This paper describes the hydration of mixtures of high alumina cement (HAC)
with Portland cement (OPC) in mortars at temperatures of 5 degrees C, 20 d
egrees C, and 60 degrees C. Hydration is characterized by the hydration pro
ducts, identified by X-ray diffraction, and by a compressive and flexural s
trength test in relation to measurements of the ultrasonic propagation velo
city after a curing period of 28 days.