Nanostructural deformation analysis of calcium silicate hydrate in Portland cement paste by atomic pair distribution function

Suzuki, Hiroshi; Bae, S.*; Kanematsu, Manabu*

Advances in Materials Science and Engineering, 2016, p.8936084_1 - 8936084_6, 2016/00

https://doi.org/10.1155/2016/8936084

The deformation behavior of nanostructure of calcium silicate hydrate (CSH) in Portland cement (PC) paste under compression was successfully characterized by the atomic pair distribution function (PDF) measured by using Synchrotron X-rays. The PDF of the PC paste showed a unique deformation behavior for a short range order below 2.0 nm in radius corresponding to the size of the CSH particle (globule), while the deformation for a long range order was similar to that of a calcium hydroxide phase measured by the diffraction peak shift. The compressive deformation of the CSH nanostructure can be divided into three stages with different interactions between globules. This behavior would originate from the granular nature of CSH which deforms with increasing packing density by slipping the interfaces between globules, rearranging the overall CSH nanostructure. This study will lead to increasing applications of the PDF technique to provide clues for understanding the deformation mechanism of CSH in PC paste.