Volume 15, No. 4, 2021
Received: 2021/06/29, Accepted: 2021/08/13
Authors:
sureshbabu N; george mathew;
Abstract:
The bond-slip behavior of geopolymer concrete equivalent to M40 grade, being exposed to high-temperature
conditions is discussed using pull-out test results. The alumino-silicate materials considered in the geopolymer
concrete are ground granulated blast furnace slag (GGBS) and fly ash, hence heat curing has been avoided. A
ribbed reinforcing bar of 8 mm diameter has been used in the pull-out specimen. Parameters like different
GGBS content (50%, 75% and 100%), exposure temperature (Ambient to 800°C) and method of cooling after
temperature exposure (air and water) are considered in this study. The result in comparison with bond-slip
behavior of OPC (Ordinary Portland Cement) concrete is an approximate grade of M40. It has been seen that
the bond strength of geopolymer concrete containing fly ash and GGBS is higher than that of OPC with almost
the same compressive strength. Also, when exposed to higher-temperature conditions, the bond strength
reduction in geopolymer concrete, primarily due to the formation of geopolymer structure, is less than in OPC.
However, while OPC concrete shows uniform rate reduction in bond strength till 800°C, the more or less
uniform decrease in the bond strength of geopolymer concrete till 600°C changes to a higher rate beyond 600°C.
Further, after water cooling, the decrease in bond strength is significantly higher in geopolymer concrete
compared to OPC concrete. A possibility of sudden bond failure has been noted in geopolymer concrete when
it is exposed to high-temperature conditions, as the critical strength between the bonds approaches the decisive
bond strength with exposure to high temperatures.
Keywords:
Bond strength, Geopolymer, GGBS, Fly ash, Bond-slip, Concrete