Learning from tradition: A potential additive combination for producing waterproof poured earth

Abstract

Inspired by a vernacular earthen construction practice retained in the tropical regions of Africa, we propose a low-environmental impact additive solution for improving the water resistance of clay materials. Oak tannin combined with iron chloride was set as an example to illustrate its e ectiveness and to understand the involved mechanism. We highlight that incorporating oak tannin and iron chloride greatly improves the water resistance of clay materials due to a reaction of complexation between tannin and iron ions. Finally, by controlling the reaction kinetic, we show that a new type of poured earth with improved water resistance can be produced.