Research on the ITZ and fiber failure properties of PVA-SHCC

Song Gao, Peng Zhang, Qiu-yi Li

Abstract


In this paper, the structure and hydration products of interfacial zone (ITZ) between fiber and matrix are analyzed by means of micromeasurements. Fiber failure adhesive type and Fiber-matrix bonding type of SHCC are furthermore studied based on its mechanism characteristics. The experimental results confirm both cohesive failure type and adhesive pullingout type in the SHCC tensile test. Results also indicate that due to fiber bridging function, SHCC exhibits smaller crack widths and delayed cracking at the same stress level than normal concrete. This is beneficial to activate the aggregate interlock on a crack, and reduction in shear modulus after cracking can be avoided. The EDS and SEM inspection and analysis discover that fly ash changes the hydration products and micro-structure of ITZ, which leads to a porous ITZ structure, and enabling fiber-matrix slippage accompanied. Furthermore, the weak chemical bond between fiber and matrix helps the occurring of multi-cracking. Consequently, the modification of matrix is an effective method to improve the mechanical properties of SHCC. And it improves the bridging function and mechanical properties of SHCC. Both micro-research and tensile test prove the unique ITZ type of PVA-SHCC.

Keywords


SHCC, ITZ, bridging function, fiber failure properties, mechanical properties


DOI
10.12783/dtmse/ictim2017/9936

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