Effect of corrosion, freeze-thaw cycles, and their combined effects on the fatigue behavior of reinforced concrete
A study was conducted to investigate the deterioration in fatigue life of reinforced concrete beams induced by corrosion and corrosion with alternate freeze-thaw cycles.^ A total of eighteen 6" x 8" x 36" concrete beams reinforced with 2 #3 epoxy coated steel bars was used to conduct the fatigue testing. The experimental investigation included testing the beams in three different phases. The first phase involved testing the specimens under fatigue loading in air as a control test. In the second phase, the specimens were tested in sea water (3% NaCl). In the third phase, the specimens were tested in the sea water for some time and then the sea water was allowed to freeze around the beams by a brine (freezing) solution (22% NaCl). The freeze and thaw cycles were at 3 to 4 hours intervals until the specimen failed.^ Measurements and readings for the crack growth, midspan deflection were recorded in phase I. In detecting corrosion existence in the reinforcing steel, the electrical potential difference between the bars and a standard colemal electrode (immersed in the sea water during testing) was recorded in phase II (corrosion-fatigue) and phase III (corrosion-fatigue and freeze-thaw cycles).^ Failure was defined when a specimen was completely cracked from bottom (tension zone) to top (compression face) or when a ductile fracture of one or both reinforcing steel took place.^ Statistical analysis was done to evaluate the significance of the effect of the independent variable, such as applied load and number of load repetition, on the dependent variable such as the crack growth. The analysis included selecting regression models that would best describe the dependent variable. Also, based on statistical analysis the S-N curves for the three phases were constructed and compared.^ The conclusion inferred from the results indicated that fatigue life of reinforced concrete beams continuously deteriorated when corrosion as well as corrosion with freeze-thaw cycles were induced. ^
Talal Abdulmalek Radian,
"Effect of corrosion, freeze-thaw cycles, and their combined effects on the fatigue behavior of reinforced concrete"
Dissertations and Master's Theses (Campus Access).