Effect of Vapour-Grown Carbon Nanofibres on Thermo-Mechanical Properties of High-Functionality Based Resin Used in CFRP Strengthening System Subjected Severe Service Conditions
Carbon-based nanomaterials are commonly used to produce nanocomposites with polymeric matrices due to their unique properties. Vapour-grown carbon nanofibres (VGCF) are employed in this work to modify highly cross-linked epoxy-based resin (DGOA) used as a bonding agent in CFRP/concrete system. The influence of such modification on adhesive properties as well as on bond performance between CF-fabrics and concrete at various services conditions is addressed. Transmission electronic microscopy (TEM) technique was employed to characterize the structure of VGCF. The latter was identified as stacked-cup and bamboo-like fibres with various thickness of grapheme walls as well as of the hollow cores. The inclusion of (1 and 2 wt%) of VGCF into DGOA was found to reduces the glass transition temperature (Tg) measured by Differential Scanning Calorimetry (DSC) technique. Results of tests at elevated temperatures showed improvement in bond strength in tension of about 7 °C for samples with 2 wt% of VGCF-modified DGOA when compared with unmodified DGOA. The exposure of loaded CFRP/concrete specimens to different temperature and humidity cycles for different exposure periods (21 and 44 days) results in achieving sufficient bond performance using VGCF-modified DGOA. This bond performance was conducted by means of single-lap shear test. The strain along the bonded length of survived CFRP/concrete specimens was measured as well using 3D image correlation photogrammetry.
KeywordsVGCF DGOA CFRP Concrete Durability
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