Analysis of Compressive Toughness and Deformability of High Ductile Fiber Reinforced Concrete

Abstract

The compressive toughness evaluation index of HDC (high ductile fiber reinforced concrete) is studied through three groups of uniaxial compressive tests of HDC specimens with different fiber mixing amounts, and an equivalent analysis of their deformability is carried out, coming to the following conclusion:<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mo stretchy="false">(</mml:mo><mml:mn fontstyle="italic">1</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:math>the peak strain of HDC under uniaxial compression can be up to 3.41~3.67 times as large as that of the mortar matrix;<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mo stretchy="false">(</mml:mo><mml:mn fontstyle="italic">2</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:math>the equivalent compressive toughness index reflects the unit volume deformation energy of specimens under uniaxial compression and it can be used as the compressive toughness evaluation index of HDC;<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mo stretchy="false">(</mml:mo><mml:mn fontstyle="italic">3</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:math>the fiber bridging effect of HDC increases the equivalent compressive toughness index and the compressive deformability up to 3 times of the mortar matrix;<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M4"><mml:mo stretchy="false">(</mml:mo><mml:mn fontstyle="italic">4</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:math>the relationship between the equivalent compressive toughness index<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M5"><mml:mrow><mml:msubsup><mml:mrow><mml:mi>W</mml:mi></mml:mrow><mml:mrow><mml:mi>c</mml:mi><mml:mi>u</mml:mi></mml:mrow><mml:mrow><mml:mn mathvariant="normal">0.85</mml:mn></mml:mrow></mml:msubsup></mml:mrow></mml:math>and the fiber mixing amount<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M6"><mml:mrow><mml:mi>φ</mml:mi></mml:mrow></mml:math>is established according to the test results; and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M7"><mml:mo stretchy="false">(</mml:mo><mml:mn fontstyle="italic">5</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:math>the fiber bridging effect of the matrix in HDC can be equaling as a large number of constraint stirrups installed in the specimens, which significantly enhances the compressive toughness and the compressive deformability of specimens.