Mechanical and fracture properties of mortars reinforced with glass fibre and prepared with different cement types

Purpose: The main aim of the current study is to investigate the effect of Anti-Crack HP 67/36 glass fibre on the mechanical performance of mortars made of cement, with a focus on post-cracking evaluations using the digital image correlation (DIC) technique. Design/methodology/approach: Experimental tests were carried out on 36-mm long fibres at 0.8% by volume and added to the normal strength (NSM), high strength (HSM) and high strength mortar with fly ash (HSMFA) mortars. CEM I 52.5 CP2 NF, CEM II/A-L 42.5 NF and CEM III/C 32.5 N-SR PM were used for each series of mortar to assess the performance of the glass fibres with the types of cement. F-class fly (FA) ash was used to reduce global CO2 emissions. Findings: The mortar's strength decreased as the cement types changed from CEM I to CEM II and III. However, due to changes in the portlandite content of the cement, water porosity increased for both types of mortar, without and with fibre. It was also found that using glass fibre increased flexural strength more than compressive strength, regardless of the type of cement used. For all the strength classes, it was found that the mortar mixes with CEM I had the highest critical crack opening (wc) and fracture energy (GF), followed by CEM II and III. No significant effects were observed in the mortar's property by replacing fly ash (12%). Research limitations/implications: Only mortars were formulated in this study, but the results must be verified at the concrete scale. Practical implications: Validation of the DIC technique to characterize the post-cracking behaviour of cement-based material. Use of glass fibres to improve the material's resistance to cracking. Social implications: Use of CEM II and CEM III cements with low CO2 footprint instead of CEMI without altering the mechanical performance of the material. Originality/value: The work is a further contribution to studying the cracking behaviour of several series of variable mortars depending on the resistance class and the type of cement used.