This article investigates the mechanical properties of cementitious repair mortars modified with styrene-butadiene rubber (SBR) at dosages of 5% and 10% by weight of cement. It includes an analysis of flexural strength (FS) and compressive strength (CS), as well as transport properties such as total shrinkage (SR) and water absorption (WA). Glass fibers (GF) were added to these mortars at rates of 0.1%, 0.3%, and 0.5% of the total volume to reinforce them. A factorial design was employed in numerical modeling to study the effects of different SBR and GF levels on the physical and mechanical properties of the repair mortars. An analysis of variance (ANOVA) was conducted to determine the significance of the factors and their interactions on the selected responses. Digital Image Correlation (DIC), using GOM software, was used to measure and quantify deformations and movements. The findings reveal that polymer mortars reinforced with glass fibers exhibit greater resistance to bending and compression than polymer mortars without fibers. Furthermore, fiberglass-reinforced mortars demonstrate good dimensional stability over time with respect to total shrinkage. Moreover, the developed mathematical models yield efficient prediction equations for FS, CS, SR, and WA by considering SBR content and fiberglass levels. DIC provides a highly effective numerical representation of stressed areas, locations of crack initiation, fracture mechanisms, and crack propagation. The repair mortar exhibits strong adhesion to concrete exposed to high temperatures.