卒 業 論 文

高炉スラグ微粉末と収縮低減剤を用いたコンクリートの鉄筋拘束下における収縮特性の把握と解析的検討

令和 3 年 2 月 4 日

神戸大学 工学部 市民工学科
学籍番号1714262T

水原 遼大
主査：三木 朋広 准教授
副査：森川 英典 教 授

Shrinkage Characteristics of Concrete Using Blast Furnace
Slag Fine Powder and Shrinkage Reducing Agent under
Restraint of Steel Bars and Its Analytical Investigations
Ryota Mizuhara
1714262T
Department of Civil Engineering
Faculty of Engineering
Kobe UniversityFebruary 4, 2021
ABSTRACTThis study presents investigations on the changes of the mechanical properties and shrinkage
properties of concrete using a blast furnace slag as a fine powder (the replacement volume
fraction of cement was set as 70%) and a shrinkage reducing agent. In the analyticalinvestigation, a sensitivity analysis was performed focusing on the shear mechanism and thecrack propagation of RC beams when the mechanical properties and the amount of shrinkage
were varied.
In the experiment, at first, the strain of autogenous shrinkage of concrete and the strain of
reinforcing bar due to the concrete shrinkage were measured. The test parameters were set as1) replacement volume fraction of blast furnace slag fine powder, 2) presence/absence of ashrinkage reducing agent and 3) steel rebar ratios. The experimental results show that how thefactors mentioned above affect the shrinkage characteristics of concrete within the curing.
As for the parametric analysis, the loading test of RC beams was targeted, and the loaddeflection curves and the crack diagram were obtained. In a series of the analysis, models wereprepared, where 1) the compressive strength, 2) the elastic modulus, 3) the tensile strength, 4)
the fracture energy of concrete, and 5) strain of autogenous shrinkage of concrete were set asparameters. From the parametric analysis, it is found that how the factors mentioned above
affect the shear resisting mechanism of RC beams and crack propagation in the beam.
Especially, the influence of the strain of autogenous shrinkage of concrete on the shear propertyof the RC beams is clarified.

i目次
1.

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

研究背景と目的 ........................................................................................................... 1

1.2

既往の研究 ................................................................................................................... 21.2.1

自己収縮に対する膨張材と収縮低減剤の効果 .............................................. 21.2.2

混和材を用いた RC はりのせん断特性と環境影響....................................... 5(1) 実験ケース ........................................................................................................... 5(2) 供試体概要 ........................................................................................................... 6(3) 測定項目と載荷方法 ........................................................................................... 6(4) RC はりの構造特性 .............................................................................................. 72.

3.

4.

実験方法 ............................................................................................................................. 92.1

コンクリートの材料および配合 ............................................................................... 92.2

実験ケース（自己収縮ひずみの計測） ................................................................. 102.3

供試体ならびに試験方法の概要 ............................................................................. 102.3.1

力学特性 ............................................................................................................ 102.3.2

自己収縮ひずみ ................................................................................................ 102.3.3

鉄筋ひずみ ........................................................................................................ 12

実験結果と考察 ............................................................................................................... 143.1

圧縮・割裂試験 ......................................................................................................... 143.2

自己収縮ひずみ ......................................................................................................... 173.3

鉄筋ひずみ ................................................................................................................. 193.3.1

鉄筋ひずみ（鉄筋 1 本） ................................................................................ 193.3.2

鉄筋ひずみ（鉄筋 4 本） ................................................................................ 22

解析的検討 ....................................................................................................................... 25
4.1

4.2

解析方法 ..................................................................................................................... 25
4.1.1

解析対象の概要 ................................................................................................ 25

4.1.2

解析モデル ........................................................................................................ 26

4.1.3

解析ステップ .................................................................................................... 27

解析結果と考察 ......................................................................................................... 27
4.2.1

再現解析（コンクリートの収縮ひずみ） .................................................... 27ii

4.2.25.

再現解析（RC はりの載荷試験）.................................................................. 31

結論 ................................................................................................................................... 34

参考文献 .................................................................................................................................. 36
謝辞 .......................................................................................................................................... 37
付録 .......................................................................................................................................... 38iii