本研究針對UHPC兩種配比，依據CNS 1230規範製作標準圓柱試體，於養護齡期12hr、1天、3天、7天、14天、28天、60天、120天及210天，進行混凝土抗壓試驗與養護齡期3天、7天、14天、28天、60天、120天及210天，進行表面電阻率試驗，探討不同齡期之抗壓強度與表面電阻率變化之程度與關聯性。
研究結果顯示兩種UHPC 1和UHPC 2配比，都有相當高的表面電阻率與抗壓強度，表示混凝土孔隙結構非常緻密，具備優良之抵抗氯離子滲透的能力，且28天之抗壓強度均能超過100MPa。
在表面電阻率與抗壓強度之線性回歸關係式中R2 > 0 .7，顯示其表面電阻率與抗壓強度兩者有良好的關聯性，因此本研究之關係式可供後續研究人員當作評估強度的參考。

In this study, the standard samples were prepared according to CNS 1230 for the two ratios of UHPC. The curing ages are 12 hr, 1 day, 3 days, 7 days,14 days, 28 days, 60 days, 120 days and 210 days. The compressive strength of concrete cylinder specimens and the electrical impedance test of concrete surface are discussed to explore the degree of change and correlation between different ages.
The results of this study showed that the two kinds of UHPC, UHPC 1 and UHPC 2, were found to have high resistivity and compressive strength. It indicates that the concrete pore structure is very dense, has excellent resistance to chloride ion penetration, and the compressive strength of 28 days can exceed 100MPa.
The linear regression relationship between resistivity and compressive strength was R2 > 0.7, It shows that there is a good correlation between the resistance value and the compressive strength. Therefore, the relationship of this study can be used as a reference for the evaluation of the strength of subsequent researchers.

[1] Hung, C. C., & Su, Y. F. (2016). Medium-term self-healing evaluation of Engineered Cementitious Composites with varying amounts of fly ash and exposure durations. Construction and Building Materials, 118, 194-203.
[2] Hung, C. C., Su, Y. F., & Su, Y. M. (2018). Mechanical properties and self-healing evaluation of strain-hardening cementitious composites with high volumes of hybrid pozzolan materials. Composites Part B: Engineering, 133, 15-25.
[3] Hung, C. C., & El-Tawil, S. (2010). Hybrid Rotating/Fixed-Crack Model for High-Performance Fiber-Reinforced Cementitious Composites. ACI Materials Journal, 107(6).
[4] Hung, C. C., & El-Tawil, S. (2011). Seismic behavior of a coupled wall system with HPFRC materials in critical regions. Journal of Structural Engineering, 137(12), 1499-1507.
[5] Hung, C. C., Su, Y. F., & Yu, K. H. (2013). Modeling the shear hysteretic response for high performance fiber reinforced cementitious composites. Construction and Building Materials, 41, 37-48.
[6] Hung, C. C., & Li, S. H. (2013). Three-dimensional model for analysis of high performance fiber reinforced cement-based composites. Composites Part B: Engineering, 45(1), 1441-1447.
[7] 洪崇展，戴艾珍，顏誠皜，溫國威，張庭維(2017)，新世代多功能性混凝土材料－高性能纖維混凝土，土木水利.第44卷第1期，頁33-51。
[8] Hung, C. C., & Chueh, C. Y. (2016). Cyclic behavior of UHPFRC flexural members reinforced with high-strength steel rebar. Engineering Structures, 122, 108-120.
[9] Hung, C. C., & Yau, W. G. (2017). Vulnerability evaluation of scoured bridges under floods. Engineering Structures, 132, 288-299.
[10] Hung, C. C., Li, H., & Chen, H. C. (2017). High-strength steel reinforced squat UHPFRC shear walls: cyclic behavior and design implications. Engineering Structures, 141, 59-74.
[11] Hung, C. C., Hu, F. Y., & Yen, C. H. (2018). Behavior of slender UHPC columns under eccentric loading. Engineering Structures, 174, 701-711.
[12] Hung, C. C., & Hu, F. Y. (2018). Behavior of high-strength concrete slender columns strengthened with steel fibers under concentric axial loading. Construction and Building Materials, 175, 422-433.
[13] Page, C. L., Short, N. R., Holden, W. R., & Materials Research Group. (1986). The influence of different cements on chloride-induced corrosion of reinforcing steel. Cement and Concrete research, 16(1), 79-86.
[14] Alexander, M. G., & Magee, B. J. (1999). Durability performance of concrete containing condensed silica fume. Cement and concrete research, 29(6), 917-922.
[15] Osborne, G. J. (1999). Durability of Portland blast-furnace slag cement concrete. Cement and Concrete Composites, 21(1), 11-21.
[16] Escalante-Garcia, J. I., Espinoza-Perez, L. J., Gorokhovsky, A., & Gomez-Zamorano, L. Y. (2009). Coarse blast furnace slag as a cementitious material, comparative study as a partial replacement of Portland cement and as an alkali activated cement. Construction and Building Materials, 23(7), 2511-2517.
[17] Zanni, H., Cheyrezy, M., Maret, V., Philippot, S., & Nieto, P. (1996). Investigation of hydration and pozzolanic reaction in reactive powder concrete (RPC) using 29Si NMR. Cement and Concrete Research, 26(1), 93-100.
[18] 林思瑋.(2010). 矽砂混凝土強度分析與火害承載行為探討. 逢甲大學土木工程學系碩士論文, 1-48.
[19] 黃兆龍.(2003). 高性能混凝土理論與實務. 詹氏書局, 1-779.
[20] Fehling, E., Leutbecher, T., & Bunje, K. (2004, September). Design relevant properties of hardened ultra high performance concrete. In Int. Symp. on Ultra High Performance Concrete (Vol. 1, pp. 327-338).
[21] 溫國威. (2018). 超高性能纖維混凝土梁構件之剪力行為研究 . 成功大學土木工程學系學位論文, 1-245.
[22] Wenner, F. (1915). A method of measuring earth resistivity. Bulletin of the Bureau of Standards, 12(4), 469-478.
[23] Gowers, K., & Millard, S. (1999). Measurement of concrete resistivity for assessment of corrosion. ACI Materials Journal, 96(5),536-542.
[24] Morris, W., Moreno, E. I., & Sagüés, A. A. (1996). Practical evaluation of resistivity of concrete in test cylinders using a Wenner array probe. Cement and concrete research, 26(12), 1779-1787.
[25] AASHTO T358.“Standard Method of Test for Surface Resistivity Indication of Concrete’s Ability to Resist Chloride Ion Penetration”2015.
[26] 王心荻.(2009).試體參數對混凝土電阻值影響之研究.國立台灣海洋大學碩士論文.1-72.
[27] CNS 1230 試驗室混凝土試體製作養護法. 經濟部標準檢驗局.2005.02.05.
[28] CNS 1232. 混凝土圓柱試體抗壓強度檢驗. 經濟部標準檢驗局.2002.12.09.
[29] ACI Committee 228 Report: In-Place Method to Estimate Concrete Strength, ACI 228.1R-95 (1995).