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Hydrophobic concrete is concrete in which water is repelled by making the concrete hydrophobic. Hydrophobic concrete also meets the standards outlined in the definition of waterproof concrete. Started in Australia hydrophobic concrete has a 45-year success story before coming to the United States in 1999. Millions of cubic yards have been laid in Australia, Asia, and Europe . It's effective use in hundreds of structures has contributed to it is large acceptance and growing use in the past two decades.,〔http://www.hycrete.com/hydrophobic-concrete-in-so-cal/ 〕〔http://www.hycrete.com/files/media-releases/Hycrete-Media-01-01-06.pdf 〕 == Structure == Typical concrete is quite hydrophilic. This comes from the intricate systems of tiny "capillaries", which work to suck water through the microcrack network within a concrete slab.〔https://workspace.imperial.ac.uk/civilengineering/Public/UG4%20conf%202014/E7%20-%20Robert%20Barakat%20FYP.pdf〕 This hardened matrix creates a continuous "source to sink" cycle, meaning water from above is constantly pulled to an area of lower elevation. Dan DArcy's Coefficient, refers to the ability of liquefied water, under pressure, to flow through the pores and capillaries that are present. Note that a lower DArcy's constant correlates with a higher quality material.〔http://continuingeducation.construction.com/article.php?L=49&C=850 〕 There are many different structures within a regular concrete mixture that companies use to create hydrophobic concrete; however all of them involve filling the porous concrete mixture somehow. Some of the most commonly used methods include polymer formation, small speck infusion, or crystalline formations. Of the three, crystalline formation is the most widely used and most effective. The way crystalline technology works in hydrophobic concrete, is through the formation of crystal structures in the tiny capillaries, pores and other air pockets left behind in the curing process of concrete. When this forms there are by-products left behind in the capillaries and pores of the freshly cured concrete. These by-products are typically calcium hydroxide, sulfates,sodium carbonates, potassium, calcium, hydrated and unhydrated cement particles. These crystal structures then plug the pores and capillaries preventing water from getting through. Once the crystalline chemicals are added to the concrete mixture, through either an admixture or coating, these crystalline chemicals react with the by-products in the presence of water. This reaction then forms an insoluble crystal structure that clogs the pores. This process continues until all the chemicals have reacted. When applied as a coating, the chemical reaction moves through the process of chemical diffusion. This is the process of a high chemical density solution migrating towards the low density chemical solution until these two come to equilibrium. Soaking the concrete in water creates low chemical density in the pores, and applying the crystalline chemical as a coating then creates a high chemical density, and these two then diffuse through the inner structure of the concrete until they reach equilibrium throughout the inner structure. Once this process is finished, the hydrophobic concrete's crystal structure is complete.〔http://continuingeducation.construction.com/article.php?L=49&C=850 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Hydrophobic concrete」の詳細全文を読む スポンサード リンク
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