Gabrielli B. Esteves (a) https://orcid.org/0009-0006-5014-942X
Gihad Mohamad (b) https://orcid.org/0000-0002-6380-364X
Rene Q. Rodriguez (a) (c) https://orcid.org/0000-0002-1676-924X
Alexandre S. Vargas (b) https://orcid.org/0000-0002-5247-3235
Armando L. M. Junior (d) https://orcid.org/0000-0002-7660-050X
a Federal University of Santa Maria (UFSM), Graduate Program in Civil and Environmental Engineering, Santa Maria, RS, Brazil
b Federal University of Santa Maria (UFSM), Department of Structures and Civil Construction, Santa Maria, RS, Brazil
c Federal University of Santa Maria (UFSM), Department of Mechanical Engineering, Santa Maria, RS, Brazil
d State University of Campinas (UNICAMP), Department of Civil Engineering, Campinas, SP, Brazil
ABSTRACT
Styrene–acrylic resin–based polymeric mortars have emerged as viable alternatives to conventional cementitious mortars for masonry bedding, particularly in thin-bed joint applications. Nevertheless, significant gaps remain in standardizing experimental protocols for specimen fabrication and in characterizing their tensile behaviour. Accordingly, this study aimed to establish an optimized molding and testing framework based on ASTM D638 to evaluate the tensile performance of polymeric masonry mortars. Two commercially available formulations from the Brazilian market—comprising a polymer blend dominated by styrene–acrylic resin, mineral fillers, and functional additives—were investigated. Eleven distinct molding configurations were iteratively evaluated using 3D-printed and silicone molds, with nominal thicknesses of 3.2 mm and 7.0 mm, in line with ASTM D638 specifications for polymeric materials. After identifying the optimal fabrication method, direct tensile tests were conducted on a universal testing machine at a displacement rate of 1 mm/min. Strain fields were captured using Digital Image Correlation (DIC), enabling the derivation of stress–strain profiles, ultimate tensile strength, strain at peak stress, Young’s modulus, and toughness. The results demonstrate that the proposed silicone-based molding method provides superior surface finish and specimen integrity. Furthermore, the mortars exhibited divergent mechanical properties: one formulation displayed higher strength and stiffness, while the other showed enhanced ductility. Despite these differences, both materials yielded comparable toughness values and failed predominantly in a ductile manner under tensile loading.
Keywords: polymeric mortar; masonry bedding; styrene–acrylic resin; molding; tensile behaviour; toughness.