{"created":"2023-06-19T10:29:42.385572+00:00","id":9683,"links":{},"metadata":{"_buckets":{"deposit":"b2ca3914-4e8a-4f32-a2d9-3e40fcd0018d"},"_deposit":{"created_by":18,"id":"9683","owners":[18],"pid":{"revision_id":0,"type":"depid","value":"9683"},"status":"published"},"_oai":{"id":"oai:muroran-it.repo.nii.ac.jp:00009683","sets":["41:227"]},"author_link":["43249"],"item_81_date_granted_17":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"2018-03-23"}]},"item_81_degree_grantor_10":{"attribute_name":"学位授与機関","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_language":"ja","subitem_degreegrantor_name":"室蘭工業大学"},{"subitem_degreegrantor_language":"en","subitem_degreegrantor_name":"Muroran Institute of Technology"}],"subitem_degreegrantor_identifier":[{"subitem_degreegrantor_identifier_name":"10103","subitem_degreegrantor_identifier_scheme":"kakenhi"}]}]},"item_81_degree_name_11":{"attribute_name":"学位名","attribute_value_mlt":[{"subitem_degreename":"博士（工学）","subitem_degreename_language":"ja"}]},"item_81_description_25":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_description":"application/pdf","subitem_description_type":"Other"}]},"item_81_description_7":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"近年，地球規模での温暖化防止に向けた動きに呼応して，建設業の低炭素化に向けた技術開発がますます加速している．主要な建設材料であるコンクリートに使用されるセメントは，製造過程での CO2 排出量が大きいことが知られており，高炉スラグ微粉末やフライアッシュに代表される産業副産物系混和材をセメントに置換した低炭素型コンクリートが有効な地球温暖化対策として期待されている．しかしながら，低炭素型コンクリートは，混和材の種類，置換率および強度レベル等で特徴が異なり，特に高強度領域における十分な知見が蓄積されているとは言い難い．今後， 環境配慮設計として低炭素型コンクリートの適用を検討する場合には，適用箇所に求められる性能を十分に満たしたうえで，最大限の CO2 排出量削減が得られるように高強度領域における知見のさらなる蓄積が必要であると考える．本研究では，前述の背景をふまえて，低炭素型コンクリートの適用性拡大を目的として， 高強度領域の低炭素型コンクリートの実用化に向けた各種性能検証を行った． 検討した低炭素型高強度コンクリートは，汎用性と耐久性をそれぞれ確保させることを目指して， 既往の研究を踏まえ高炉セメントにフライアッシュを置換したコンクリートとした．性能の検証は，室内実験と実製造を想定した実機実験により実施し， 高強度領域では十分な中性化抵抗性の確保が可能であること，優れた発熱抑制効果による温度ひび割れ対策として有効であることを確認した．一方で，実部材のように高温履歴を受ける条件下では，長期強度の停滞現象が顕著になることを示し， それが環境影響の観点からも課題となり得ることを指摘し，メカニズムの解明に向けた検証実験を実施した．その結果，主な原因の一つがモルタルと粗骨材の線膨張係数の差に起因するひずみ差にともなう粗骨材界面の剥離現象であることを示し，有効な対策の提案を行った．また， 建築物への低炭素型コンクリートの実用化には発注者・監理者の理解を得ることが重要であることから，低炭素型コンクリートの適用が建築物全体の CO2 排出量削減にどれだけ寄与するかを定量的に発注者・監理者へ提示できる手法の確立を目指し，調査・検証を行った．その結果，海外や国内の他産業を中心に普及が進んでいるカーボンフットプリント制度に着目し，国内で初めての建築物への適用を実現させ，その有効性について示した．さらに，実際の建築物をベースに低炭素型コンクリートの適用による CO2 削減効果のケーススタディを実施し，低炭素型コンクリート自体の長期強度性状の改善が CO2 排出量削減の観点からも有効であることを定量的に示した．これらの一連の取組みにより，要素技術である低炭素型コンクリートと建築物の CO2 排出量の評価手法に関連性を持たせることで，環境配慮設計による持続型社会構築に向けた一つの指標を提示した．","subitem_description_language":"ja","subitem_description_type":"Abstract"},{"subitem_description":"In response to recent global movements to prevent climate change, recent years have seen efforts to develop low-carbon technologies accelerate, aimed at reducing the carbon emissions of the construction industry. Cement is one the primary components of concrete, and its manufacture is the primary source of CO2 emissions during concrete production. Therefore, utilizing low-carbon concrete—in which some cement is replaced with admixtures, such as ground-granulated blast-furnace slag or other industrial byproducts—should be a useful strategy to help fight global warming. However, the properties of low-carbon concrete can vary depending on admixture type, cement replacement ratio, strength level, and other factors, and relevant literature data on the material, especially for high-strength mixtures, are far from adequate. Investigations aimed at determining the feasibility of low-carbon concrete in environmentally friendly designs should first ensure the material’s performance is sufficient for its intended application, then gather more evidence on high-strength varieties of low-carbon concrete to maximize the reduction of CO2 emissions. The present study was conducted to test the performance of a high-strength low-carbon concrete for use in practical applications in consideration of the above, with the aim of expanding its potential scope of use. The test material was created from blast-furnace cement with fly ash replacement, a mixture chosen based on preceding research to ensure both versatility and durability. Both laboratory experiments and full-scale simulations were conducted to validate its performance, adopting a cement manufacturing process that could be applied in real construction projects. The resulting high-strength concrete exhibited suitable carbonation resistance, and an excellent ability to suppress the generation of heat, which effectively controlled thermal cracking. However, specimens subjected to a temperature history similar to conditions experienced by actual members exhibited severe reductions in long-term strength. Additional verification experiments were performed to elucidate the responsible