I! Pretending to Be Reborn, Director of Doomsday Hoax

Xu Qiu asked: "Is there a self-built sand and gravel aggregate processing system in the factory?"

Yan Yan nodded quickly: "Yes, yes, in order to facilitate our research, the chairman allocated funds for us to build a sand and gravel aggregate processing system!"

Xu Qiu thought for a moment.

At the same time, he has master-level knowledge of physics, mechanics, and architecture, which makes his thinking and knowledge reach a very terrifying height!

There is almost an extremely huge gap between different subjects. Being able to master two or more at the same time can often produce an effect of 1+1 far greater than 2, or even greater than 10!

After thinking for as long as 5 minutes, Xu Qiu finally came to his senses and gave his plan.

"First of all, the concrete coarse aggregate must be able to ensure that the total mass loss after 5 freeze-thaws is less than 5.00%, and it must be a solid graded crushed stone. Moreover, the aggregate particle gradation must be continuous, and the particle size should be in the range of 5-40mm Inside."

"Secondly, the fine aggregate should be able to ensure that the fineness modulus is greater than 14684 medium sand, the mud content is less than 2011%, and the particle gradation and other indicators meet the requirements of the specification GB/T[-]-[-]! "

"Producing according to these two standards, the process may go a step further."

At this moment, Xu Qiu looked at Xu Qiu with eyes full of reverence.

This is not here to inspect, this is to guide!

"If all these are realized, how can we further improve the cold resistance of concrete?" Yan Yan's eyes are full of thirst for knowledge.

Xu Qiu was thinking.

The cold resistance of concrete refers to the property that the material can withstand multiple freeze-thaw cycles in a water-containing state without damage and without a significant decrease in strength.

The reason why concrete freezes and thaws under cold conditions is that the volume expands after the water in the concrete freezes. When the expansion force exceeds its tensile strength, the concrete produces fine cracks, and the repeated freeze-thaw cracks continue to expand, resulting in concrete Reduced strength until failure.

The cold resistance of concrete is mainly affected by the average air cell spacing, water-binder ratio, air content, aggregate and cementitious materials.

"Director Xu, please sit down!"

At some point, Yan Yan moved a chair and put it behind Xu Qiu.

The chairman and the others were horrified.

This is the first time they have seen this stubborn old man treat someone so politely!

Xu Qiu sat down, still deep in thought.

In international construction projects, most of the improvement of the cold resistance of concrete lies in the heating and heat preservation of raw materials.

They built an insulated and closed material shed to store construction materials such as cement, sand, gravel, and admixtures.

These material sheds are usually built with brick walls, and a hot water boiler is installed inside for heating to ensure the temperature requirements of these raw materials.

In other words, these improvements, for the improvement of the cold resistance of concrete, can only treat the symptoms, not the root cause!

But now, what Xu Qiu was thinking about was a way to allow concrete to leave the hot water boiler and other heating equipment and use it in the cold conditions of minus 30 degrees! This time, the thinking lasted for a whole night.

That night, thousands of special soldiers came to the outskirts of Shenlong Construction Engineering Group, and at the same time, more than a dozen military helicopters came to guard the place all night long.And at the dawn of the next day, Xu Qiu finally opened his eyes again.

And this sentence made everyone stunned. .

The eighth + - chapter ice breaking, giant ship!The Steam Age Comeback?

A deep voice came from Xu Qiu's throat.

"Come into the workshop, I'll come in person."

At this moment, everyone was stunned.

Zou Botao, Li Bingqing and others subconsciously wanted to stop it.

There is no other reason, Xu Qiu is too important to Longguo, and there can be no mistakes.

Moreover, Xu Qiu played more of a strategist and a military adviser, and almost never played the scene himself.

Xu Qiu shook his head, waved his hand and said, "Concrete that can maintain excellent performance under the conditions of minus [-] to [-] degrees is the key to ensuring the normal construction of our Little Ice Age."

"What's more, the sun won't go out until June next year. During this period, we will experience another winter. The temperature in the south will not be too low, but in the north, the temperature in some areas may drop to minus [-] or [-] degrees!"

"And the construction of the dungeon is urgent. Because of the severe cold, giving up the construction opportunity in winter will save millions of people!"

The crowd was silent.

Construction stagnation in winter will be a huge problem.

If the construction is really stopped because of this concrete, then the northern region will lose one to two months of construction period in vain, and this will cause a serious lag in the construction of the dungeon!

"Director, be careful..." Li Bingqing said in a low voice.

Xu Qiu nodded, looked at Yan Yan, and said, "Professor Yan, please introduce our production workshop to me."

Yan Yan walked to the main console, pointed to the interior of the workshop, and said proudly:

"Director Xu, this production workshop was almost entirely designed by me."

"We have a fully automatic aggregate loading system, which uses precise high-level automatic alarms, combined with the production volume, does not require loaders, forklifts, or even personnel operations. Everything will be carried out according to the ratio we set in advance. Intelligent configuration."

"At the same time, each production room is equipped with geomagnetic induction and infrared automatic detection equipment, combined with intelligent automatic spraying devices, which can speed up the efficiency, and remove dust and ash in time to ensure the purity of the concrete."

"In addition, inside the production line, there are large-scale pulse dust collectors and vertical filter dust collectors."

Xu Qiu looked along Yan Yan's fingers,

It was a huge, precise, and complex mechanical workshop, with a large number of manipulators, mixers, and pulverizers running non-stop, and the air smelled of concrete, lubricating oil, and petroleum.

Except for the mixer truck, there are almost no people in the whole workshop. This is a fully automatic intelligent workshop.

Different materials are transported on rows of crawlers, and the materials are automatically unloaded under the control of the central control system.

