*Article* **E**ff**ects of Tra**ffi**c Vibrations on the Flexural Properties of Newly Placed PVA-ECC Bridge Repairs**

**Xiaodong Zhang <sup>1</sup> , Shuguang Liu 1,2,\*, Changwang Yan <sup>2</sup> , Xiaoxiao Wang 1,\* and Huiwen Wang <sup>3</sup>**


Received: 21 September 2019; Accepted: 11 October 2019; Published: 13 October 2019

**Abstract:** Polyvinyl alcohol fiber reinforced engineering cementitious composites (PVA-ECCs) exhibit excellent tight-cracking and super-high toughness behaviors and have been widely used in bridge repair projects. In reality, the conventional method in bridge repair is that a portion of the bridge is closed and repaired while the other portion is left open to traffic. Consequently, newly placed PVA-ECC bridge repairs (NP-ECC-BRs) are exposed to continuous traffic vibrations (TRVs), even during the setting periods. However, whether or not TRVs affect the expected flexural properties of NP-ECC-BRs remains unknown. The purpose of this investigation was to determine the effects of TRVs on the attainable flexural properties of NP-ECC-BRs. For this purpose, a total of 324 newly fabricated thin-plate specimens were exposed to different vibration variables using self-designed vibration equipment. After vibration, a four-point flexural test was conducted to determine the flexural properties of the specimens. The results indicate that the effects of TRVs on the strengths of NP-ECC-BRs was significantly negative, but insignificantly positive for flexural deformation. We concluded that in the design of PVA-ECC bridge repairs, effects of TRVs on the flexural deformation capacity of NP-ECC-BRs are not a cause for concern, but serious consideration should be given to the associated reduction of flexural load-bearing capacity.

**Keywords:** PVA-ECCs; bridge repairs; setting periods; traffic vibrations; strain-hardening characteristics; flexural properties
