Engineered Cementitious Composite for Pavement Applications: Materials Development and Design Framework

Engineered Cementitious Composites (ECCs) are a novel class of high-performance fiber-reinforced cementitious composites characterized by their high tensile strain capacity. While ECCs have been presented as a promising material alternative for the construction of durable pavements and overlays, the cost of these materials is a major drawback, which limits their widespread implementation. More importantly, performance prediction models for ECC pavements existing in the literature are incomplete as the effect of ECC plasticity has not been considered in the integration of finite element (FE) analysis and beam flexural fatigue experimental test results. Moreover, the existing ECC pavements performance prediction models are generally limited to a single mixture design studied and cannot be generalized to other ECCs with various mechanical properties. Therefore, the objectives of this study are to (a) explore the possibility of developing cost-effective and practical ECC materials for pavement applications through reduction of fiber content and use of economical and widely available ingredients in the ECC production; (b) develop a novel thickness design framework considering the effects of ECC plasticity, and (c) develop thickness design equations for fatigue failure mode of ECC pavements considering ECCs’ elastic and plastic regimes as well as a broad range of mechanical properties. The research approach included experimental measurements and simulations using FE modeling. More cost-effective ECCs were developed by the use of more economical fibers at a reduced content, different types of locally available sand, and replacing fine aggregate and cement partially with crumb rubber and fly ash, respectively. Furthermore, a novel thickness design framework was developed by integrating three components of experimentally measured beam flexural fatigue performance models of ECCs, FE-quantified stress response of ECC pavements to vehicular loading, and a stress equivalency function. Finally, using the novel design framework, two general thickness design equations (both for the elastic and plastic regimes) were developed for ECCs with different mechanical properties. The findings of this study suggest that by implementing the proposed thickness design equations, a more accurate representation of the service life of ECC pavement is obtained during the plastic deformation regime in contrast to previous design frameworks proposed in the literature.