A laboratory investigation of steel to fly ash-based geopolymer paste bonding behavior after exposure to elevated temperatures

By Xi Jiang, Rui Xiao, Miaomiao Zhang, Wei Hu, Yun Bai, Baoshan Huang. 2020

218 citations recorded by the source corpus.

Abstract Geopolymers are generally agreed to provide good steel-to-concrete bonding performance and fire resistance. However, few previous studies on geopolymer investigated the steel-to-concrete bonding behavior and fire-resistance at very high temperatures (>800 °C), hence cannot reveal the damage of a severe fire accident. This paper presents the results of an extensive experimental study carried out to investigate the effect of elevated temperature on the thermal-physical behaviors and mechanical properties of fly ash-based geopolymer paste. After being exposed up to 1200 °C according to the RATB fire curve, the damage stages of geopolymer paste (GPC) and ordinary Portland cement (OPC) were investigated through the unconfined compressive strength test, push-out test, thermogravimetric analysis (TGA), differential thermal analysis (DTA) and scanning electron microscopy (SEM) analysis. Based on the results and existing literature, there was a less mass loss and a better compressive strength for GPC paste after the treatment, which led to a better bonding behavior of GPC compared with OPC paste. In addition, a positive linear relationship between the bond strength and the compressive strength was found for both GPC and OPC. Furthermore, the stable properties of phases change and porous micro-structure in GPC identified by SEM and XRD methods were important for a better bond behavior at elevated temperatures. Thus, the GPC offers a feasible alternative to OPC in practical fire-resistant building applications.

Subfields: Civil and Structural Engineering

View Paper: https://www.semanticscholar.org/paper/3bb2ca2236c2fad922fc1118037ab517bc4763ba