Ternesite as a component of sulfobelitic cements

Abstract

Abstract. The cement industry is presently devoting substantial effort to the development of less energy intensive, lower emission cements. Calcium sulfoaluminate (CSA) cements, one of the most promising alternatives, are known as 'eco-cements' in light of their lower energy costs and GHG emissions. Whilst their clinker composition may vary, all these cements lie in the CaO-A l2 O 3 -SiO 2 -Fe 2 O 3 -CaSO 4 system, with constituent minerals that include C 2 A, C 2 S, C 12 A 7 , CA, CŜ, and C 4 AF. Ternesite (C 5 S 2 Ŝ), a phase compatible with ye'elemite (C 4 A 3 Ŝ) and C 2 S, can also be found in that system.Recent studies show that it is activated and hydrated in the presence of AH 3 and gypsum, yielding ettringite and C-S-H gel, the main hydration products of CSA and OPC, respectively, as well as C 2 ASH 8 .This study analyses ternesite reactivity in different aluminate blends.