Rheological Optimization of Polyester Resin-calcite Mortars for Tailored Structural Crack Repair

Abstract

The primary goal of this study was to evaluate the rheological performance and fresh-state workability of a repair mortar formulated using polyester resin and calcite filler, and to establish a precise correlation between the filler-to-binder ratio and the mortar’s suitability for various structural crack applications. An experimental design focusing on systematic variations in filler dosage (Resin/Calcite ratios ranging from 50/50 to 30/70) was utilized to characterize the material’s flowability limits and workability thresholds. The mixtures were prepared using a precision balance (± 0.01 g) with Polyester Resin (PP 70*60) and calcite, activated by the Methyl Ethyl Ketone Peroxide (MEKP) catalyst. Flowability was quantitatively assessed using a scaled cone method adapted from ASTM C1437/C1437M. Fluidity exhibited a clear inverse correlation with the calcite content, ranging from a 100% overflow benchmark (50R-50C) to a critical non-workable limit established at the 70% calcite proportion. In conclusion, the established correlation provides a direct framework for the structural engineer to formulate application-specific mortar dosages, optimizing workability to match crack geometry and orientation, thereby minimizing the use of external formwork and ensuring the complete, durable sealing of structural defects in both horizontal and overhead placements.