Research on the Mechanical Properties of Recycled Aggregate Concrete under Uniaxial Compression Based on the Statistical Damage Model

Abstract

In this paper, uniaxial compression tests were carried out for recycled aggregate concrete with water cement ratios of 0.38, 0.49, and 0.66 and replacement ratios of 0%, 25%, 50%, 75%, and 100%, respectively. The influence of the replacement ratio of recycled aggregate and water cement ratio on the strength, elastic modulus, and deformation characteristics of concrete was discussed. The results show that the replacement rate of recycled aggregate has a significant effect on the macro stress–strain behavior of concrete. In the case of a constant water cement ratio, the peak nominal stress first decreases and then increases with the increase of the replacement rate; while the water cement ratios equal 0.38, 0.49, and 0.66, the corresponding transition states are 25%, 50%, and 50% of the replacement rate, respectively. The deformation and failure is characterized by two stages: distributed damage and local failure. Combined with the statistical damage mechanics, the influence of the aggregate replacement rate on the damage evolution mechanism of recycled concrete on a mesoscopic scale was explored. Two mesoscopic damage modes, fracture and yield, are considered. Their cumulative evolutions are assumed to follow triangular probability distributions, which could be characterized by four parameters. The peak nominal stress state and the critical state are distinguished, and the latter is defined as a precursor to local failure. With the increase of the replacement rate of recycled aggregate, the inhomogeneous evolution of mesoscopic damage shows obvious regular change, which is consistent with the internal chemical and physical mechanism and macro nonlinear stress–strain behavior.

Compressive stress-strain relationships of concrete exposed to elevated temperatures based on mesoscopic damage method

“…The theory of mechanism of intrinsic mechanical capacities exerting was put forward by Bai et al (2007Bai et al ( , 2020. It holds that the deformation of concrete is virtually a kind of self-organizing behavior of material system, which can adapt to changes in external loads through the exertion and release of potential mechanical capacity.…”

“…In essence, uniaxial compression for concrete is a damage course in 3D space. Damage in compression direction is controlled by lateral tensile strain (Bai et al, 2007(Bai et al, , 2020. e 3 þ (e 3 þ > 0) is introduced as the equivalent transfer tensile damage strain.…”

“…The macroscopic nonlinear mechanical behavior of concrete could be traced back to the details of the heterogeneous evolution of damage on the mesoscale. Combining synergetics and catastrophe theory with statistical damage theory, Bai et al (2010Bai et al ( , 2014Bai et al ( , 2020 proposed the statistical damage model of concrete to predict the constitutive behavior of concrete under complex load conditions and investigate the damage mechanism at the mesoscopic scale. It considered there are two types of meso-damage modes, fracture and yield.…”

Calculation and Analysis of Temperature Damage of Shimantan Concrete Gravity Dam Based on Macro–Meso Model

“…Obviously, the damage evolution equation expressed in Equation (26) can reflect the damage anisotropy of concrete material, but when the principal strain is compressive strain, the calculated damage value may deviate from the actual situation. As stated in the literature [ 39 , 52 ], the damage of concrete material is mainly caused by tensile strain. When the material is under tensile loading, the micro-cracks propagate perpendicular to the direction of tension.…”

Recycled Materials for Concrete and Other Composites

“…A number of works in this Special Issue present the latest achievements in the synthesis of innovative concrete-containing recycled waste and materials and their properties. Bai et al [ 10 ] determine the mechanical properties of recycled aggregate concrete under uniaxial compression based on a statistical damage model. Choi et al [ 11 ] determine the compressive strength, chloride ion penetrability, and carbonation characteristics of concrete with both ferronickel slag and blast furnace slag.…”