Shrinkage and creep characteristic of recycled plastic fiber reinforced sustainable self-compacting concrete with recycled concrete aggregates

This study investigates the drying shrinkage and creep deformation of sustainable self-compacting concrete (SCC) made with recycled waste polyethylene terephthalate bottles, industry by-products and waste concrete. In order to reduce the drying shrinkage and creep deformation of recycled aggregate SCC (RSCC), composite comprising of supplementary cementitious materials (SCMs) and recycled polyethylene terephthalate fiber (RPET) was proposed in this study. Four series, ten RPET reinforced RSCC (RPET-R-RSCC) were produced by substituting recycled coarse aggregates (RCAs) for natural coarse aggregates (NCAs), SCMs for cement, and reinforced with RPET. Fresh and mechanical properties, drying shrinkage and creep deformation of the RPET-R-RSCC were measured and discussed. The effect of RPET, different SCM combinations on the drying shrinkage and creep strain of RSCC mixes was analyzed. The microstructural characteristics were analyzed using scanning electron microscopy (SEM). According to the test results, adding RPET minimized the creep and shrinkage deformation by up to 22 % and 15 %, respectively. In addition, the composite comprising RPET and various SCM combinations had synergistic effect , and considerably reduced the shrinkage and creep deformation of RSCC by approximately 31.5 % and 53.3 %, respectively. SEM analysis confirmed that the composite addition of SCMs and RPET resulted in denser microstructure and stronger interfacial transition zone (ITZ). The observed shrinkage and creep strains were evaluated against existing prediction models. The shrinkage and creep prediction model for RPET-R-RSCC was proposed by introducing amplification factors to account for the effect of RCAs, SCMs and RPET and in conjunction with EC2 model, which exhibited superior accuracy. • An eco-efficient and cost-effective RSCC prepared by composite comprising RPET and SCMs. • Mechanical properties, shrinkage and creep performance simultaneously improved by comprising of SCMs and RPET. • Composite inclusion of RPET and SCMs result in excellent synergistic effect and additional reduction. • The excellent synergistic effect was validated by the SEM analysis. • Modified models proposed to predict the shrinkage and creep of RPET-R-RSCC.