Full-Scale Use of Microwave Heating in Construction of Longitudinal Joints and Crack Healing in Asphalt Pavements

Abstract

Asphalt pavement construction technology is an industry branch that undergoes constant development. Analyzing the directions of the development, one can divide it into two mainstreams: the development of roadworks equipment and the development of roadworks technology. Microwave heating technique has been mentioned in the road industry from the early ‘70s, but research records from practical full-scale use are very rare. This article presents the evaluation of the possible use of microwave heating technique during a particular aspect of the construction process, namely, the formation of longitudinal joints and the potential repair process of the cracked asphalt pavement. Research results showed that joints constructed using microwave-assisted heating performed the same or even better with regards to tensile characteristics comparing to other techniques. Also, the highest level of compaction was reached among the other tested techniques applied to the wearing course level. The second part of the research experiment showed the large potential of the microwave crack healing technique. The asphalt pavement was healed on its full depth of 10 cm with the single healing operation applied. Although some limitations may occur in the practical use of microwave heating, the test results suggest that it is a very promising technique and should be further developed (for, e.g., shielding concerns, electricity supply). The microwave heating technique is powered with electricity, which is important when there is a constant need for further reductions of CO2 emissions. It can be reached in parallel with clean energy or clean electricity sources.

Calculation Derivation and Test Verification of Indirect Tensile Strength of Asphalt Pavement Interlayers at Low Temperatures

“…As shown in Table 1, the indirect tensile strength of the three types of bonding materials at 5 • C and 10 • C is greater than their corresponding direct tensile strength. The indirect tensile strength average is about 1.48 times that of the direct tensile strength at 5 • C, and, 1.51 times at 10 • C. The above differential is mainly related to the stress transmission and redistribution in the specimens during the loading period [43]. This effect is more significant for the direct tensile loading due to the longer stress transfer path [46,47].…”

“…First, the tensile strength of the interlayer bond will decrease sharply with large discreteness because the material is no longer elastic at higher temperatures. Apart from that, when the temperature rises, the asphalt mixture on and below the interlayer bond loosens with a consequent degradation in the interface adhesion and the friction [43,44]. Its mechanical performance will fluctuate or redistribute, even go beyond the elastic limit [45].…”

Effect of non-thermal effects in microwave heating on the rheology and chemical properties of petroleum asphalt

“…Currently, the main application of microwave heating in the field of roads is the heating of pavements after rutting repair [15][16][17] or on-site regeneration [18][19][20]. The study of microwave heating to promote the self-healing of pavement cracks [21,22] is also a hot research topic in road engineering. However, the physical and chemical effects attached to the non-thermal effects of microwave heating of bitumen are not yet recognized, and such information may be significant and far-reaching for the engineering application properties of bitumen.…”