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Sasobit has been widely applied as warm-mix asphalt (WMA) additive in an environment friendly and energy saving pavement construction. Epoxy asphalt (EA) has been extensively used on the pavement of steel bridge decks. In the present paper, Sasobit was introduced into warm-mix epoxy asphalt binder (WEAB) to prepare Sasobit modified WEAB. The effect of Sasobit on the viscosity, thermal, damping and mechanical properties and morphology of the neat WEAB were investigated using various characterisation techniques. Sasobit significantly lowered the viscosity of the neat WEAB and prolonged the operational lifetime for mixture pavement. Sasobit lowered the glass transition temperature of the neat WEAB. Sasobit slightly decreases the damping properties and thermal stability of the neat WEAB. However, Sasobit increased the tensile strength of the neat WEAB. The crystalline network structures of Sasobit formed in asphalts were clearly observed. The lamellar crystalline structure of Sasobit turned to gel-like structure in curly ribbon shape with an increase of the WMA additive contents. Reaction-induced phase separation occurred in the neat WEAB and Sasobit modified WEABs. No crystalline network structures of Sasobit were observed in the dispersed asphalt phase of the modified WEABs. Sasobit decreased the size of asphalt particles in the continuous epoxy phase. [ABSTRACT FROM AUTHOR]

Highlights • Sasobit modified epoxy asphalt rubber (EAR) has been developed. • The addition of Sasobit lowers the viscosity and glass transition temperature of the neat EAR. • The inclusion of Sasobit increases the number of spherical AR particles in the continuous epoxy phase. • The mechanical properties of the neat EAR are enhanced with the addition 1 wt% Sasobit. Abstract The utilization of crumb rubber to produce asphalt rubber (AR) for asphalt mixture pavement has been proven to be an economical and environmental way for the disposal of waste tires. As one of the most significant thermosetting polymer modified asphalt with prominent performances, epoxy asphalt (EA) has been widely used on the pavement of steel bridge decks. In present study, the mixture of epoxy oligomer and curing agent was incorporated into AR to prepare epoxy asphalt rubber (EAR). To lower the viscosity of AR, a WMA additive, Sasobit was introduced into AR to prepare Sasobit modified EARs. The effects of Sasobit on the rotational viscosity, glass transition temperature (T g), damping performance, mechanical properties and phase-separated morphology of the neat EAR were investigated. The inclusion of Sasobit significantly decreased the viscosity of the neat EAR during the whole curing process and prolonged the operational lifetime for asphalt mixture pavement. The addition of Sasobit slightly decreased the T g of the neat EAR. The T g of Sasobit modified EARs decreased with WMA additive content increasing. Meanwhile, the presence of Sasobit improved the damping properties of the neat EAR. The existence of Sasobit enhanced the mechanical properties of the neat EAR at lower WMA additive concentration. The mechanical properties of Sasobit modified EARs decreased with increasing WMA additive content. Morphological observations revealed that the phase-separated microstructures of the neat EAR consisted of the dispersed spherical and co-continuous AR particles and the continuous epoxy phase. The existence of Sasobit decreased the number of co-continuous AR particles in the epoxy matrix. In addition, the number of co-continuous AR particles decreased with increasing WMA additive content. The presence of Sasobit decreased the average diameter of the dispersed AR particles and area fraction of AR domains in the neat EAR. [ABSTRACT FROM AUTHOR]

[Display omitted] • Core-shell rubbers (CSRs) with two core polymers have been used to toughen epoxy asphalt (EA). • 2 wt% CSR with polybutadiene (PB) core alters the phase separation mechanism of EA. • Both swollen polymer and asphalt particles form in the continuous epoxy phase of EA. • The area fraction of swollen PB particles is higher that of swollen SB particles. • EA modified by CSR with PB core exhibits higher damping and mechanical properties. Core-shell rubber (CSR) is a good candidate for toughening epoxy asphalt binders. However, the knowledge of the effect of the core polymer on the performance of CSR modified hot-mix epoxy asphalt binder (HEAB) is not completed and systematic yet. In this paper, CSR modified HEABs were prepared by the incorporation of 2 wt% CSR particles with different core polymers, which were in turn subjected to viscous measurements, confocal microscopy, thermogravimetric analysis, dynamic mechanical analysis and tensile tests. The results revealed that the viscosity of CSR with styrene-butadiene copolymer (SB) core (CSR SB) modified HEAB is higher than that of CSR with polybutadiene (PB) core (CSR PB) modified HEAB during curing. The shell destruction of CSR particles resulted in the swelling of the core polymers and dispersion of swollen core polymer particles in the epoxy phase in the micron scale along with asphalt particles. The phase separation of CSR PB modified HEAB occurred in the spinodal decomposition mode, which was different from the nucleation and growth mechanism of the neat and CSR SB modified HEABs. The area fraction of swollen PB particles in the CSR modified HEAB was greater than that of swollen SB particles. The core polymer had a negligible effect on the thermal stability of CSR modified HEABs. The glass transition temperatures of epoxy and asphalt, damping ability and mechanical properties of the neat HEAB were increased with the addition of CSR particles. Especially, CSR PB modified HEAB had higher tensile strength and toughness than CSR SB modified HEAB. With 2 wt% CSR PB particles being adding, the tensile strength, elongation at break and toughness of the neat HEAB were increased by 53%, 42% and 110%, respectively. [ABSTRACT FROM AUTHOR]

