Micro-Mechanical Properties of Slag Rim Formed in Cement–Slag System Evaluated by Nanoindentation Combined with SEM
Yu Zhang, Minfei Liang, Yidong Gan, Oğuzhan Çopuroğlu
Abstract
Slag rim mainly consists of secondary precipitations such as C-S-H gel phase and hydrotalcite-like phase, which originate from the hydration of slag. In this paper, the micro-mechanical properties of slag rim were characterized by nanoindentation in combination with SEM. It was found that, compared to the C-S-H gel phase, slag rim showed about a 15 GPa higher modulus of elasticity. At the early age, slag cement paste mainly consisted of low-density C-S-H gel phase, high-density C-S-H gel phase, and unhydrated slag particles, as well as calcium hydroxide based on the results of nanoindentation; at the later age, the system contained C-S-H gel phase, slag rim (a mixture of C-S-H gel phase and hydrotalcite-like phase), and unhydrated slag particles.