A model combining structure and properties of a 160/220 bituminous binder modified with polymer/clay nanocomposites. A rheological and morphological study

Abstract

The present contribution focuses on the modification of a 160/220 bituminous binder with clay and polymer/clay nanocomposites. Bitumen/polymer/clay ternary blends were prepared using styrene–butadiene–styrene, ethylene vinyl acetate and ethylene methylacrylate copolymers mixed with an organomodified montmorillonite. Dynamic mechanical analyses were performed in the extended domain of stress, temperature and frequency to analyse the thermorheological behaviour of the blends. The time–temperature superposition principle was applied to shift the experimental data recorded at different temperatures and generate master curves of the linear viscoelastic functions. For all blends, the mechanical response of the system was found to be strongly and intimately influenced by the nanocomposite modification. In some cases, a solid-like behaviour appears and delays the Newtonian transition. Morphological analyses performed with fluorescence microscopy allowed to associate the binder properties with the presence of clay silicates, which alter the colloidal equilibrium of the bitumen and enhances the compatibility between bitumen and polymers. Based on the morphological and rheological results, a structural model of the prepared blends is proposed

Evaluation of Rheological Behavior, Resistance to Permanent Deformation, and Resistance to Fatigue of Asphalt Mixtures Modified with Nanoclay and SBS Polymer

“…Results of the laboratory modified asphalt binders' characterization can be observed in Table 5. In comparing the results in Table 5 with those provided for the empirical characterization of CAP 50/70 (Table 3) and SBS 60/85 (Table 4), it can be observed that, as expected and also demonstrated by other authors in similar studies [13][14][15][16][17][18][19][20][21], the binders modification caused a penetration decrease and a softening point increase. Notable among these results are the relatively low penetration obtained for the binder 3% NC + 2% SBS and the relatively high softening point for the binder SBS 60/85.…”

“…More recently, the behavior of asphalt binders and mixtures modified with polymers and nanomaterials have been investigated. The results obtained in this line of research have also been positive [13][14][15][16][17][18][19][20][21]. However, most studies have been limited to the binders, and there is a need for more investigations that consider the mixtures, taking into account the interaction between the binder, the granulometry, and the aggregate characteristics.…”

“…The inclusion of nanoclay and the polymer SBS in the base binder CAP 50/70 was carried out in a laboratory high shear mixer (Silverson, model L5M-A), and the modification procedures were defined based on studies reported in the literature [5,11,12,[15][16][17][18][19][20]. The modification to produce the 3% NC binder was carried out at 150 • C, with a shearing speed of 5000 rpm and compatibilization period of 100 min.…”

Bitumen and Bitumen Modification: A Review on Latest Advances

“…However, storage stability is not simply due to a decrease in density difference between the PRP and ARP phases. Several studies have shown that compatibility between bitumen and polymer also plays a fundamental role [215]. Therefore, the improved storage stability can be ascribed mainly to two factors: decrease in density difference between the PRP and ARP phases and, to a greater extent, to a real bitumen/polymer compatibilizing effect.…”

Effect of Nanoadditives on Bitumen Aging Resistance: A Critical Review

“…Even though somehow unexpected, this is not surprising, because it was already known that LS might be used as compatibilizer agents in polymer blends. This aspect of LS acting as a polymer/bitumen compatibilizer is fully considered in previous works [83,84] and will not be discussed in detail here. We can limit our work to the observation that the compatibilization is related to selective interactions between clay, polymer, and some bitumen molecules.…”