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为研究预应力钢筋混凝土结构的耐久性,在预应力度分别为0.35、0.52和0.62的预应力混凝土梁试件分别经历50、75次冻融循环作用和氯离子溶液腐蚀后,对其进行静力受弯试验。研究表明:动弹性模量随冻融循环次数的增加下降较快,预应力度高的试件动弹性模量损失较小;预应力度分别为0.35、0.52和0.62的试件,在冻融循环75次后的开裂荷载较冻融循环50次的试件分别下降6.9%、6.7%、5.7%,极限荷载分别下降14.7%、17.5%、11.6%;冻融循环50次后,预应力度为0.52和0.62的试件较预应力度为0.35试件的开裂荷载分别高20%、17.85%,极限荷载分别高21.4%、8.7%;冻融循环75次后,预应力度为0.52和0.62的试件较预应力度为0.35试件的开裂荷载分别高23.8%、19.0%,极限荷载分别高24.1%、19.4%;氯离子侵蚀在短期内对试件极限承载力影响较小。
In order to study the durability of prestressed reinforced concrete structures, specimens of prestressed concrete beams with prestressing forces of 0.35, 0.52 and 0.62 were respectively subjected to 50,75 freeze-thaw cycles and chloride ion solution corrosion, Bending test. The results show that the dynamic elastic modulus decreases rapidly with the increase of the number of freeze-thaw cycles, and the loss of dynamic elastic modulus of the specimens with high prestressing strength is small. The samples with prestressing strength of 0.35, 0.52 and 0.62, respectively, After 75 cycles, the cracking load decreased by 6.9%, 6.7% and 5.7% respectively, and the ultimate load decreased by 14.7%, 17.5% and 11.6%, respectively. After 50 cycles of freeze-thaw cycle, The cracking loads of 0.52 and 0.62 were 20% and 17.85% higher than the pre-stress 0.35 and the ultimate loads were 21.4% and 8.7% respectively. After 75 cycles of freezing and thawing, the pre-stress was 0.52 and 0.62 Were 23.8% and 19.0% higher than the pre-stress 0.35, respectively. The ultimate load was 24.1% and 19.4% higher respectively. Chloride erosion had less effect on the ultimate bearing capacity of the specimens in a short period of time.