卒 業 論 文

高炉スラグを多量に用いたコンクリートの破壊力学特性に関する基礎的研究

平成３１年 2 月

神戸大学 工学部 市民工学科
学籍番号1334219t

北村 紘基

指導教員 三木 朋広 准教授

Fundamental Study on Fracture Properties of ConcreteContaining Large Volume of Granulated Blast-Furnace Slag
Koki KITAMURA
1334219t
Department of Civil Engineering
Faculty of Engineering
Kobe University

February 5, 2019

ABSTRACTThis thesis investigates the mechanical properties of concrete with large volume of blast furnace
slag as a fine powder which is replaced to the ordinary Portland cement (OPC) with a volumeratio 0% (no replacement), 70%, and 80%, respectively. The mechanical properties including thecompressive strength, the tensile strength, the Young’s modulus and also the fracture propertiesof the fracture energy and the tension softening curve at 7, 28 and 91 days of the age. In addition,
the amount of shrinkage is measured for 91 days by means of an embedded strain gage in order
to experimentally investigate the relationship between mechanical and fracture properties and theshrinkage. Experiments revealed the relationship between the shrinkage and mechanical andfracture properties of concrete replaced with a large volume of blast furnace slag of 80%
replacement of the OPC.

i論

文

要旨

本論文は，高炉スラグ微粉末を多量に用いたコンクリート(置換率 70％，80％)の材齢に伴う力学特性の変化，特に，材齢 7 日，28 日ならびに 91 日における圧縮強度，引張強度，静弾性係数，ならびに破壊力学特性として破壊エネルギーと引張軟化曲線を実験的に調べた．あわせて，収縮量を長期間測定し，その経時変化を調べるとともに，各種力学特性と収縮量の関係を明らかにすることを試みた．実験結果から，高炉スラグ微粉末を多量に用いたコンクリートの収縮量と力学特性の関係を明らかにした．

ii

目次
1.

2.

序論 ....................................................................................................................................... 1
1.1

研究背景 ....................................................................................................................... 1

1.2

研究目的 ....................................................................................................................... 1

既往の研究 ........................................................................................................................... 22.1

高炉スラグ微粉末を高含有したコンクリートの圧縮強度特性 ........................... 22.2

高炉スラグ微粉末の置換率の違いがコンクリートの自己収縮特性に与える影響...................................................................................................................................................... 33.

4.

2.3

コンクリートの破壊力学 ........................................................................................... 42.4

引張軟化曲線の決定手法 ........................................................................................... 52.4.1

多直線近似解析法 ................................................................................................ 52.4.2

エネルギーバランスに基づく引張軟化曲線の決定手法 ................................ 72.4.3

拡張 J 積分法......................................................................................................... 8実験概要 ............................................................................................................................. 113.1

実験ケース ................................................................................................................. 113.2

コンクリートの材料および配合 ............................................................................... 113.3

供試体概要 ................................................................................................................. 123.4

試験概要 .........................................................................................................................

3.4.1

円柱供試体 .......................................................................................................... 153.4.2

スパン長 800mm の切り欠きはり供試体 ........................................................ 153.4.3

スパン長 360mm の切り欠きはり供試体 ........................................................ 16実験結果 ............................................................................................................................. 184.1

自己収縮ひずみ ......................................................................................................... 184.2

圧縮強度，引張強度ならびに静弾性係数 ............................................................. 194.3

3 点曲げ試験(スパン長 800mm) .............................................................................. 224.4

3 点曲げ試験(スパン長 360mm) .............................................................................. 264.5

引張軟化曲線 ............................................................................................................. 28iii

5.

6.

自己収縮ひずみと各力学特性の関係 ............................................................................. 305.1

圧縮強度-収縮ひずみ ................................................................................................ 305.2

引張強度-収縮ひずみ ................................................................................................ 315.3

静弾性係数-収縮ひずみ ............................................................................................ 31

5.4

破壊エネルギー-収縮ひずみ .................................................................................... 32

結論 ..................................................................................................................................... 33

参考文献 .................................................................................................................................... 34
謝辞 ............................................................................................................................................ 35iv