This session provides general information on various analytical techniques used to characterize concrete material properties. The purpose of this session is to provide an overview of available methods and offer guidelines to both, the researchers and practitioners, as to how they can be utilized. For each technique presented, practical information such as best use, sample type, test procedures, results analysis, and limitations will be discussed.
(1) Recognize advanced analysis techniques available for concrete characterization;
(2) Explain principles of the methods;
(3) Identify sample types and preparation commonly utilized for these methods;
(4) Report on the type of results that are generated as well as their limitations.
This session has been AIA/ICC approved for 2 CEU/PDH credits.
Advances in X-ray Computed Tomography for the Characterization of Cementitious Materials
Presented By: David Lange
Affiliation: University of Illinois At Urbana-Champaign
Description: X-ray Computed Tomography (XCT) has gained popularity as a characterization technique for cementitious materials because it is non-invasive, non-destructive, and produces three dimensional reconstructions of samples allowing for a unique view of microstructure. Recent advances have increased the resolution capability and speed of data acquisition. The advantages and limitations in lab-based and synchrotron XCTs are demonstrated via case studies. In the first case study XCT is used for the characterization of cellular concrete microstructure, showing advances in the quantification of both bulk volumetric properties and individual features. The distribution of phases in hydrated portland cement paste showing advances in micro-scale resolution and phase detection were the focus of case study two. In the third study advances in XCT technology for detection of deterioration of alkali-silica reaction was examined. These three case studies demonstrate how XCT technology is useful for investigations of a wide range of properties related to cementitious materials.
Differential Scanning Calorimetry in the Study of the Influence of Phase Change Materials in Cementitious Systems
Presented By: Narayanan Neithalath
Affiliation: Arizona State University
Description: DSC is a valuable tool to study the phase transition temperature and enthalpy of phase change of PCMs that are used in cementitious systems. DSC can be used to characterize PCMs as well as to examine the stability of the enthalpy of phase change. Such data can be used in the modeling of the thermal efficiency of cementitious materials containing phase change materials, as will be explained in this talk.
Advanced Characterization of Cementitious Systems using X-ray Diffraction Analysis
Presented By: Farshad Rajabipour
Affiliation: Pennsylvania State University
Description: X-ray diffraction (XRD) can be used for characterizing the crystalline phases present and quantifying the amorphous content of fine-grained anhydrous and hydrated cementitious materials. Given the complexity of cementitious materials, sample preparation, measurement setup, and data analysis play a key role in obtaining reliable results from XRD analysis. Two case studies are presented to describe the use of this technique for the quantitative phase analysis of hydrated cementitious pastes and to describe the relative advantages and disadvantages of the different protocols available. In the first case study, the early age (= 24 hours) phase composition of blended cementitious pastes was obtained using in-situ XRD analysis with external standard method and minimal sample preparation. In the second case study, internal standard method with appropriate sample preparation steps (hydration stoppage and grinding) was used to obtain the later age (7, 28, and 56 days) phase composition of blended cementitious pastes.
Isothermal Calorimetry – An Essential Cement Chemist’s Tool
Presented By: Lisa Burris
Affiliation: Ohio State University
Description: Isothermal calorimetry is a technique commonly used essential tool for examining the hydration kinetics of cementitious systems. Isothermal calorimetry is frequently used to evaluate early age reactions and the influence of materials, including supplementary cementitious materials, sulfate phases, and admixtures on cement hydration rates and extents and understanding gained from use of this technique can predict changes in setting time and strength development. Recently use of calorimetry at higher temperatures and with controlled pore solutions has begun to enable exploration of later age or more inherent material properties of cementitious mixtures such as ‘reactivity.’ This presentation will provide an overview of the isothermal calorimetry technique, review significant factors that can ensure the creation of high-quality calorimetry data, discuss approaches for evaluating system reactions, and provide examples of extensions of isothermal calorimetry data to assess other performance properties such as set time, strength development, and reactivity.
Applications of Infrared Absorption Carbon/Sulfur Analysis
Presented By: Sean Monkman
Affiliation: CarbonCure Technologies
Description: Infrared absorption analysis is an elemental analysis technique in which the carbon and/or sulfur content of a sample is quantified through analysis of evolved gas produced as the sample is heated. During the combustion process, all carbon- and/or sulphur-containing compounds react with the available oxygen to produce CO2 and/or SO2 gas. The gas analyzer can determine the original carbon and/or sulfur content of the sample. The technique has applications related to the characterization of cementitious materials (unburned carbon in fly ash), the quantification of mineralized CO2 from carbon utilization technologies, and profiling carbonate or sulphate penetration for service life modelling. The technique allows for rapid and accurate determination of the carbon and sulphur in a sample of interest.
Use of Neutron Imaging for Assessing Concrete
Presented By: W Jason Weiss
Affiliation: Oregon State University
Description: This presentation highlights the use of neutron imaging in concrete. Specifically, it discusses the use of neutron imaging to detect water content and movement. Background will be provided on the test as well as its use of absorption, curing, internal curing, and hydration studies.