In order to study the maintenance strategy of Epoxy Asphalt Concrete (EAC) in low temperature environment, the similarity of four anti-cracking performance indexes (plane strain fracture toughness, bending stiffness modulus, ultimate tensile stress and ultimate elongation linear strain) of EAC were analyzed, and the mathematical model for investigating the relationship between the number of freeze-thaw cycles and the comprehensive evaluation index of the crack resistance of epoxy asphalt mixture (EAM) was established in this paper. At first, the weight of each index is determined by one-way ANOVA. Then the anti-cracking performance of EAC under freezing-thawing condition is evaluated by fuzzy comprehensive evaluation method. The results show that the pavement maintenance bureau needs to carry out the maintenance of epoxy asphalt pavement on steel bridge deck every 30 days (1 month) for ensuring the crack resistance of EAC in winter with low temperature.@en

Proportional-integral (PI) control, as one of the most popular classic control methods, has been applied widely to the real-world practice of canal automatic control. The performance of a PI controller largely depends on two key parameters, namely the proportional constant Kp and the integrational time constant Ti. Rather than tuning these parameters empirically or in terms of the canal morphology, this study proposes a linear quadratic regulator (LQR) to determine their optimal values. The proposed LQR utilizes an integrator delay model to represent the hydrodynamics of open canals in order to minimize changes in water levels and flow rates. In addition, the weights for the optimization objective in the LQR are determined by an optimized quadratic performance indicators estimate (OQPIE), using the precalculated nondimensional integrated square of error and nondimensional integrated absolute discharge change as well as inherent designed parameters, which potentially impact the stability of system states. In this way, the LQR can fit various canal automation applications, especially for low-gradient canals. The optimal PI controller was tested on two different-scaled canals. Results showed that the objective was met satisfactorily, and stability can be reached in hours.

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