Numerical Study on Static and Fatigue Behavior of Alkali-Activated Fly Ash Concrete Modelled using Concrete Damage Plasticity (CDP) Model

Abstract

Alkali-activated concretes (AAC) are considered as an alternative to Portland cement concretes because of their much lower carbon emissions. To study its characteristics is of utmost importance. In the present research, an attempt is made to create a numerical model to analyze the static and fatigue flexural behavior of alkali-activated fly ash concrete (FC) and compare them with ordinary Portland cement concrete (PCC). Three-point bending tests are simulated for the monotonic load to obtain the static behavior of a 2D notched rectangular beam. A 2D beam specimen of size 262.5 mm x 75 mm, with a notch of size 15 mm x 3 mm was provided at the bottom middle. Fly ash-based alkali-activated concrete (FC) and corresponding PCC of similar strength are modeled in ABAQUS CAE using the concrete damage plasticity (CDP) model. The ultimate loads, maximum deflection, and CMOD for each of them were obtained from the history output manager. The results of monotonic tests are utilized for creating a sinusoidal load cycle for fatigue tests with various loading frequencies and stress ratios. Different structural responses are examined under the fatigue test. The results showed that FC performs better than PCC under static and fatigue tests. Fatigue performance of both FC and PCC is influenced by the frequency of loading and fatigue life increases at higher frequencies. It is also found that stress reversal negatively impacts the fatigue life of both FC and PCC.