Monitoring and Modeling of Formwork Pressure Exerted by Castable Earthen Materials

Castable earth appears to be a promising solution for an efficient modern earthen construction method. In this construction technique, a setting agent is added to the earthen material (biopolymer or hydraulic binder), induces a material hardening and allows for the formwork removal. However, and contrarily to castable concrete, there is no available study dealing with the monitoring and the modeling of the pressure exerted by the earth at fresh state on the formwork. Nevertheless, it is critical to be able to predict the formwork pressure and its evolution with time after casting in order to design the formwork structure and to schedule its removal. In this study, a formwork mock-up equipped with interstitial pressure sensor is used to monitor the formwork pressure and the ability of theories developed for the prediction of pressure exerted by cement-based materials are tested and adapted to self-compacting earthen materials, one using alginate as a setting agent and the other incorporating 5% of CEM IIIA cement.