Investigation on the formation of ettringite in the presence of BaO

✍ Scribed by Long Shizong; Wu Yanrong; Liu Chen

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 354 KB
• Volume: 25
• Category: Article
• ISSN: 0008-8846
• DOI: 10.1016/0008-8846(95)00136-z

✦ Synopsis

Two mechanisms of forming ettringite have been proposed: one, through solution reaction; the other, through topochemical reaction. Using XRD and SEM, ettringite were investigated, which formed form very low SQr-concentration ([SOJ2-] +V lO_r" M/L). That low S012-concentration was caused by adding soluble BaO. The results

show that ettringite can still form when mixing CaSa.ZH,O with C,A. CA, C1?A7 or C,A,z* respectively. Since the SOd2-concentration is far below that notma@ needed to crystallize ettringite ([S0,2-]>10-5 M/L), it is diffkult to explain the formation of these ettringite by the above mentioned two mechankns. The authors believe that solid-phase rear;tion mechanism should be the answer.