Since the completion of the high reservoir, there has been a backlog of cement produced on Baltrum Island. Pen × fun × Pavilion www. ｂｉｑｕｇｅ。 However, Marin did not order the cement plant to reduce production. Because, in any case, cement is a strategic material with great use.

After the construction of the high reservoir, Marin ordered the start of adding a layer of reinforced concrete to the outside of the walls of Aurich to enhance the resistance to blows.

However, there is no rush in this matter. The main reason is that land heavy artillery has not yet become popular in other countries. Therefore, Aurich was not worried about the city walls being bombarded by heavy artillery clusters.

In fact, it is not that other countries do not have heavy artillery casting technology. Rather, it is because the speed at which heavy artillery consumes gunpowder is too frightening for the average country to afford. Moreover, the amount of copper required to cast heavy artillery is also intimidating. Therefore, very few countries in Europe played with heavy artillery and did not develop that technology. Even France, the first artillery power in Europe on the surface (in fact, Marin had the most artillery), only began to develop a 12-pounder bronze cannon after seeing the power of heavy artillery bombardment of the city gates. On Marin's side, cast iron heavy artillery has been widely used. But Marin has too many eyes, and all the cast iron cannons that are open to the public are coated with a layer of copper paint, which makes people mistakenly think that Marin has so many copper cannons.

In addition, due to the urgent need to provide a batch of chest armor and helmets to the Duchy of God, the steel mill did not have as many steel bars to supply the reinforced concrete needs of the city walls. Therefore, for a short time, the construction of adding a layer of reinforced concrete to the exterior of the city was suspended.

But Marin wasn't willing to leave thousands of construction workers unemployed. After all, it's a waste of labor. So, Marin decided to find something else for them to do.

What do you do? After thinking about it, Marin finally decided to pave a concrete road first......

Anyway, to lay ordinary cement roads, you don't need to use steel bars. Moreover, the concrete road should not be too cool. A smooth road on which a horse-drawn carriage walks up and can run at the speed of a tractor. Even, there is a feeling that I can't stop at all.

The most important thing is that even on rainy days, the cement road is very cool to walk on, and it does not affect the speed at all.

The Roman avenues, on the other hand, are paved with stone slabs and stones. However, if you drive on a rainy day, if a horse-drawn carriage passes through, it is easy to press the stone slab and warp it, causing the road surface to deform. Moreover, the Roman road is also far less smooth than the cement road.

The carriage walked on the stone paved roads of the Roman Avenue, and there were bumps. Walking on the concrete road, there are basically no bumps. Therefore, the cement road is obviously superior to the stone road of the Roman road.

Moreover, in terms of cost, cement roads are also lower than stone roads. After all, stone roads require workers to mine the stones, which are then polished into slabs by stonemasons, which is labor-intensive.

Cement, on the other hand, is made of limestone and clay, and the cost is naturally not high.

Moreover, what Marin wants to lay is not a national highway or a provincial road, but just an ordinary rural cement road. That is, 3.5 meters wide and 20 centimeters thick, the most common rural cement road.

Such cement roads are everywhere in Marin's hometown in his previous life. As long as you don't go on a rainy day, the kind of truck weighing more than ten tons will not be crushed.

Because, on rainy days, the roadbed of the cement road will become soft. At this time, if there is an overweight truck such as a more than ten tons of Yellow River heavy trucks, it is easy to crush the cement road.

However, in this era, the load of the four-wheeled carriage, the heaviest, was only 1.5 tons, and it was absolutely not capable of crushing the rural cement road. Even a few tons of carriages can't crush the rural cement road.

Of course, Marin did not want to promote cement roads in Europe, his real purpose was to build a concrete road across the Isthmus of Panama.

After all, the Isthmus of Panama is bordered by the Caribbean Sea to the north and the Pacific Ocean to the south, and it rains a lot. If you were to transport goods from Peru or the Ming Dynasty through the isthmus, if it rained, the dirt road would not be possible. In particular, it's going to rain over there, and it's going to be torrential rain. The carriage was completely incapable of walking on dirt roads.

Therefore, it is important to build a cement road that is not afraid of rain. When the time came, Peruvian gold and silver, Ming silk and porcelain, could be transported to Cologne on the Caribbean coast by this cement route, and then shipped back to Europe. Porcelain, in particular, is the most resistant to bumps. If you walk on a bad road, the porcelain is easy to break. But if you walk on the cement road, the carriage is not bumpy, and the porcelain is naturally not easy to break.

Now, Marin has asked the workers to build a concrete road first, which is actually an attempt. Accumulate skills first, and when Gaurard has established himself on the Panamanian side, he has cut down trees and cut a road, and the concrete road can be built.

With this concrete road, the horse-drawn carriage gallops on the concrete road, effortlessly, and on the ground. At that time, the 65-kilometer-wide isthmus, the horse-drawn carriage will be able to run in one day. This way, you don't have to stop in the middle of the night in the rainforests of Panama and get bitten by poisonous insects and mosquitoes. You know, that's deadly.

The laying phase of the cement road is very simple, that is, bricks are now erected on both sides of the road as a block. Then, pour the mixed cement into it, smooth it out, and then press it with a wooden plank.

But laying the foundation is a bit troublesome, you know, the quality of a road, in addition to the material, the most important thing is the foundation. If the roadbed is not strong, the road surface is prone to problems.

The problem was that there were no rollers, so Marin decided to have the workers tamp the road with hammers. Then, use the ox to pull the stone and roll it several times.

Because the Panama region is a tropical rainforest, it is not possible to use ordinary dirt roadbed. Otherwise, if you soak in the water, it will be fluffy.

Therefore, Marin decided to use a large amount of gravel and lime in the roadbed, mixing the earth, gravel and lime, tamping it with an iron hammer, and then rolling it several times with oxen.

Wait until the roadbed is solid, and then start erecting the bricks on the edges and pouring cement on them. It was then manually smoothed and compacted with wooden planks.

In addition, on both sides of the roadbed, drainage ditches need to be dug. Once it rains, it can ensure that there is no water accumulation on both sides of the roadbed, so as not to be damaged by the roadbed.

So, building a concrete road is not simple. In particular, there are many issues to consider when building a concrete road in a rainy area.

Marin's plan was to build a 3.5-metre-wide, 20-centimeter-thick subgrade of gravel and lime mixed mud with a drainage ditch from the north gate to the horse farm in the north of Aurich.

This road construction is mainly about exploration and attempt. After all, Marin is not an expert in road construction, and these experiences are also hearsay in his previous life, and he has not personally verified them. This time, he plans to accumulate experience and select excellent craftsmen through this road construction. Then, those skilled craftsmen were sent to Panama to supervise and guide the black slaves to build cement roads.

As for the cement used to build the road, Marin decided to continue to use fly ash cement. Because fly ash cement has the advantages of small dry shrinkage, high tensile strength, good crack resistance, etc., and is also corrosion-resistant, it is definitely more suitable for building cement roads than ordinary grade cement. Moreover, because there is a large amount of fly ash in the boiling salt base, which is directly supplied to the cement plant, there is no shortage of fly ash cement in Marin's hands. Even a 65-kilometer-long concrete road is sufficient.

Once the concrete road of the Isthmus of Panama is completed, the Isthmus of Panama will become a convenient place for transportation, quickly connecting the Pacific Ocean and the Caribbean Sea, and becoming a transportation hub in the Americas......