Feasibility study on the Early-High-Strength Repairing Geopolymer Materials at Bridge Expansion Joints

高早強無機聚合修復材料於橋梁伸縮縫之可行性研究

瑞子灣(Mohammad Rizwan Bhina) ； 劉光晏(Kuang-Yen Liu) ； 蔡志達(Chih-Ta Tsai)

《結構工程》 37卷2期 (2022/06) Pp. 29-58

https://doi.org/10.6849/SE.202206_37(2).0002

摘要

Global warming has become a serious issue worldwide and it was evident that the greenhouse gases are mainly responsible for global warming. CO_2 is considered as the major greenhouse gas. Among all the industries, cement industries contributed 5-7 % CO_2 emissions to the environment. Demand for concrete is increasing by 3% per year as concrete is the material used worldwide next to the water. If the engineering materials can be exempted from the use of cement, the purpose of carbon reduction can be achieved. Additionally, expansion joints play an important role in the stability of the bridge deck and also in accommodating thermal, lateral, and rotational moments. Hence, bridge industries demanded a high-strength, rapid setting material to replace the joints quickly and reopen the traffic. Considering all these issues, the early-high-strength repairing geopolymer material by using fly-ash and ground granulated blast-furnace slag (GGBS) are developed in this study. The high calcium inorganic polymer material was prepared by mixing fly-ash (Class-F) and GGBS (S4000) as a bonding agent with a varied ratio, NaOH alkali solution with 10 molarity (SiO_2/Na_2O=1.28) as an activator and pre-heated river sand as a fine aggregate to enhance the polymerization reaction. The main objectives of the present investigation were to develop a high strength geopolymer material (GPM) to provide 35MPa in 5 hours and examined the properties with regard to the effect of pre-heated fine aggregate, compressive strength (hot air-cured for 1,3 and 5 hours) and bond strength of GPM with ultra-high-performance material (UHPM) as well as high-strength non-shrinkage material (HS-NSM) from the slant shear test. The experiment was also carried out by varying the fly-ash to GGBS ratio and water to NaOH ratio. A total of 36 GPM specimens with an aspect ratio of 1 were tested. Results revealed that the hot mix procedure of GPM with the fly-ash to GGBS and water to NaOH ratio 1:3 and 10%, respectively produced greater compressive strength (52.67 MPa/5 hours) and fly-ash to GGBS and water to NaOH ratio 1:2 and 10%, respectively indicated excellent bond strength of 34.93 MPa. Results of the present investigation revealed that by increasing the amount of GGBS, the initial and final setting time and the flow rate of GPM have decreased. It was suggested that by applying GPM on the actual construction site, strength and workability should be considered simultaneously.

關鍵字

Geopolymer material ； early-high-strength ； rapid repairing ； expansion joint

並列摘要

全球暖化是現今世界的關鍵議題，溫室氣體是造成全球變暖的原因。CO_2被認為是一種溫室氣體，水泥行業在環境中的總排放量貢獻5-7% CO_2排放量。此外，水泥量以每年3%之需求增加被視為僅次於水之外最被廣泛使用的材料。如果工程材料可免除水泥使用量將可達到減碳目的。另一方面，橋梁中的伸縮縫因可吸收因溫度、側向移動與轉動的功能，在橋面的穩定性中具有重要的角色。因此，橋梁從業人員需要一種高強度、快速凝固的材料來更換伸縮縫並迅速重新開放交通。基於前述討論，本研究使用飛灰、爐石粉來開發高早強無機聚合修復材料。高鈣的無機聚合材料係以F級飛灰和爐石粉（S4000）以不同比例混合作為黏結劑，鹼液NaOH濃度為10M；SiO_2/Na_2O為1.28，和預熱的河砂作為細粒料以增強聚合反應。本研究的主要目的是開發高強度無機聚合物材料（35MPa/5小時），並考慮預熱細粒料的影響、抗壓強度（加熱1、3、5小時），以及其與超高性能砂漿、無收縮高強度砂漿的黏結強度及剪切強度。實驗針對不同的飛灰－爐石粉比例、水－NaOH比例而設計。實驗結果顯示，根據36個高寬比為1的試體，當飛灰－爐石粉比例為1:3、水－NaOH比為10%，抗壓強度在5小時內可達52.67 MPa。當飛灰－爐石粉比例為1:2、水－NaOH比為10%，黏結強度為34.93 MPa。增加爐石粉用量將減少無機聚合材料的初凝、終凝時間，以及的流速。因此，工程實務使用時，仍應同時滿足強度與工作性的需求。

並列關鍵字

無機聚合材料 ； 高早強 ； 快速修復 ； 伸縮縫

參考文獻

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