Spacers are important devices used in all concrete structures to support reinforcing steel and achieve the required cover. However, spacers induce a weak, porous and microcracked interface that facilitates ingress of aggressive agents. This paper aims to address the problem by developing a method to produce cementitious spacers with a range of small-scale surface textures including grooves, squares, rectangles, hemispheres and pyramids. The textured spacers were cast in Portland cement mortar or concrete, cured up to 28 days, and tested for tensile bond strength, accessible porosity and mass transport properties. The properties were correlated to surface characteristics to establish the effects of texture on spacer-concrete interface. Results show that textured spacers promote mechanical interlocking with concrete, thereby increasing bond strength, resistance against microcracking and pressure-induced flow. The use of certain textures can compensate for the negative effects of spacers, achieving similar bond strength and permeability to monolithic concrete without the interface.

垫片是所有混凝土结构中用于支撑钢筋并实现所需覆盖层的重要装置。然而，间隔物会导致脆弱的、多孔的和微裂纹的界面，这有助于侵蚀性物质的进入。本文旨在通过开发一种方法来生产具有一系列小尺度表面纹理（包括凹槽、正方形、矩形、半球和金字塔）的水泥间隔件来解决该问题。带纹理的隔板浇注在波特兰水泥砂浆或混凝土中，固化时间长达 28 天，并测试拉伸粘合强度、可接近的孔隙率和传质性能。将这些特性与表面特性相关联，以确定纹理对间隔件-混凝土界面的影响。结果表明，带纹理的隔板促进了与混凝土的机械互锁，从而提高了粘结强度，抗微裂和压力诱导流动。某些纹理的使用可以补偿垫片的负面影响，实现与没有界面的整体混凝土相似的粘合强度和渗透性。