Effect of Aging and Temperature on the Viscosity of the Adhesive Used for Retard-Bonded Prestressed Systems

摘要

The viscosity of Retard-Hardening Adhesive (RHA) varies with the hardening of resin-based materials and greatly affects the workability and prestress loss of retard-bonded prestressed systems. So far, the effect of aging time on the viscosity of the RHA has not been revealed, which hampers the further application of Retard-Bonded Prestressed Reinforcements. In the current article, therefore, an experimental study is developed to evaluate the effect of aging time on the viscosity of RHA. Different exposure temperatures and hardening periods of RHA are considered in the rheological test. Test results show that when the aging time and exposure temperature remain the same, and as the shear rate increases, the viscosity of the RHA firstly decreases rapidly and then remains basically constant. The peak viscosity increases with the aging time, exposure temperature, or both. The effects of temperature on the peak viscosity are different at different stages of aging. The effect of the hardening period on the peak viscosity can be eliminated by introducing the relative aging time. Finally, an empirical model is suggested to predict the peak viscosity of the RHA at different aging times, and the results show that the proposed model agrees well with the experimental results.