Strain-hardening cementitious composites ultra-thin whitetopping (SHCC-PUTW) for rapid asphalt pavement rehabilitation

Whitetopping is the concrete overlay used to upgrade distressed asphalt road surface, where the distressed asphalt is milled off and concrete is cast on top as the new wearing course. However, it requires road closure for multiple days, which is not accepted in many urban constructions. Precast concrete pavement (PCP) is the technology that shortens the construction period. However, it is associated with complicated construction procedures due to the brittleness of conventional concrete. In this paper, a brand-new PCP design, i.e., ultra-thin whitetopping (PUTW) is studied and applied in a demonstration project in Singapore. The PUTW is enabled by employing strain-hardening cementitious composites (SHCC) with significantly higher ductility than conventional concrete. The current work includes four parts. First, the desirable combinations of SHCC's tensile and compressive uniaxial behaviors are identified in the analytical model and experimental study to enhance its flexural strength for pavement application. Second, the slab-to-slab joint efficiency in the PUTW, the critical mechanism in the structural design, is examined and validated with a full-scale cyclic wheel test. Third, the structural performance of the entire SHCC-PUTW is examined in a new finite element (FE) model validated against the wheel test. Based on the FE model, parametric studies on the SHCC material properties and PUTW slab dimensions are conducted to optimize the structural design. Fourth, a small-scale field project on the Jurong Island of Singapore, which involves the fabrication and installation of 11 SHCC-PUTW slabs, is reported to assess the feasibility of this new structural design.