Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 4 of 4
Full-Text Articles in Architecture
Quantifying The Workability Of Calcium Sulfoaluminate Cement Paste Using Time-Dependent Rheology, Sukanta K. Mondal, Adam Welz, Carrie Clinton, Kamal Khayat, Aditya Kumar, Monday Uchenna Okoronkwo
Quantifying The Workability Of Calcium Sulfoaluminate Cement Paste Using Time-Dependent Rheology, Sukanta K. Mondal, Adam Welz, Carrie Clinton, Kamal Khayat, Aditya Kumar, Monday Uchenna Okoronkwo
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Poor workability is a common feature of calcium sulfoaluminate (CSA) cement paste. Multiple chemical admixtures, such as set retarders and dispersants, are frequently employed to improve the workability and delay the setting of CSA cement paste. A quantitative assessment of the compatibility, efficiency, and the effects of the admixtures on cement paste workability is critical for the design of an appropriate paste formulation and admixture proportioning. Very limited studies are available on the quantitative rheology-based method for evaluating the workability of calcium sulfoaluminate cement pastes. This study presents a novel and robust time-dependent rheological method for quantifying the workability of …
Hydration Of High-Alumina Calcium Aluminate Cements With Carbonate And Sulfate Additives, Jonathan Lapeyre, Sai Akshay Ponduru, Monday Uchenna Okoronkwo, Hongyan Ma, Aditya Kumar
Hydration Of High-Alumina Calcium Aluminate Cements With Carbonate And Sulfate Additives, Jonathan Lapeyre, Sai Akshay Ponduru, Monday Uchenna Okoronkwo, Hongyan Ma, Aditya Kumar
Chemical and Biochemical Engineering Faculty Research & Creative Works
This study investigated the influence of limestone (LS) and calcium sulfate (C$) mineral additives on the hydration kinetics of high-α-Al2O3 calcium aluminate cement (CAC) utilizing experimental techniques and thermodynamic simulations. Increasing the replacement level of limestone or calcium sulfate increased the cumulative heat of the hydration reaction. The limestone exhibited limited acceleratory effects to the CAC hydration kinetics due to the coarseness of the powder. The coarse particle size distribution limited any heterogenous nucleation that would have occurred with a finer particle size as well as the intrinsic insolubility kinetically limits the formation of monocarboaluminate phases. Conversely, …
Feasibility Study Of Implementing Gamma-Ray Computed Tomography On Measuring Aggregate Distribution And Radiation Shielding Properties Of Concrete Samples, Omar Farid, Nima Farzadnia, Kamal Khayat, Muthanna H. Al-Dahhan
Feasibility Study Of Implementing Gamma-Ray Computed Tomography On Measuring Aggregate Distribution And Radiation Shielding Properties Of Concrete Samples, Omar Farid, Nima Farzadnia, Kamal Khayat, Muthanna H. Al-Dahhan
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Aggregate segregation is one of the key defects that impair the performance of concrete at fresh and hardened stages. This study aims to assess the feasibility of using an advanced technique to identify/scan/determine the aggregate segregation of concrete elements and determine radiation shielding properties of the concrete. The gamma-ray computed tomography (γ-CT) technique was employed to study aggregate distribution/dispersion in self-consolidating concrete (SCC). Accordingly, two SCC mixtures with moderate segregation (MS) and high segregation (HS) levels were cast and compared with highly stable SCC with no segregation (NS). The γ-CT scans were located on three different levels of concrete specimens …
Examining The Effect Of A Chitosan Biopolymer On Alkali-Activated Inorganic Material For Aqueous Pb(Ii) And Zn(Ii) Sorption, Sukanta K. Mondal, Chenglin Wu, Felix C. Nwadire, Ali A. Rownaghi, Aditya Kumar, Yusuf Adewuyi, Monday Uchenna Okoronkwo
Examining The Effect Of A Chitosan Biopolymer On Alkali-Activated Inorganic Material For Aqueous Pb(Ii) And Zn(Ii) Sorption, Sukanta K. Mondal, Chenglin Wu, Felix C. Nwadire, Ali A. Rownaghi, Aditya Kumar, Yusuf Adewuyi, Monday Uchenna Okoronkwo
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Biopolymers and alkali-activated materials have attracted a great deal of attention as adsorbents for the removal of heavy metal contaminants from aqueous solutions. Both materials are sustainable and feature unique properties, but biopolymers are relatively more expensive or difficult to prepare and exhibit low mechanical and surface properties, a narrow pH range, and thermal stability. In this study, hybrid adsorbents were prepared from both types of material, by alkali activation of low-cost fly ash precursors accompanied by incorporation of 0-2%mass chitosan biopolymer. Two types of alkaline activating solutions, NaOH and Na2SiO3, were employed to generate two sets of hybrid adsorbents …