Nano-scratch as a new tool for assessing the nano-tribological behavior of cement composite

This paper presents a preliminary exploration on tribological properties of cement composite material at micro- and nano-scales by means of the nano-scratch technique, which is a new instrument overcoming the limitations of both the classical stylus scratch test and the atomic force microscope. Measurements were conducted on two very different types of material: cement clinker paste and polymer-based cement clinker. Mechanical parameters related to the nano-tribological performance, i.e. penetration depth, coefficient of friction, and elastic deformation ratio, were obtained from the scratching processes. By statistical deconvolution analysis, microstructure constituents with a large discrepancy in elastic modulus and hardness values can be captured as single peaks, but not for the mixture of C-S-H and Ca(OH)(2) phases. A reverse tendency was observed between penetration depth and coefficient of friction of both the substrate and hard particle phase embedded in. An H/E ratio dependent elasto-plastic behavior was identified, with the elastic deformation to be dominant in high H/E ratio phases. The results confirm this new technique as a promising method for quantitative characterization of elasticity, hardness and mar resistance of heterogonous phases in cement composite.