## 1 Introduction  
The overall and local deformations of long-span steel box girder bridges are much larger than those of cement concrete bridges because of the differences in bridge structure design and materials used [1]. Therefore, the stress state of orthotropic steel bridge deck (OSBD) pavement of long-span steel box girder bridges is more complex than that of cement concrete bridges or traditional asphalt pavement [2]. In addition, due to the high thermal conductivity of steel, the temperature of steel deck pavement in summer is much higher than other pavement structures. Therefore, the working condition of the steel deck pavement requires that the paving materials used show better performance in cracking resistance and high-temperature stability than conventional pavement materials. Among the existing pavement materials, Gussasphalt concrete can hardly been applied into the steel bridge deck pavement structure because of its poor high temperature stability, which can easily lead to serious rutting diseases [3]. At present, the application of epoxy asphalt concrete (EAC), which is the most successful material for steel deck pavement, has improved the high temperature stability of OSBD pavement significantly, but with insufficient fatigue cracking resistance at intermediate temperature. The fatigue cracking diseases usually appear after 2-3 years under the action of negative bending caused by longitudinal stiffening ribs in the lower part of the steel deck, which seriously affects the durability of the pavement [4; 5]. ECC is the abbreviation of engineered cementitious composite, the basic design concept of this material was proposed by Prof. [PERSON] (University of Michigan) and Prof. [PERSON] (Massachusetts Institute of Technology) based on basic principles of meso-mechanics and fracture mechanics [6; 7; 8]. Nowadays, ECC is a generalized concept, representing high ductile cementitious composite materials with ultimate tensile strains over 3%. Typical ECC material consists of cement, sand, fly ash, water, additives, and polymeric fibers (e.g., polyethylene, polyvinyl alcohol) [9; 10]. After first cracking, the tensile load capability of ECC material continues to rise, resulting in a macroscopic strain-hardening phenomenon accompanied by multiple micro-cracks. These multiple-crack widths increase steadily up to about 60 \(\upmu\)m, at about 1% strain. Between 1% and 5% strain, the crack width stabilizes and tends to remain constant at 60 \(\upmu\)m while the number of cracks increases [11]. Unlike most concrete and fiber- reinforced concrete materials, crack width in ECC is an intrinsic material property, independent of structural size, steel reinforcement, or the load applied to a structure built with ECC. Besides, ECC material exhibits excellent fatigue resistance under the four point bending fatigue test [12]. Because ECC has wonderful self-healing capabilities, micro-cracks can be closed and healed after they have been initiated [13; 14; 15; 16]. These special properties ensure that ECC can meet the stringent requirement of resiliency and durability in infrastructure. ECC has been successfully applied in bridge deck link slabs [17], bridge deck overlays, dam repair and coupling beams in high rise buildings [18; 19]. After ECC was introduced into China, researchers such as Dr. [PERSON] made an effort to use local raw materials to prepare ECC, so as to decrease the cost and expand the application scenarios. The results indicate that the locally produced material can totally achieve the design targets of ECC [20]. But the feasibility of ECC materials applied in the orthotropic steel bridge deck (OSBD) pavement has not been proved sufficiently, especially in the fatigue cracking aspect, due to the severe working conditions of the OSBD pavement. Therefore, this study focuses on the cracking resistance of ECC under OSBD pavement working condition. Based on the above considerations, the main objectives of this study were as follows:  
1.