Measuring and modifying interface properties of PVA fibers in ECC matrix
Measuring and modifying interface properties of PVA fibers in ECC matrix
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DOI：
10.1061/(asce)0899-1561(2001)13:6(399
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发表时间：
2001-11-01
影响因子：
3.2
通讯作者：
Ogawa, A
中科院分区：
文献类型：
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作者：
Redon, C;Li, VC;Ogawa, A
本研究采用单纤维拉拔试验来测量不同直径的聚乙烯醇纤维在砂浆基体中的粘结性能。尽管纤维嵌入长度较短，但在拔出试验中，小直径纤维仍发生破裂。然而，研究表明，即使不能完全拔出纤维，仍然可以确定化学脱键能G(d)和初始界面摩擦键强度tau (o)。尽管G(d)值很高，但在纤维化学脱粘过程中纤维没有断裂，但在纤维拉出过程中，纤维表面出现了强烈的滑移硬化效应，其特征是滑移硬化系数β值很高，在扫描电镜下可以看到严重的磨损损伤。因此，当纤维的表观抗拉强度超过时，纤维会因分层而断裂。最后，尝试降低粘结性能值，以尽量减少拉拔过程中纤维断裂。通过在亲水性聚乙烯醇纤维表面涂油以减少纤维/砂浆的强相互作用，部分实现了这一目标。
A single fiber pullout test was used in this study to measure the bond properties of polyvinyl alcohol fibers that are available at various diameters in a mortar matrix. Despite short fiber embedment lengths, the small diameter fibers ruptured during the pullout tests. However, it is shown that even if full fiber pullout is not achieved, it is still possible to determine a chemical debonding energy, G(d), and an initial interfacial frictional bond strength, tau (o). Despite high G(d) values, the fibers did not rupture during the fiber chemical debonding process, but during fiber pull-out, a strong slip-hardening effect, characterized by the high values of the slip-hardening coefficient, beta, induced severe abrasion damage visible under scanning electron microscope on the fiber surface. As a consequence, when the fiber apparent tensile strength was exceeded, fibers ruptured by delamination. Finally, an attempt was made to lower the values of the bond properties to minimize fiber rupture during pullout. This goal was partially achieved by applying an oil coating on the hydrophilic polyvinyl alcohol fiber surface to reduce any strong fiber/mortar interaction.