Bacteria-fungi mortar: construction with reclaimed materials and microbial composite

Abstract

Heavily relying on extraction-based materials in Architecture, Engineering and Construction (AEC), the industry is one of the strongest consumers of raw materials. This research explores the temporalities of material layers in architecture, where high durability can be connected to materials with shorter lifespan, allowing for repair, restoration, reconfiguration and reclamation of material at the end of life in one built environment. By exchanging short lived materials with regenerative and fast-growing biogenic alternatives, we can maximise the lifespan of long-lasting materials and therefore reduce unnecessary extraction of raw-materials. This paper presents the qualitative development and testing of a method exploring a biogenic mortar solution for reclaimed clay-based brick assemblies. It offers insight into the method of co-cultivation of the used bacteria Sporosarcina pasteurii and fungus Ganoderma lucidum, forming a mycelium-bacteria based composite (MBBC). It explores the qualitative potential of this material in a fabrication strategy in three settings; (1) the joint between two bricks, (2) an assembly of four bricks and (3) a demonstrator of a wall fragment prototype at full scale. Additionally, the paper includes initial tensile bond strength tests. While only having a small specimen set which have been tested on a self-built test-setup, the exploration results in similar tensile properties (MBBC: 0,05 MPa) as described by hydraulic lime-based mortar (0,045 − 0,068 MPa).