This paper presents the results of an experimental investigation to determine the size effect on flex- ural toughness of high performance short fiber reinforced cementitious composite incorporating a low fiber vol- ume fraction of 2% and showing excellent tensile strain…
This paper presents the results of an experimental investigation to determine the size effect on flex- ural toughness of high performance short fiber reinforced cementitious composite incorporating a low fiber vol- ume fraction of 2% and showing excellent tensile strain hardening capacity in excess of 3%. Evaluation of tough- ness was made using a pair of new proposed parameters, i.e., flexural strength and energy dissipation per unit volume of plastic hinge region, termed as σ and T , respectively. Five groups of strain hardening cementitious v composite specimens with constant length of 400mm and width of 100mm but varying thickness of 15mm, 30mm, 50mm, 70mm and 100mm were investigated. Four-point bending tests were carried out under displace- ment control at the rate of 0.15mm/min. Referring to ASTM C 1609 toughness testing procedure, 100mm thick- ness specimens were identified as the control and four pairs of additional toughness parameters(σ , T ; σ v, 1.0 v, 1.0 v, , T ; σ , T ; σ , T ) were recommended with the consideration of remarkable deflection hardening 1.5 v, 1.5 v, 2.5 v, 2.5 v, 3.0 v, 3.0 behavior of such materials prior to the reach of peak load. For other series of specimens’ thickness, the deflection governing points at which toughness properties were calculated were determined by multiplying the deflection values of 100mm thickness specimens by a transforming factor defined as a function of specimens’ thickness. It was found that two toughness parameters at all seven governing points have nothing to do with specimens’ thick- ness, being no size effect. Further theoretical dimension analysis proves such experimental observations. 1 INSTRUCTION tious composite, is generally evaluated through flex- ural test.