A durable and easy-to-operate treatment, modified epoxy composite coating (MECC), was proposed in this study as a potential alternative to traditional epoxy resin protectants to enhance the protection of concrete structures. This new material consists of epoxy resin as the base material, dimethyl carbonate as the solvent, and modified amines and polyaniline as a composite curing agent that reacts with epoxy resin to form a film over the surface of concrete, thus protecting concrete structures from surface cracking, peeling, and spalling when exposed to chloride. Salt frost resistance tests indicated that MECC specimens had lower water absorption and much higher salt frost resistance. Compared with non-coating (NS) specimens, after 200 freeze–thaw cycles, the relative dynamic elastic modulus (RDEM) was 21.62% higher, and the mass loss was merely 19.14% of that of the NS specimens. Better performance was achieved as compared with ordinary epoxy resin coating (EC) and silicate coating (SC) too. After 120 days of erosion in 10.0% NaCl, the coating could effectively prevent environmental liquids and chloride from intruding through the cracks. The reason behind the increased salt frost durability is that treatment with MECC improved the internal structure of concrete and made its surface dense enough to prevent the intrusion of environmental liquids and chloride. Under repeated freezing and thawing, the degree of chloride-induced damage and the icing pressure inside the concrete were greatly reduced. This relieved the frost damage inside the concrete and elongated the service life of the concrete.

We propose a durable and easy-to-operate treatment, modified epoxy composite coating (MECC)., as a potential alternative to traditional epoxy resin protectants to enhance the protection of concrete structures. This new material consists of epoxy resin as the base material, dimethyl carbonate as the solvent, and modified amines + polyaniline as a composite curing agent that reacts with epoxy resin to form a film over the surface of concrete, thus protecting concrete structures from surface cracking, peeling and spalling when exposed to chloride. Salt frost resistance test indicated that the MECC specimens had lower water absorption and much higher salt frost resistance. Compared with the non-coating (NS) specimens, after 200 freeze-thaw cycles, the relative dynamic elastic modulus (RDEM) was 21.62% higher and the mass loss was merely 19.14% of that of the NS specimens. Better performance was achieved as compared with ordinary epoxy resin coating (EC) and silicate coating (SC), too. After 120 days of erosion in 10.0% NaCl, the coating could effectively prevent environmental liquids and chloride from intruding through the cracks. The reason behind the increased salt frost durability is that treatment with MECC improved the internal structure of concrete and made its surface dense enough to prevent the intrusion of environmental liquids and chloride. Under repeated freezing and thawing, the degree of chloride-induced damage and the icing pressure inside the concrete were greatly reduced. This relieved the frost damage inside the concrete and elongated the service life of concrete.

A new type of reclaiming agent was prepared by adding a plasticizer and an anti-aging agent to waste palm oil. A dynamic shear rheological test, bending beam rheological test, dynamic modulus test, static creep test, and road performance test were used to compare and analyze the viscoelastic characteristics of vegetable oil (WPO) and a traditional petrochemical reclaiming agent (PCO). The results showed that the WPO has better low-temperature crack resistance compared with the PCO, and the optimal dosage is about 12% of the mass fraction of aged asphalt. The addition of a regenerator reduces the dynamic modulus of the reclaimed asphalt mixture (RAP) under study and increases the phase angle. The improved CAM model showed good fit with the dynamic modulus and phase angle of recycled asphalt mixtures with the development of frequency. When the loading frequency was higher than 10 Hz, the dynamic modulus of the waste palm oil recycled asphalt mixture was lower, and the phase angle was higher. Conversely, when the loading frequency was lower than 0.01 Hz, the waste palm oil regenerant showed better temperature sensitivity. The waste palm oil recycled asphalt mixture demonstrated a higher steady creep rate and strain magnitude, lower stress relaxation time, and higher dissipation energy ratio under low-temperature conditions, thus improving the low-temperature crack resistance. Furthermore, the road performance test results of the asphalt mixtures indicated that the waste palm oil reclaimed asphalt mixture has excellent high-temperature rutting resistance, low-temperature cracking resistance, and water damage resistance, which confirms the reliability of the above analysis results. Therefore, the waste palm oil regenerant has great potential application prospects with wide source availability, low price, and outstanding mechanical properties.