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Effect of hybrid steel-polypropylene fiber on punching shear behavior of flat slab with an opening

Zaezue Shahzinan J., Hadi Waleed K.

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

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2023

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Vol. 32, No. 1

3--17

EN

This research aimed to gain a better understanding of how the addition of fiber influences the punching shear capacity of two-way slabs by conducting an experiment into the structural behavior of flat slabs with and without a square opening using different volume fractions of hybrid steel-polypropylene fiber (0%, 0.9%, 1.05% and 1.8%). Ten 700 × 700 × 70 mm slabs were divided into five pairs, with two samples used as control samples (with and without openings), and eight other samples with different volume fraction of fibers. Results showed that an increase in fiber content enhanced the shear strength of the slabs. For example, as the volume fraction of hybrid fiber increased from 0.0 to 1.8%, the ultimate load increased by 52% for slabs without an opening and up to 42% for slabs with an opening.

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Experimental and analytical study of steel–PVA hybrid fiber-reinforced mortar containing CaCO3 whiskers subjected to freeze–thaw cycles

Liu Zixing, Cao Mingli, Xie Chaopeng

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 4

art. no. e190, 2022

EN

In high latitude and altitude areas, cement-based composite is subject to freeze–thaw cycles. The uniaxial compressive properties and microstructure of steel–PVA fiber reinforced cement mortar incorporating CaCO3 whiskers (SPFRC-CW) before and after freeze–thaw cycles were studied in this paper. The relative mass loss (RML), relative ultrasonic pulse velocity (RUPV), and the stress–strain relationship of frost–damaged SPFRC-CW was measured for a study of the durability and mechanical property degradation rules. A damage model was established considering the freeze–thaw cycles and CW volume fraction for SPFRC-CW, which demonstrated decent consistency between theoretical and experimental curves. The microstructure was analyzed using an optical microscope (OM), scanning electron microscope (SEM), vacuum epoxy impregnation (VEI), and mercury intrusion porosimetry (MIP). The results suggest that the physical and mechanical properties of SPFRC-CW decreased with prolonged freeze–thaw cycles. The better frost resistance of SPFRC was related to the improved pore structure because of the presence of CW, as per the results of VEI and MIP.

3

Analysis on axial compressive capacity of hybrid fiber cement-based composites encased CFST columns

Sun Linzhu, Wu Weiji, Li Wei

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 4

art. no. e197, 2022

EN

In order to investigate the ultimate bearing capacity of hybrid fiber cement-based composite (HFC) encased concrete-filled steel tube (CFST) columns under axial compression. This study conducted theoretical analysis on HFC encased CFST columns. Theoretical formulas of the ultimate bearing capacity for the HFC encased CFST columns based on the elastoplastic theory and limit analysis method are presented. The calculated results of the theoretical formulas are compared with the experimental results and the values calculated by the typical codes. The results show that the theoretical models have high accuracy in predicting the ultimate bearing capacity of HFC encased CFST columns.