Limecrete testing was undertaken at the University of Bath to confirm the optimum mix design to be used on the Clore Learning Centre and Bath World Heritage Centre at the Roman Baths. Limecrete was chosen as an alternative to concrete to provide a floor which is breathable to protect the archaeology.
Low strength limecretes (pure limes or low strength hydraulic limes) can provide a breathable surface; however, the high humidity within the undercroft would make it difficult for low strength limecretes, which cure primarily through carbonation, to gain strength quickly enough. Several mix designs of varying water and pozzolanic content for breathability and compressive strength were tested to determine the optimum mix for this application. Samples were cast in the undercroft to check that the limecrete could achieve an initial set in the high humidity environment.
Our testing resulted in a limecrete mix being approved and used for all areas except on ‘wearing surfaces’ where there was foot traffic.