Nature and concentration effect of stabilizing elements of beta-dicalcium silicate on its hydration rate

Abstract Boron, vanadium, phosphorus, arsenic and chromium, well-known for their stabilizing action on beta-dicalcium silicate, are introduced at 0.5 or 3 at-g per cent in the synthesis raw mix. During the earky hydration stage, paste electrical conductance and conduction microcalorimetry results show how strong the beta-dicalcium silicate reactivity depends on the nature but also on the concentration of the stabilizing ion. Hydration kinetics over longer periods, determined by ignition loss and quantitative X.R.D. analysis, are narrower than during the early stage and every preparation reaches a conversion degree of about 0.6 after two months. Related reactivity sequences strongly differ from the short duration kinetic data and depend also on the stabilizer content. Final discussion concerns chemical stabilization and hydration reactivity of beta-dicalcium silicate.