Practical Design Criteria for Saturated Pseudo Strain Hardening Behavior in ECC

Abstract

Engineered Cementitious Composites (ECCs) have recently demonstrated their high performance with pseudo strain hardening (PSH) behavior in civil engineering structures and buildings. These materials incorporate low cost fibers such as Polyvinyl Alcohol fibers, which often rupture in composites. Such fiber rupture type ECCs tend to have inferior and unsaturated PSH behavior compared with those incorporating properly designed pull out type fiber. The present study focuses on presenting practical design criteria to achieve saturated PSH behavior in fiber rupture type ECCs. These criteria are proposed based on two performance indices, which are measures of energy exchange during steady state flat crack propagation and stress level to initiate micro-cracks. The latter performance index necessitates a new cracking strength prediction theory, which is proposed in the current study. Finally the cracking strength theory is justified using tensile test data, and the criteria are proposed based on the data in terms of these two indices.

Control of Tensile Behavior of Ultra-High Performance Concrete Through Artificial Flaws and Fiber Hybridization

“…The ratios of ultimate tensile strength to first cracking strength of M-S, M-S-PB, M-PE, and M-PE-PB mixtures were 1.4, 1.5, 1.7 and 1.8, respectively. The potential of higher multiple cracking behavior increases with the higher ratio of ultimate tensile strength to first cracking strength (Kanda and Li 2006). It should also be noted that, ultimate tensile strength values were less affected by plastic bead addition and PE fiber usage compared to the compressive strength values reported in previous section which can be attributed to the enhanced multiple cracking behavior with these composite modifications.…”

Self-Healing Capability of Fibre Reinforced Cementitious Composites

“…Some studies on ductile high strength concrete columns toughened by containing steel fibre were reported (Sharma et al 2007;Sugano et al 2007;Kimura et al 2007). Ultra ductile fibre reinforced cementitious composites (so called strain hardening cementitious composite: SHCC) have been also developed (Li 2003;Kanda and Li 2006) and a simplified inverse method for determining the tensile properties of SHCC that is essential for quality control in practice was proposed (Qian and Li 2007;Qian and Li 2008).…”

Tailoring ECC for Special Attributes: A Review

“…In order words, a high (r 0 /r cr ) ratio is desired (Kanda and Li 2006). Low r cr can be attained by lowering the matrix fracture toughness K m or by having large flaw size c. However, excessive lowering of K m or large flaw size c could lead to low first crack strength and compressive strength.…”

“…A high ratio of J 0 b /J tip is preferred for robust multiple cracking in the presence of material variability (Kanda and Li 2006). J tip is the energy equivalent of the matrix fracture toughness K m .…”