埋置深度对黄麻纤维束与水泥基体粘结性能的影响

Effect of embedded depth on bond property between jute yarn and cement matrix

为了探究埋置深度对黄麻纤维束与水泥基体粘结性能的影响,利用C43电子式万能试验机进行了水泥基中黄麻纤维束的拔出试验,获得了拔出刚度、最大拔出力、等效粘结强度和拔出功随埋置深度的变化规律。试验在6mm/min恒定试验速率下进行,测试了4组不同埋置深度(20mm、40mm、60mm和80mm)的试件。试验结果表明:随着埋置深度的增大,拔出刚度整体呈减小趋势但局部有波动;最大拔出力持续增大,并在埋置深度为60mm时趋于稳定;等效粘结强度持续减小;拔出功初始增大,在埋置深度为60mm处出现转折,而后迅速减小。为了进一步分析这种变化产生的具体作用机制,对不同埋置深度的破坏试件进行了观察,获得了试件破坏模式随埋置深度的变化规律。

In order to investigate the effect of embedded depth on the bond property between jute yarn and cement matrix,pull-out tests of jute yearns from the cement matrix were conducted by utilizing a Criterion 43 electromechanical universal test system.Correlations between mechanical parameters（pullout stiffness,peak pullout load,equivalent bond strength and work of pullout force）and embedded depths were obtained through the tests.Samples with four different embedded depths（20 mm,40 mm,60 mm and 80 mm）were tested at a constant displacement rate of 6 mm/min.The experimental results show that pullout stiffness decreases in spite of local undulation happened as embedded depth increases,while peak pullout load increases initially and then tends to be stable when the embedded depth is larger than 60 mm,and equivalent bond strength decreases with the increasing of embedded depth,and work of pullout force increases initially but then turns to decrease sharply at the embedded depth of 60 mm.Tested samples with different embedded depths were observed for the purpose of investigating the mechanisms of this variation further,through which the correlation between failure modes and embedded depths was obtained.