Title:
From Experimental Silica Fume Dissolution to Microstructure Modeling and Hydration Kinetics Simulation
Author(s):
Mine Ucak-Astarlioglu
Publication:
Web Session
Volume:
ws_F23_MineUcak-Astarlioglu.pdf
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/29/2023
Abstract:
Silica fume (SF) plays a key role in the rheology and mechanical properties of ultra-high-performance concrete (UHPC) by improving its particle packing behavior and promoting its hydration kinetics. Finer particle size and larger specific surface area of SF could accelerate the early cement hydration of UHPC. To improve the material performance of UHPC, dispersion of SF in the cement-based materials can be optimized by understanding the dissolution kinetics of densified or undensified SFs in cement pore solution. This project explores experimental SF dissolution kinetics in cementitious mixtures, integrates them into the Virtual Cement and Concrete Testing Laboratory (VCCTL) model, and compares its results to the Thermodynamically Assisted Microstructure Evolution Simulator (THAMES) to obtain an accurate simulation of the hydration reaction and the microstructure development of cement-SF blends in UHPC. To investigate the effect of the physical and chemical properties of SF on the hydration rate of portland cement, six SFs were studied with varying amorphous content, chemical composition, and particle morphology. By analyzing the rate of dissolution in terms of SF characteristics, the cement microstructure was obtained, and hydration reaction simulations were completed. VCCTL was used as a powerful tool to predict the cement hydration as well as its respective three-dimensional microstructure, whereas THAMES was used to interconnect thermodynamics, microstructure, and kinetics investigation under one model. In addition, THAMES was used due to its advanced simulation capability, not only for portland cement, but also for other material structures. These studies will provide invaluable benefits in mitigating climate change and in advancing sustainable civil works and military construction. Permission to publish was granted by Director, Geotechnical & Structures Laboratory.