Abstract
abstract: Concrete with recycled aggregate is a fragile material under tensile stresses. However, like conventional concrete, it is possible that its contribution is relevant in the design of reinforced concrete elements under tension or bending, even after cracking. The objective of this work is to evaluate the application of the analytical models used to predict the effect of tension stiffening on recycled reinforced concrete. Tests of reinforced concrete under tensile were performed using conventional concrete and concrete containing 25% and 50% replacement of the natural aggregate with recycled aggregate. From the experimental results of reinforced concrete, the contribution of the concrete was isolated and a parametric study was carried out to identify which analytical model in the literature may be more appropriate. The models proposed by Carreira and Chu (1986), Vecchio and Collins (1986) and Hsu and Mo (2010) were evaluated. A numerical analysis, based on the finite element method, was implemented to model the mechanical behavior of the reinforced concrete under tensile using the analytical models already adjusted to concrete with recycled aggregate. The stress distribution in steel and concrete and the cracking mode were evaluated numerically. The results indicate that the parameters used in the analytical models for conventional concrete cannot predict the behavior of concrete with recycled aggregate and need to be modified to obtain a more accurate answer.
Highlights
The great success obtained by reinforced concrete as a structural material is due to the excellent bond between the reinforcement and the concrete, which allows the redistribution of stresses between the materials after the cracking of the concrete
Despite the good results obtained with the theoretical models for determining the tension stiffening effect, the parameters obtained for the design have been validated through experimental results of conventional reinforced concrete elements, which may limit its applicability to structures produced with recycled concrete aggregate
The experimental curve of the direct tensile test of the isolated steel bar is presented. It appears that all tension stiffening elements, with conventional concrete or recycled concrete, exhibit a behavior similar to that predicted in Figure 1, with a linear phase followed by a baseline of constant force in which multiple cracking occurs
Summary
The great success obtained by reinforced concrete as a structural material is due to the excellent bond between the reinforcement and the concrete, which allows the redistribution of stresses between the materials after the cracking of the concrete. The tension stiffening effect has been defined as the contribution of intact concrete between cracks to the stiffness of the structural element or even by the ability of intact concrete between cracks to resist part of the resulting tensile forces. Due to the importance of this phenomenon, several studies have been carried out to determine theoretical models of the tension stiffening effect, as a way of incorporating it into the design standards for reinforced concrete structures. In this context, two different approaches have been used to determine the constitutive models: i) change in the constitutive equation associated with steel [1], [5], [6]; ii) or modification of the constitutive law of concrete, after the opening of the first crack [2], [7], [8]. Despite the good results obtained with the theoretical models for determining the tension stiffening effect, the parameters obtained for the design have been validated through experimental results of conventional reinforced concrete elements, which may limit its applicability to structures produced with recycled concrete aggregate
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
