Quantitative assessment of self-healing in cementitious systems
Doehring, Jacob William
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/120409
Description
Title
Quantitative assessment of self-healing in cementitious systems
Author(s)
Doehring, Jacob William
Issue Date
2023-05-01
Director of Research (if dissertation) or Advisor (if thesis)
Garg, Nishant
Department of Study
Civil & Environmental Eng
Discipline
Civil Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
M.S.
Degree Level
Thesis
Keyword(s)
Cement
Self-healing
Quantitative
Cementitious
Calcium nitrite
Abstract
The discussions around self-healing cements have grown over the past decade as researchers in construction materials aim to find a more sustainable approach to cement and
supplementary cementitious materials (SCM). Current efforts in self-healing cements have used a variety of designs ranging from micro-encapsulated healing agents, embedded in concrete or cement during the mixing process, to enzymes or bacteria which consume a calcium-sourced nutrient solution to precipitate mineral growth, healing cracked or void spaces. Within many of these concepts, ideal or altered conditions are often needed to adjust for the high pH levels of the concrete or the harsh mixing process. As such, altering the concrete mix design to adjust for self-healing potential may result in further deterioration issues such as altered cement reactions, increased void space, or strength loss. Subsequently, with this rise in processes for self-healing cements and other SCMs, there lacks in the literature a simplified, novel method for quantifying self-healing in construction materials. Many such methods currently used to quantify healing result in topological crack healing which fails to capture crack depth. Other methods use weight-change and compressive testing to correlate to a quantified value. Many such methods fail to grasp the breadth of capability in collecting meaningful data and consistently reproducing quantified results. In the following report, we first present a novel approach for self-healing cements in the form of an aqueous calcium nitrite solution that, within less than 24 hours, can produce significant crystal growth, filling cracked space with upwards of 60% efficiency. These crystals additionally act as nucleation sites for continual carbonation to form on the surface of precipitated calcium nitrite crystals, strengthening and healing the cracked cement spaces. Secondly, we propose a new method for quantifying self-healing cements through a Laser Scanning Confocal Microscope (LSCM), used to track the mineral precipitation occurring in the cracked space. The results from the LSCM proved consistent in multiple samples and the resulting mineral precipitate would correlate directly with the concentration of calcium nitrite solution and quantified growth.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
