Hydration products of alkali-activated slag-red mud cementitious material

A new kind of alkali-slag-red mud cementitious material, abbreviated as ASRC, with both high early and ultimate strength and excellent resistance against chemical attacks has been developed by the application of composite solid alkali activator into slag-red mud mixture system. The hydration products of this cement at ambient temperature have been investigated by means of XRD, IR, TG-DTA, TEM, EDXA, etc, The results showed that the hardened cement paste was mostly consisted of C-S-H gel, being very low in Ca/Si ratio, very fine in size and extremely irregular in its shape. Neither Ca(OH)(2) and AFt, which are usually present in the hardened Portland cement paste. nor zeolite-like products have been detected. These characteristics are considered to be the chemical reasons for the high early and ultimate strength and good resistance against chemical attacks of the hardened ASRC cement paste. (C) 2002 Elsevier Science Ltd. All rights reserved.