Qin Chuan still understands casting cement, and when he was a child, his family built a house, and he was used as a coolie to help with the work.

As soon as someone builds a house in the village, they will go to play with a group of children to see if they can pick up some steel bars or something, and the methods and processes of pouring cement are basically remembered in their minds.

In order to develop concrete buildings, Qinchuan also deliberately built a sand and gravel factory, specializing in digging sand and pebbles on the river beach.

Crushed stone is temporarily not used, there is no mechanical era, manpower to break the stone is too hard, the cement plant to break the limestone is already a very hard and very inefficient work, the city wall of Montenegro Fort to use gravel, I am afraid to build a stone factory of thousands of people, day and night constantly pounding stones to meet the demand.

The southern wall of Montenegro Fort is about 300 steps long, and Qinchuan is ready to adopt the method of layered casting, first casting the foundation as a whole, and then pouring it layer by layer.

There were 1,500 workers involved in the construction of the wall, some of whom were laborers responsible for transporting materials, and as many as 800 people who were actually involved in the concrete stirring and casting, divided into 20 groups, each with its own area of responsibility.

After the quarantine period in Qinchuan ended, he began to instruct the workers to tie steel bars and teach them hand in hand.

Due to the unskilled workers, it took three days to complete the steel bars of the foundation alone, and another day to arrange the formwork.

Qin Chuan began to worry, concrete pouring is technical, to pour the whole within a certain period of time, otherwise it will form a gap, affecting the quality of the building, and when pouring, it is necessary to use sticks to keep tinkering, exhaust the air inside, and increase the density of concrete.

None of these workers have experience in concrete pouring, and it is difficult to make any mistakes.

Qin Chuan simply postponed the construction period, first found a piece of land, dug the foundation, tied steel bars, arranged templates, and then gathered dozens of craftsmen together, taught them how to tinker, and focused on reminding some problems that should be paid attention to, such as the interval between pouring concrete in a place can not exceed two quarters of an hour, otherwise the two layers of concrete are difficult to bond, and the height of the concrete can not exceed five feet.

After teaching for two days, it was not until all the craftsmen knew how to do it that Qin Chuan decided to start work.

On the morning of the start of construction, as soon as the sky was slightly bright, Qin Chuan yawned and walked out of the inner courtyard to the construction site.

More than 1,000 workers had eaten and drunk enough, and they ate dry food early in the morning, and everyone ate meat, so as to ensure that they had the strength to do their work for an hour or two in a row.

Qin Chuan arrived at the construction site and shouted "start work", and all the workers were busy under the urging of the foreman.

First, the concrete is fried, according to the best ratio that has been found before, the cement, pebbles and sand are shoveled to the open ground and mixed, then water is added, and the shovel is constantly stirred.

After the slurry is made, the grout is carried to the foundation in a wooden barrel and poured into a trough, while the craftsman begins to pound it with a stick.

Qin Chuan, the big foreman, was the busiest, running around all the time, pointing fingers everywhere.

The 300-step construction site was full of people, and 1,500 workers were in full swing, shouting and urging endlessly.

The workers at the construction site, plus workers from cement factories, steel rebar factories, sand and gravel factories, a total of five or six thousand people, spent seventy or eighty stone of grain and more than three hundred taels of wages in one day.

Although there were many problems in the process, it was generally smooth.

After the completion of the 300-step city wall, it is actually a row of reinforced buildings, and the foundation is the style of the buildings in the later townships, one grid at a time, with three zhang between each interval, and there will be fifty rooms on each floor after completion, a total of three floors, which can be used as warehouses, office rooms, barracks, etc.

The whole foundation is composed of a ground beam and a pile foundation, because the following is a solid layer of loess, so the ground beam is only three feet deep, and every two zhang a six-foot deep pile is dug again, and the ground beam is poured into a pile foundation at one time.

After an hour and a half, the entire foundation frame was poured.

Qin Chuan ordered people to cover the steel bars left above with sacks of wet sacks for water retention and maintenance.

