I! Pretending to Be Reborn, Director of Doomsday Hoax

Only after waiting for about a week, the drought resistance and durability of air-entrained silica fume concrete will be revealed! !

The cold concrete that can be used below minus [-] degrees was tested a week later, and the results were obtained!

Yan Yan was dumbfounded, and said: "Compared with the benchmark concrete in terms of frost resistance durability of non-air-entrained silica fume concrete, under the condition that the total amount of cementing materials is the same and the slump remains the same, the frost resistance of non-air-entrained silica fume concrete It can actually increase by about 17.00%!"

The professor of the Polar Laboratory said: "Director Xu, I still don't understand how you dare to conclude that controlling the air-entraining silica fume concrete within a certain concentration to maintain the production of silica fume can improve the durability of frost resistance

This kind of technical performance, but it will take a week to show up!

They have analyzed this concrete.

Finally, it was found that when the air-entrained silica fume concrete just started to solidify, there was not much difference in the pore structure,

And with the passage of time, these pores gradually become thinner and smaller, and this is the root cause of the significant improvement in frost resistance durability! Although the principle is very simple,

However, no one could have thought of this before Xu Qiu mentioned it! !

Who would have imagined that after the addition of silicon powder, its ability to improve performance would have to wait until a week later?

"There is another kind, slag!"

Thinking of this, Yan Yan felt his scalp go numb.

He even wondered if Xu Qiu's brain was really a human brain...

The slag used in the past was also used to reduce costs.

The pulled slag can be directly thrown into the concrete and used instead of cement, and it is not expected to play a big role.

even.…

The increase of slag content will actually lead to the worsening of the freeze-thaw resistance of concrete.

Therefore, both Yan Yan and researchers in other countries who are studying low-temperature-resistant concrete have subconsciously avoided slag.

However, Xu Qiu specifically added the slag by name!

And the way Xu Qiu used the slag was very unexpected!

He asked Yan Yan and others to grind the slag into fine pieces before adding it to the concrete.

When the mixing ratio reached a certain range, Yan Yan and others were surprised to find that the frost resistance and durability of this kind of concrete added with ground slag had been significantly improved again! !When the result came out, everyone in the laboratory was dumbfounded.

Because, a law previously recognized by the international engineering community is,

Adding slag will reduce the freeze-thaw resistance of concrete.

Moreover, the amount of addition affects only the extent of the decrease in freeze-thaw resistance. There is no such thing as adding a certain proportion of slag, but it improves the freeze-thaw resistance!

Even Yan Yan himself had done experiments before.

He personally tested the effect of slag blending from 20.00% to [-]% on frost resistance.

No matter how high it is, it is meaningless. Slag is only one of the mixed materials, and it is impossible to replace cement as the main material of concrete.

However, within the scope of the test, the frost resistance of concrete has declined without exception, and the rate of decline is getting bigger and bigger!

Freeze resistance is getting worse!

However, according to Xu Qiu's request, the matter of adding slag and improving the frost resistance really happened in front of them...

So, at that time, Yan Yan and others jointly wrote a letter to Xu Qiu, asking for an answer.

On the same day, a reply letter cleared all their doubts! ! .

Chapter 110 Nine Blue Star Ring, a shocking plan around the Blue Star!

Yan Yan and the others finally came to a realization.

The problem lies in the size of the slag!

If according to the previous treatment measures in the engineering field, coarse slag is directly added to the concrete to replace the mixed material,

No matter how much you add, it will only affect the frost resistance.

And if the slag is ground finely,

The finely ground slag will combine with the calcium hydroxide formed by the hydration of cement in the concrete to form a potentially active substance.

This substance can improve the antifreeze performance!

In addition, there is fly ash.

Fly ash has been used in concrete for decades. The first person to study the effect of fly ash in concrete was the professor of Berry Country Jiazhou Institute of Technology.At that time, it was surprising that fly ash, as an industrial waste, could be used in the production of concrete and save cement.

However, when Jiazhou Institute of Technology carried out the research and promotion of the active performance, it was found that,

The frost resistance of fly ash concrete decreases with the increase of fly ash content.

However, the frost resistance of concrete was not much needed in those days.

Big deal, no construction in winter.

Research on low-temperature concrete in various countries in the world has not considered fly ash.

however,

Xu Qiu once again put forward a point of view that does not conform to common sense in the engineering field.

