A self-compacting steel slag epoxy resin concrete (SERC) was designed with steel slag as aggregate and epoxy resin as binder for rapid repair of road expansion joints and pavement. At the same time, a group of self-compacting basalt epoxy resin concrete (BERC) with basalt as coarse aggregate and limestone as fine aggregate was set up as the control group. The element analysis and micro morphology of SERC and BERC were studied by X-ray fluorescence spectrometry (XRF) and scanning electron microscope (SEM) to reveal the strength-forming mechanism of the two epoxy resin concretes. The cube compression test and Marshall stability test were used to study the effect of the strength formation rate and temperature of SERC and BERC on the strength. In addition, the high-temperature stability, low-temperature crack resistance, water damage resistance, fatigue resistance and interlayer bonding properties of SERC and BERC were also studied. The results showed that both SERC and BERC have good mechanical properties, high temperature properties and good bonding properties, and the low-temperature crack resistance and fatigue properties of SERC are better than that of BERC. According to the verification of the actual project that has been in service for one year, SERC can be perfectly used for road expansion joints.

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Traditional asphalt mixtures can't absorb microwave energy efficiently, which limits the development of microwave heating technology in the field of road maintenance. Based on the microwave heating characteristics of basalt aggregates, the overall microwave self-healing rate of the asphalt mixture can be enhanced. The basalt was tested by XRF, XPS, XRD and electromagnetic parameters to reveal its microwave heating mechanism. Through the heating rate test, SCB test and fatigue test of asphalt mixture, its heating characteristics, flexural strength, fatigue resistance and self-healing performance were studied. The results showed that the excellent wave-absorbing properties of basalt are highly correlated with the elements of Si, Fe and Al. Its TanδM was slightly larger than TanδE, which indicated that basalt can absorb microwave energy through dielectric loss and magnetic loss. The aggregate type and particle size both affected the microwave heating rate of the aggregates. After microwave heating, the flexural strength and fatigue resistance of asphalt mixture with basalt and limestone aggregates can recover at least 65% and 23% respectively.@en

Conventional asphalt mixture has poor microwave absorbing performance and microwave heating efficiency. Based on the characteristics of dielectric loss of scrap tire pyrolysis carbon black (PCB), it is proposed to improve the microwave absorbing performance and self-healing rate of bitumen. The phase composition and electromagnetic parameters of PCB were tested to reveal its microwave heating mechanism. The preparation parameters, heating characteristics and self-healing properties of PCB modified bitumen were studied through the dispersion uniformity test, microwave heating test and SCB test. The main phases of PCB are microwave absorbing carbon and silicon, indicating that PCB is a good electric loss microwave absorbing material. 40 min is the recommended mixing time of 15% PCB modified bitumen. PCB's dosage, microwave frequency and microwave heating time have significant effects on the microwave heating characteristics of PCB modified bitumen. PCB can improve high-temperature stability, thermal conductance, heat storage capacity and self-healing rate of bitumen.

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