use this cement to build it. If you don't understand anything, just ask the Qin County man and the Yun County man."
Chapter completed!