Title:
Microstructural and Thermodynamic Analyses Elucidate Effects of Expansive Agent and Shrinkage Reducing Admixtures on Performance of Fiber-Reinforced Mortar
Author(s):
Kamran Aghaee
Publication:
Web Session
Volume:
ws_F24_KamranAghaee.pdf
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
11/3/2024
Abstract:
An expansive agent (EA) reduces shrinkage through initial expansion, while a shrinkage reducing admixture (SRA) does so by lowering the surface tension of the pore solution. Although EA and SRA effectively reduce shrinkage, excessive use can adversely affect the microstructure and macro mechanical properties of concrete. This presentation explores the detrimental effects of high contents of EA, SRA, and their combination on the performance of fiber-reinforced mortar (FRM). Mercury intrusion porosimetry was utilized to examine the pore structure of FRM. The hydration products were characterized by X-ray diffraction and derivative thermogravimetric. Backscatter scanning electron microscopy, energy dispersive spectroscopy, and micro-hardness experiments were employed to characterize the microstructure of fiber-matrix ITZ at distances of 50 and 100 µm from the fibers. Experimental results indicated that the quality of ITZ and fiber-matrix bonding was compromised using either EA or SRA. Thermodynamic simulations and phase assemblages elucidated the influence of EA and SRA on the performance of FRM.