Behavior of Geopolymer Concrete Confined by Circular Hoops

¹ Dept. of Civil and Environmental Engineering, Gadjah Mada University, Yogyakarta, Indonesia
² Master Student of Civil Engineering, Diponegoro University, Semarang, Indonesia
³ Professor of Civil Engineering, Petra Christian University, Surabaya, Indonesia
⁴ Professor of Civil Engineering, Sultan Agung Islamic University, Semarang, Indonesia

^* Corresponding author: muslikh2007@gmail.com

Abstract

This paper discusses the behavior of geopolymer concrete subjected to passive confinement under compression loads. The confinement is induced by the use of lateral hoops, assembled from un-deformed reinforcing bars. To compare the effect of confinement, identical specimens were produced using conventional concrete with the similar concrete compressive strength. The cylinder specimens were 100 mm in diameter and 200 mm in height, and the hoops were placed on the outer most fibers of the cylinders, perpendicular to the line of loading, with no concrete cover. The parameters analyzed in this study were the steel bar to concrete volumetric ratio, the hoop spacings and the steel yield stresses. The experimental results show that unconfined geopolymer concrete were very brittle compared to the unconfined Portland cement concrete. The strength enhancement (K value) of the confined geopolymer concrete was higher than K value of Portland cement concrete. Confined geopolymer concrete also has better deformability compared to the confined Portland cement concrete. The average confinement effectiveness of geopolymer concrete also has a higher value than that commonly used in the Indonesian Concrete Standard (SNI), that is 4.1. The results were further assessed to the most recent experimental test results conducted in this area.