INFLUENCE OF LATEX POLYMER ADDITION ON THE BEHAVIOR OF MATERIALS CONTAINING CSA CEMENT CURED AT LOW HUMIDITY
The present study assesses the hydration behavior of polymer modified and non-polymer containing calcium sulfoaluminate (CSA) cement pastes containing minor phase tri-calcium aluminate (C3A) when cured at ambient laboratory temperature with 50% relative humidity. The particular CSA cement is unique as it offers two potential paths for ettringite formation. In the presence of sufficient calcium sulfate, these two potential paths stem from either hydration of yeelimite or hydration of tri-calcium aluminate. The study assesses the microstructural behavior of cement pastes utilizing powdered x-ray diffraction (XRD) and thermogravimetric analysis (TGA/SDT). Additionally, the study utilizes direct tensile strength testing according to ASTM C307, Standard Test Method for Tensile Strength of Chemical Resistant Mortar, Grouts and Monolithic Surfacings to quantify relationships between microstructural characteristics and mechanical property performance for representative mortars. The present study is significant as it illustrates differences in microstructural behavior for CSA cement materials with and without polymer cured at constant 50% relative humidity. The present study suggests ettringite decomposition occurs within non-polymer containing CSA cement paste samples cured at constant low humidity. The present study presents polymer modification as an effective means for mitigating ettringite decomposition and subsequent strength loss in materials containing CSA cement cured at constant 50% relative humidity and 23°C.ABSTRACT
Contributor Notes
Joshua V. Brien received both a BS Chemical Engineering and MBA from the University of Kentucky in 1998 and 1999, respectively. Mr. Brien was employed by a market leading latex polymer producer for ten years before resigning from his position as Plant Manager to pursue a Ph.D. in Civil Engineering with a focus on construction materials from the University of Kentucky. 120 E Main Street Apt 1408, Lexington, KY, 40507, USA; 270-994-7031; jbrien51@gmail.com.
Kevin R. Henke received both an MS and Ph.D. in geology, from the University of North Dakota. Dr. Henke now works as a research scientist at the University of Kentucky Center for Applied Energy Research where his interests include mineralogy, metamorphic petrology, heavy metal removal from waste waters geochemistry and mercury and arsenic chemistry.
K.C. Mahboub, Ph.D., P.E, is the Lawson Professor of Civil Engineering at University of Kentucky. He received his BSCE from UT-Austin, and MSCE and Ph.D. from Texas A&M University. He is a member of ACI 522 Committee on Pervious Concrete. He is also a member of TRB, ASCE, ASTM, KSPE, NSPE and AAPT.