2022 Volume 76 Issue 1 Pages 461-467
The purpose of this study is to investigate the effect of mix proportioning factors and age on the electrical resistivity of polymer-modified mortars using redispersible polymer powder for repair work of reinforced concrete structures. Polymer-modified mortars using the redispersible polymer powder and various types of fine aggregates are prepared with fine aggregate-cement ratios of 1, 2 and 3, polymer-cement ratios of 0, 5, 10 and 15％, or polymer contents of 0 and 4.56％. The polymer-modified mortar specimens are cured under 2d-wet＋5dwater＋21d-dry condition for 28d. The cured specimens are stored under dry condition up to the age of 182d. The electrical resistivity and apparent water retention of the specimens are measured at the age of 28, 56, 91 and 182d. As a result, the electrical resistivity of the polymer-modified mortar is increased with an elapsing the age. However, the specimens give the almost constant value of the apparent water retention proposed in this study at the age of 182d. The electrical resistivity of the polymer-modified mortars at the age of 182d is larger than the electrical resistivity of the unmodified mortars, and increased with an increase in the polymer-cement ratio and the fine aggregate-cement ratio. The lesser effectiveness of the types of polymer and fine aggregate on the electrical resistivity of the polymer-modified mortar is recognized as compare to the effectiveness of the fine aggregate-cement ratio.
