Pull-Out behavior and microstructure characteristics of binary blended self-compacting geopolymer concrete subjected to elevated temperature

Abstract

Geopolymer concrete (GPC) is an emerging green substitute for conventional cement-based concrete. Due to the eco-friendly benefits of GPC, it possesses superior strength properties. Self-compacting concrete (SCC) is a special concrete, it has the tendency to pass and fill congested areas without the help of vibrators. As the Self-compacting based Geopolymer concrete (SCGC) is a sustainable construction material, the knowledge about the thermal performance of SCGC is vital. Therefore, the current work examined the behavior of binary blended SCGC under room temperature and elevated temperatures of 821 °C, 925 °C, 986 °C, and 1029 °C. The investigation's main objectives are to examine the bond performance and microstructure of binary blended SCGC composites subjected to temperature exposure. Three types of mixes are considered in the investigation, namely FA (100% Fly Ash (FA)), F-G (50% Fly Ash (FA) and 50% Ground Granulated Blast Furnace Slag (GGBS)), and F-M (50% Fly Ash (FA) and 50% Metakaolin (MK)). The workability tests, such as the Flow test, T500 test, V-funnel test, and J-ring tests, were carried out in line with EFNARC guidelines to examine the rheological properties of SCGC. The SCGC composites were subjected to temperature exposure following ISO 834 standard fire curve. The Pull-Out (PO) test was carried out to investigate the Bond stress (BS) of the heated and unheated SCGC composites. The Bond stress of the SCGC composites decreases with an increase in temperature exposure. Test results show that the F-G mix possesses higher BS for unheated specimens, followed by F-M and FA mix. When exposed to elevated temperature, the SCGC composite mix F-G and F-M exhibit higher strength loss (%) than the FA mix. A relationship has been established between the compressive and bond stress of SCGC.

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