Graduation Semester and Year
Fall 2025
Language
English
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Civil Engineering
Department
Civil Engineering
First Advisor
Maria S. Konsta-Gdoutos
Second Advisor
Surendra P. Shah
Third Advisor
Mark C. Hersam
Fourth Advisor
Efstathios I. Meletis
Fifth Advisor
Panagiotis A. Danoglidis
Abstract
Enhancing the resiliency of concrete has traditionally focused on modifying the cementitious hydration products using supplementary cementitious materials (SCMs). However, the introduction of modern binders such as Portland Limestone Cement and emerging, off spec SCMs demands a deeper understanding of concrete's post-cracking behavior, which is the key to structural serviceability. Metakaolin (MK), a highly reactive pozzolanic admixture is known to improve stiffness and compressive strength but often leads to a more brittle failure mode, limiting durability. This research addresses that gap by investigating the nanoscale modifications of MK-based matrices using small amounts of one-dimensional carbon nanomaterials. Through a multiscale experimental approach, this study demonstrates that enhanced interactions between the functional groups on carbon nanotube surfaces and the calcium-silicate hydrates (CSH) result in modifications of the Ca/Si ratio and promote the development of a denser and more resilient interfacial transition zone (ITZ), enhancing concrete's overall toughness, resiliency, and tensile strain capacity. Moreover, the nanomodified MK blends exhibit superior resistance to cracking under ASR conditions. Beyond MK, this work explores exfoliated nano-kaolinite platelets as an additive to modify fresh-state behavior and enhance the early-age mechanical properties. The findings aim to advance sustainable, high-performance concrete systems with multifunctional capabilities, bridging the gap between conventional design and next-generation construction technologies.
Keywords
Metakaolin, Carbon nanotubes, Ca/Si ratio, Interfacial Transition Zone, ASR, Alkali binding capacity, Retained Modulus, Nano-kaolinite, Rheology
Disciplines
Civil Engineering | Structural Engineering | Structural Materials
License
This work is licensed under a Creative Commons Attribution-NonCommercial-No Derivative Works 4.0 International License.
Recommended Citation
Singh, Rohitashva Kumar, "ON THE INTERACTIONS OF CARBON NANOTUBES WITH METAKAOLIN – OPC & PLC BLENDS: EFFECTS ON THE ITZ, MODULUS, TOUGHNESS AND ASR MITIGATION" (2025). Civil Engineering Dissertations. 532.
https://mavmatrix.uta.edu/civilengineering_dissertations/532