Effetto delle fibre naturali sulle capacità di autoriparazione di compositi cementizi fibrorinforzati

In this paper the effect of natural fibres on the self healing capacity of cementitious composites has been studied. Natural fibres, through their porous micro-structure, can create a large number of moisture paths, through which moisture, absorbed by the same fibres, can be released “on demand” and activate delayed hydration processes which contribute to the healing of the cracks. Reference has been herein made to a High Performance Cementitious Composite reinforced either with steel fibres only or with a hybrid mix of steel and sisal fibres. Influence of environmental conditions has also been studied, including exposure in a climate chamber with high humidity (90% RH), low humidity (50% RH), wet and dry cycles and immersion in water has been performed. The effects of self healing on the recovery, if any, of mechanical performance has been quantified by means of mechanical performance in bending (residual stresses at prescribed openings, stiffness etc.). Visual microscopy observation will be instrumental at visualizing the healed cracks and also assess the amount of crack closure to be correlated to the recovery of mechanical properties, evaluated as above