The Influence of High Temperature (40~60.degree.C) Climate Environment of the Transport Properties and Pore Structure of Concrete

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Project title

Code/計畫編號

NSC97-2221-E019-033

Translated Name/計畫中文名

高溫氣候環境（40∼60℃）對混凝土傳輸性質及孔隙結構之影響

Project Coordinator/計畫主持人

Chung-Chia Yang

Funding Organization/主管機關

National Science and Technology Center for Disaster Reduction

Department/Unit

Institude of Optoelectronic Sciences

Website

https://www.grb.gov.tw/search/planDetail?id=1687452

Year

2008

Start date/計畫起

01-08-2008

Expected Completion/計畫迄

31-07-2009

Bugetid/研究經費

538千元

ResearchField/研究領域

土木水利工程

本研究團對於過去的研究中顯示，混凝土置於室溫及約95℃之烘箱中，試體之壓力強度差異不大，但於約95℃之氯離子於混凝土的非穩態傳輸係數及穩態傳輸係數為室溫環境的4.6至14.6倍及2.3至7.1倍，。本計劃擬進一步探討40℃~60℃之高氣溫環境下對混凝土傳輸性質之影響。計劃將採純水泥混凝土及爐灰混凝土兩類，兩類混凝土各採四種水膠比(w/b=0.35, 0.45, 0.55, 0.65) ，共8種配比進行混凝土耐久性與力學相關實驗。本計劃混凝土試體於水中養護91天以後，分別置於室溫（空氣養護）及40℃、60℃、80℃烘箱中四種貯存溫度，至21天貯存時間再進行各項實驗。將進行之實驗含加速氯離子傳輸試驗(Accelerated chloride migration test; ACMT)、鹽水浸泡試驗（Ponding test；AASHTO T259）、混凝土壓力試驗及壓汞試驗(MIP)。經由加速氯離子傳輸試驗結果將可求得混凝土穩態及非穩態氯離子傳輸係數。鹽水浸泡試驗將用來求得氯離子之擴散係數。使用傳輸係數與擴散係數評估40℃~60℃之高氣溫環境下對混凝土傳輸性質之影響，並利用壓汞試驗結果，以溫度改變後混凝土中孔隙尺寸分布評估影響傳輸行為之孔隙尺寸範圍，及Continuous pore diameter評估孔隙之連續性，尋求貯存溫度改變影響氯離子於混凝土中的傳輸行為的主因。 In the previous studies shown that the difference of concrete compressive strength between air dry and oven dry at 95℃ is not significant. But the chloride non-steady-state migration coefficients and steady-state chloride migration coefficients of concrete are increased under the condition of oven dry at 95℃. The non-steady-state migration coefficients increase of 4.6 to 14.6 times, and the steady-state migration coefficients increase of 2.3 to 7.1 times. In order to study the effect of transport properties (the non-steady-state migration coefficient and the steady-state migration coefficient) of concrete exposed at 40℃~60℃ temperature, the plain cement concrete and ash-slag concrete with w/b ratios of 0.35, 0.45, 0.55, and 0.65 will used. After store in air and in an oven at 80,60,40andT=℃ for 21 days, the ACMT (Accelerated chloride migration test), ponding test (AASHTO T259), and the MIP test will be used to investigate the concrete durability and the pore structure. The chloride migration coefficient for concrete is calculated using the constant flux from the Nernst-Planck equation in ACMT. The chloride content and penetration depth of concretes are measured after the ponding test, and the Fick’s second law of diffusion is fitted to the data from experiment to determine the diffusion coefficient. The chloride migration coefficient and the diffusion coefficient will be used to assess the influence of the temperature effect on the durability of concrete, and the pore structure of concrete will be used to study the influence of the temperature effect on the transport properties of concrete.

Keyword(s)

溫度
加速氯離子傳輸試驗
混凝土耐久性
Temperature
Accelerated chloride migration test
Concrete durability

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The Influence of High Temperature (40~60.degree.C) Climate Environment of the Transport Properties and Pore Structure of Concrete

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