Pozzolanic Reactivity and Hydration Products of Hedenbergite

Abstract

With hedenbergite, desulfurized gypsum and calcium hydroxide as the materials, this paper studies the pozzolanic reactivity of finely ground hedenbergite and performs XRD, IR, NMR and SEM analysis on the hydration products of the neat paste specimens. The results show that the compressive strength of the finely ground neat hedenbergite paste is 5.66MPa and 23.49MPa respectively at the age of 3d and 28d, which indicates that the finely ground hedenbergite has the pozzolanic reactivity, and that its hydration products are mainly C-S-H gel and ettringite. With the curing age, gypsum and silicate minerals are continuously consumed, the bonds connecting the silica tetrahedral network structures rupture, Si⁴⁺ is replaced by Al³⁺ disorderly, and the polymerization of the whole network is reduced, enhancing the activity and gradually increasing the hydration products.