About the TermoBitum-GTL

January 9, 2015  |  By  | 

About the ” Termo Bitum ” (ThermoBitum en)? Porous asphalt shows excellent performance i n both noise reduction and water drainage. Although porous asphal t has these gre at qualities, its service life is much shorter (sometimes only half) compared to d ense graded asphalt roads. Ravelling, which is the loss of aggre gate particles fro m the surface layer, is the main damage mechanism of porous asphalt surface we aring courses. In this brochure, an induction healing approach (namely, activating the healing process of asphalt concrete through induction hea ting) was developed to enhance the durability of the porous asphalt roads. St eel fibers are added t o a porous asphalt mixture to make it electrically condu ctive and suitable for i nduction heating. When micro cracks are expected to o ccur in the asphalt mast ic of the pavement, the temperature of the mastic can be increased locally by in duction heating of the steel fibers so that porous asphalt concrete can repair it self and close the cracks through the high temperature healing of the bitumen (diff usion and flow). The closure of micro cracks will prevent the formation of m acro cracks. In such a way, ravelling can be avoided or delayed in the end. To make asphalt mastic and porous asphalt concrete electrically conductive and suitable for induction heating, steel (wool) fibers were incorporated into them. Asphalt mastic and porous asphalt concrete with steel fibers can be heated with induction energy. There is an optimal volume content of steel fiber in asphalt mastic or porous asphalt concrete to obtain the highest induction heating speed. Adding more steel fiber above this optimal volume content does not increase the induction heating speed anymore. Furthermore, the highest induction heating speed corresponds to the minimum electrical resistivity. However, porous asphalt concrete does not need to be fully conductive for induction heating. Every single steel wool is a heating unit. Nonconductive samples with steel fiber can still be heated with induction heating, but at a low heating speed. The diameter, length and content of steel wool fiber are important for the conductivity and heating speed of asphalt concrete matrix. It is proven that induction heating does not cause extra ageing to bitumen. Addition of steel wool also reduces the binder drainage problem in porous asphalt concrete. Damaged porous asphalt concrete with steel wool fiber can greatly restore its stiffness, strength and fatigue life with induction heating, which proves that the healing capacity of porous asphalt concrete with steel wool fiber is enhanced by induction heating. Reheating does not decrease the healing rate of porous asphalt concrete, which means that heating can be repeated when cracks appear again. 1

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