| abstract |
A composition of cement additive material for improving the durability of cementitious structures is disclosed. The cement additive composition comprises an admixture of one or more divalent magnesium metal silicates capable of acting as a latent hydraulic binder in the composition activated by a hydration process under aqueous conditions, In particular the divalent metal silicates are magnesium-based silicates, preferably minerals including olivine, orthopyroxene, amphibole, talc and serpentine or mixtures thereof. The composition also contains chloride ions or brine. Also disclosed is the use of the composition, particularly when exposed to water and brine, to exploit the hydration properties as the primary trigger for the latent hydraulic reaction of magnesium silicate, particularly the olivine, to obtain self-healing cementitious material. |