کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
261109 | 503682 | 2007 | 8 صفحه PDF | دانلود رایگان |
An experimental program was conducted to investigate the effect of stresses and cracks, caused by alkali-silica reaction (ASR) and freezing and thawing (F/T), on bond between reinforcing steel and concrete. Pullout test cylinders, reinforced with 18 mm steel bars, were used to evaluate bond behavior. Concrete prisms (50 × 50 × 300 mm) were also cast to evaluate expansion and reduction in ultrasonic velocity due to ASR and F/T cycles, respectively. Specimens were cured for 40 days before being either immersed in sodium hydroxide solution of 0.5 normality in order to accelerate ASR, or subjected to different cycles of F/T. Bond behavior, expansion, and ultrasonic pulse velocity tests were carried out as ASR progressed or under F/T cycles.The progress of ASR resulted in significant losses in critical bond stress and ultimate bond strength capacity reaching as high as 44% and 24%, respectively, accompanied by a significant increase in free-end slip at failure. The loss in bond due to ASR was higher for specimens prepared using concrete with lower concrete strength and higher percentage of reactive aggregate. F/T action caused a significant reduction in critical bond stress and ultimate bond strength that reached as high as 100% and 55%, respectively, and an increase in free-end slip at failure. Neither ASR nor F/T cycles affected trends in the behavior of bond stress versus free end slip curves.
Journal: Construction and Building Materials - Volume 21, Issue 2, February 2007, Pages 428–435