This study investigated potential physical and chemical parameters that could govern the carbonation rate of calcium sulfoaluminate (CSA) mortars and endeavored to elucidate the microstructural and chemical factors that govern CSA cement's carbonation rate. Experiments included: water absorption, oxygen diffusion, mercury intrusion porosimetry, quantitative X-ray diffraction, thermogravimetric analysis, accelerated carbonation, compression and flexure tests. Additionally, the carbonation process was investigated using thermodynamic modeling. The results show that CSA mortars carbonate much faster than Portland cement mortars and at approximately the same rate as calcium aluminate cement mortars. Additionally, CSA mortars carbonate slower with decreasing w/c, and the anhydrite content of the CSA mortars strongly affects the ye'elimite reaction kinetics which plays an important role in imparting carbonation resistance in CSA mortars. Finally, calcium sulfate additions to CSA clinker to produce CSA cement dilutes the clinker content and reduces the amount of CO2 that the CSA cement can ultimately bind.

Carbonation of calcium sulfoaluminate mortars

Using gypsum to control hydration kinetics of CSA cements

Influence of polymer latex on the setting time, mechanical properties and durability of calcium sulfoaluminate cement mortar

Through systematical experiments,the mechanical properties,carbonation characteristics and shrinkage properties of concretes with fly ash contents of 50% and 60% for long-term curing ages were investigated in more detail.The results show that,for the concretes with fly ash contents of 50% and 60%,their later strength increases so rapidly and have a little difference with that of concretes without fly ash when they were cured for long-term ages and added an appropriate amount of activator.Moreover,long-term curing ages can obviously increase their carbonation resistance and certainly improve their shrinkage propertiy,but almost have no effect on the tendency of shrinkage.

High-performance High-volume Fly Ash Concrete

Experimental and analytical investigations on the behavior of interface between concrete and polymer cement mortar under hygrothermal conditions

Influence of polymer type on adhesion performance of a blended cement mortar

The purpose of this study was to assess the mechanical property performance behavior of calcium sulfoaluminate (CSA) cement mortar when cured at ambient laboratory temperature of ~23°C (73°F) and constant 50% relative humidity for an extended period of time. Four CSA cement mortars were tested. Three CSA cement mortars contained equivalent mass amounts of calcium sulfate; whereas, the fourth mortar contained double the amount of calcium sulfate. The three CSA cement mortars containing constant mass amounts of calcium sulfate differed as the specific type of calcium sulfate varied across the three formulations—one mortar containing solely anhydrite, one mortar contained half anhydrite and half gypsum while the other mortar solely contained gypsum. The fourth mortar contained double the amount of calcium sulfate when compared with the others while having a 1/1 blend of anhydrite and gypsum. Specific mortars were either tested for direct tensile strength according to ASTM C307 or for compressive str...

https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1003&context=ce_facpub

Observations of Peak Strength Behavior in CSA Cement Mortars

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 signi...

Influence of latex polymer addition on the behavior of materials containing csa cement cured at low humidity

The purpose of this study was to assess the effect of polymer glass-transition temperature (Tg) on the mechanical property performance of mortars containing calcium sulfoaluminate (CSA) cement and vinyl acetate/ethylene dispersible polymer powder (VAE DPP). Competitive products were acquired from companies A, B, and C. Company A supplied VAE DPP with glass-transition temperatures of 64°F (18°C) and 19°F (−7°C). Company B supplied VAE DPP with glass-transition temperatures of 59°F (15°C) and 5°F (−15°C). Company C provided VAE DPP with glass-transition temperatures of 68°F (20°C) and −8°F (−22°C). It is important to note that differences in glass-transition temperature result from differences in the ratio of monomers utilized for production of the liquid polymeric dispersion during reaction polymerization, where the pertinent ratio is that of ethylene to vinyl acetate for materials germane to this study. Additionally, each utilized polymer powder may also differ in constituent components comprising the polymer powder as a result of the drying process, where constituent materials should not be limited to products typically utilized for forming protective colloids or products utilized as anti-caking agents. Each polymer was tested in a standard mortar formulation with polymer/cement ratio of 2/5 and water/cement ratio of 0.48. Experimental results show that polymer modification improves the ductile performance of CSA cement mortars. Additionally, experimental results show that the glass-transition temperature of vendor-specific products influences the mechanical property performance of polymer-modified CSA cement mortars.

Joshua V. Brien

Papers

Influence of polymer type on adhesion performance of a blended cement mortar

Observations of Peak Strength Behavior in CSA Cement Mortars

Influence of latex polymer addition on the behavior of materials containing csa cement cured at low humidity

Mechanical Property Performance of Polymer-Modified Calcium Sulfoaluminate Cement Mortar Systems