废弃纤维再生混凝土受压徐变及预测模型

Pressure and creep characteristics of waste fiber recycled concrete and estimation model

为研究再生粗骨料替代率、废弃纤维体积掺入量对废弃纤维再生混凝土受压徐变破坏时间、徐变变形和徐变度的影响规律,对普通混凝土、再生混凝土和废弃纤维再生混凝土试件在实验室条件下进行了85%、90%和95%应力水平的徐变试验。试验结果表明:随着再生粗骨料替代率的增加,徐变破坏的时间缩短、徐变变形及徐变度增大;随着废弃纤维体积掺入量的增加,徐变变形及徐变度减小,徐变破坏时间增加。废弃纤维的加入能有效缓解再生混凝土受压徐变的破坏程度。在考虑再生粗骨料替代率及废弃纤维体积掺入量的基础上,对ACI209R徐变预测模型进行修正,模型预测结果与试验值吻合较好。

In order to study the effect of the replacement ratio of recycled coarse aggregates and the volume of waste fibers on the creep failure time,creep deformation and creep of waste fiber recycled concrete,a group of ordinary concrete and 4 groups of waste fiber recycled concrete specimens creep tests at 85%,90%and 95%stress levels were carried out under laboratory conditions.The test results showed that with the increase of the replacement rate of recycled coarse aggregate,the time of creep failure,the creep deformation and the creep degree increase;with the increase of the volume of waste fibers,the creep deformation and creep degree decrease,the time of creep failure increases.The addition of waste fibers can effectively alleviate the degree of compression and creep damage of recycled concrete.The ACI209R creep prediction model was modified based on the replacement rate of recycled coarse aggregate and the volume of waste fiber.The model prediction results were in good agreement with the experimental values.