Title: Colloidal Nano-silica for Low Carbon Self-healing Cementitious Materials

Author(s): Su

Publication: Web Session

Volume:

Issue:

Appears on pages(s):

Keywords:

DOI:

Date: 3/28/2022

Abstract:
The concrete industry is one of the primary sources contributing to the world’s carbon dioxide (CO2) emissions. Therefore, the researcher and the industry are striving to improve sustainability and reduce the carbon footprint of cementitious materials. Enhancing the self-healing performance and mechanical properties of cementitious materials would positively benefit the life cycles and sustainability of concrete structures. In this study, colloidal nano silica (CNS) was incorporated in low carbon self-healing cementitious materials to investigate their mechanical properties and self-healing performance. The important mechanical behavior, including compressive, tensile, flexural properties, and bonding strength were assessed. The results indicated that the incorporation of CNS could effectively improve the mechanical properties of cementitious materials, particularly, the compressive strength would rise 13% to 27%, and flexural strength can increase 7% to 9% with the CNS additional ratio of less than 1% by weight of cementitious materials. Both non-destructive and destructive testing methods were implemented to monitor the medium-term self-healing performance of cementitious materials with various CNS incorporation rates. The samples were pre-cracked and placed under two different environmental conditions during the healing period. The thermal gravity analysis (TGA) and scanning electron microscope (SEM) were conducted to understand the hydration performance of each mixture. It is summarized that the CNS incorporation rate between 0.3% to 0.6% percent would be the optimal ratio for low carbon self-healing cementitious materials to have remarkable mechanical properties and self-healing performance.