Moisture and temperature influence on frp masonry bonding

Durability and bonding of FRP system on masonry is crucial, especially for possible application in historical context, where moisture in the support can influence the application phases, and thermal cycles occurring in the environment can cause de-bonding. Durability tests as humidity variation and thermal cycles were programmed. The pull-off test was chosen as reference test in order to check the loss of bond. Solid brick samples, and small assemblages including mortar joints have been strengthened with CFRP strips in three different configurations. The bond was firstly checked on reference unreiforced specimens. Two types of damage were studied: the effects of different humidity of the support and of ageing due to thermal cycles. Both the phenomena can happen in nature. A first set of thermal ageing tests were carried out for a range of temperature between -10°C and +70°C, applied with a gradient of 0.8°C/min for 40 cycles on two samples. During this first ageing program pull-off tests could not be carried out since most of the strips lost their bond. A new set of tests was carried out on single bricks and other tests on masonry specimens are now in progress during which the damage will be checked at each 2 cycles in order to know the time when the damages start. The results and comments are reported in the paper