Development of reinforced ultra-high toughness cementitious composite permanent formwork: Experimental study and Digital Image Correlation analysis

This paper presents a development of reinforced ultra-high toughness cementitious composite (UHTCC) participating permanent formwork, which acts as a self-supporting formwork during construction and contributes to the load capacity and durability of the concrete member through the service life of the structure. The flexural behavior of the specimens made with the formwork is analyzed with the help of Digital Image Correlation (DIC) technology. Compared to reinforced concrete beam, the specimens made with UHTCC formwork own a larger deflection, when their maximum crack width reached 0.45 mm. The cracks caused by the delamination of the formwork have little effect on the longitudinal bars, but they would reduce the load capacity in some circumstance. Based on the failure process of specimens, several design details, including the load capacity of various sections and the surface treatment methods, were given to improve the performance of the formwork.