Title: Bond Performance between Normal-Strength Concrete and Sand-Lightweight Concrete

Author(s): Patricia Figueiredo, Sergio Luis Garcia, Renato Cossetti, and Afonso Leite

Publication: Structural Journal

Volume: 119

Issue: 1

Appears on pages(s): 199-213

Keywords: interface; pulloff; pushoff; roughness; shear strength; slant shear

DOI: 10.14359/51733007

Date: 1/1/2022

Abstract:
This work presents an experimental study to characterize the adhesion strength of concrete interfaces with conventional and lightweight aggregate density. For this purpose, 75 specimens of slant shear (SS), 24 for pushoff (PS) and pulloff (PO) were performed. For the SS test, a modified model was proposed inducing different stresses at the interface of that traditional slant shear. The substrates were manufactured with conventional density concrete with a compressive strength of approximately 50 MPa, and for the overlay and four lightweight concrete with percentages of 25, 50, 75, and 100% aggregate replacement. In the modified slant shear (MSS) substrates five types of roughness were performed: smooth, as vibrated and three intentionally rough (R1, R2, and R3), and for the PS and PO tests only the ones: as vibrated (V) and the intentionally rough (R2). An automatic roughness measuring method was developed using a laser displacement sensor. Comparing experimental and theoretical results showed that they provide different values for each type of test. For the MSS, Eurocode 2 and fib model codes can be used for these types of concrete interfaces, but for the PS they have proved to be very conservative.