• Thermal shock significantly increases the pull-off strength of the touch-dry BEBC. • The hydrophilic touch-dry BEBC becomes hydrophobic after the thermal shock. • Thermal shock greatly increases the T g of the touch-dry BEBC. • The touch-dry BEBC's tensile strength increases by about 300% after the thermal shock. • Thermal shock temperature has a limited effect on the mechanical properties of BEBCs. B-staged epoxy bond coat (BEBC) has been widely applied as a waterproof adhesive layer in the pavements of orthotropic steel bridges. During its application, the uncured BEBC layer was first paved on the surface of the steel deck or the bituminous surfacing and hot bituminous mixture would be constructed until the BEBC layer became touch-dry. In this paper, the impacts of thermal shock on the degree of cure (DOC), pull-off strength, hydrophilicity, glass transition temperature (T g), damping performance, thermal stability and mechanical behaviors of the touch-dry BEBC were investigated. Thermal shock greatly increased the DOC of the touch-dry BEBC and the touch-dry BEBC turned to be nearly fully cured after the thermal shock at a higher temperature. The pull-off strength of the touch-dry BEBC was remarkably improved by the thermal shock. After the thermal shock at 160 °C, the pull-off strengths at room temperature and at 60 °C of the touch-dry BEBC were increased by 584% and 914%, respectively. After the thermal shock, the contact angle of the touch-dry BEBC was greatly increased and the hydrophilicity of the touch-dry BEBC was converted to hydrophobicity. Thermal shock significantly increased the T g of the touch-dry BEBC. Furthermore, the T g of thermally shocked BEBCs slightly increased in the temperature. Thermal shock improved the damping performance of the fully cured BEBC. The tensile strength and toughness of the touch-dry BEBC were greatly improved by the thermal shock. However, thermal shock lowered the elongation at break of touch-dry BEBC. In the case of thermally shocked BEBCs, the temperature had a limited effect on the tensile strength, while the elongation at break increased in the temperature. The fracture energy first decreased in the temperature and increased after 150 °C. Maximum fracture energy appeared at 160 °C. After the thermal shock, the tensile strength of the touch-dry BEBC was increased by as much as 3-fold. The fracture energy of the BEBC thermally shocked at 160 °C was 182% greater than that of the touch-dry BEBC. [ABSTRACT FROM AUTHOR]

• Phase separation of ESBA disrupts the original dispersion of SBS in the asphalt. • The size of SBS domains in ESBAs increases in the SBS loading. • ESBA's viscosity increases in the SBS loading. • The thermal stability of ESBAs enhances with the increase of SBS loading. • The neat EA's elongation at break increases by 56% with the addition of 3 wt% SBS. Both styrene–butadiene-styrene copolymer (SBS) and epoxy resin have been widely applied in the asphalt modification. The influence of SBS concentration on the morphology, viscosity, thermal stability, glass transition temperature (T g), damping performance and mechanical behaviors of the neat EA binder was studied. Double phase separation occurred in the epoxy SBS modified asphalt (ESBA): main phase separation between epoxy and the SBS modified asphalt (SBA) and secondary phase separation between asphalt and SBS. The occurrence of phase separation in the ESBA disrupted the original dispersion of SBS particles in SBA and resulted in the redistribution of SBS in the form of smaller spherical particles. The inclusion of SBS increased the viscosity of the neat EA. Furthermore, the viscosity of ESBAs increased with the SBS content. ESBAs had as long as 150-min construction time for the mixture pavement. The presence of SBS improved the thermostability of the neat EA. In terms of ESBAs, the thermostability increased with the SBS content. The addition of SBS lowered the T g of the neat EA when the SBS content was lower than 4 wt%. The T g of ESBAs increased with the SBS content. The incorporation of SBS significantly enhanced the damping behaviors of the neat EA. The tensile strength of the neat EA was improved with the addition of 2 wt% SBS. The inclusion of SBS improved the elongation at break and the toughness of the neat EA when the SBS loading was greater than 1 wt%. [ABSTRACT FROM AUTHOR]

• Waste cooking oil (WCO) modified epoxy asphalt binder (EAB) has been developed. • WCO lowers the viscosity and thus extends the construction time of the neat EAB. • Phase inversion in WEAB occurs when 6 wt% WCO is added. • WCO improves the low-temperature performance of the neat EAB. • WCO enhances the damping properties and thermal stability of the neat EAB. Waste cooking oil (WCO) was used as a warm mix asphalt (WMA) additive to modify warm-mix asphalt binder (WEAB) with the expectation of lowering the viscosity and prolonging the construction time of the binder. The viscosity, phase separation, viscoelasticity, thermostability and mechanical properties of WCO modified WEABs were studied and compared with the neat WEAB. WCO significantly reduced the WEAB's viscosity and extended the construction time of the neat WEAB. Moreover, the reducing and prolonging effects increased with the WCO content. Phase-inverted microstructure and secondary phase separation formed in the modified WEAB with 6 wt% WCO. The inclusion of WCO improved the low-temperature performance of the neat WEAB. The damping behavior and thermostability of the neat WEAB were improved with the inclusion of WCO. The presence of WCO increased the elongation at break of the neat WEAB when the waste oil content was lower than 4 wt%. [ABSTRACT FROM AUTHOR]