Acoustical and mechanical characteristics of mortars with pineapple leaf fiber and silica aerogel infills-Measurement and modeling

While offering good thermal insulation, silica aerogels inclusion in cementitious matrices compromises hugely the products' compressive strength. Enhancement of the mechanical performance of concrete reinforced by fibers, on the other hand, has been well evident in existing scholarly works. Even so, natural fibers are underexploited compared to their synthetic counterpart. Therefore, this study examines the acoustical and mechanical characteristics of mortars mixed with silica aerogel and pineapple leaf fiber for various mixture designs in determining the optimal blends that exhibit good performance in both compressive strength, sigma u, and sound absorption coefficient, Sa. Due to the widely reported mixing issue of silica aerogel in cement matrix, the examined samples have been fabricated through a carefully planned dry mixing method with a slow introduction of water in stages. The investigated silica aerogels are in powder form whereas pineapple leaf fibers are prepared in 10 mm length, from which their examined proportions are 0 %, 10 %, 20 %, 30 %, and 40 % as well as 0 %, 1 %, and 2 %, respectively. Scanning electron microscopy and Fourier transform infrared spectroscopy are additionally conducted to offer insight into the variation observed in sigma u and Sa for different mixes. The commonly reported drop in mechanical strength attributed to silica aerogel inclusion is witnessed but offset by the added pineapple leaf fiber. To circumvent laborious laboratory effort, statistical and machine learning explicit expressions are derived to generalize sigma u and Sa as functions of silica aerogel and pineapple leaf fiber contents. Also, the optimal constituents' contents that exhibit good soundproofing while low in mechanical strength degradation are determined from the models for future design convenience.