Optimization of Mechanical Properties and Quality Index of Perlite Lightweight Concrete Reinforced with Microsilica and Glass Wool Fibers Using Response Surface Methodology

Perlite lightweight concrete has attracted considerable attention because of its low density and favorable thermal performance. However, its relatively low mechanical strength and brittle behavior still limit its structural applications. This study investigates the combined effects of microsilica content (۷.۵-۱۲.۵%), glass wool fiber dosage (۰-۱.۵ vol%), and fiber length (۵-۵۰ mm) on the mechanical properties and quality index of perlite lightweight concrete. A total of ۳۰ concrete mixtures were designed and experimentally tested under compression, and the obtained data were subsequently analyzed using response surface methodology (RSM) to evaluate factor interactions and determine the optimum mixture proportions. Compressive strength tests were conducted on all mixtures, whereas stress-strain behavior was evaluated for ۱۴ representative mixtures selected to characterize the deformation response. Overall, the simultaneous incorporation of microsilica and glass wool fibers improved the compressive strength, ductility, and energy absorption capacity of perlite lightweight concrete. The experimental results demonstrated that the highest compressive strength of ۴۰.۰ MPa was achieved for the mixture containing ۱۰% microsilica and ۰.۵% glass wool fibers with a length of ۲۷.۵ mm. In contrast, the RSM-based multi-objective optimization identified a different optimum mixture containing approximately ۹.۴% microsilica and ۰.۹% glass wool fibers, which yielded the maximum quality index (R/ρ), defined as the compressive strength-to-density ratio, representing the optimum balance between mechanical performance and density. The novelty of this study lies in integrating experimental investigation with RSM-based multi-objective optimization to distinguish between the optimum compressive strength obtained experimentally and the mathematically optimized quality index, thereby providing a practical framework for optimizing both strength and strength-to-density efficiency of structural lightweight concrete.

کلیدواژه ها:

Perlite lightweight concrete ، Microsilica ، Glass wool fibers ، Compressive strength ، Quality index ، Response Surface Methodology