Microscopic reaction process of cement with asphalt emulsion and its influence on macroscopic properties of binder

This research aimed at studying the reaction process between cement and asphalt emulsion from a microscopic view and the variations of macroscopic properties with cured time. The microstructure of cement asphalt emulsion (CAE) with a mass ratio of cement to asphalt (C/A) of 0.6 was scanned with scanning electron microscope (SEM) and its functional groups were measured with Fourier-transform infrared spectrometer (FTIR) after being cured for 7 days. Six CAEs with different C/A ratios were prepared and cured for different days, then DSR tests and beam bend rheometer (BBR) tests were conducted to evaluate their macroscopic performance. The results indicated that emulsion residue was relatively porous. Hydration reaction occurred between cement and water secreted by demulsification of asphalt emulsion, hydrates would gradually fill the voids. Asphalt and hydrates were interrelated into a cross-linking structure. As the rigidity of hydrates increased with cured time, the rutting resistance of CAE was improved, but its low-temperature performance and fatigue resistance were reduced. Key words: cement asphalt emulsion, scanning electron microscope (SEM), Fourier-transform infrared spectrometer (FTIR), dynamic shear rheometer (DSR), beam bend rheometer (BBR). Pour etudier les processus de reaction entre le ciment et une emulsion de bitume d'une perspective microscopique et les variations des proprietes macroscopiques avec le temps de durcissement, la microstructure d'un ciment et emulsion de bitume (<< CEB >>) avec un rapport de masse de ciment a bitume (C/B) de 0,6 a ete balaye avec un microscope electronique a balayage (MEB), et ses groupes fonctionnels ont ete mesures avec un spectrometre infrarouge a transformee de Fourier (IRTF) apres une periode de durcissement de 7 jours. Six echantillons de CEB ont ete prepares et durcis pendant un nombre de jours different, puis des essais rheologiques de cisaillement dynamique et des essais de rheometre a flexion de poutre ont ete effectues pour evaluer leur performance macroscopique. Les resultats indiquent que le residu d'emulsion est relativement poreux. Une reaction d'hydratation se produira entre le ciment et l'eau provenant de l'emulsion; les hydrates rempliront graduellement les vides. Le bitume et les hydrates deviennent interrelies pour former une structure a liaisons croisees. A mesure que la rigidite des hydrates a augmente avec le temps de durcissement, la resistance a l'ornierage de CEB a ete amelioree, mais ses performances a basse temperature et sa resistance a la fatigue ont ete reduites. [Traduit par la Redaction] Mots-cles ciment emulsion de bitume, microscope electronique a balayage (MEB), spectrometre infrarouge a transformee de Fourier (IRTF), rheometre de cisaillement dynamique, rheometre de flexion de poutre.
Introduction Asphalt emulsion mixture has the advantages of normal construction temperature, energy saving, convenient construction, environmental friendliness, no toxicity and side effects (Tian et al. 2018). However, it needs a [...]