Study of Geopolymer Concrete Filled Stainless Steel Tubular Column with GGBS Mixture Under Compression

Abstract

Concrete-filled stainless steel tubular (CFSST) columns are currently used in modern newlinehigh rise buildings and larger span structures. Stainless steel tubular section acts as an newlineouter core which confines the filled material. Due to confinement, there is newlineenhancement in the load carrying capacity of the column cross-section and also large newlineenergy absorption capacity. Recently, the potential utilization of fly-ash, ground newlinegranulated blast furnace slag (GGBS), silica fume (SF) are used as binder material to newlineform a new concrete called geopolymer concrete along with an alkaline activator newlinesolution, fine aggregate and coarse aggregates. Geopolymer concrete is also termed as newlinegreen concrete. This research is focused on experimental investigation of GGBS newlinemixed geopolymer concrete filled stainless steel tubular (GCFSST) columns tested newlineunder axial compressive load. In order to understand the strength capacity and newlinebuckling behaviour of GCFSST columns, it is compared with GGBS mixed newlinegeopolymer concrete filled mild steel tubular (GCFMST) columns. For this study newlinetotally 57 columns are tested, out of which 18 for GCFSST columns, 18 for GCFMST newlinecolumns, 12 for outer core hollow steel tubes and 9 for inner core columns. The newlineaforementioned stainless steel and mild steel tubular specimens are of two different newlinewall thickness (1.5 and 2.0 mm), three different lengths (300 mm, 400 mm and 500 newlinemm) and with constant diameter 75 mm. Each column specimen is tested with two dial newlinegauges to measure vertical and lateral deformation and two electrical strain gauges to newlinemeasure strain variation at different load intervals. To determine the mechanical newlineproperties for infilled material, 18 cubes, 12 prisms and 12 cylinders are cast and newlinetested. The parameters such as compressive strength of GGBS mixed geopolymer newlineconcrete, diameter-to-thickness ratio (D/t) and length-to-diameter ratio (L/D) are newlineconsidered to compare GCFSST columns with GCFMST columns. The effects of (D/t) newlineand (L/D) ratio are also analysed and it is also observed that the dominant failure mod