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Displaying 26 - 50 of 178

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

Dissolution and Initial Hydration Behavior of Tricalcium Aluminate in Low Activity Sulfate Solutions

January 22, 2020
Author(s)
Alexander Brand, Steven B. Feldman, Paul E. Stutzman, Anton V. Ievlev, Matthias Lorenz, Darren C. Pagan, Sriramya Nair, Justin Gorham, Jeffrey W. Bullard
The effects on cubic tricalcium aluminate (C3A) hydration of alkali or alkaline earth sulfate electrolytes were evaluated by in situ dissolution rate measurements, by ex situ near-surface composition measurements with secondary ion mass spectrometry, and

Potential Use of Lightweight Aggregate (LWA) Produced from Bottom Coal Ash for Internal Curing of Concrete Systems

October 1, 2019
Author(s)
Mohammad Balapour, Weijin Zhao, Edward Garboczi, Nay Ye Oo, Sabrina Spatari, Grace Hsuan, Peter Billen, Yaghoob Farnam
This study evaluates the potential use of a novel lightweight aggregate (LWA), spherical porous reactive aggregate (SPoRA), which is produced from waste coal bottom ash, for internal curing of concrete. Engineering properties of SPoRA required for concrete

Improved Mesoscale Segmentation of Concrete from 3D X-ray Images Using Contrast Enhancers

June 28, 2018
Author(s)
Pietro Carrara, Rolands Kruse, Dale P. Bentz, M Lunardelli, Thorsten Leusmann, P Varady, Laura De Lorenzis
Obtaining the mesostructure of concrete from X-ray computed tomography (CT) requires segmentation of the data into distinct phases, a process complicated by the limited contrast between aggregates and mortar matrix. This paper explores the possibility to

Relating the Electrical Resistance of Fresh Concrete to Mixture Proportions

March 5, 2018
Author(s)
K H. Obla, Rongjin Hong, Stuart Sherman, Dale P. Bentz, Scott Jones
Characterization of fresh concrete is critical for assuring the quality of our nation's constructed infrastructure. While fresh concrete arriving at a job site in a ready-mixed concrete truck is typically characterized by measuring temperature, slump, unit

A Multiscale Framework for the Prediction of Concrete Self-Desiccation

March 1, 2018
Author(s)
Madura Pathirage, Dale P. Bentz, Giovanni Di Luzio, Enrico Masoero, Gianluca Cusatis
Cement hydration in concrete and mortar has been studied thoroughly over the past 50 years. To fully understand hydration in concrete and predict the evolution of the hygral, thermal, and mechanical properties at the structural level, one needs to study
Displaying 26 - 50 of 178