A lab study to develop polyurethane concrete for bridge deck pavement

Conventional pavement materials like SMA and GA do not meet the requirement for steel bridge decks. Epoxy asphalt concrete (EAC) has good performances but also has fatigue problems stemming from their inherent chemical structures, which, in some cases, led to short service life. Herein, we report a polyurethane concrete (PUC) consisting of a one-phase tough polyurethane binder as the matrix and dolerite aggregates as filler. First, PUC samples are prepared by mixing liquid reactants like polycarbonate diol, aliphatic isocyanate and glycerine with dolerite aggregates. The optimum formula of the PUC (binder-aggregate ratio of 8.5%) is determined by the Marshall stability and compressive strength tests. Second, Hamburg wheel tracking, freeze-thaw splitting, low temperature bending and linear contraction coefficient measurements are conducted on the PUC samples. Test results show that PUC composites have strong low-temperature toughness (the flexural strength 24.3 +/- 1.3 MPa and flexural strain of 7020*10(-6)at -10 degrees C) and high dynamic stability (153,000 cycles/mm, about as 5 times as epoxy asphalt concrete (EAC). The alkaline hydrolysis tests show PUC has excellent durability (remained strong after 24 days of hot alkaline water treatment). These results support PUC is a promising material for bridge deck pavement.