Although cement-based grouts are widely used in geotechnical and geoenvironmental engineering applications, e.g. for the stabilisation of soft soils, their performance can be adversely affected by exposure to aggressive chemicals. The use of zeolites, which are alumino-silicates with rigid hollow structures, has recently been suggested as a means of enhancing the durability of cement-based grouts especially for sulphate attack. As a result, an experimental study was carried out to verify the potential improvements in the behaviour of cement-based grouts containing zeolites in various aggressive environments. This paper focuses on the durability of soft clays stabilised with cement-bentonite and cement-zeolite grouts and addresses the diversity in their behaviour. The aggressive environments applied included sulphate and acid solutions and freeze/thaw cycles. The impact of the aggressive environment is assessed using the unconfined compressive strength (UCS). The results showed a clear difference in behaviour between the cement-zeolite and cement-bentonite grouts with the former significantly outperforming the latter in their resistance to both sulphate and acid solutions, although the latter still maintained its superior resistance to freeze-thaw cycling. The strength was also generally much higher due to the pozzolanic nature of zeolite and hence also enhanced the UCS compared to cement grouts alone.