Influence of Natural Sand Replacement by Mineral Wastes on Earth and Air Lime Plastering Mortars, and Professionals Training

Abstract

It is increasingly necessary to rethink constructive solutions to minimize the construction industry’s environmental impact without compromising technical characteristics, including conservation. The replacement of natural sand by ceramic waste and clayish earth was analyzed in the fresh and hardened state of earth and air lime mortars. Seven different mortars with clayish earth and air lime as binders were produced and characterized: two earth mortars with added sand and with brick waste instead of sand; five air lime mortars with sand, with clayish earth, or with brick waste instead of sand. The replacement of sand by brick waste promotes a decrease in the mortars’ dry bulk density and mechanical strengths. For the air lime mortar, the replacement of sand by brick waste promotes an increase in dynamic modulus of elasticity, compared with the reference mortar with low flow. The air lime mortar with clayish earth presents lower flexural strength and dynamic modulus of elasticity. Many of the mortars with alternative added aggregate fulfil the requirements for plastering old and new buildings and, based on old practices, can be a more sustainable alternative with natural pigmentation. However, training is needed for professionals using this type of mortars.