مقاله انگلیسی رایگان در مورد رفتار پیوند بین خوردگی-شکسته بتن مسلح و ورق CFRP – تیلور و فرانسیس 2017

In field, concrete structures may be subjected to different forms of attack; the most common of which is chloride induced corrosion; especially in coastal environments or whenever deicing agent are used. Once chloride concentration at steel location surpasses a certain threshold value, corrosion initiates and progresses towards cracking of concrete; aggravating the physical states of exposed structural elements [1]. Beams and slabs (or bridge decks) are the most susceptible because their horizontal alignment allow easy intrusion of chloride and hence corrosion initiation and progression. Corrosion damage accompanied with loss in reinforcing steel cross-sectional area as well as undesirable changes in steel surface characteristics and mechanical properties result in sever reductions in the mechanical performance of flexural members [2–6]. Thus, repair becomes essential to preserve structural integrity and prevent catastrophic failures; especially in bridge decks. Repair of corroded flexural elements goes through several steps represented in removal of concrete cover, cleaning of rust, protecting steel, replacing concrete cover with new one, and finally providing additional reinforcement using either concrete jackets, steel plates, or fiber reinforced polymer composites (FRP) [7–10]. Even if existing concrete cover in corroded elements is replaced as a standard measure before strengthening, the probability of cracks’ reappearance in newly cast concrete cover remains high. As well stipulated, cracking of concrete cover in beams or slabs impact negatively their bond with carbon fiber reinforced polymer (CFRP), attached to regain flexural load capacity; undermining the significance of the proposed repair process [11–13]. The intensity, distribution, and size of cracking are key factors that determine the degradation extent in bond between damaged concrete and attached FRP composites [11–14]. Presence of openings in concrete structural elements was stipulated to impact negatively their performance unless efficient repair techniques were applied [15]. Recent published works indicated that cracks, produced by heating of concrete to temperatures of 600 °C, had resulted in significant degradation in bond strength between heat-damaged concrete and CFRP sheets reaching as high 64% [11,12]. Pre and post-repair sodium sulfate attack on flexural elements had a less negative impact on bond behavior between concrete and attached CFRP sheets represented in loss of bond strength by as much as 40% [13]. Load induced cracks are wider yet are more localized than durability induced ones; hence their effect on bond behavior would be different [14]. Thermal incompatibility between FRP and concrete induces additional concrete cover cracking hence aggravates bond performance further [16].