How serious are fertility problems today? People don't want to give birth,can't afford it, and can't give birth that has become the "three mountains".
The problem of childbirth is related to the people's livelihood. Whether a country can prosper or not depends on the population. I saw a set of data a few days ago. The data shows that on January 1, 1990, 2,784 babies were born in Shanghai. Ten years later, on January 1, 2000, 1,148 babies were born in Shanghai. In 2010, the number became 380. , 2020 only 156 people, the decline in the birth rate is shocking. The three most critical reasons are: I don't want to give birth, I can't afford it, I can't give birth! The decline of the global population will bring a series of economic and social problems, among which the demand for foam concrete will also be affected.
The common problems of foamed concrete are bubbling, cracking, collapse, shrinkage, and other phenomena. To treat these phenomena, the proper medicine can be found, and the cause can be effectively solved.
The main reason for the collapse of foamed cement is that the cement solidification speed is too slow. We can solve this situation from the following aspects
1. Add accelerator to improve the setting time of foamed cement
Accelerators are used in more and more concrete applications. Foamed cement has high requirements for accelerators. It is not just a fast setting but also needs to be adapted to the performance of foamed cement, and accelerators cannot be added. After affecting the foaming situation.
2 Add an early strength agent to improve the early strength of foamed cement and reduce the stress generated during the exothermic process of cement hydration. Only when these two forces are balanced can it be ensured that the foamed cement will not crack and collapse in the later stage.
3. An appropriate amount of sulfoaluminate cement can be added, which many manufacturers choose to use in winter, and the cost performance is still relatively high. However, this amount of addition should also be paid attention to. It should not be added blindly. After many customers add sulfoaluminate cement, the finished product becomes very brittle in the later stage, without toughness, low strength, and severe pulverization. So we still have to adjust according to the current situation.
4 The water-cement ratio is not suitable. Collapse, retraction, bleeding, insufficient strength. To a large extent, it has something to do with the inappropriate water-cement balance. The adjustment of the water-cement ratio is a technical activity that requires trial and error. It has a lot to do with the cement of foamed cement and the fly ash aggregate, and it needs to be practiced repeatedly according to the actual situation. In this, we can add a plasticizer to adjust the water-cement ratio. This effect is very immediate.
The above contents are some solutions summed up by Tongrun according to the reasons for the collapse of foamed cement. If you encounter other problems or reasonable solutions in the actual process, you are also welcome to communicate us.
The United States urges the U.N. Security Council to impose additional sanctions on North Korea in response to its latest ballistic missile launch, including a ban on tobacco and oil exports to North Korea and a blacklist of the Lazarus hacking group.
The United States circulated the draft to the 15 members of the Security Council this week. It was not immediately clear if or when a vote would take place. A resolution requires nine "yes" votes and no vetoes from Russia, China, France, Britain, or the United States.
Russia and China have already voiced opposition to tightening sanctions in response to Pyongyang's launch of an intercontinental ballistic missile last month -- the first since 2017.
U.S. and South Korean officials and analysts also say there are growing indications that North Korea may soon conduct its first nuclear weapons test since 2017, too.
The U.S. -drafted U.N. resolution would expand the ban on ballistic missile launches to include cruise missiles or "any other delivery system capable of delivering a nuclear weapon."
The deal would halve crude oil exports to North Korea to 2 million barrels a year and refined oil exports to 250,000 barrels a year. The resolution also seeks to ban North Korea's export of "fossil fuels, mineral oils, and their distilled foam concrete are estimated to be influenced by international political situation changes.
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