Experimental Determination of Temperature Thresholds for Portland Cement Storage in Tropical Climates via Spectro-Mechanical Techniques

The deterioration of Portland cement after manufacture was investigated considering that storage conditions such as temperature and humidity are the main causes of deterioration. Infrared spectroscopy, fluorescence microscopy and mechanical performance, X-ray diffraction (XRD) and ultrasonic tests were used. In this sense, an experimental procedure was designed to evaluate the chemical behavior of the hydration reactions of cement stored in a set of samples under conditions (dry, ambient and humid) with different temperatures. The results of infrared spectroscopy revealed a similar behavior between the cement in humid conditions and the cement with water addition. In addition, a pronounced impact of humid conditions on the characteristics of Portland cement when compared to drier environments was also verified. In addition, the fluorescence microscopy experiments easily identified signs of deterioration of cement stored under temperature conditions with high humidity. Ultrasonic tests reveal that specimens prepared with cement stored at 30 °C have greater porosity when the cement is stored for 45 days. Similarly to the compressive strength results, the ultrasonic pulse test identified that cement stored at 10°C and 50°C presented better mechanical behavior when added to the mortar. Finally, to preserve the quality of Portland cement, hot or cold storage temperatures are promising to be applied as a replacement for ambient temperatures, where problems due to its deterioration in tropical climates can be mitigated.