Authors: Graça Vasconcelos, Alessandra Alves, Mário Pereira

Lime and gypsum are mineral binders traditionally used in historic mortars, recognized for their compatibility with ancient masonry and their distinct physical–mechanical behavior. Aerial lime hardens predominantly through carbonation, resulting in porous and deformable mortars, whereas gypsum is characterized by rapid hydration and the early development of mechanical strength. In this context, the incorporation of gypsum into lime-based mortars has been investigated as a means to improve mechanical performance and accelerate the curing process. This study investigates the effect of incorporating different percentages of gypsum into lime mortars, analyzing its influence on physical and mechanical properties and on the evolution of carbonation over curing time. For this purpose, an experimental campaign was carried out, including porosity and capillary water absorption tests, flexural and compressive strength tests, as well as thermogravimetric and mineralogical analyses, allowing relationships to be established between composition, microstructure, and mortar performance.

Graça Vasconcelos₁ | Alessandra Alves₂ | Mário Pereira₂
1 ISISE– Instituto para a Sustentabilidade e Inovação em Engenharia de Estruturas, Departamento de Engenharia Civil,
Universidade do Minho, Portugal
2 Departamento de Física, Universidade do Minho, Portugal