Chapter 149: The Birth of Cement

"Your Highness."

Wang Ying stood up, not knowing where to put his mud-covered hands.

He had been concentrating on making the Mud Cannon, and it was only when Zhao Xu spoke that his attention was diverted.

"This is already the third one; the previous ones failed." Wang Ying pointed to a puddle of mud nearby, his smile somewhat awkward.

The Mud Cannon was made to a large size according to the blueprints, and because the mud was soft, the resulting Mud Cannon easily cracked or broke.

Originally, he thought it would be very simple, but after getting his hands on it, he realized the difficulty involved.

"It's fine, learning lessons from failure is a good thing," Zhao Xu said.

The difficulty of the mud mold lies in mixing the mud; the mixed mud cannot be too soft, nor can it be too hard.

Soft mud is easy to break, while hard mud is difficult to shape.

This can only be mastered by them; after failing a few times, they will get the hang of the timing.

Looking up and around, he said, "Where is the iron-smelting slag being dumped?"

This was something he had asked Wang Ying to save back when he was smelting iron.

The purpose was to take it out and use it in the future.

"Your Highness, follow this subordinate." Wang Ying stood up and led Zhao Xu to a storeroom inside.

Inside were piles of slag left over from iron smelting.

At this moment, craftsmen were still continuously bringing slag over.

"Your Highness, what exactly is this stuff for?" Wang Ying had been confused for a long time.

Now that Yan Wang finally mentioned these slags, he couldn't help but ask.

"To make cement," Zhao Xu said.

"What is that?" Both Wang Ying and Zou Rong showed curious expressions.

"You will know in a moment." Hearing is not as good as seeing; he decided to create the cement himself.

Silicate Cement, also called Portland Cement, appeared in the mid-nineteenth century.

In earlier periods, people mostly calcined Limestone and then used it as plaster to bind buildings.

Later, when a builder was purchasing Limestone, he discovered that it was mixed with clay, but the lime produced after burning had better binding properties than before.

Afterward, he tried adding volcanic ash, ceramic tile powder, and other materials, finding the effect even better.

Finally, he thought of using the slag after iron smelting to replace volcanic ash and other materials, ultimately determining the composition of cement.

What Zhao Xu is doing now is this kind of cement.

He had Wang Ying take out some slag, grind it into powder, mix it with clay, and then calcine it in a kiln.

Both men were single-mindedly waiting to see the surprise Yan Wang had for them.

They did whatever Zhao Xu told them to do.

After more than two hours, the craftsmen took the powder out of the kiln.

This was the gray powder, which was exactly the cement of the modern era.

"Find a few blue bricks, and get some Sha and water," Zhao Xu said.

Once the materials were ready, Zhao Xu personally mixed the cement with the Sha and water.

After stirring it into a paste, he spread the cement between two bricks and placed them on the ground.

"Alright, let's come back and look tomorrow. Wang Ying, you must keep a close eye on it," Zhao Xu laughed.

Wang Ying and Zou Rong were still confused upon hearing this.

The next day.

Zou Rong came to the Armory again.

He found that quite a few people were gathered around the place where the blue bricks were placed.

After a while, Yan Wang also arrived, and the craftsmen immediately made way.

"Official Zou, pick up the top brick and try," Zhao Xu said.

Zou Rong nodded; he had endured his curiosity for an entire night.

He walked over and carefully held the top blue brick, then lifted it, discovering that the brick below was also lifted up.

"Eh." Zou Rong showed a surprised expression, but thinking that there was mud here, he felt that mud could also stick things together.

"Pull it again," Zhao Xu said.

Zou Rong nodded and grabbed one brick in each hand to pull, but he surprisingly couldn't pull them apart at all.

Then he gathered all his strength and gave a fierce tug, which finally pulled the two bricks apart.

At this, he showed an astonished expression, "This is truly magical. If we use this stuff to build houses, they will surely be very sturdy."

"This is only after one day; after a week, you won't be able to pull them apart even if you try," Zhao Xu said, always aiming to shock. "And this cement has another benefit: even if soaked in water, it won't be eroded or ruined."

Zou Rong's mouth hung open in surprise; Yan Wang's claim was too shocking for him.

Wang Ying and Wang Chong also came over to watch the excitement; both men bowed down to Yan Wang once again, feeling that Yan Wang's head contained endless brilliant ideas.

"If you mix cement, Sha, and stone again, this is another even sturdier material; you can go back and try it slowly," Zhao Xu said to Zou Rong. "Now there's no problem with building the houses for the Workshop, right?"

"No problem, absolutely no problem," Zou Rong swallowed his saliva.

He was eager to use the cement immediately to see to what extent this thing could be applied.

The effect of the cement was known to everyone at once.

Zhao Xu said to Wang Ying, "Allocate a batch of craftsmen to calcine cement; this slag is enough to use."

During this period of iron and steel smelting, the Armory had accumulated thousands of tons of slag; the cement made from this slag would be enough to last for a long time.

"Yes, Your Highness," Wang Ying said.

Nodding, Zhao Xu and Zou Rong left the Armory.

On the road, Zhao Xu recalled the matter of the Northern Di's Autumn Hunt last time.

Currently, he did not yet have the capability to attack the Northern Di.

Because the longer the supply line was stretched, the more disadvantageous it was for him.

For a very long time in the future, he would remain in a defensive position.

Therefore, during this period, he had also been thinking about countermeasures.

After much thought, he felt it was necessary to use Wuan County as the center and establish a defensive fortress zone along the Yanshan line against the Northern Di.

Although Yanshan is vast, there are only four or five small paths through the mountains that lead to Yan Commandery.

If Lengbao built with Concrete were established along the paths of these trails, supplemented by Artillery, wouldn't it be possible to block the Northern Di's passages for moving south?

This kind of Lengbao is different from ordinary walled cities.

In terms of structure, it turns a Fortress from a convex polygon into a concave polygon.

Such an improvement ensures that no matter which point of the fortress is attacked, the attacking side will be exposed to more than one, or even three, faces of the Lengbao.

And the defending side can use crossfire to conduct multiple strikes against the enemy.

Before there was Artillery, such crossfire consisted of bows and arrows and other long-range Weapons.

If Artillery were added, the enemy would certainly find attacking such a Lengbao quite miserable.

In the past, the Imperial Court could not do it because ordinary Fortresses were ineffective at guarding such small paths.

If there were few soldiers, they would collapse without a fight.

If there were many soldiers, it would greatly disperse the military strength, and one would have to build a fortress large enough to accommodate so many troops.

Of course, in the final analysis, this is a matter of cost.

The Imperial Court would rather let the Northern Di people rob the commoners year after year than spend money and grain on this.

In any case, it did not affect the safety of the Great Song.

However, it was different for him.

Yan Commandery and Shanggu Commandery were his fiefs; who could stand having this happen every now and then?

Furthermore, without a peaceful environment, how could internal construction be carried out?

Therefore, he simply had to build these Bastion Fortresses.

Thinking of this, he said to Zou Rong, "You can leave the affairs of the Chengde Workshop to the officials below; there is a very important matter that this Prince must entrust to you."