Impact of water on peak and residual shear strength parameters and triaxial deformability of high-porosity building calcarenite stones: Interconnection with their physical and petrological characteristics

Abstract

Several studies have found that water can cause substantial reductions of mechanical properties of building stones such as unconfined compressive strength, tangent Young´s modulus or tensile strength. However, the influence of water content on shear strength parameters, triaxial compressive strength and modulus of elasticity under different confining pressures has been scarcely examined. For this reason, the present paper assesses the impact of water on peak and residual compressive strength and tangent Young´s modulus of three porous building geomaterials widely used in civil and architectural constructions under different confining pressure through triaxial compressive tests. Furthermore, the corresponding peak and residual shear strength parameters computed from Mohr-Coulomb (c and ϕ) and from Hoek-Brown (σci and mi) failure criteria are obtained under dry and saturated conditions. Complementary physical and petrological analyses are performed in order to understand the main causes of the effect of water observed in these rock materials. The results indicate that water causes significant reductions of peak and residual compressive strength and tangent Young´s modulus in the tested porous building stones for all the different applied confining pressures. Additionally, important changes of peak and residual shear strength parameters (c, ϕ, σci and mi) are exhibited by the studied stones when become saturated. This could be related to physicochemical changes such as the hydrolysis of quartz and silicates in crack tip region inducing subcritical crack growth (stress corrosion), the decrease of the cement quality and the deterioration of the intergranular bonds due to the dispersion or dissolution of some minerals (calcite or chlorite) and the formation of microcracks caused by the swelling of the clay minerals present in these materials when they come into contact with water.

Micro and macro-structural effects of high temperatures in Prada limestone: Key factors for future fire-intervention protocols in Tres Ponts Tunnel (Spain)

“…Research reveals that water content can play a key role in the determination of UCS and the deformational features of the intact rock, even for small variations in the moisture content due to changes in the relative humidity of the air [44,45]. Natural moisture in rocks is also related to spalling events at temperatures lower than 200º C [7][8][9].…”

Assessing water-induced changes in tensile behaviour of porous limestones by means of uniaxial direct pull test and indirect methods

“…The petrological characteristics and physico-mecanical properties of these geomaterials under compressive conditions have been extensively analysed by Rabat et al (2020c) (Fig. 2).…”

“…They have demonstrated that uniaxial compressive strength (UCS), compressive Young's modulus (E c ) and shear strength parameters of sedimentary rocks can be significantly reduced after their full and partial water saturation (e.g. Hawkins and McConnell, 1992;Vásárhelyi, 2005;Erguler and Ulusay, 2009;Shakoor and Barefield, 2009;Kim and Changani, 2016;Rabat et al, 2020aRabat et al, , 2020bRabat et al, , 2020cRabat et al, , 2021. However, the mechanical response of these geomaterials under tensile stress and its water-induced variation have been poorly analysed due to the difficulties in tensile testing (Briševac et al, 2015;Hashiba and Fukui, 2015;Okubo and Fukui, 1996).…”

Investigation of Pore and Filling Material Bond in Filled Travertine Used as a Building Material

“…Porous structures are exposed to different environmental factors (relative humidity and water permeability) throughout their lifetime and cracks can occur as a result of the deterioration of intergranular bonds in the rock under the effect of water pressure. As a result, the mechanical properties of the rocks decreases and their strength decreases in time [35][36][37][38].…”