Fracture properties of geopolymer paste and concrete

Abstract

Geopolymers are an emerging type of cementitious material purported to provide an environmentally friendly alternative to Portland cement-based concrete. This paper reports the results of experimental research on fracture properties (fracture energy and brittleness) of fly ash based geopolymer concrete and paste with various mix parameters. The characteristic length of the geopolymer concrete was approximately three times less than that of ordinary Portland cement (OPC) concrete, due to an increase in tensile splitting strength of about 28%, a decrease in elastic modulus of about 22% and a decrease in fracture energy of about 24%. The difference in characteristic length is similar to that reported between high-strength and normal-strength OPC concretes, indicating that the geopolymer concrete exhibits higher brittleness than its OPC counterpart. This trend was found to be consistent between pastes and concretes, implying that the difference between geopolymer and OPC concrete is due to the type of matrix formation (geopolymerisation or hydration). For geopolymer concretes made with different mix parameters, fracture properties are closely correlated to their compressive strength.

Fracture behaviour of heat cured fly ash based geopolymer concrete

“…Three identical specimens were tested for each mixture except for mixture GPC2, for which two specimens were tested. The loading rate used in the fracture tests of concrete specimens by previous researchers varied in a considerable range, such as 0.05 mm/min [19], 0.18 mm/min [23] and 0.5 mm/min [24]. A loading rate of 0.18 mm/min was used in the tests of this study.…”

Estimation and Minimization of Embodied Carbon of Buildings: A Review

“…Geopolymer concrete is formed by a reaction of silicon and aluminium in byproduct materials such as fly ash, ground granulated blast furnace slag and rice husk ash with an alkaline liquid, which leads to the formation of a cement-like binder [48][49][50]. Numerous studies have been conducted to investigate the mechanical properties and durability of geopolymer concrete to explore its suitability as a replacement for Portland cement concrete and to assess its competitive performance in terms of compressive strength, tensile strength and modulus of elasticity as well as shrinkage, creep, corrosion resistance, sulphate resistance, fire resistance and acid resistance [47,[51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66].…”

Fibre-reinforced geopolymer concrete with ambient curing for in situ applications

“…Its use is, however, limited by concerns regarding an increased brittleness compared to OPC concrete [10]. Neville & Brooks [11] suggested that cementitious materials are generally brittle in behaviour and are inherently weak in resisting tensile forces.…”