Moreover, the high-performance mixing host inside the machine and the powder pre-homogenization system can maximize the performance of concrete without increasing the amount of cement.

Yan Yan stomped his feet, with joy in his eyes, and said: "Director Xu, there is also an intelligent powder bin loading and processing system underground, which can realize automatic supervision of dust feeding!"

"Moreover, when we wash mixer trucks and tank trucks, the sewage will also enter the sewage treatment system. This system has a sand and gravel separation device that can screen out the sand and gravel involved in the sewage. The treatment capacity reaches [-] to [-] per hour. Ton."

"After four cycles of treatment, one big, three small, and four times, the fine sand particles are separated again through the cyclone separator, and the particles that do not contain fine sand enter the slurry tank."

"In the slurry tank, the wastewater is deposited again, and the remaining sand and gravel are recycled, while the remaining slurry is used for the production of the mixing station and car washing."

"The coarse sand and fine sand particles that have been screened out are sent to the stockpiling area through belt conveyors, screw conveyors, etc., and reused."

"The entire feeding, crushing, mixing, filling, and sewage treatment systems form a three-dimensional water cycle, which can be as close to zero discharge as possible!"

Xu Qiu shook his head, with a regretful expression on his face, and asked, "Are you very proud of this sewage treatment system?"

Yan Yan was stunned for a moment, "Yes... Director Xu, is there something wrong with this system?"

Xu Qiu said mercilessly: "Yes, and there is a big problem!"

"It's like an automatic feeding system."

"How do you think aggregates affect the cold resistance of concrete?"

Yan Yan thought for a while and replied: "The main reason is the size of the aggregate. The larger the size, the easier it will be damaged after being frozen. In addition, the firmness of the aggregate, the degree of weathering, the quality of clay, and the quality of impurities are also important. It will affect the cold resistance of concrete to a certain extent!"

Xu Qiu smiled and said, "Not bad, but there is still one more thing, water content."

"Water content?" Yan Yan frowned, his face full of incomprehension.

Xu Qiu explained: "If the aggregate is saturated with water, it will generate static pressure in the aggregate void and the aggregate-cement slurry interface after being frozen. Once the aggregate or interface strength is exceeded, freezing damage will occur."

"We...haven't paid attention to this!!"

Yan Yan's expression turned into disbelief.

He is also a master of concrete. He has been studying this thing for decades. The research on extremely cold concrete started before the end of the day, and has been going on for almost five years.

However, what they thought before was how to crush the aggregate as much as possible and reduce the size of the aggregate.

But rarely consider the problem of aggregate water absorption!

"That is to say, the three-dimensional water circulation affects the quality of the aggregate, and drags down the strength and performance of concrete?!"

Yan Yan got it right, and immediately started to draw on the blueprint, planning to re-plan the entire sewage treatment system and separate the automatic feeding system.

Xu Qiu reminded: "In addition to the fact that the automatic feeding system does not get wet, it is also very important to choose aggregates with high water absorption."

Yan Yan's eyes revealed obsession. Hearing this, he came back to his senses and said, "I'm afraid it won't work. What we use is lightweight aggregate. I'm afraid it will be difficult to find a substitute with a higher water absorption rate!"

Xu Qiudao: "Increasing the water absorption rate is more important than changing the type of aggregate. In fact, it is the addition of... the air-entraining agent!"

"Air-entraining agent? This...can increase water absorption?" Yan Yan was shocked and expressed his incomprehension.

Xu Qiu looked at the automated concrete manufacturing system that was running continuously.

Although concrete is something made with a simpler process, it can be used after the steps of design, trial mix, adjustment, production, mixing, and molding.

But in fact, the coagulation system is very complicated. In a sense, its complexity can even be compared with that of the human body!

The air-entraining agent, for the help of concrete, is definitely not just to improve the water absorption.

One more important point.....reducing the average bubble spacing!

The most important factor affecting the cold resistance of concrete is the average air cell distance. The larger the average air cell distance, the greater the hydrostatic pressure and osmotic pressure in the capillary pores during the freeze-thaw process, and the lower the cold resistance of concrete.Generally, high cold-resistant concrete can be obtained when the average cell spacing coefficient is below 500 microns.

When the average bubble spacing coefficient is below 500 microns, it is difficult to improve the cold resistance due to technical limitations.

"If I'm not wrong, you should have reduced the average bubble spacing below 500 microns, which has reached a critical value, and can no longer be improved through this method."

Yan Yan said in embarrassment: "Director Xu, you guessed right, we have already reduced the average bubble spacing to a limit, and it cannot be shortened any further."

"Easy, admixture!"

Xu Qiu said: "Through air-entrainment and admixtures, the cold resistance of concrete will further increase!"

He began to issue configuration requirements for the new type of concrete:

"The first is to add a high-quality air-entraining agent to reduce the average air-cell spacing of the concrete. In addition, due to the difference between the structure parameters of the surface air cells and the interior of dry hard concrete and normal concrete, deterioration will occur, and it is necessary to choose a variety that is deeper from the surface."

"In other words, only the concrete that is wrapped in the interior is selected, and the concrete on the surface is re-entered into circulation, or even eliminated!"

This made Yan Yan and the others a little bit pained.

Now all kinds of material resources are very precious, only select a small part of the middle of the concrete, and the rest have to be discarded...too wasteful!

But after thinking about it carefully, Yan Yan suddenly found that this is a very necessary approach!

The closer the concrete is to the upper surface, the larger the air content and the diameter of the bubbles, and the larger the average bubble spacing!

Only after the depth exceeds ten centimeters, the parameters of the hardened concrete bubble structure will be relatively stable!

"I never thought about this before..." Yan Yan felt that his thoughts had been completely opened up, and he looked at Xu Qiu with awe.