In the quest for sustainable construction materials, researchers have made a significant stride by enhancing the performance of alkali-activated mortar (AAM) using desulfurization gypsum (DG). This innovation, led by Xiaolong Zhou from the College of Civil Engineering & Architecture at Qingdao Agricultural University in China, addresses key limitations of AAM, such as high shrinkage and rapid setting time, paving the way for broader engineering applications.
Alkali-activated mortar, known for its eco-friendly credentials, has long been hampered by practical challenges. “The high shrinkage and fast setting time of AAM have been major obstacles to its widespread use,” Zhou explains. “Our study demonstrates that incorporating desulfurization gypsum can effectively regulate these properties, making AAM a more viable option for construction.”
The research, published in the journal Buildings (which translates to “Buildings” in English), reveals that adding DG to AAM prolongs the setting time and reduces drying shrinkage. Notably, with a 10% DG content, the setting time of AAM matches that of ordinary Portland cement (OPC), a significant milestone for the industry. “When the DG content was 10%, the alkali-activated materials exhibited a setting time similar to that of OPC,” Zhou notes. “This is a crucial finding for practical applications.”
The study also investigated the impact of DG on workability, corrosion resistance, and mechanical properties. While fluidity, water erosion resistance, and sulfate resistance decreased with higher DG content, the mechanical properties showed an initial increase before declining. The optimal DG content was found to be 6%, where the 28-day compressive strength reached an impressive 63.25 MPa. Even after 60 days of water and sulfate corrosion, the residual strength of AAM-6 surpassed that of OPC in similar conditions.
Microscopic analysis provided further insights, revealing that DG promotes the formation of ettringite. This mineral fills pores over time, creating a dense structure that enhances mechanical properties and inhibits shrinkage. “The formation of ettringite is key to improving the performance of AAM,” Zhou explains. “It fills the pores and forms a dense structure, which is crucial for long-term durability.”
The implications of this research are far-reaching. By enhancing the engineering applicability of AAM, this study not only promotes sustainable construction practices but also enables the high-value utilization of industrial solid waste. “This research is a step towards more sustainable construction materials,” Zhou says. “It shows that industrial by-products can be effectively used to improve the performance of eco-friendly materials.”
As the construction industry continues to seek sustainable solutions, this research offers a promising path forward. By leveraging desulfurization gypsum, developers can create more durable and eco-friendly construction materials, ultimately contributing to a greener future. The findings published in Buildings highlight the potential of this approach and set the stage for further innovations in the field.