Determination of the elastic properties of amorphous materials: Case study of alkali–silica reaction gel

Moon, Juhyuk; Speziale, S.; Meral, Cagla; Kalkan, Bora; Clark, S. M.; Monteiro, Paulo J.M.

doi:10.1016/j.cemconres.2013.08.012

Cited by 26 publications

(10 citation statements)

References 37 publications

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“…A similar scaling effect has been confirmed in the nano-indentation measurements of C-S-H which also contains nano-porosity (Hu et al, 2019;Constantinides & Ulm, 2007;Geng et al, 2017b). Ca-free gels extruded to the surface of the Furnas Dam (Brazil) were studied by high-pressure X-ray diffraction (HP-XRD) (Moon et al, 2013) and nano-indentation (Johnson et al, 2017), resulting in elastic moduli between 25 and 30 GPa. Yet these amorphous gels are distinct from crystalline ASR products in both chemical compositions and structural order.…”

Section: Introductionsupporting

confidence: 59%

Mechanical behavior and phase change of alkali-silica reaction products under hydrostatic compression

Geng

Shi

Leemann

et al. 2020

Acta Crystallogr Sect B

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Alkali-silica reaction (ASR) causes severe degradation of concrete. The mechanical property of the ASR product is fundamental to the multiscale modeling of concrete behavior over the long term. Despite years of study, there is a lack of consensus regarding the structure and elastic modulus of the ASR product. Here, ASR products from both degraded field infrastructures and laboratory synthesis were investigated using high-pressure X-ray diffraction. The results unveiled the multiphase and metastable nature of ASR products from the field. The dominant phase undergoes permanent phase change via collapsing of the interlayer region and in-planar glide of the main layer, under pressure >2 GPa. The bulk moduli of the low- and high-pressure polymorphs are 27±3 and 46±3 GPa, respectively. The laboratory-synthesized sample and the minor phase in the field samples undergo no changes of phase during compression. Their bulk moduli are 35±2 and 76±4 GPa, respectively. The results provide the first atomistic-scale measurement of the mechanical property of crystalline ASR products.

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Section: Introductionsupporting

confidence: 59%

Mechanical behavior and phase change of alkali-silica reaction products under hydrostatic compression

Geng

Shi

Leemann

et al. 2020

Acta Crystallogr Sect B

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“…In fact, different experimental setups explore mechanical properties at different confining pressures. For instance, whereas atomic force microscopy (AFM) and nanoindentation measure mechanical properties with shear contributions under the tip (Bobko et al 2011;Zhang et al 2009), high-pressure XRD measures the properties at high confining pressure (Moon et al 2013;Oh et al 2012). Furthermore, the failure mechanism at the nanoscale is at a length scale below the scale of friction and wear, describing how solid bodies are rubbed against each other.…”

Section: Hardness Calculation Methodologymentioning

confidence: 99%

Methodology for Estimation of Nanoscale Hardness via Atomistic Simulations

Qomi

Ebrahimi

Bauchy

et al. 2017

J. Nanomech. Micromech.

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Statistical mechanics has provided powerful techniques to measure mechanical properties of materials at the nanoscale and paved the way for bottom-up computational materials design. The introduction of such techniques in civil engineering applications, namely construction and geotechnical materials, remains limited to the elastic and fracture properties. This paper presents an atomistic approach to calculate the nanoscale cohesion, friction angle, and hardness. This method is based on the application of biaxial external deformation, or stress, in the weakest crystallographic direction in the material. The onset of the failure is characterized by investigating the unloading paths from several points on the stress-strain curve. Such calculations of the failure stress along different deformation paths provide multiple failure Mohr circles in the normal-shear stress space, which is found to provide a failure envelope akin to the Mohr-Coulomb failure criterion that is widely used for the plastic analysis of granular geomaterials. The failure envelope characterizes the nanoscale cohesion and friction angle, which in conjunction with continuum mechanics can be utilized to estimate the nanoscale hardness of layered materials. Application of this method to tobermorite and Na-montmorillonite crystals yields values that are close to the experimental measurements obtained using nanoindentation and atomic force microscopy techniques.

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“…2with error bars. Synchrotron XRD has widely been applied to cementitious materials to characterize crystalline or amorphous components under various conditions[28][29][30][31]. The high flux of photon energy from synchrotron allows to obtain diffraction peaks in ordinary 2theta range as well as in small-angle range with a high resolution (i.e., high peak intensity with less noise and lower background)[32, 33].…”

mentioning

confidence: 99%

Characterization of natural pozzolan-based geopolymeric binders

Moon

Bae

Çelik

et al. 2014

Cement and Concrete Composites

Self Cite

101

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Properties and characteristics of fly ash-or slag-based geopolymers have been extensively explored but comparatively less information is available for natural pozzolan-based geopolymers. The present work focuses on microstructural characteristics of natural pozzolan-based geopolymers activated by sodium hydroxide and a mixture of sodium hydroxide and sodium silicate. Synchrotron XRD and SEM-EDS studies combined with compressive strength tests successfully demonstrate the feasibility of the use of natural pozzolan for sustainable construction material. It is concluded that the geopolymers have sufficient strength as structural materials and matrices contain C-S-H like crystal as well as zeolites of hydroxysodalite and zeolite Y. Two zeolites of hydroxysodalite and zeolite Y are found as the main activation products in sodium hydroxide activation. Substitution with sodium silicate solution yields higher compressive strength and a denser microstructure with dominant activation products of C-S-H like crystal, zeolite Y, and phillipsite. It has been proposed that the crystal size of the activation products ranges from 10 nm to 1 μm. Different microstructural characteristics found herein provide a valuable information to develop natural pozzolan-based sustainable structural materials with improved properties.

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Determination of the elastic properties of amorphous materials: Case study of alkali–silica reaction gel

Cited by 26 publications

References 37 publications

Mechanical behavior and phase change of alkali-silica reaction products under hydrostatic compression

Mechanical behavior and phase change of alkali-silica reaction products under hydrostatic compression

Methodology for Estimation of Nanoscale Hardness via Atomistic Simulations

Characterization of natural pozzolan-based geopolymeric binders

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