Characterizing the crack development in strain-hardening cement-based composites (SHCC) by means of acoustic emission

Abstract

The article at hand presents an investigation on crack development in three different types of strain-hardening cement-based composites (SHCC) subjected to uni-axial tensile loading. The aim of the work was to evaluate the applicability of acoustic emission (AE) measurements for determining the progressive damage within the material, as well as for differentiating the individual damage events by their origin and decisive mechanisms, such as matrix cracking, fiber pullout or fiber rupture. The acoustic emission method proved to be fully appropriate for recording and evaluating the fracture related processes in various types of SHCC. Valuable information on failure mechanisms and quantitative description of damage depending on SHCC composition was obtained and evaluated with respect to the measured stress-displacement curves and under consideration of fracture surfaces and crack patterns observed on the specimens.

Mechanical Behavior of Strain-Hardening Cement-Based Composites (SHCC) Subjected to Torsional Loading and to Combined Torsional and Axial Loading

“…PE-SHCC yielded an average work-to-fracture of 127.1 kJ/m 3 . These results do not completely agree with the findings of the previous studies by Curosu and Mechtcherine [40][41][42], in which PVA-SHCC yielded superior mechanical properties, e.g. the strain capacity of 1.5% [40].…”

“…In this study, two types of SHCC were investigated. Their mixture compositions were already addressed by Curosu and Mechtcherine in previous works [40][41][42][43]. Both held the same normalstrength matrix, differing only in the type of dispersed fiber.…”

“…Furthermore, they exhibit superior tensile strength, Young's modulus, and abrasion resistance, making them especially suitable for use in high-strength cementitious matrices [39]. The crack-bridging behavior of these fibers in the normal-strength matrix was addressed in previous investigations by the authors Curosu and Mechtcherine [40][41][42]. Despite the relatively low bond strength in comparison to the PVA fibers, the smaller diameter of the PE fibers ensures sufficient collective crack-bridging capacity for tensile strain-hardening and multiple cracking.…”

“…Despite the relatively low bond strength in comparison to the PVA fibers, the smaller diameter of the PE fibers ensures sufficient collective crack-bridging capacity for tensile strain-hardening and multiple cracking. Furthermore, PE-SHCC is more suitable for applications involving highly dynamic loading [41,42] and when proper crack control at larger crack openings is required [40]. Note that the cementitious matrices in both SHCCs are practically identical.…”

Strain Hardening of Polypropylene Microfiber Reinforced Composite Based on Alkali-Activated Slag Matrix

“…Analysis of the signal parameters (e.g., amplitude and average frequency) makes it possible to classify the cracks, e.g., as described in papers [47][48][49]. In combination with the stressstrain curves one can draw conclusions about the destruction mechanism of SHCCs [46,50].…”