Evaluación del Comportamiento Físico de Morteros Base Cal con Aditivos Orgánicos

The intervention in historic buildings faces limitations due to the shortage of skilled labor and specific materials. The lack of knowledge about traditional construction techniques hinders accurate replication; restorations often rely on commercial solutions, accelerating the deterioration of buildings. The study examines the effects of natural additives of Chúkum (Havardia albicans), Chakáj (Bursera simaruba) and Pixoy (Guazuma ulmifolia) bark extracts on the properties of lime mortars by evaluating their performance in comparison with a control mortar without additives. Lime mortars were prepared with liquid extract of pixoy, chákay and chukum with a lime-sand ratio of 1:3 and parameters such as fluidity, density, absorption, moisture loss, morphological characteristics and mechanical strength were analyzed. From the preparation stage, the mortars added with bark extracts showed higher flowability (16%-35%) compared to the mortar without additives. After setting, the mortars with extracts exhibited less cracking, a smooth, compact surface finish and reduced roughness compared to the control; these mortars presented lower water absorption percentages, especially with pixoy extract. As for compressive strength, a progressive increase was observed in all mortars with time. Mortars with Pixoy, Chákaj and Chúkum extracts did not reach the same strength values as the control mortar at 28 days, those with Chúkum and Pixoy showed a significant increase in compressive strength (37%-50%) after 90 days, however only the mortar with Chákaj managed to equal the strength of the control mortar. The results suggest that the use of these extracts should be evaluated according to the specific needs of each project.