Sulphate resistance of lime-based barium mortars

This work studies the effect of barium hydroxide on the sulphate-resistance of lime-based mortars when used as an additive material to the lime binder. The overall aim of the work is to study the potential of barium hydroxide in producing a mixed binder with lime, which is able to fix the sulphate ions, block the diffusion of sulphate solutions and therefore, reduce the degradation rate of mixtures.The durability of different mixtures was studied through sulphate salt crystallisation and acid rain simulation tests, along with the characterisation of their pore-space properties. X-ray diffraction (XRD), scanning electron microscopy (SEM/EDX) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) were used for materials characterisation. Experimental results proved that barium hydroxide increases the durability of hardened mixtures against sulphate attack, without affecting the microstructure characteristics.