As part of a continuous effort to create sustainable concrete, supplementary cementitious materials (SCMs) are being continuously researched. Fly ash is one of the existing SCMs currently in the Australian market that has been relied on as an SCM, however the production of fly ash has rapidly declined due to pressure to use more sustainable practices, as coal-fired power plants are closing down. Limestone Calcined Clay Cement, or LC3, is an alternative to cement that has recently gained a lot of attention. In this paper, clays from Australia that are considered overburden are analysed and characterised to determine their suitability to be used in the application of LC3. Preliminary results from characterisation experimentation showed that, out of the 46 samples collected from 9 different sites, 4 sites indicated kaolinite content ranging from 30.9% to 65.3% suggesting LC3 application suitable. Based on these results, LC3 mortars and pastes made out of the 4 sites selected were measured and compared to the performance of reference general purpose cement (GP) and fly ash (FA) blended cement pastes for compressive testing and autogenous shrinkage. The investigation into autogenous shrinkage of LC3 pastes is further carried out suggesting autogenous shrinkage is linked to varying characteristics of each individual clay.