硫酸盐环境下再生混凝土的损伤演化研究

在干湿交替环境下，再生混凝土的硫酸盐侵蚀不仅会引发其外观上的损伤，而且对再生混凝土材料的耐久性也会产生严重的影响。采用硫酸盐-干湿循环试验，研究了3％、5％、10％Na2SO4溶液下全再生混凝土材料性能的衰减退化规律，以及5％Na2SO4溶液下不同再生粗骨料取代率混凝土材料性能的衰减退化规律。试验结果表明：在5％Na2SO4溶液侵蚀作用下，再生混凝土的线膨胀率△L随再生粗骨料取代率r的增加而增大，相对动弹性模量Er达到最大值Emax（r）时所需的干湿循环次数随r的增大而减少，Er的衰减速率随r的增大而增大；全再生混凝土Er的衰减速率和△L都将随Na2SO4浓度水平的升高而增大；Emax（r）／Er约为1．07。

Research on the damage behaviors of the recycled aggregate concrete in the sulfate environment

A method to solve sulfate corrosion damage of recycled aggregate concrete （RAC） from the wetdry cycles test was used to study material performance degradation rules for all RAC （r = 100% ） and RAC with different recycled aggregate replacement ratio （r） under sulfate environments 3% , 5% and 10% （by mass） Na2SO4. The results show that： （1） linear dilatation ratio （/XL ） of RAC increases with the increase of r, and the change trend of relative dynamic modulus of elasticity （ Er） were consistent, and the attenuation rate for Er increases with the decrease of r under different r and 5% （ by mass） Na2SO4 ; （~） the attenuation rate of Er and the △L for the all RAC increase with the increase of the level of Na2SO4 solution concentration; （3） the specific value of Emax（r）/Er close to 1.07. At the same time, the damage computation model of RAC in sulfate environment was put for- ward based on test results.