Solidification Characteristics Of Si-Al Based Cementitious Materials And Its Durability Mechanism

According to the principle of sedimentary rocks as well as the theory of simulation of rock formation, mechanical properties and durable performance of Sialite concrete were investigated systematically. In particular, stabilization/solidification properties of Sialite were studied with the aim of revealing that the framework structure of hydrated Sialite has a strong ability to stabilize/solidify hazardous elements. The results showed that Sialite concrete has good performances such as excellent resistances to alkali-aggregate reaction, permeability, freeze-thaw attack, carbonation, reinforcement corrosion, chloride ion penetration, acid corrosion and salt attack. In addition, mechanism of interface bonding between Sialite and aggregate was focused to be studied. The experimental results indicate that the whole bonding process can be divided into three stages:1) Early stage:Ca-Al, Ca-Si bonding,2) Medium stage:Ca-Si-Al bonding,3) Late stage:Si-Al bonding. Moreover, it is found that the interface of Sialite concrete is Si-Al bonding while not Ca bonding, and this results in the interface of Sialite and aggregate hard to be attacked, therefore the hazardous elements are difficult to be leached out from the hardened Sialite concrete. Furthermore, a roadmap of interface hydration of Sialite concrete was established to vividly explain the mechanism of Sialite-aggregate interface reaction.