mechanism, as strength reductions due to environment effects could complicate the material’s real-world application. The results showed that one major cause was spalling at the coarse aggregate–mortar interface due to differences in strain, a phenomenon due to differences between the linear expansion coefficients of the mortar and coarse aggregate. Effective countermeasures were proposed based on these findings. It is also important that the individuals who order and supervise construction projects appreciate the advantages of employing low-carbon concrete in building projects. Accordingly, another investigation was conducted with the aim of establishing a quantitative method to demonstrate how much the CO2 emissions of entire buildings could be reduced by applying low-carbon concrete, in a way understandable to ordering parties and managers involved in construction alike. These efforts centered on the carbon footprint system, already widespread in other industries in Japan and overseas. The result was the system’s first-ever application to buildings in Japan, which demonstrated the method’s usefulness. Furthermore, a case study was run on how applying low-carbon concrete, primarily to real buildings, could help to reduce CO2 production, and it was quantitatively demonstrated how improvements to the long-term strength behavior of the concrete itself could help to reduce CO2 emissions. This series of efforts established a connection between the core technology of low-carbon concrete and a method for evaluating the CO2 emissions of buildings: in doing so, this thesis provides the field with a measurable index for building a sustainable society based on environmental friendly design.","subitem_description_language":"en","subitem_description_type":"Abstract"}]},"item_81_dissertation_number_13":{"attribute_name":"学位授与番号","attribute_value_mlt":[{"subitem_dissertationnumber":"甲第414号"}]},"item_81_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.15118/00009635","subitem_identifier_reg_type":"JaLC"}]},"item_81_subject_9":{"attribute_name":"日本十進分類法","attribute_value_mlt":[{"subitem_subject":"511","subitem_subject_scheme":"NDC"}]},"item_81_text_12":{"attribute_name":"学位の種別","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"課程博士"}]},"item_81_text_14":{"attribute_name":"報告番号","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"甲第414号"}]},"item_81_text_15":{"attribute_name":"学位記番号","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"博甲第414号"}]},"item_81_text_16":{"attribute_name":"研究科・専攻","attribute_value_mlt":[{"subitem_text_language":"ja","subitem_text_value":"工学専攻"}]},"item_81_version_type_24":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_version_resource":"http://purl.org/coar/version/c_970fb48d4fbd8a85","subitem_version_type":"VoR"}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"open access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_abf2"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorAffiliations":[{"affiliationNameIdentifiers":[],"affiliationNames":[{"affiliationName":""}]}],"creatorNames":[{"creatorName":"鈴木, 好幸","creatorNameLang":"ja"},{"creatorName":"SUZUKI, Yoshiyuki","creatorNameLang":"en"},{"creatorName":"スズキ, ヨシユキ","creatorNameLang":"ja-Kana"}],"familyNames":[{},{},{}],"givenNames":[{},{},{}],"nameIdentifiers":[{}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2018-06-06"}],"displaytype":"detail","filename":"A414.pdf","filesize":[{"value":"7.1 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"A414","objectType":"fulltext","url":"https://muroran-it.repo.nii.ac.jp/record/9683/files/A414.pdf"},"version_id":"19295692-011d-4002-90a4-f33ab6ce4b57"},{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2018-06-06"}],"displaytype":"detail","filename":"A414_summary.pdf","filesize":[{"value":"237.1 kB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"A414_summary","objectType":"abstract","url":"https://muroran-it.repo.nii.ac.jp/record/9683/files/A414_summary.pdf"},"version_id":"4891da9a-e653-4108-8123-c1fe24f42e53"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"jpn"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"doctoral thesis","resourceuri":"http://purl.org/coar/resource_type/c_db06"}]},"item_title":"低炭素型⾼強度コンクリートの実⽤化に関する研究","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"低炭素型⾼強度コンクリートの実⽤化に関する研究","subitem_title_language":"ja"}]},"item_type_id":"81","owner":"18","path":["227"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2018-06-06"},"publish_date":"2018-06-06","publish_status":"0","recid":"9683","relation_version_is_last":true,"title":["低炭素型⾼強度コンクリートの実⽤化に関する研究"],"weko_creator_id":"18","weko_shared_id":-1},"updated":"2023-11-13T00:35:51.160116+00:00"}