The effect of RCA pavements on the liquefaction-induced settlement

The use of recycled concrete aggregates (RCA) not only reduces the demand for natural aggregates (NA) but also might improve the behavior of soil under earthquake loading. In this study, the behavior of the pavement constructed using 100% RCA and NA on a sandy soil layer with high liquefaction potential under dynamic loads was investigated by numerical analysis and compared with free field conditions. For this purpose, first, the classical geotechnical properties of 100% RCA and NA materials were obtained, and then the stiffness properties were determined by resilient modulus and permanent deformation tests. In the second stage, three different models were created with pavement with NA and RCA and without pavement on high liquefaction potential sand, and dynamic analyses were carried out by PM4Sand. Numerical analyses show that constructing a subbase and base layers significantly reduces liquefaction-induced settlement on the surface of flexible pavements built on liquefied soils. Moreover, when the case of using RCA instead of NA in the subbase and base layers built on the liquefied soil is examined, the liquefaction-induced settlement values on the surface are obtained either lower or very close. Consequently, this study proposes a new alternative to the use of RCA waste materials instead of NA. It is expected the use of these waste materials will reduce the need for storage space and also reduce the negative environmental effects associated with storage.