Preparation and performance of autoclaved aerated concrete reinforced by dopamine-modified polyethylene terephthalate waste fibers

Abstract

• Waste granite powder and polyethylene terephthalate (PET) fiber were used to prepare autoclaved aerated concrete (AAC). • A simple and efficient process was used to improve the interface bonding of the composites. • The flexural and compressive strengths of the AAC with the modified waste PET fiber increased by 37.2% and 12.7%, respectively. The low tensile and flexural strengths make autoclaved aerated concrete (AAC) susceptible to cracking and damage during transportation and service. This study investigated the use of waste polyethylene terephthalate (PET) fiber as AAC reinforcement, which is a byproduct from the textile industry. Meanwhile, waste granite powder from stone plate processing byproducts was used as a siliceous material in the preparation of fiber-reinforced AAC composites. The waste PET fibers were modified by dopamine hydrochloride to improve the interfacial adhesion between the fibers and the AAC matrix. Results showed that the AAC blocks with 0.1 wt% PET fiber (1 mm in length and 18 μm in diameter) increased the compressive and flexural strengths by 6.0 % and 28.4 %, respectively. By adding 2 g/L dopamine-modified waste PET fiber, the compressive and flexural strengths of the blocks were further increased by 12.7 % and 37.2 %, respectively. The PET fibers were characterized using water contact angle test, SEM, FTIR, XPS, and TG analyses. It was confirmed that the amino and hydroxyl groups were grafted onto the modified fiber surface, leading to improved hydrophilicity and reactivity of the fibers and thus enhanced interfacial bonding between the fibers and the AAC matrix.