Influence of sodium borate on the early age hydration of calcium sulfoaluminate cement
Calcium sulfoaluminate (CSA) cements are potential candidates for the conditioning of radioactive wastes with high sodium borate concen trations.This work thus investigates early age hydration of two CSA ce ments with different gypsum contents (0 or 10%) as a function of the mix ing solution composition (borate and NaOH concentrations).Gypsum plays a key role in controlling the reactivity of cement.When the mixing solution is pure water, increasing the gypsum concentration accelerates ce ment hydration.However, the reverse is observed when the mixing solu tion contains sodium borate.Until gypsum exhaustion, the pore solution pH remains constant at ~ 10.8, and a poorly crystallized borate compound (ulexite) precipitates.A correlation is established between this transient precipitation and the hydration delay.Decreasing the gypsum content in the binder, or increasing the sodium content in the mixing solution, are two ways for reducing the stability of ulexite, and thus decreasing the hy dration delay.
Calcium sulfoaluminate cement Hydration Sodium borate Retardation Mineralogy Thermodynamic modeling
Champenois Jean-Baptiste Cau Dit Coumes Céline Le Bescop Patrick Damidot Denis
Commissariatàl Energie Atomique et aux Energies Alternatives,DEN/MAR/DTCD/SPDE BP17171,30207 Bagnol Commissariatàl Energie Atomique et aux Energies Alternatives,DEN/DANS/DPC/SECR,91192 Gi f-sur-Yvett Ecole des Mines de Douai,LGCgE-GCE,F-59508 Douai,France
国际会议
武汉
英文
348-365
2013-10-23（万方平台首次上网日期，不代表论文的发表时间）