气冻气融环境下钢筋混凝土梁抗冻性研究

Frost-Resistance of RC Beam under Atmospheric Freeze-Thaw Cycles

采用气冻气融方式,对足尺(150mm×300mm×2 700mm)钢筋混凝土梁的抗冻性进行了研究,分析了冻融对试件相对动弹性模量、损伤层厚度、抗压强度及质量的影响,并研究了浸泡时间及钢筋对超声测试结果的影响;同时,研究了冻融对钢筋混凝土梁极限承载力的影响,并建立了气冻气融环境下钢筋混凝土梁的承载力退化模型.结果表明:随着冻融循环次数的增加,梁构件的相对动弹性模量、极限承载力及其混凝土芯样抗压强度降低,损伤层厚度增加,冻融循环150次时,其相对动弹性模量降至0.54,极限承载力降至未冻融时的86.7%,芯样抗压强度降至未冻融时的55%.

Frost-resistance of full scale（150 mm×300 mm×2 700 mm）reinforced concrete（RC）beams were studied by using air-freezing and air-thawing regime.The influences of freeze-thaw cycles on the relative dynamic elastic modulus,damage layer thickness,compressive strength and mass of RC beams were investigated.And the influences of immersion time and reinforcing steel on ultrasonic test results were studied.Meanwhile,the influence of freeze-thaw cycles on the ultimate bearing capacity of RC beams was clarified and the ultimate bearing capacity deterioration model of RC beams under freeze-thaw cycles was established.The results show that the relative dynamic elastic modulus of RC beams gradually decreases to0.54 after 150times of freeze-thaw cycles,the damage layer thickness of RC beams increases under freezethaw cycles,while compressive strength of RC beams decreases under freeze-thaw cycles.The mass of RC beams has a slightly raise of 0.9%after 125 times of freeze-thaw cycles,and the ultimate bearing capacity decreases to 86.7%that of the control RC beam after 150 times of freeze-thaw cycles.