Moisture Damage and Its Relation to Surface Adsorption/Desorption of Rejuvenators

Abstract

This paper uses a multiscale approach to study the preferential surface adsorption of bio-based rejuvenators to siliceous substrates, used here as surrogates for mineral stones like quartz in bituminous composites. Bituminous composites are the main building blocks of asphalt pavements and roofing shingles. Various rejuvenators, including bio-based rejuvenators, are commonly used to extend the service life or facilitate the recycling of aged bituminous composites reclaimed at the end of their service life. While rejuvenators may be able to restore the thermomechanical properties of aged asphalt, the rejuvenators' susceptibility to moisture damage is a rising concern as various types and dosages of biorejuvenators gain traction in the market.Here, we hypothesize that by controlling the composition of rejuvenators, the adsorption of rejuvenators to siliceous minerals in a wet environment can be increased, leading to enhanced resistance to moisture damage in revitalized aged asphalt. To test this hypothesis, we specifically designed a rejuvenator from a balanced feedstock of algae (high in protein and nucleic acids) and manure (high in lipid), and we compare its resistance to moisture damage with that of two commercial rejuvenators, using molecular modeling and laboratory experiments. Molecular modeling was geared toward simulation, and laboratory experiments were performed using the moisture-induced shear-thinning index (MISTI) and the wheel-tracking test under water. The study results showed that even though the aged asphalt was not susceptible to moisture damage, its moisture susceptibility varied significantly after it was revitalized by each of the three rejuvenators tested. Our molecular simulations showed that water promoted the desorption of molecules of low-performing rejuvenators from the siliceous stone surface, giving rise to moisture damage. This finding was supported by laboratory experiments showing a water-stripping inflection point (SIP) and a significant change in the shearthinning slope after water exposure. The hybrid rejuvenator did not show any evidence of desorption or a stripping inflection point; this can be attributed to the presence of amide-enriched compounds in the hybrid rejuvenator that resulted from feedstock with a balanced combination of protein, nucleic acids, and lipids. The results of this study highlight the importance of accounting for a rejuvenator's composition to ensure that the rejuvenator's introduction to aged bitumen does not negatively impact the durability of the bituminous composite. This is even more critical for severely aged asphalts, which may require a higher concentration of rejuvenators to restore their properties. The study outcome provides insights to formulators and manufacturers to account for durability in their attempts at recycling and resource conservation to enhance sustainability in construction.

Effects of Wax-Impregnated Nanozeolites on Bitumen’s Thermomechanical Properties

“…Absorbing the acid from bitumen can improve the moisture susceptibility of pavement. 39,40 ■ CONCLUSIONS Introduction of Winz promotes sustainability by enhancing pavements' durability via enhanced wax dispersion within the bitumen matrix and increased resistance to moisture damage by diverting acids from the interface of bitumen and stones. The study results can be summarized as follows: • SEM images confirmed that the nanozeolites were impregnated by paraffin waxes producing wax-impregnated nanozeolite referred to as Winz.…”

“…This phenomenon results in the release of wax, which was shown in the results of experiments. Absorbing the acid from bitumen can improve the moisture susceptibility of pavement. , …”

Waste Cooking Oil as a Sustainable Bio Modifier for Asphalt Modification: A Review

“…It has been noticed that linoleic acid and hexadecenoic acid are water-insoluble fatty acids and can easily be absorbed effectively in dry conditions. Thus, in a wet environment, these fatty acids are immediately replaced by water molecules, which in turn raises moisture susceptibility [107,108]. It can be inferred from the summarized studies that WCO-modified asphalt mixtures may fulfil the specification criteria.…”

Using Fundamental Material Properties to Predict the Moisture Susceptibility of the Asphalt Binder: Polarizability and a Moisture-Induced Shear-Thinning Index

“…18 We have recently shown that by controlling the composition of biomodifiers, the adsorption of biomodifiers to siliceous minerals in a wet environment can be increased, leading to enhanced resistance to moisture damage in revitalized aged asphalt. 19 In terms of modifier's composition, the biomodifiers with lower polarizability have shown better resistance to aging and moisture damage. 20 Studies show that the binders containing biomodifiers made from swine manure are less susceptible to both moisture and oxidative aging.…”

“…It is worth noting that DFT-based reactivity descriptors demonstrate the molecular level reactivity of the target species, while rheology-or energy-based reactivity descriptors work at the matrix level. In the energy-based case, a significant change in energy of the bitumen matrix after water exposure indicates that bitumen has a lower affinity for the select substrate than the water; as such water molecules are expected to replace bitumen molecules, which were originally adsorbed to the glass substrate; 33 this in turn indicates susceptibility of target bitumen to moisture damage.…”