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

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 fiberreinforced 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 mu m 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.

Automated summary

This study investigated the use of waste PET fibers and waste granite powder as reinforcement materials in autoclaved aerated concrete (AAC). The PET fibers were modified with dopamine to improve the interfacial adhesion between the fibers and the AAC matrix. The results showed that the addition of PET fibers and dopamine-modified PET fibers significantly increased the compressive and flexural strengths of the AAC blocks.