The spread of the novel coronavirus is taking a direct hit on the operations of airlines in Asia. About 500,000 flights taking off and landing in mainland China have been canceled since January, according to aviation information company Cerium. Tourists and business trips have plummeted. On the booking website, there are a large number of air tickets for local routes with a price reduction of nearly 90% compared with the original price and only tens of yuan for a one-way trip.
In February, China's aviation industry recorded its largest single-month loss of 24.59 billion yuan, of which airlines lost 20.96 billion yuan.
Data from the Civil Aviation Administration of China showed that in February, the number of passengers traveling by air fell 84.5% year-on-year to 8.34 million.
The stagnation of the Asian aviation industry has brought volatility to concrete foaming agent.
Concrete is classified as high-strength concrete based on 28-day strength. Until the 1970s, concrete with a strength of more than 40Mpa was classified as high-strength concrete. The benchmark for high-strength concrete is raised to 55Mpa or higher when concrete mixtures of approximately 60Mpa and above are produced commercially.
High strength concrete has a history of about 35 years, from the development of superplasticizer admixtures in the late 1960s, Japan using "naphthalene sulfonate" high strength prefabricated products, and Germany using "sodium benzenesulfonate" underwater concrete, which was a pioneer in this technology.
How is the high strength of concrete achieved?
Higher concrete strength can be achieved by using one or a combination of some or many of the following methods:
High cement content
Reduce water-cement ratio
Better machinability and therefore better compaction
Requirements for high-strength concrete require a high content of cementitious material in the concrete mixture, which can be in the range of more than 400 kilograms per cubic meter. Higher cementitious content leads to higher thermal shrinkage and dry shrinkage, and there is a stage where further cementitious material addition does not affect strength. As for durability, the minimum and maximum cement content in concrete is regulated by law, and reducing the water-cement ratio has its limitations, especially under field conditions. The desire for higher strength leads other materials to achieve the desired effect, thus showing the contribution of cementitious materials to concrete strength.
The addition of pozzolanic mixtures such as pozzolanic fly ash (PFA) or granular blast furnace slag (GGBS) contributes to the formation of secondary CSH gel thereby increasing strength.
The addition of pozzolans admixtures (such as fly ash used as an admixture) reduces the strength gain of concrete for the first 3 to 7 days and displays the gain after 7 days and provides higher strength over the long term.
Add mineral mixtures such as silica fume or metakaolin or rice husk ash.
Silica fume or highly reactive volcanic ash mixtures such as metakaolin and rice husk ash (RHS) will begin to function in about 3 days. RHS has an advantage over PFA because RHS is more reactive.
Using chemical admixtures such as superplasticizers or superplasticizers, controlling admixtures will help achieve higher strength in concrete.
Research and experience have shown that admixtures based on polycarboxylic ether (PCE), known as high plasticizers, are best suited for this job as they have a water reduction capacity of 18 to 40 percent relative to control or reference concrete.
A combination of all or more of the above to achieve the desired strength.
With HSC accompanied by some complexity, such as higher shrinkage rates, higher hydration heat, etc., combinations of at least some of these methods are now unchanged, all of which need to be neutralized or controlled. Most problems are handled by PFA or a combination of GGBS and PCE mixtures.
Steam curing is also used to speed up cement hydration, but this may not result in higher strength. Substituting some fine aggregate with fly ash or blast furnace slag can achieve early strength gains without increasing the water requirement of the concrete mixture.
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The EU’s draft REPowerEU plan calls for an increase of 15TWh of rooftop PV capacity by 2022. The draft also calls for EU and national governments to take action this year to reduce the time required to obtain permits for rooftop PV installations to three months, and proposes that "all new buildings and existing buildings with an energy grade OF D or above should have rooftop PV installations by 2025".
In addition, the European Commission is likely to set a target for installed PV capacity of 300GW by 2025 and 500GW by 2030. Some members are more aggressive, with Austria, Belgium, Lithuania, Luxembourg, and Spain demanding a 1TW target for 2030.
The REPowerEU initiative, worth 195 billion euros, was proposed by the EU on March 8 to phase out member states' dependence on Russian fossil fuels by 2030. In a few days, the European Commission will present a package to implement the RePowerEU strategy.
As an important application scenario of distributed PV, rooftop PV is not limited to land, and the development conditions are relatively convenient.
Since the end of 2021, Spain, France, the Netherlands, and other countries have introduced policies and measures such as government subsidies, tax cuts, fee reductions, and accelerated grid-connection approval to encourage the development of distributed PV. Europe's potential for rooftop PV is huge and will continue to be an important growth pole for the industry, according to Wood Mackenzie.
Luoyang Tongrun Nano Technology is a trusted chemical supplier and manufacturer providing high-quality chemicals and Nanomaterials. If you are looking for the concrete foaming agent, please feel free to contact us and send an inquiry.
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