A numerical study of mechanical behavior of a cement paste under mechanical loading and chemical leaching

Abstract

Summary Based on relevant experimental data of a petroleum cement paste under mechanical loading and chemical leaching, an elastic‐plastic model is first proposed by taking into account plastic shearing and pore collapse. The degradation of mechanical properties induced by the chemical leaching is characterized by a chemical damage variable which is defined as the increase of porosity. Both elastic and plastic properties of the cement paste are affected by the chemical damage. The proposed model is calibrated from and applied to describe mechanical responses in triaxial compression tests respectively on sound and fully leached samples. In the second part, a phenomenological chemical model is defined to establish the relationship between porosity change and calcium dissolution process. The dissolution kinetics is governed by a diffusion law taking into account the variation of diffusion coefficient with calcium concentration. The chemical model is coupled with the mechanical model, and both are applied to describe mechanical response of cement paste samples subjected to progressive chemical leaching and compressive stresses. Comparisons between experimental data and numerical results are presented.

Influence of pre-carbonation on hydro-mechanical properties of cement paste subjected to leaching

“…On the other hand, a large number of experimental studies have been performed to study the leaching of cementitious materials [19,20,21,22,23,24,25,26]. Leaching of cement paste dissolves the solid phases (for instance, portlandite, calcium silicate hydrates, and ettringite etc.)…”

“…and induces a porosity/permeability increase as well as a reduction of mechanical properties. Moreover, the leached material exhibits a more ductile behaviour than the sound one [23,26]. The leaching kinetics depend strongly on temperature [20].…”

The influence of coupled physical swelling and chemical reactions on deformable geomaterials

“…8 The mechanism and influence of such dissolution/precipitation have been explored both experimentally and numerically. [9][10][11][12][13][14] Both swelling and dissolution/precipitation occur at the molecular scale and may significantly change the microstructure and components of the geomaterials, resulting in changes of macroscopic physical properties. Swelling and dissolution/precipitation have been studied extensively as individual processes, without sufficiently considering couplings between each other.…”

“…Such leachates with a pH range from 10 to 13.5 will react with the mineral components of the host rock and result in dissolution/precipitation of the barrier 8 . The mechanism and influence of such dissolution/precipitation have been explored both experimentally and numerically 9–14 …”

XRD‐Rietveld Method for Evaluating the Leaching Characteristics of Hardened Cement Paste in Flowing Water

“…Concrete structures such as dams, bridges, ports, wharves, and tunnels are vulnerable to erosion by flowing water [1,2], which affects the durability and service life of them [3,4]. Calcium ion is the main component of hydration products of Portland cement, and its content affects the stability of hydration products.…”