Roland waited in the back yard of the kiln for the first batch of cement to come out.
This brick structure was specifically designed for cement production, measuring approximately fifteen meters in length and four meters in width. Both the front and rear doors were present, with the front door being exceptionally wide to facilitate material transportation. The rear door, however, was narrow enough for a single person to slip through, allowing Anna to sneak into the kiln.
To secure the area, he built a perimeter wall halfway up the house, enclosing the latter section of the kiln. The entrances and exits were guarded by Knights—Carter's loyal subordinates whose devotion was beyond question.
The production process of cement is relatively straightforward. The limestone is crushed into a fine powder and mixed with clay and iron powder. The mixture is then calcined into clinker using either dry or wet methods, followed by grinding with gypsum to produce the final product. The raw materials are quite common, and the iron powder can be omitted if it is difficult to obtain in large quantities. The key factor lies in the calcination temperature of the clinker.
Roland couldn't recall the exact temperature required for cement firing. Even if he remembered, he couldn't measure or control it—both infrared thermometers and thermocouple thermometers were far more complex than cement itself. All he knew was that the temperature was close to iron's melting point, and the calcination process was a major challenge in cement production.
In the era of underdeveloped smelting technology, maintaining blast furnace temperatures remained a persistent challenge. Conventional open hearth furnaces suffered from massive heat loss, making it difficult to sustain temperatures above 1,200 degrees. Refractory furnaces, meanwhile, required high-temperature resistant linings, yet the development of suitable refractory bricks remained elusive. Traditional blast furnaces proved even more inadequate—while they might achieve the required temperatures, relying solely on their narrow chambers to calcine cement would likely result in insufficient output even after the critical production period had passed.
Therefore, Roland's kiln had no heating system at all, relying entirely on Anna.
The finely crushed limestone was blended with clay, watered down, and stirred into a slurry that was evenly spread across the firing chamber. Knight then locked the door and dismissed the workers. Anna entered through the back door, letting the flames scorch the slurry on the ground until the iron rods inside melted.
Roland felt restless, marking his first step in guarding Border Town. Without cement, the three-month plan to build a wall would be nothing but empty talk. Without a wall to block the way, no one would be willing to defend this cursed place. Whether in real history or fictional literature, a stable base is essential for farming.
"Your Highness, can this substance you mentioned actually bond stones together?" Carter Lannis, who had been stationed by the Fourth Prince, asked. Though the Prince assured him it was the latest breakthrough from Graycastle's alchemy workshop, Carter remained skeptical. After all, that group had never produced any truly reliable alchemical products.
"Who knows? Anyway, that's what they say," Roland said, spreading his hands.
In this world, alchemy and astrology are collectively known as the arts of the wise, widely practiced across continental nations. Royal families typically train their own alchemists and astrologers for crafting secret potions and predicting destinies. To ordinary people, such studies seem so esoteric that they breed blind faith. Recognizing this, Roland naturally shifted the blame for the cement formula's origin to the alchemy workshop. Whether Chief Knight believed it or not, it didn't matter.
The flames in the window gradually died down, indicating the pottery was ready.
Roland sprang to his feet, shoved Carter out of the yard, and stood alone at the back door of the brick house, waiting.
The iron gate creaked open, and Anna emerged in her bare skin. Roland immediately draped a robe over her and brought her a glass of water. "How's it coming along?" he asked. The Witch's face was covered in dust. While wet-process cement production generated minimal dust, the scorching air during firing still stirred up particles. For someone who couldn't wear a mask, staying inside for even a few minutes would be unbearable. She cleared her throat twice and nodded. "The slurry has turned to fine dust." Roland couldn't wait for the kiln to cool enough. Wrapping a damp towel around his head, he grabbed a shovel and slipped through the back door.
He was instantly enveloped by scorching air, experiencing temporary dyspnea with burning pain in the skin of his hands. Fortunately, removing a handful of dust required minimal time; otherwise, exposure to such conditions for even a few minutes could potentially induce heat shock.
"That's what you want?" Anna asked, turning her head after putting on the Witch suit.
"It looks similar," Roland said, smoothing the powder and feeling its lingering warmth with his fingers. "We'll have to test it to see if it works." "What's its purpose?" "It can be used to build houses, bridges, and roads—there are countless applications. If successful, people's homes won't be vulnerable to wind, rain, or snow." He patted the girl's head with his other hand. "It's all thanks to you." Anna lowered her head. He sensed her breathing quickened slightly, though he wasn't sure if it was just an illusion.
Theoretically, the calcined clinker should be ground with gypsum to adjust its setting time. But at this stage, no need to overthink it. After a brief rest, Roland scooped out two more handfuls and called Carter, who was standing outside the yard, to mix cement mortar in a ratio of three parts lime powder to one part river sand.
Chief Knight had no qualms about doing menial tasks. To him, such work was far preferable to the brawls he'd faced for Your Highness at Graycastle or the romantic escapades with Noble Misses.
Since no iron powder was added to the raw materials, the resulting cement slurry appeared pale and grayish-white. Roland poured the mixture onto a stone brick and placed another brick on top. The cement took about four hours to set. Given the instability of the test specimen, he decided to wait until tomorrow to see the results.
Early the next morning, Roland rushed to the kiln's backyard with Carter and Anna. When he pushed open the door, the cement surface was already solidified, tightly bonded to two stone bricks. The hardened surface appeared uneven, with patches of frosty white coating.
Roland crouched down and scraped off the white frost from the alkalization reaction. Pressing the hardened cement with his fingers, he felt a sudden delight—the surface was rock-solid, a stark contrast to the gritty texture of compacted soil. Even if he tried to scratch it with his nails, not a single scratch would leave a mark.
After receiving the Fourth Prince's signal, Carter first attempted to lift the stone bricks but failed. He kicked the cement from the side several times until the joint with the ground broke, though the two bricks remained firmly attached. Finally, he swung the sword hilt and struck them forcefully, but only managed to chip off a small fragment.
"Is this what 'cement' does?" Carter immediately grasped its power. "It's unbelievable. What flowed like molten wax just yesterday has hardened into rock overnight. With this, we can build walls as fast as we want. With enough stones, we could erect a border wall within five years!" "What's the point?" Roland scoffed. "No matter how high the walls, they can't stop enemies from within. I'd rather turn Border Town's dilapidated wooden huts into sturdy cement houses, sparing my people the fear of being left homeless after a disaster." "..." Chief Knight froze. He hadn't expected the Fourth Prince, who embodied all the vices of the Nobles, to utter such words.
"You'll see," Roland reaffirmed his path—while technology is the primary driver for most traversers, in this realm, witches reign supreme.