Post-cracking behaviour of the PP fibre reinforced concrete beams was studied using a residual flexural tensile strength test with CMOD, according to BS EN 14651-2005+A1-2007 [46]. The flexural beams were of size of 150 mm × 150 mm × 600 mm. A notch of 2 mm wide and 25 mm deep were cut at mid-span of each beam as shown in Fig. 5. The notched beams were loaded using a 500 kN hydraulic testing machine on a three-point loading setup. The CMOD was measured using two clip gauges installed at the centre of the notch and averaged CMOD values were adopted. The clip gauges attached to knife edges glued to the bottom of the beam were connected to a data acquisition system and a Linear Variable Displacement Transformer (LVDT), as shown in Fig. 5. This test was under closed-loop displacement control to maintain the increase of CMOD at a constant rate of 0.05 mm/min. All the tests were carried out at K&H Geotechnical Services Pty Ltd, Australia. Three CMOD beam specimens for each fibre type were tested. One plain concrete beam was tested as a control specimen.