Analysis of Compressive Fatigue Failure of Recycled Aggregate Concrete

• Main Authors: Fan You, Surong Luo, Jianlan Zheng, Kaibin Lin
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Materials
• Subjects: recycled aggregate concrete (RAC); fatigue life; Weibull distribution; fatigue deformation; nanoindentation; interfacial transition zone (ITZ)
• Online Access: https://www.mdpi.com/1996-1944/14/16/4620

Using recycled aggregate in concrete is effective in recycling construction and demolition waste. It is of critical significance to understand the fatigue properties of recycled aggregate concrete (RAC) to implement it safely in structures subjected to repeated or fatigue load. In this study, a series of fatigue tests was performed to investigate the compressive fatigue behavior of RAC. The performance of interfacial transition zones (ITZs) was analyzed by nanoindentation. Moreover, the influence of ITZs on the fatigue life of RAC was discussed. The results showed that the fatigue life of RAC obeyed the Weibull distribution, and the <i>S-N-p</i> equation could be obtained based on the fitting of Weibull parameters. In the high cycle fatigue zone (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>N</mi><mo>≥</mo><msup><mn>10</mn><mn>4</mn></msup></mrow></semantics></math></inline-formula>), the fatigue life of RAC was lower than that of natural aggregate concrete (NAC) under the same stress level. The fatigue deformation of RAC presented a three-stage deformation regularity, and the maximum deformation at the point of fatigue failure closely matched the monotonic stress-strain envelope. The multiple ITZs matched the weak areas of RAC, and the negative effect of ITZs on the fatigue life of RAC in the high cycle fatigue zone was found to be greater than that of NAC.