In the evening, after he felt that the surface of the concrete had hardened, he asked people to start watering, and the concrete should have enough water for hydration, otherwise the surface will form cracks and sand, and the strength will rise very slowly.

The watering process lasts about seven days, five or six times a day.

There were only a few wells in Mengjiazhuang, and there were no streams around, so it had to draw water from the Fen River, and before the start of construction, hundreds of people brought water back from the Lan River and stored it in large tanks, or poured it directly into the moat in front of the city wall.

The construction team did not stop work, but was busy rolling steel bars, cutting wires, building formwork, sawing supporting logs, and so on.

Twenty-eight days after the foundation of the high-rise building in later generations, it can only be built after passing the inspection, Qin Chuan can't wait that long, because the weather is getting cold, and the city wall he built is only three floors, and the requirements for the foundation are not very high.

Therefore, five days later, Qin Chuan asked the workers to tie the steel bars and support the formwork, including the steel bar and formwork on the roof of the second floor.

This process is estimated to take five or six days, during which the formwork of the foundation has not been dismantled, and it is necessary to continue watering, and when the steel bars of all the walls on the first floor are tied, the formwork is supported, and the strength of the foundation under it is about the same.

At that point, all the walls and roofs can be poured in one go.

During the reinforcing bar, Wang Helun, a great salt merchant in the Guanzhong Plain, sent someone to deliver the news that his fleet would arrive at the Yellow River Mokou Ferry with grain in ten days at most, and asked Qin Chuan to immediately send iron materials and iron pots to the Mokou Ferry for trading, and he had to rush back before the Yellow River froze

This time, he brought 8,000 stone of grain, 100,000 catties of raw and wrought iron, and 10,000 large and small iron pots.

Qin Chuan put down the work at hand and began to gather the transport team.

As early as a month ago, he asked Yan Sanqi to increase the iron pot production line, and now the iron pot factory can produce 600 pots a day, with a monthly output of nearly 20,000.

The Black Mountain Iron Yard also built a large furnace to expand the production of raw and wrought iron, and he had sufficient stocks of both iron pots and iron.

Iron and iron pots and accompanying grain, a total of 350 mules and horses, a total of 800 coachmen and lifu, and also let Luo Da Niu lead 700 first to the camp and 300 tiger and leopard battalions to escort him.

It took eight days to travel from Lou Fu to the Mokou Ferry, and it would take them about twenty days to return.

On the tenth day after the foundation was poured, the pouring work on the first floor of the ground began.

As soon as the morning dawned, Qin Chuan appeared on the template on the top of the first floor of the city wall, stepped on the steel mesh under his feet, and began to point fingers.

The construction site was busy, this time there were more than the last time, a total of 1,000 people, 50 people in each team, constantly frying the cement slurry, buckets of cement slurry were continuously hung up to the roof and poured into the groove of the wall.

In the era when there were no machines, it was necessary to rely on a large number of people to catch up with the speed.

After about an hour, the walls were poured, and then it was the roof of the building.

Qin Chuan once considered using prefabricated slabs, that is, when he was a child, the kind of flat top buildings built in rural areas were prefabricated in advance with cement and steel bars, and then transferred to place the prefabricated slabs that formed the roof of the building when the building was built.

But this thing is not strong enough, uneasy, so it is still directly used steel to pour cement, the pouring of the roof is about six inches, that is, about 20 centimeters in later generations, every one zhang away also poured a beam, used to bear the load.

About two hours later, the roof was finished.

After the cement slurry on the roof of the building solidified, Qin Chuan asked people to spread the entire roof with sacks, and began to water and maintain it in the evening, which also took about seven days.

Like last time, five days later, Qin Chuan asked the workers to tie up the steel bars and start arranging the second layer of formwork.

At this rate, in another twenty days, the walls will be ready to be poured.

After dismantling the formwork and installing doors and windows, an unprecedented steel wall was built.