Waste shell powders as valuable bio- filler in gypsum plaster – Efficient waste management technique by effective utilization

Abstract

The present day construction industry mainly focuses on the reduction of waste accumulation by effective utilization of wastes and by-products in the production of high value building units. This present study encompasses the comprehensive research work conducted on the potentials of using biological shell powders from aviculture and aquaculture wastes as valuable bio - based filler in the production of gypsum plaster. The four different powders obtained from grinding the egg shell, conch shell, scallop shell and cuttle bone were used as replacements for gypsum binder at different proportions (2.5%, 5%, 7.5%, 10%, 12.5% and 15%) by weight. Initially the shell powders were subjected to particular treatment namely distilled water, heat, NaOCl (bleach) and H2O2 to remove their organic matter. The best treatment method was chosen from the obtained elemental analysis conducted on the shell powders after subjecting to various treatments. The elemental analysis results were further complemented by FTIR analysis to validate the removal of the organic matter. Mechanical, thermal and durability studies were conducted on the shell powders substituted gypsum binder to determine the efficiency of bio based shell powder as filling agent. The results showed that the gypsum plaster with enhanced mechanical properties, improved thermal performance and remarkable resistance to water absorption was obtained due to the shell powder substitution. A considerable improvement in the pore structure with well refined and compact microstructure was also evident from the SEM images. The manufactured eco-friendly bio based gypsum binder proves to be an eco-sustainable and economical solution for shell waste management.