DOI: 10.5061/dryad.ksn02v7d4
title: Data from: Nanoindentation methods for viscoelastic characterization of stiff porous materials

description: Background Modifying the mechanical properties of the solid phase of a
 porous material, in this study calcium-silicate-hydrate, is frequently
 possible by changing synthesis conditions, but changes in these conditions
 can also influence porosity, which in turn may affect the mechanical
 properties of the porous material. Experimental methods to decouple
 porosity from the viscoelastic properties of the porous material will aid
 in optimization of the structure of the solid phase to achieve the desired
 mechanical properties.   Objective Explore different
 nanoindentation techniques in order to determine the viscoelastic
 properties of the solid phase (without the affect of porosity) of a stiff
 porous material via experimental methods alone.   Methods
 Compacted pellets of calcium-silicate-hydrate were prepared with different
 porosity and subjected to three nanoindentation techniques to determine
 viscoelastic behavior and the influence of porosity: dynamic, stress
 relaxation, and creep. Results of the porosity and of the viscoelastic
 behavior measurements were analyzed with a reverse-micromechanics model to
 determine viscoelastic properties of the solid phase, which has not been
 achieved previously for calcium-silicate-hydrate. These methods can be
 used in development and refinement of materials to determine how changes
 in the solid phase (e.g. molecular structure) influence viscoelastic
 behavior while considering the effect of porosity.   Results
 Dynamic nanoindentation was found to be unreliable for the stiff material
 studied in this work. Normalized stress relaxation and creep data were
 found to be independent of porosity. Reverse micro-mechanics modeling
 allowed for characterization of the creep modulus that is consistent with
 other studies that used computational or synchrotron x-ray methods to
 characterize mechanical properties of the solid calcium-silicate-hydrate
 phase.   Conclusion Creep experiments provide more reliable data
 than dynamic or stress relaxation experiments. When the porosity is known,
 reverse-micromechanics modeling can be used determine the creep modulus of
 the solid phase and thus be used to predict creep modulus of a composite
 with an arbitrary porosity. If the porosity is not known, the viscoelastic
 properties of the solid phase can still be compared to each other using a
 normalized creep modulus that is independent of porosity.
description: Compacted pellets of calcium-silicate-hydrate were prepared with
 different porosity and subjected to three nanoindentation techniques to
 determine viscoelastic behavior and the influence of porosity: dynamic,
 stress relaxation, and creep. Results of the porosity and of the
 viscoelastic behavior measurements were analyzed with a
 reverse-micromechanics model to determine viscoelastic properties of the
 solid phase, which has not been achieved previously for
 calcium-silicate-hydrate. These methods can be used in development and
 refinement of materials to determine how changes in the solid phase (e.g.
 molecular structure) influence viscoelastic behavior while considering the
 effect of porosity.
description: # Nanoindentation Methods for Viscoelastic Characterization of Stiff
 Porous Materials This data set contains data from three different types of
 nanoindentation experiments (stress relaxation, creep, and dynamic) on two
 different specimens (calcium-silicate-hydrate with different levels of
 porosity). The data are organized into folders for each experiment and
 specimen type. Stress relaxation: 1. "Load and Depth" folder
 contains the raw data for indents used in analysis 2. .txt file ending in
 "SR_analysis.txt" contains nanoindentation data analyzed by the
 nanoindenter software package 3. .txt file beginning with
 "SR_fittedmean" contains the mean normalized stress relaxation
 data with 95% confidence intervals. Creep: 1. "Load and Depth"
 folder contains the raw data for indents used in analysis 2. .txt file
 ending in "crp_analysis.txt" contains nanoindentation data
 analyzed by the nanoindenter software package 3. .txt file beginning with
 "SC_E_s" contains the mean solid elastic modulus using the
 self-consistent homogenization scheme with 95% confidence intervals 4.
 .txt file beginning with "CrpComp" contains the mean composite
 creep compliance data with 95% confidence intervals 5. .txt file beginning
 with "CrpMod" contains the mean composite creep modulus data
 with 95% confidence intervals Dynamic: 1. "Load and Depth"
 folder contains the raw data for indents 2. "Averages" folder
 contains average and standard deviations for individual dynamic indents 3.
 .txt file ending in "DMA_analysis.txt" contains nanoindentation
 data analyzed by the nanoindenter software package 4. .txt file beginning
 with "mean_tand" contains the mean loss factor with 95%
 confidence intervals ## Description of the data and file structure Raw
 data and analyzed data used in the article on .txt files. The data are
 organized into folders for each experiment and specimen type. ##
 Sharing/Access information These data were collected by the author,
 further details can be requested via email.