Influence of polyvinyl alcohol fiber and fly ash content on compressive creep properties of high ductility cementitious composites

¹ State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, 210029, China
² Collaborative Innovation Center for Advanced Civil Engineering Materials, Southeast University, Nanjing, 211189, China

^* Corresponding author’s e-mail: bchen@nhri.cn

Abstract

The influence of polyvinyl alcohol (PVA) fiber volume fraction and fly ash content on the creep behavior of high ductility cementitious composites (HDCC) under compression was investigated. For this investigation, the creep behavior of four HDCC groups with cube compressive strength of 30–50 MPa, PVA fiber volume fraction of 1.5% and 2.0%, and fly ash content of 60% and 80% at 7 d and 28 d loading periods, respectively, were evaluated. A compressive creep model, which reflects the loading age and holding time, was established. The results revealed that when the load was applied at 7 d and 28 d, and then maintained for 245 d, the specific creep of HDCC ranged from 95×10^-6/ MPa to 165×10^-6/ MPa and from 59×10^-6/ MPa to 135 × 10⁻⁶/ MPa, respectively. The corresponding creep coefficients ranged from 1.48 to 2.25 and from 1.10 to 1.94, respectively. The PVA fiber volume fraction and fly ash content were the main factors affecting the specific creep of HDCC, which increased with increasing fiber fraction and fly ash content. Under short-term loading, the fiber volume fraction played a leading role in the specific creep, and the fly ash content played the leading role during long-term loading. Furthermore, the specific creep and creep coefficient decreased significantly with increasing loading age. The classical creep model described by a power exponent function is suitable for HDCC.