After Russia pledged to scale back its military operations around Kyiv and in northern Ukraine, the prices of most industrial metals fell, led by aluminum, showing people's concerns for supply shortage eased.
At an earlier time, the West imposed sweeping sanctions on Russia for its invasion of Ukraine, which aroused concerns about the supply problem because Russia is a major producer of nickel, aluminum, and copper.
Russia is also a major gas supplier to Europe, where potential supply disruptions are seen as hitting power-intensive aluminum and zinc HPMC are still very uncertain.
Viscosity and fineness are important indicators that affect the performance of hydroxypropyl methylcellulose HPMC. Studies have shown that the water retention effect of HPMC increases with the increase of its viscosity, but after the viscosity exceeds 40000 MPa•s, the water retention increases limited with the increase of viscosity. The higher the viscosity, the larger the molecular weight of HPMC, and the corresponding decrease in solubility. It will not improve the water retention of mortar, but it will have a negative impact on strength and workability. Comprehensive consideration, it is more appropriate to use cellulose ether with a viscosity of 40000 MPa•s in the cement mortar.
As the HPMC particles gradually become finer, the water retention of the mortar is also improved to a certain extent. Fineness affects the solubility of HPMC. Coarse HPMC dissolves very slowly in water and should not be used in dry mix mortars. In dry-mix mortar, HPMC is dispersed between aggregates, fine fillers and cementitious materials such as cement, and only a fine enough powder can prevent it from caking when mixed with water. When HPMC is added with water to dissolve the agglomerates, it is difficult to re-disperse and dissolve. HPMC with coarse particle size is not only wasteful, but also reduces the local strength of the mortar. When such dry-mixed mortar is used in large-scale construction, the curing speed of the local mortar may be significantly reduced, which may cause uneven hydration of the cementitious material. of cracking. For mechanically constructed spray mortars, due to the shorter mixing time, the requirements for the fineness of HPMC are higher. Therefore, after comprehensive consideration, the particle size of cellulose ether used for cement mortar should be less than 80 μm.
It can be seen that HPMC is a high-efficiency water-retaining agent for dry-mixed mortar, which reduces the bleeding rate and stratification of the mortar, and improves the cohesion and sag resistance of the mortar. Although HPMC slightly reduces the flexural and compressive strength of mortar, it can significantly improve the tensile strength and bond strength of mortar. In addition, HPMC can effectively inhibit the formation of mortar plastic cracks and reduce the mortar plastic cracking index. The water retention of mortar increases with the increase of HPMC viscosity, and when the viscosity exceeds 40000MPa•s, the water retention does not increase significantly. The fineness of HPMC also has a certain influence on the water retention rate of the mortar. When the particles are finer, the water retention rate of the mortar increases. The particle size of HPMC usually used for cement mortar should be less than 80μm.
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According to the bank of Spain's latest forecast data, the average inflation is expected to hit 7.6% in 2022, but the average wage increase for workers in this country is expected to be less than 4% in 2022.
If the Bank of Spain's forecast comes true, the gap between price and wage growth in Spain in a single year will be the largest since 1984.
Prices in Spain rose 9.8% year on year in March 2022 and average wages rose 2.4% year on year, with the Bank of Spain forecasting that the country's inflation rate will improve from July.
Recent changes in the international situation have had a big impact on commodity and energy prices. How the prices of the HPMC will develop in the future is still uncertain.
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