Experimental and numerical evaluations of composite concrete-to-concrete interfacial shear strength under horizontal and normal stresses.

M Yahya Al-Fasih,I S Ibrahim,A B H Kueh,N N Sarbini,M A Mohd Ariffin,M E Mohamad,R N Mohamed,Y Ahmad,Jianguo Wang

doi:10.1371/journal.pone.0252050

M Yahya Al-Fasih, I S Ibrahim + Show 7 more

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https://doi.org/10.1371/journal.pone.0252050

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Abstract

Effects of different surface textures on the interface shear strength, interface slip, and failure modes of the concrete-to-concrete bond are examined through finite element numerical model and experimental methods in the presence of the horizontal load with ‘push-off’ technique under different normal stresses. Three different surface textures are considered; smooth, indented, and transversely roughened to finish the top surfaces of the concrete bases. In the three-dimensional modeling via the ABAQUS solver, the Cohesive Zone Model (CZM) is used to simulate the interface shear failure. It is observed that the interface shear strength increases with the applied normal stress. The transversely roughened surface achieves the highest interface shear strength compared with those finished with the indented and smooth approaches. The smooth and indented surfaces are controlled by the adhesive failure mode while the transversely roughened surface is dominated by the cohesive failure mode. Also, it is observed that the CZM approach can accurately model the interface shear failure with 3–29% differences between the modeled and the experimental test findings.

Highlights

The composite concrete slab is constructed by integrating a precast concrete slab with the castin-place concrete topping, both of which are performing monolithically in unison as a single element as dictated by their shear strength at the interface
The failure load increases corresponding to the rise in the normal stress from 0 N/mm2 to 1.5 N/mm2
The corresponding lowest load magnitudes were close to 0 kN for all the specimens except in some cases depending on the applied normal stress

Summary

Introduction

The composite concrete slab is constructed by integrating a precast concrete slab with the castin-place concrete topping, both of which are performing monolithically in unison as a single element as dictated by their shear strength at the interface. The cohesion and frictional characteristics of concrete, as well as its external normal stress all contribute to the capacity of the composite action near the interface region of the slab [1,2,3]. In the interface of a composite slab, failure may occur in the concrete topping, which tends to not conform to the curvature of the precast slab under a deformed state [7]. Understanding the interface texture behaviors of the concrete-to-concrete composite may contribute to an efficient interface shear strength design of the slab under horizontal and normal loadings

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