The influence of molarity variations to the mechanical behavior of geopolymer concrete

¹ Structural and Material Laboratory, Diponegoro University, Tembalang, Semarang, Indonesia
² fib-Indonesia, Prof. Soedarto SH, Tembalang, Semarang, Indonesia
³ Civil Engineering Departement, Diponegoro University, Tembalang, Semarang, Indonesia
⁴ Civil Engineering Departement, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia

^* Corresponding author: purwatrend@gmail.com

Abstract

Research on geopolymer concrete has seen a new light in the analyses and experiments for special topics in the field of their mechanical properties. Among the most important are studies of geopolymer concrete subjected to confinement and bond. Regarding the basic material behavior, research of material proportions formulations, mix design formulas and inventions towards the development of a high-performance geopolymer concrete, were conducted. The latest looked into the effects of molar activator concentrations to the 28 days compression strength, and the strength development as a function of concrete age for geopolymer concretes. The specimens were 150 by 300-millimeter cylinders tested in uniaxial compression. The molarity variations were set at 6, 8, and 10 molars. The geopolymer concrete samples were compared to conventional concrete specimens, having the exact same volumetric material proportions. The cement was replaced with fly ash, and the activator with water. The aggregate content was taken as a constant. The concrete strength as a function of molar increase followed a parabolic, convex pattern, suggesting that a maximum value exists. The strength development of all geopolymer concretes had a slower rate when compared to conventional concrete.