Impacts of Space Restriction on the Microstructure of Calcium Silicate Hydrate.

Yue Zhou,Linglin Xu,Yuting Chen,Kai Wu,Zhongping Wang,Zheyu Zhu

doi:10.3390/ma14133645

Abstract

The effect of hydration space on cement hydration is essential. After a few days, space restriction affects the hydration kinetics which dominate the expansion, shrinkage and creep of cement materials. The influence of space restriction on the hydration products of tricalcium silicate was studied in this paper. The microstructure, morphology and composition of calcium silicate hydrate (C-S-H) were explored from the perspective of a specific single micropore. A combination of Raman spectra, Fourier transform infrared spectra, scanning electron microscopy and energy dispersive X-ray spectroscopy were employed. The results show that space restriction affects the structure of the hydration products. The C-S-H formed in the micropores was mainly composed of Q3 silicate tetrahedra with a high degree of polymerization. The C-S-H formed under standard conditions with a water to cement ratio of 0.5 mostly existed as Q2 units. Space restriction during hydration is conducive to the formation of C-S-H with silica tetrahedra of a high polymerization degree, while the amount of water filling the micropore plays no obvious role on the polymeric structure of C-S-H during hydration.

Highlights

calcium silicate hydrate (C-S-H) grows when the cement is mixed with water [1], and this hydration continues until the water is exhausted [2]
This paper studied the microstructure of C3 S hydrates in the restricted space of micropores in a sheet, by means of Raman, FT-IR spectra and SEM-EDS
Results indicate that space restriction affected the structure of the hydration products, and that the microstructure of the C-S-H which formed in the micropores was mainly composed of Q3 silicate tetrahedra with a high degree of polymerization

Summary

Introduction

C-S-H grows when the cement is mixed with water [1], and this hydration continues until the water is exhausted [2]. Its structure varies with factors during hydration, especially the water to binder ratio [3,4], temperature [5,6,7,8] and curing age [6,9]. The growth of C-S-H involves the competition between water and hydration space, which are essential to the microstructure evolution. The importance of water to the structure of C-S-H is prominent, and the role of space on the structure of C-S-H has been paid more and more attention, especially for those studies on the kinetics and mechanisms of cement hydration

Methods

Results

Conclusion