Structural Analysis of Ferrocement Composite Panels with Expanded Perlite Based Mortar

A laboratory investigation was conducted to evaluate the structural behavior of ferrocement composite panels (FCPs) incorporating expanded perlite lightweight aggregate (LWA) at varying volume fractions (55%, 35%, and 15%). Twelve lightweight FCPs (60 × 60 × 4 cm) were fabricated with one, two, or three layers of expanded rib lath and tested under three-point flexural loading. Structural response was assessed using digital image correlation (DIC) and theoretical analysis based on the thin plate theory. The results showed that increasing the number of rib lath layers significantly enhanced the first crack load (F _cr ) and ultimate load (F _u ), with improvements ranging from 11–224% in F _cr and 18–76% in F _u . Deflection at first crack (\(\:{\text{D}}_{{\text{F}}_{\text{c}\text{r}}})\) and ultimate load (\(\:{\text{D}}_{{\text{F}}_{\text{u}}}\)) increased by an average of 47% and 229%, respectively. Additionally, the use of perlite LWA increased \(\:{\text{D}}_{{\text{F}}_{\text{c}\text{r}}}\) and \(\:{\text{D}}_{{\text{F}}_{\text{u}}}\) by 29% and 26% compared to regular FCPs, highlighting its effectiveness in enhancing flexibility. DIC analysis identified transverse strain (ε _xx ) as the most sensitive parameter for early crack detection. Taguchi optimization further revealed that the number of rib lath layers had a more significant impact on Fcr and Fu than perlite content. These findings suggest that a three-layer FCP system with 15% perlite replacement optimizes load-bearing capacity, making it well-suited for high-strength, lightweight applications such as modular buildings and prefabricated structural elements.