Development of building material utilizing a low pozzolanic activity mineral

In this work, the effects of different activators, particle size and curing conditions on the mechanical properties and hydration progress of alkali activated Pisha mortars were studied. Four different activators (NaOH, Na2CO3, Na2SO4 and water glass) based on two different fineness Pisha were used, two kinds of curing temperature, 25 and 80 °C were considerate. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG) and scanning electron microscopy (SEM) were conducted to analyze the reaction products, indentify the phase composition and observe the micro-morphology, respectively. It was found that the modulus of water glass and fineness of Pisha have significant influence on the compressive strength and hydration process of alkali activated Pisha mortars. The optimum activators were water glass, the sample (Ms = 1.5, curing at 80 °C) exhibited the highest compressive strength (14.4 MPa) at 28 days. The results of the investigation also show that the amorphous aluminosilicate gels were the main hydration products.