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Displaying 1 - 25 of 162

Three-dimensional characterization of particle size, shape, and internal porosity for Apollo 11 and Apollo 14 lunar regolith and JSC-1A lunar regolith soil simulant

June 8, 2024
Author(s)
Jay Goguen, Andrew Sharits, Ann Chiaramonti Debay, Thomas V. Lafarge, Edward Garboczi
Samples of soils collected by the Apollo 11 mission (10084) and the Apollo 14 mission (14163) were obtained from the NASA CAPTEM program. The particle size, shape, and internal porosity were characterized in three dimensions (3D) using a combination of X

Spherical harmonic reconstruction and preferred parameter research of 3D morphology of manufactured aggregate with different particle sizes

May 23, 2024
Author(s)
Edward Garboczi, Peng Gao, Juan Wu, Peiyun Qiu, Jingzhe Li, Hongjie Liu, Zhiwei Qian, Jiangziong Wei, Qijun Yu
The spherical harmonic (SH) series have been widely used in recent years to reconstruct three-dimensional (3D) particle shape for reducing the memory requirements of morphological data and facilitating the calculation of various particle shape parameters

Autonomous cementitious materials formulation for critical infrastructure repair

January 17, 2024
Author(s)
Howie Joress, Rachel Cook, Austin McDannald, Mark Kozdras, Jason hattrick-simpers, Aron Newman, Scott Jones
Despite the long history of cement and concrete, there are still large gaps in fundamental knowledge of their properties development. The dire need for improved cementitious repair materials, requires a revolution in the way they are formulated and tested

Electrosteric control of the aggregation and yielding behavior of concentrated portlandite suspensions

June 13, 2023
Author(s)
Sharu Kandy, Mathieu Bauchy, Gaurav Sant, Aditya Kumar, Narayanan Neithalath, Samanvaya Srivastava, Torben Gaedt, Edward Garboczi
Portlandite (calcium hydroxide: CH: Ca(OH)2) suspensions aggregate spontaneously and form percolated fractal aggregate networks when dispersed in water. As a result, the yield stress and viscosity of portlandite suspensions diverge at low particle loadings

Off-spec fly ash-based lightweight aggregate properties and their influence on the fresh, mechanical, and hydration properties of lightweight concrete: A comparative study

August 1, 2022
Author(s)
Edward Garboczi, Mohammad Balapour, Mohammad Khaneghahi, Yick Hsuan, Diana Hun, Yaghoob Farnam
In this study, an off-spec fly ash-based spherical lightweight aggregate (LWA), designated SPoRA, was manufactured through a pilot-scale production and its engineering properties, including specific gravity, dry rodded unit weight, water absorption

Ultrafast stiffening of concentrated thermoresponsive polymer-mineral suspensions

July 21, 2022
Author(s)
Edward Garboczi, Sharu Kandy, Iman Mehdipour, Narayanan Neithalath, Aditya Kumar, Mathieu Bauchy, Samanvaya Srivastava, Torben Gaedt, Gaurav Sant
Extrusion-based 3D printing with rapidly hardening polymeric materials is capable of building almost any conceivable structure. However, concrete, one of the most widely used materials for large-scale structural components, is generally based on inorganic

Density Driven Damage Mechanics (D3-M) Model for Concrete I: mechanical damage

July 6, 2022
Author(s)
Pavitra Murrua, Christa Torrence, Zachary Grasley, KR Rajagopal, P Alagappan, Edward Garboczi
Damage in concrete has been modeled using various approaches such as fracture mechanics, continuum damage mechanics and failure envelope theories. This study proposes a new theory to model damage in concrete that addresses the limitations associated with

Print Fidelity Metrics for Additive Manufacturing of Cement-based Materials

March 24, 2022
Author(s)
Edward Garboczi, Newell Moser, Joseph Biernacki, Hajar Afarani, Ebrahim Esfahani
Additively manufactured cement-based structures for infrastructure applications suffer from in-construction shape deformations, which are a strong function of process conditions and the rheology of the printing material (cement paste, mortar, or concrete)

Using fine sand shape metrics determined from X-ray microcomputed tomography to illustrate the influence of particle shape on the properties of dispersed mortars

July 10, 2021
Author(s)
Edward Garboczi, Jeffrey W. Bullard, Olafur Wallevik, Pierre Estephane
This study follows a first paper written on some three-dimensional geometrical quantities of a selection of sand particles from the United Arab Emirates (UAE), determined using a combination of X-ray microcomputed tomography (µCT) and spherical harmonic

Structural Performance of Nuclear Power Plant Concrete Structures Affected by Alkali-Silica Reaction (ASR) - Task 1: Assessing In-Situ Mechanical Properties of ASR-Affected Concrete

February 8, 2021
Author(s)
Fahim H. Sadek, Travis E. Thonstad, Sorin Marcu, Jonathan Weigand, timothy J. barrett, Hai S. Lew, Long Phan, Adam L. Pintar
This report describes the results of Task 1 of a five-task comprehensive research program being conducted at the National Institute of Standards and Technology (NIST) under the sponsorship of the U.S. Nuclear Regulatory Commission (NRC). The overall study

Structural Performance of Nuclear Power Plant Concrete Structures Affected by Alkali-Silica Reaction (ASR) - Task 2: Assessing Bond and Anchorage of Reinforcing Bars in ASR-Affected Concrete

February 3, 2021
Author(s)
Travis E. Thonstad, Jonathan Weigand, Fahim H. Sadek, Sorin Marcu, timothy J. barrett, Hai S. Lew, Long Phan, Adam L. Pintar
This report describes the results of Task 2 of a five-task comprehensive research program being conducted at the National Institute of Standards and Technology (NIST) under the sponsorship of the U.S. Nuclear Regulatory Commission (NRC). The overall study

Homogenization of Concrete Microstructures in Nuclear Power Plants

December 31, 2020
Author(s)
Christa Torrence, Aishwarya Baranikumar, Zachary Grasley, Edward Garboczi
Nearly all nuclear power plants in the United States are operating past their intended lifetimes or are requesting lifetime extensions, therefore understanding changes to the concrete containment structure over time is crucial to evaluate the structure's

Microstructure Homogenization of Concrete Used in Nuclear Power Plants

December 31, 2020
Author(s)
Edward Garboczi, Christa Torrence, Zachary Grasley, Aishwarya Baranikumar, William Lawrimore
Nearly all nuclear power plants in the United States are operating past their intended lifetimes or are requesting lifetime extensions. Therefore, understanding changes to the concrete containment structure over time is crucial to evaluate the structure's

Designing 3D printable cementitious materials with gel-forming polymers

December 11, 2020
Author(s)
Edward Garboczi, Hajar Taheri Afarani, William carroll, Joseph J. Biernacki
Cement based pastes for 3D printing applications were prepared using hydrogel-forming polymers. Preliminary results suggest that such gel-forming polymers can reduce the need for more complex admixture packages as printing aids. The influence of polymer
Displaying 1 - 25 of 162