Falling into the mortal world

In this era, there was no cement. Those who built houses with lime and clay were all noble families. Ordinary people used clay and wheat stalks.

Craftsmen of this era typically used lime as their primary raw material. They would collect rocks containing high-purity limestone and heat them to high temperatures, causing them to decompose into calcium oxide (quicklime). Next, the quicklime was mixed with water, producing a violent chemical reaction to generate calcium hydroxide (hydrated lime). Hydrated lime has a certain degree of stickiness and binding ability.

They didn't understand the underlying principles; they only knew that this method had excellent adhesive properties, and that only high-ranking officials, nobles, and royalty would use such a method of bonding.

The cement that Lan Qingqing wanted was not this kind of cement.

What she wanted was the real cement from her past life.

Lan Qingqing knew the principle behind cement production; it wasn't a secret in modern times, and anyone who wanted to know would find out.

Cement is made by grinding and mixing limestone, clay, and iron ore powder in a certain proportion. This mixture is called raw meal. Then it is calcined, usually at a temperature of around 1450 degrees Celsius. The product after calcination is called clinker.

Then, the clinker and gypsum are ground together and mixed in a specific ratio to produce cement. This type of cement is called ordinary Portland cement.

Cement is generally classified into ordinary Portland cement, blended Portland cement, and special cement. Blended Portland cement is made by adding other substances to ordinary Portland cement in a certain proportion and through a specific processing procedure to achieve special effects. Examples include slag cement, pozzolanic Portland cement, fly ash Portland cement, and composite Portland cement. These cements contain more active or inactive admixtures than ordinary Portland cement.

Special cements differ in their material stage and manufacturing process. For example, high-alumina cement (aluminate cement) is made from bauxite and limestone, which are calcined to obtain clinker, and then ground into aluminate cement.

Lan Qingqing doesn't need special cement like this for the time being; ordinary cement is already top-notch for this era.

A city built with cement must be indestructible. In this era of cold weapons, a city wall made of cement is indeed indestructible.

Lan Qingqing had iron ore mined, intending to take some back for initial testing. The experiment was successful, leading to mass production.

Limestone is not a rare commodity in the continuous mountain range. Soon, Lan Qingqing discovered limestone.

During her search, Lan Qingqing also discovered a coal mine. Coal is a valuable resource, which delighted Lan Qingqing. With a coal mine, the subsequent progress would be much faster; for example, iron smelting requires a lot of charcoal.

Lan Qingqing gathered all the raw materials for cement and began experimenting. After many attempts, she finally succeeded.

With the other members of the Lan family as witnesses, Lan Qingqing found sand and gravel, mixed it with cement, stirred it evenly, added water, and spread it on the ground. The next day, Lan Qingqing found that the cement had solidified, and the other members of the Lan family were all surprised by the result.

Lan Xiaoxi exclaimed in shock: "This is cement? It's amazing!"

Lan Xiaotian touched the cement with his hand; it was very hard. How could it be so amazing? His shocked expression was clearly visible on his face.

Needless to say, Mr. and Mrs. Lan were just as shocked as the others.

Lan Qingqing patiently explained: This isn't completely dry yet. Come back in a few days, and it will definitely be as hard as a rock.

None of them doubted Lan Qingqing's words at all.

Since the cement was being developed correctly, Lan Qingqing ordered a large-scale mining operation.

Lan Qingqing planned to find some people she trusted to make the cement formula, as she didn't want it to fall into the wrong hands.

The Lan family was well aware of the implications and knew that the prescription had to be made by someone they could trust, which would be the best approach.

Lan Xiaotian only hires people whose character is deemed acceptable.

With a large number of people, everything can be done very quickly. The bricks are being made non-stop every day. Although the brick kilns are small and the output is not large, the sheer number of people means that more bricks can be built!

The fired bricks were stacked neatly in a square, which was quite a sight. Cement production had also begun. Only the core personnel knew the proportions for making the cement.

The people who make cement are very tight-lipped; naturally, they wouldn't dare utter a single word about it to outsiders—it's a secret. They wouldn't even reveal a word to their family.

The first batch of cement was quickly produced, and Lan Qingqing led Wang Dachui to the place where they had previously experimented with cement. Pointing to the cement, she asked, "If we use cement like this to make cement, will there still be any safety hazards?"

Wang Dachui stared at the cement on the ground, not understanding what it meant. He didn't know why Lan Qingqing had asked him to look at the stones on the ground; stones were the most common thing on the mountain. He didn't understand Lan Qingqing's meaning.

Lan Qingqing noticed Wang Dachui's confusion, so in front of him, she mixed the cement and sand evenly, then added water. First, she applied cement to the cement floor and then placed bricks on it. Then she applied cement to the bricks and placed bricks on them. In this way, the two bricks were stuck together with the floor.

Lan Qingqing said: Come back and check the results in two days.

Although Wang Dachui was completely confused, he still nodded. Two days later, Lan Qingqing brought Wang Dachui to see the bricks that had been glued together the day before.

Wang Dachui first tried to move the brick with his hands, but he was shocked to find that he couldn't budge it.

Wang Dachui noticed that the glued area looked very similar to the stones on the ground.

Wang Dachui excitedly asked, "Lord, what is this thing? How can it be so sturdy?"

Lan Qingqing took out a hammer and forcefully struck the cement surface. No cracks appeared in the ground.

This ground is made of cement. With this, can the brick kiln on the blueprints be built?

"Yes, we can build anything, even at great heights," Wang Dachui said excitedly.

Lan Qingqing was relieved to hear that she could build, since construction was not her forte.

Lan Qingqing explained the advantages and disadvantages of cement to Wang Dachui in detail. After that, Lan Qingqing directly handed over the task of building the brick kiln to Wang Dachui.

Once Lan Qingqing has arranged the thought process, she can leave the rest to them.

With iron ore, it's natural to smelt iron; otherwise, wouldn't the iron ore be wasted?

Lan Qingqing found several men with blacksmithing experience in the information registration book.

Having learned that the men had no bad habits, he simply handed them over to smelt iron.

Lan Qingqing first asked them to refine some steel bars, since now that they had the means, she wanted to add steel bars to the city wall.