Wassim Tabet, Ph.D. (Kennesaw) coauthored a technical paper “Characterization of Hydration Products’ Formation and Strength Development in Cement-Stabilized Kaolinite Using TG and XRD” that will be published in the Journal of Materials in Civil Engineering, a publication from American Society of Civil Engineers (ASCE) in October 2018.
Wassim is a Senior Staff Engineer who joined Geosyntec’s Kennesaw, Georgia office in February 2016 after graduating with a Ph.D. in geotechnical engineering from the University of Oklahoma. Since joining Geosyntec, he has served as a team member for several geotechnical and geoenvironmental projects. His professional consulting experience has involved design and analysis of coal combustion residual (CCR) impoundments, slope stability analysis, settlement analysis, seepage analysis, foundation design and foundation improvement, field investigation, and permit application supporting, among others.
His coauthors were Amy B. Cerato, Ph.D., P.E., M.ASCE; Andrew S. Elwood Madden, Ph.D.; and Rolf E. Jentoft, Ph.D.
The Journal of Materials in Civil Engineering covers the development, processing, evaluation, applications, and performance of construction materials in civil engineering.
The American Society of Civil Engineers represents more than 150,000 members of the civil engineering profession in 177 countries. Founded in 1852, ASCE is the nation’s oldest engineering society. It serves a profession that plans, designs, constructs, and operates society’s economic and social engine, the built environment, while protecting and restoring the natural environment.
This study investigates the use of thermogravimetry (TG) and X-ray diffraction (XRD) to characterize and quantify the hydration products, particularly calcium silicate hydrate (CSH) and calcium hydroxide [Ca(OH)2], in stabilized soils and to establish correlations between these products and strength gain over time. A pure kaolinite is the soil for this study and portland cement is the selected stabilizer. Untreated and cement-stabilized samples are compacted at their optimum conditions and cured for different periods of up to 90 days. The unconfined compression test, which is a relatively simple and commonly used test, is performed to measure the unconfined compressive strength (UCS) for all the samples and record the macroscopic behavior. A portion of soil from each set of samples is recovered and subsequently subjected to the TG test coupled with mass spectrometry (MS) and XRD. Using TG, the amounts of CSH (mass loss between 105 and 440°C) and calcium hydroxide (mass loss between 440 and 580°C) are measured and monitored with time to establish their correlation with strength gain. Quantitative XRD using whole-pattern fitting (Rietveld analysis) and the reference intensity ratio (RIR) indicated that the amount of kaolinite decreases logarithmically with curing time and a strong linear correlation is observed between the amount of kaolinite and the unconfined compression strength.
Learn more about the paper: https://ascelibrary.org/doi/pdf/10.1061/%28ASCE%29MT.1943-5533.0002454
Learn more about Wassim: https://www.linkedin.com/in/wassim-tabet-80556999/