Trajnost betona vključuje odpornost betona proti zmrzovanju, neprepustnosti, kemikalijam, jekleni odpornosti proti koroziji in odpornosti proti eroziji. Govoril bom le o odpornosti proti zmrzali, neprepustnosti in kemični odpornosti na beton. Erozivni učinek.
a) Odpornost proti zmrzovanju: Ko količinaSilicijev dioksid v prahumajhna, odpornost proti zmrzovanju silicijevega dioksida je v bistvu enaka kot pri navadnem betonu. Ko količina silicijevega dioksida v prahu preseže 15%, je njegova odpornost proti zmrzali slaba. Z velikim številom testov je bilo to stališče v osnovi potrjeno. Glavni razlog je v tem, da ko dim silicijevega dioksida preseže 15%, se raztezanje betona poveča, relativni dinamični modul elastičnosti se zmanjša in tlačna trdnost močno pade. Z vidika notranjih značilnosti betona je specifična površina majhna, razmik pa velik.
b) Impermeability: Because Silicijev dioksid v prahu particles are small, 20-100 times smaller than cement particles, they can be filled into the voids between cement particles to make concrete compact. At the same time, the secondary hydration of silica powder blocks new products. Permeation channels in concrete, so the impermeability of silica fume concrete is very strong, the permeability of concrete increases with the increase of water-binder ratio, this is because the compactness of water-cement is relatively poorer than that of concrete.
c) Chemical resistance: Mixing Silicijev dioksid v prahu into concrete can reduce the content of Ca (OH) 2 and increase the compactness of concrete. It can effectively improve the corrosion ability of weak acid. However, it cannot be used in strong acid or high-depth weak acid. CSH decomposes in acid. In addition, it is also resistant to salt corrosion, especially to chlorides and sulfates. The reason why it is resistant to salt corrosion is that the silica fume concrete is denser and the pore structure is improved, thereby reducing The transmission speed of harmful ions is reduced and the formation of soluble Ca (OH) 2 and ettringite (3CaO·Al2O3·3CaSO4 ·32H2) is reduced, and the result of increasing hydrated calcium silicate crystals.