硫酸盐环境下预应力混凝土梁性能劣化研究

Study on the degradation behaviors of prestressed concrete beams in sulfate solutions

为研究预应力混凝土梁受硫酸盐腐蚀后的性能劣化,制作了10根预应力混凝土试验梁分别浸泡在质量分数w=3%,5%,10%的Na2SO4溶液中,并进行腐蚀后静力受弯试验.研究表明,混凝土抗压强度和动弹性模量随腐蚀时间均表现出前期提高而后期下降的趋势,当腐蚀期为3a时,混凝土抗压强度和动弹性模量的降低分别达23.8%和15.1%;与未腐蚀试件对比,试验梁经短期或长期浸泡腐蚀后,其开裂荷载均有所提高;经溶液腐蚀60d和2a的试件承载力与未腐蚀试件相比没有明显的变化,而腐蚀3a后的试件承载力降低达12.1%;受硫酸盐腐蚀后试验梁刚度及延性均有所下降,延性的降低与溶液的质量分数和浸泡腐蚀时间呈线性关系.

In order to study the tressed concrete members, ten effect of sulphate corrosion on prestressed concrete beams are the degradation behaviors of pres- made and eroded in 3%, 5% and 10% （mass fraction） Na2SO2 solutions. The static load test result shows that concrete compressive strength and dynamic elastic modulus increase after 60 days corrosion, but decrease after a longer time; cracking load of tested Beam has improved after immersion; ultimate load has no obvious change after 60 days or 2 years corrosion while decreases significantly after 3 years corrosion; stiff- ness and ductility of test beams decrease after sulfate corrosion, and the decrease has a linear rela- tionship with sulface concentration and corrosion time.