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Abstract

This study investigates the effectiveness of using mesoscale modelling by performing a parametric study on the effect of varying steel fibres’ dosage, length and diameter on the performance of steel fibre-reinforced concrete. A thorough literature review was realised which highlighted the current reliance of research on the conventional finite element modelling techniques by using experimental stress-strain curves.
The methodology presented in detail an available Matlab code which was used throughout the work, explaining the geometry and meshing generation algorithms, the materials constitutive models that the model was based on; concrete followed an isotropic damage model using Rankine failure criteria, the steel was represented using an elastic-plastic relationship with no hardening, while the interface between the two used a traction separation model. The load and support conditions were also chosen to represent a 3-point flexural test so that the findings could be compared to existing experimental results, which were found to be very similar using the khi2 test of similarity.
19 simulations were realised in total with 6 variations in each of the three parameters; fibre dosage varying from 0.2% to 0.85%, fibre length varying from 45mm to 95mm and fibre diameter from 0.45mm to 0.95mm along with a plain concrete simulation for reference.
The flexural strength was found to increase linearly from 3.05 MPa to 3.58 MPa for 0.2% to 0.7% fibre dosages respectively with the last iteration plateauing while changing the fibres’ aspect ratio didn’t vary significantly. All increases in the fibre dosage increased the load-bearing capacity significantly, with fibres with long aspect ratios showing excellent strain-hardening behaviour.
Fibre axial stresses were found not to change when changing the fibre dosage but increased linearly with the varying of the aspect ratio of the fibres. The mesoscale model was also found to perfectly highlight the effect of the enhancement of the fibres on the spread of the damage, with SFRC having a much better damage distribution.
Finally, both the increase in fibre content and aspect ratio were found to linearly increase the toughness of the overall material with the 0.85% model slightly plateauing while the highest aspect ratio performed better than expected.

Course: Civil Engineering - MSc - C0618

Date Deposited: 2025-01-17

URI/permalink: https://library.port.ac.uk/dissert/dis14670.html