Salt resistance of metakaolin and asphalt waste dust-based geopolymer

Abstract

Conventional Portland cement concrete is prone to durability issues in environments with salt contamination, where corrosion, expansion, and cracking are common. Dissolved salts are particularly aggressive and act as direct agents of concrete deterioration. The study focuses on synthesizing geo-polymer materials made of metakaolin (MK) and asphalt waste dust (AD) to evaluate their influence on salt resistance performance, aiming to develop a new type of construction material similar to cement-free concrete. Physical and chemical properties were examined using XRD, XRF, ICP, and FESEM techniques. In addition, compressive strength and weight loss after salt exposure were measured to evaluate the mechanical and durability performance of the geopolymer samples. Geopolymer samples were prepared with 10 wt%, 30 wt%, 50 wt%, and 70 wt% AD replacing MK. Specimens were cured for 2 day, 7 day, and 28 day, followed by immersion in salt solutions for 90 day. Results showed that up to 30 wt% AD and at least 70 wt% MK were appropriate ratios for geopolymer synthesis. Cement samples lost compressive strength and weight, whereas the compressive strength of the geopolymer increased after 90 day of salt immersion. Geopolymer with 10 wt% AD showed the best corrosion resistance, compressive strength, and maintained weight after 28 day of curing.