The Influence of Animal Glue as an Additive on the Properties of Lime Architectural Grouts

Abstract

Organic additives from plant and animal extracts were commonly used in lime mortar in the past to improve and modify its properties. In modern times, they have been replaced by inorganic additives. The objective of this research is to investigate the influence of fish animal glue and the role of the filler particle size distribution on the fresh and hardened properties and durability of lime grouts. Wet density, water retention, fluidity, and injectability were tested in the fresh state. It was found that the particle size distribution of the selected filler, which can increase the packing density of the solid particles of the grout, and the W/B ratio have a great influence on water retention and fluidity. In the hardened state, porosity and compressive and splitting tensile strength were evaluated on 90-day- and 365-day-old specimens. The presence of animal glue improved the mechanical properties, due to a higher carbonation rate. The combination of the two fillers that resulted in a better packing of filler particles decreased the splitting tensile strength of the grout. To investigate the durability of the selected grouts, adhesion strength was measured on disc-sandwich models after non-accelerated and accelerated aging. The results show that the adhesive strength of grouts aged under laboratory conditions is lower than that of grouts subjected to accelerated aging.