Sustainable bio-based earth mortar with self-healing capacity

Abstract

This paper describes the hygrothermal and mechanical properties and self-healing capacity of a sustainable bio-based mortar repair system for earth construction. There is currently limited characterisation of materials that directly compare earth, bio-fibres and self-healing behaviour. Additionally, the thermal performance of self-healing materials has been under-researched. Both prismatic and 0.1 m × 0.1 m samples were cast with plain mixes, saw mill residue (SMR), straw, wool and wood pellets. Executing both structural and hygrothermal experimentation provided an indication of the performance and durability of the samples. The bio-based agent added to the bio-based composite consisted of bacteria. Adding the bio-based agent to an earth matrix with (wheat) straw, (sheep) wool, SMR and wood pellets showed promising results for the hygric properties, as the initial water adsorption and absorption were lessened. The thermal conductivity was reduced from 0.32 to 0.23 W/m.K when bio-based agents were combined into the earth-based mix design with SMR. Overall, it is evident that out of all ten mix designs, bio-SMR provided the best environmental conditions for the bio-agent.