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Displaying 26 - 50 of 291

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

Temperature-induced heteroaggregation in polydisperse portlandite suspensions

August 17, 2020
Author(s)
Edward Garboczi, Gaurav Sant, Iman Mehdipour, Narayanan Neithalath, Mathieu Bauchy, Samanvaya Srivastava, Sharu Bhagavathi Kandy
Temperature is well-known to affect the aggregation behavior of colloidal suspensions. This paper elucidates the temperature dependence of the rheology of portlandite (calcium hydroxide: Ca(OH)2) suspensions that feature a high ionic strength and a pH

Dispersing nanosized portlandite particulates via electrosteric exclusion at short screening lengths

March 16, 2020
Author(s)
Jason Timmons, Iman Mehdipour, Shang Gao, Hakan Atahan, Narayanan Neithalath, Mathieu Bauchy, Edward Garboczi, Samanvaya Srivastava, Gaurav Sant
In spite of their high surface charge (ζ = + 34 mV), aqueous suspensions of portlandite (calcium hydroxide: Ca(OH)2) exhibit a strong tendency to aggregate, and thereby present unstable suspensions. While a variety of commercial dispersants seek to modify
Displaying 26 - 50 of 291