Interaction process on the phases interface “bitumen – dispersed phase from cement stone”

Building Materials

The results of the study of the effect of the main properties of mineral fillers from cement stone with different degrees of hydration, phase composition and pore volume characteristics on the properties of the bitumen-mineral binder are presented. Dependencies of the influence of mineral filler on the basis of cement stone on the basic parameter of the structure of bitumen-mineral binders-the thickness of the adsorption-solvate layer of bitumen, which was established using the rheological method. Analysis of the empirical data obtained shows that bitumen chemically interacts with mineral fillers obtained from cement stone. It is proved that during the interaction of bitumen with the waste of cement concrete, processes of physical and chemical adsorption take place. Maltenes of bitumen penetrate the pores of cement concrete during physical adsorption. Calcium hydroxide Ca(OH)2 and bitumen active functional groups -OH, -COH, -COOH, C = C-, etc. interact with the formation of new bonds that are reflected in IR spectra in the form of peaks of 820 cm-1, 944 cm-1, 947 cm-1 or 1430 cm-1. The intensity of the given processes and the degree of the structuring of the bituminous films will depend on the degree of hydration of the cement in the fragments of the concrete present in construction waste. When the degree of hydration increases, the thickness of the adsorption-solvate coating of bitumen increases from 1.5 to 2 times. During the interaction of bitumen with the waste of the building cement of concrete, more heat-resistant bitumen films are formed. When the degree of hydration is an increment, the resistance to high-temperature exposure of structured bitumen increases from 1.2 to 2.4 times