A discussion of the paper “Dynamic microstructural evolution of hardened cement paste during first drying monitored by 1H NMR relaxometry” by I. Maruyama, T. Ohkubo, T. Haji et al.

Abstract

The recent paper “Dynamic microstructural evolution of hardened cement paste during first drying monitored by 1H NMR relaxometry” authored by I. Maruyama et al. is discussed. Besides the observed transformation of relatively thin gel pores into interlayer pores, it is worth noting that the coarse gel pores and inter-hydrate pores become coarser during drying. Additionally, interlayer pores simultaneously contract during drying at beyond 40% RH. The drying shrinkage of cement-based material may be physically rooted in the remarkable contraction of C-S-H gel, which is also responsible to the considerably lower specific surface area accessible to nitrogen than that to water.