Investigation of The Effect of Ground Colemanite Additive on Hydraulic Lime-Based Mortars

Boron is a rare metalloid found in borate minerals like borax, kernite, colemanite, and ulexite. In the construction sector, it is used to protect wood from fungi, insects, and decay, as well as to enhance fire resistance in building materials. Additionally, it serves as an additive in cement and concrete to improve structural properties. This study investigated the effects of ground colemanite (45 µm and 75 µm) as a partial substitute (0-3%) for natural hydraulic lime (NHL 3.5) in mortar. The 28-day mechanical strength and physical properties of the samples were analyzed. Results showed that colemanite improved compressive strength but had little impact on other characteristics, including water absorption. This indicates that at low concentrations, colemanite does not significantly affect the mortar's water permeability.