Experimental study of the mechanical behavior of self-compacting concrete based on fracture mechanics

Gabriel O Ribeiro ,P C Guetti,Pedro Serna

doi:10.1590/s1983-41952017000300010

Abstract

ABSTRACT Considering the physical nonlinearity of concrete and the fundamentals of fracture mechanics for quasi-brittle materials, the objective of this study was to determine the fracture energy and the length of the fracture process zone (FPZ) as well as the modulus of elasticity, the tensile strength and the compressive strength of self-compacting concrete (SCC) to characterize its mechanical behavior. A series of tests, including a three-point bending test of SCC and conventional vibrated concrete (CVC) specimens, with a notch at mid-span, and tensile and compressive tests were performed. The mechanical parameters obtained from the CVC specimens were considered as a comparative reference. The effect of the following variables was evaluated and considered at two levels: compressive strength (30 and 50 MPa), granular composition (fine and coarse particle size) and maximum diameter of the aggregate (12 and 20 mm). The effect of these variables on the mechanical behaviors of the SCC specimens was evaluated based on the test results of specimens of four types of concrete, which were obtained from the combination of the variables. The bending tests were performed according to the RILEM TC 89-FMT recommendations, which are based on the size-effect method.

Highlights

Self-compacting concrete (SCC) originated in Japan in 1986; the first use of self-compacting concrete (SCC) occurred in 1988
The three-point bending tests were performed according to the RILEM TC 89-FMT recommendation, which is based on the size effect method
A suitable correlation between the modulus of elasticity and the compressive strength is shown in Table [4], with a trend toward an increase in the elastic modulus with an increase in the compressive strength in the conventional vibrated concrete (CVC) and the SCC; this relationship is well known in the literature on the subject

Summary

Introduction

Self-compacting concrete (SCC) originated in Japan in 1986; the first use of SCC occurred in 1988. SCC can be defined as a concrete that can flow and spread in a mold by the action of its weight and can transpose obstacles without exhibiting segregation and exudation, which ensures a uniform aggregate distribution throughout the volume of the structure These features are the main characteristics of this composite in its fresh state. Concrete with two levels of compressive strength (30 and 50 MPa), two granular compositions (fine and coarse particle sizes) and two maximum aggregate diameters (12 and 20 mm) were investigated. The influence of these variables on the mechanical behavior of SCC was evaluated by mixing four types of concrete that were obtained by combining the variables of interest. The three-point bending tests were performed according to the RILEM TC 89-FMT recommendation, which is based on the size effect method

Objectives

Results

Conclusion