Research on the Interaction Capability and Microscopic Interfacial Mechanism between Asphalt-Binder and Steel Slag Aggregate-Filler

Abstract

To explore the applicability of steel slag porous asphalt mixture, the interaction capability and microscopic interfacial mechanism between asphalt-binder and steel slag aggregate-filler were investigated in this laboratory study. These objectives were accomplished by comparing and analyzing the differences between steel slag and basalt aggregates in interacting with the asphalt-binder. The study methodology involved preparing basalt and steel slag asphalt mortar to evaluate the penetration, ductility, softening point, toughness, and tenacity. Thereafter, the interaction capability between the asphalt-binder and aggregates was characterized using the interaction parameters of the asphalt mortar obtained from dynamic shear rheometer (DSR) testing. For studying the functional groups and chemical bonding of the asphalt mortar, the Fourier Transform infrared (FTIR) spectrometer was used, whilst the interfacial bonding between the asphalt-binder and aggregates was analyzed using the scanning electron microscope (SEM). The corresponding test results indicated that the physical and rheological properties of the two asphalt mortars were similar. However, whilst the FTIR analysis indicated domination through chemical reactions, the interaction capability and interfacial bonding between the asphalt-binder and steel slag aggregates exhibited superiority over that between the asphalt-binder and basalt aggregates, with pronounced adsorption peaks appearing in the steel slag asphalt mortar spectrum. On the other hand, the SEM test revealed that, compared with the basalt, the micro-interfacial phases between the steel slag and asphalt-binder were more continuous and uniform, which could potentially enhance the interfacial bond strength between the asphalt-binder and aggregates (filler).

Research on Water Stability and Moisture Damage Mechanism of a Steel Slag Porous Asphalt Mixture

“…Furthermore, the asphalt film on the steel slag aggregate surfaces played a crucial role in enhancing the water resistance and reducing the possibility of hydration of the steel slag aggregates, as well as inhibiting the volume expansion of the steel slag aggregates. However, with an increase in the H 2 O immersion time and temperature, the adhesion between the asphalt and steel slag aggregates decreased; this led to the asphalt film on the surfaces of the steel slag aggregates to gradually fall off, with the pores on the surfaces of the steel slag aggregates quickly absorbing a lot of water [82]; that is, the volume stability of the steel slag aggregates declines and contributes to weakening the internal stability of the structure of SSPA, causing surface volume expansion of the SSPA and, ultimately, a decrease in the water stability.…”

The Use of Steel Slags in Asphalt Pavements: A State-of-the-Art Review

“…Conventionally, good characteristics of oxidizing steel slags (BOFS or EAFS) make these by-products useful for several construction fields [11], whereas LFS are suitable for many applications related to agriculture (soil acidity correction), environmental engineering (water depuration) [98], aquaculture (fishing block development) [99], the cement industry (clinker fabrication) [100,101], masonry mortars [102], and soil stabilization [103]. From the physical point of view, coarse and fine slags typically present a rough surface with numerous micro-pores and uniform angularity distribution [104]. These features, together with a larger specific surface area, increase the contact area with asphalt and, thus, promote the adhesion phenomena [105], improving the bonding with bitumen [106].…”