Mechanical Properties of Hydrated Cement Paste: Development of Structure-property Relationships

Abstract

Theoretical models based on modern interpretations of the morphology and interactions of cement hydration products are developed for prediction of the mechanical properties of hydrated cement paste (hcp). The models are based on the emerging nanostructural vision of calcium silicate hydrate (C-S-H) morphology, and account for the intermolecular interactions between nano-scale calcium C-S-H particles. The models also incorporate the effects of capillary porosity and microcracking within hydrated cement paste. The intrinsic modulus of elasticity and tensile strength of hydrated cement paste are determined based on intermolecular interactions between C-S-H nano-particles. Modeling of fracture toughness indicates that frictional pull-out of the micro-scale calcium hydroxide (CH) platelets makes major contributions to the fracture energy of hcp. A tensile strength model was developed for hcp based on the linear elastic fracture mechanics theories. The predicted theoretical models are in reasonable agreements with empirical models developed based on the experimental performance of hcp.

Small scale tests of cement with focused ion beam and nanoindentation

“…1. MD simulations give fracture energies in the range of 0.4-3 J/m 2 [10,11] which is a bit less than our supremum energies.…”

Combined investigation of Low-scale Fracture in Hydrated Cement and metal alloys Assessed by Nanoindentation and FIB

“…It follows from theoretical works (e.g. Ghebrab and Soroushian [11]) that CH crystal pull-out raises the values of pure C-S-H to much higher values, 16.9-283 J/m 2 , which is in relation to our findings, whereas the pure C-S-H fracture energy ranges only between 0.38-2.85 J/m 2 [11,12].…”

Experimentally informed fracture modelling of interfacial transition zone at micro-scale

“…As aggregates are harder than cement paste, it was assumed that the damage caused to the aggregates during this procedure is negligible. 1 The thin-sectioning was conducted by grinding using a Struers Labopol-5 thin sectioning machine. To obtain smooth and parallel surfaces and to eliminate the effect of different surface roughness, both sides were ground using discs with grit sizes of 135 μm and 35 μm in a descending order.…”

“…Concrete is the dominant construction material in the world [1]. It is a composite material consisting of cement paste and aggregate inclusions with various particle sizes.…”