FRCM (Fiber Reinforced Cementitious Matrix) can be considered, in some applications, as an alternative to FRP (Fiber Reinforced Polymer) for strengthening and/or seismic retrofitting and upgrading of concrete structures. Structural efficiency, together with good high temperature and fire resistance make FRCM materials a consistent option. In this study, Poliparafenilenbenzobisoxazole (PBO) fibers, arranged in net shape and embedded in cement based matrix, are considered. Experimental results of bending tests on beams strengthened with PBO-FRCM are described, especially focusing on collapse modes. These results are also compared to those of a previous experimental campaign (presented elsewhere), also involving FRCM with carbon fibers and FRP. All these tests showed that failure of PBO-FRCM strengthened beams is caused by the loss of composite action; nevertheless, this failure mode can happen in different modalities. In this paper, tensile bond tests are also presented and discussed. Results of these tests allowed to estimate the Fibres/Matrix bond properties, including the influence of bond length and the estimation of effective anchor length. This research gives quantitative information about bond to substrate, collapse mode, structural efficiency of FRCM as EBR (External Bonded Reinforcement).
PBO-FRCM composites to strengthen r.c. beams: mechanics of adhesion and efficiency
FOCACCI, FRANCESCO;
2008-01-01
Abstract
FRCM (Fiber Reinforced Cementitious Matrix) can be considered, in some applications, as an alternative to FRP (Fiber Reinforced Polymer) for strengthening and/or seismic retrofitting and upgrading of concrete structures. Structural efficiency, together with good high temperature and fire resistance make FRCM materials a consistent option. In this study, Poliparafenilenbenzobisoxazole (PBO) fibers, arranged in net shape and embedded in cement based matrix, are considered. Experimental results of bending tests on beams strengthened with PBO-FRCM are described, especially focusing on collapse modes. These results are also compared to those of a previous experimental campaign (presented elsewhere), also involving FRCM with carbon fibers and FRP. All these tests showed that failure of PBO-FRCM strengthened beams is caused by the loss of composite action; nevertheless, this failure mode can happen in different modalities. In this paper, tensile bond tests are also presented and discussed. Results of these tests allowed to estimate the Fibres/Matrix bond properties, including the influence of bond length and the estimation of effective anchor length. This research gives quantitative information about bond to substrate, collapse mode, structural efficiency of FRCM as EBR (External Bonded Reinforcement).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
