The assessment over time of the performance of jute-basalt hybrid composites for cladding panels

Abstract

The technology of dry assembly to produce multi-layer panels is an efficient alternative to traditional systems. Eco-sustainable systems are increasingly studied, particularly fiber reinforced composites for external cladding, based on natural fibers. Nevertheless, durability data on these composites are still lacking, being this is a really actual theme, especially for their potential use in outdoor applications. In this way, hybridization of natural fibers with mineral fibers as basalt ones appears promising. In the present paper, the performance of jute-reinforced laminate was compared with those of two jute/basalt reinforced hybrid laminates. The laminates were manufactured by means of vacuum infusion process and then cured, varying the number of layers in order to achieve both thickness and fiber content almost constant. In particular, not hybridized jute reinforced composite is made of eight layers of jute plain weave fabric (290 g/m2 areal density). The hybridization of jute was performed by using unidirectional basalt fabrics (300 g/m2), to manufacture two hybrid laminates: in the first one, layers were stacked as a sandwich sequence with six jute fiber reinforced layers as core and two basalt fiber layers as skins, for each side of the laminate; in the second laminate, fabrics of basalt and jute fibers were alternatively stacked with basalt fabrics as outer layers. All laminates were exposed to 4 steps of accelerated aging into climatic chamber, for a whole period of 84 days, by developing aging cycles of hygrothermal stress and UV radiation, reproducing the climatic conditions of the Mediterranean context of South Italy. After each step of accelerating aging, several mechanical tests (i.e., quasi-static three point bending tests, Charpy impact tests and dynamic thermal tests) were performed according to International standards. Initial results show the effectiveness over time of produced composite laminates and initial increase of measured performances after the 1st step of accelerated aging.