Effect of innovative bioproducts on air lime mortars

Abstract

In this work, air lime mortars were bioformulated with two innovative bioproducts, one resulting from iron supplemented Escherichia coli cultures and a second one exploiting microbial mixed cultures grown with crude glycerol as substrate. The bioproducts were lyophilized and, for the mortar formulation, suspended in water and used as mixing liquid. Workability of mortars was evaluated by the flow table consistency and 90-days-old samples were tested for different properties, such as thermal conductivity, bulk density, porosimetry, water absorption, drying, surface hardness and compressive strength. With water content to ensure workability, bioformulated mortars presented higher thermal insulation and reduced water absorption when compared with a non-bioformulated control mortar. However, the presence of bioproducts decreased the compressive strength of the air lime mortar. Contact with water, simulating weathering, diminished that decrease. The strategy utilized in the present work meet some of the goals of a circular economy approach maximizing natural resources by the use of wastes to produce the bioproducts and increasing lime mortars durability.