鹼骨材反應引致之破裂行為; the behavior of cracking is due to AAR

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Title:	鹼骨材反應引致之破裂行為;the behavior of cracking is due to AAR
Authors:	徐豐裕;Feng-Yu Xu
Contributors:	土木工程研究所
Keywords:	鹼骨材反應;破裂;AAR;crack
Date:	2003-07-07
Issue Date:	2009-09-18 17:13:07 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	摘?要鹼-骨材反應對混凝土結構物所造成的主要影響有裂隙生長及表面的起泡爆裂(pop-outs)等等。目前鹼-骨材反應的相關試驗規範最後所獲得的成果僅為試體的膨脹量，對於因鹼-骨材反應所引致之裂隙發展，最多只能以文字描述及拍茧奶閬“e現最終現象，無法回溯裂隙生長機制及延伸過程。另外，台灣骨材鹼反應潛能資料庫乃彙整本研究室歷年來所累積本土骨材之室內標準試驗結果、案例調查成果及抑制鹼-骨材反應的方法等研究成果所建立而成，但其中部分區域骨材檢測結果仍然短少，加上部分檢測結果與現地案例調查成果不符，因此應進行補充調查，作為資料庫成果補充及修正之用。本文首先係以平台式掃描器，擷取以白守蓮安山岩為骨材所製成的混凝土版及純安山岩版的表面影像，回溯觀察在不同浸置（1N NaOH溶液）時間下裂縫的生長情況及其他劣化現象，以瞭解鹼-骨材反應引致之破裂行為。此外，針對蘇花公路、台九線及西部河川等區域進行現地案例調查及骨材取樣，進行混凝土角柱、水泥砂漿棒及加速砂漿棒等標準試驗，檢測這些區域骨材的鹼反應潛能。根據裂縫成長的回溯觀察，發現裂縫的生成係因水泥漿體無法承受因混凝土內、外部膨脹差異所造成的張力。其他所觀察的破裂行為包括骨材起泡爆裂、貫穿骨材的裂縫及骨材剝離等等。根據資料庫的補充調查試驗結果，發現蘇花公路沿線河川骨材的膨脹量大多高於花東地區之骨材，加上幾處疑似案例的發現，顯示蘇花公路沿線河川區域之骨材應具有相當程度的鹼反應性。此外，台九線上疑似案例所在周遭河川之鹼-骨材反應潛能檢測判定為有害，顯示這些案例劣化現象極可能為鹼-骨材反應所造成的。 ABSTRACT Typical deleterious features of alkali-aggregate reaction in concrete structures include cracking and spalling of fragments of surface concrete as ‘op-outs’. Most of the standard tests predict aggregate reactivity by measuring the expansion of specimens. The results just show the change in length and are unable to know the causes of cracking and process of cracking due to AAR. Furthermore, the database for potential alkali reactivity of aggregates in Taiwan contain various test data of aggregate reactivity , the investigation results of suspected cases and the methods of inhibitive AAR. Nevertheless, some regions still lack the inspection results of aggregate reactivity or inspection results differ from investigated results of suspected case. Therefore, we should be carried out the supplementary investigations to add the inspection results. In the study, a scanner is used to get surface image of the specimens which are made with andesite aggregate grains and immersed in a 1-N concentration sodium hydroxide solution. We can realize that deleterious features due to AAR by observing these images. Therefore, this work which contain the investigation of suspected case and sampling in Su-hua road, No.9 road and rivers of the west are enforced. The aggregates from these areas were carried out mortar bar test, concrete prism test and accelerated mortar bar test to predict potential alkali reactivity of aggregates from areas above mentioned. The results indicate that the surface crack is caused by differential expansion between the surface and the interior concrete. The other deleterious features include pop-outs, stripes of aggregate particles of surface specimen and the cracks passing through aggregate etc. According to the results of supplementary investigation, we obtain a result that the potential alkali reactivity of aggregates which come from the river along Su-hua road is high. In addition, according to the inspected results of aggregate which come from the river around suspected cases of No.9 road, we know that deleterious features of these suspected cases are possibly caused to AAR.
Appears in Collections:	[Graduate Institute of Civil Engineering] Electronic Thesis & Dissertation

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