Due to the hydration of high-volume fly ash and concrete,

In this process, the amount of fly ash and the water-cement ratio affect the pore structure of high-volume fly ash concrete,

And, with the increase of dosage and water-cement ratio, the porosity also increases!

Increased porosity means better frost resistance within a certain range!

However, porosity decreases with increasing ratio and time.. …

Just find the balance in this,

Find the porosity just to the point where the best frost resistance occurs, and you can make cold concrete!

then,

Yan Yan and others applied for an electron microscope and a nuclear magnetic resonance instrument worth more than 2000 million yuan.

Finally, through repeated research on the frost resistance and durability of fly ash high-performance concrete, a surprising point was discovered...

This time, what caused the fly ash to reduce the cold resistance turned out to be... the air-entraining agent! !

Air-entraining agent is the most effective way to improve cold resistance. However, when air-entraining agent and fly ash are mixed, air-entraining agent will cause fly ash to have a negative impact on frost resistance!Of course, this discovery is limited.

When the water-binder ratio is in the range of 0.25 to 0.27,

With the increase of the content of fly ash, without adding air-entraining agent, the durability of concrete frost resistance increases with the increase of fly ash!

And if the air-entraining agent is added, the frost resistance durability of concrete will first decrease, then increase, and finally decrease again! !

This discovery made everyone, including Yan Yan, very excited.

Who would have thought that the impact of fly ash on frost resistance would have twists and turns.

After more than a month of careful research, finally, Yan Yan’s team developed an air-entraining agent, water reducing agent, mixed with silica fume, finely ground slag, ultra-fine fly ash and their composites, and steel fiber. Concrete! After the advent of the first generation of cold concrete,

Yan Yan's team conducted experiments all night long,

Do more surprising ratio control work, assign the proportion of each component,

Finally, the No.70 No. [-] concrete sample completed the experiment perfectly!

When ultra-fine fly ash is mixed with silica fume, the lowest temperature of frost resistance and durability reaches minus 71 degrees Celsius,

After [-] freeze-thaw cycles, the dynamic elastic modulus and weight basically do not change.

And the steel fiber has also undergone further compounding, which has not been affected by the severe cold, and still maintains the strength of the concrete!

And now, it is this No. 70 No. [-] severe cold concrete sample that is announced to the world.

In the research and development report reviewed by Xu Qiu just now and sealed up by Li Bingqing, the ratio of each ingredient, as well as the method, steps, and details of the preparation are clearly written.

Worth a thousand dollars?

Do not!

Berry Country spent hundreds of billions of dollars, but failed to produce cold concrete.

Moreover, the distance from success is still far away.

Today, Longguo's severe cold concrete has completely monopolized the entire low-temperature environment concrete industry!

"In Antarctica and North Pole, it may become possible to build tall concrete buildings." In the team, a professor's passionate voice sounded quietly, full of pride.

Xu Qiu stood with his hands behind his back, shook his head and said:

"No matter how much concrete can be improved, there is a limit after all.

"Its role is only to support the country through the Little Ice Age and the coming winter. As for the extremely cold era, we can't count on cold concrete."

The implication,

It is enough for the cold concrete to reach the cold resistance of minus [-] degrees to [-] degrees.

Next, there is no need to improve the cold resistance,

Strengthening hardness, reducing costs, and improving economic benefits and social effects are the main directions.

Yan Yan himself is an expert in material science and one of the top scientists in concrete science in Longguo, so he understands this in his heart.

"Director Xu, in the era of extreme cold, where is the way out for concrete?"

Xu Qiu fell silent.

After a long time, [also raised his head, with a regretful tone, and said: "The arrival of an era often means the decline and even extinction of many products of the old era.

"Concrete is the greatest engineering material before the era of extreme cold for mankind, bar none.

"However, after the era of extreme cold, materials of a new era will emerge as the times require."

Yan Yan only felt a sense of desolation, gritted his teeth unwillingly, and said: "Then those of us who spend our whole lives studying for higher-strength and more advanced concrete, aren't we abandoned by the times?"

Xu Qiu turned around, looked at Yan Yan, and said: "I will find a way to come up with a new material a few months after the arrival of the extremely cold era, which will be able to replace concrete and become the greatest material in human engineering. It is a product that can stand in the extreme cold with excellent building materials...

"And you will be the first batch of people who accept the development and production of this new type of material.