Flexural performance of a fully-prefabricated concrete slab with double-grouted sleeve connectors: An experimental and theoretical study

A novel fully-prefabricated concrete slab linked using double-grouted sleeve connectors is proposed to avoid projecting rebar and in-situ concrete, reduce linking length, and accelerate construction. This paper provides a systematic experimental investigation on the flexural performance of fully-prefabricated slabs under four-point bending. A total of four prefabricated specimens were tested with various diameters of the bottom transition and gap bars, and one cast-in-situ specimen served as a comparison. The results showed that the double sleeve connectors and gap bars in the slabs performed satisfactorily, and the load-bearing capacity of the proposed slab was very close to that of the control counterpart. The precast slab showed 19.1% and 42.8% increases in yield load-bearing capacity and 9.0% and 22.4% increases in ultimate load-bearing capacity, respectively, as the bottom gap rebar diameter increased by 4 mm and 8 mm. The cracking load of the precast slab was 30.0% smaller than that of the control slab, whereas all the cracks did not cross the interface between the grouting mortar and prefabricated part. Altering the linking bar diameter had a significant impact on the deformation shape of the slab. Increasing the bottom transition or gap bar diameter can significantly improve the deflection control capability of the slab. Theoretical calculations are conducted to predict the cracking load, load-bearing capacity, and deflection of the proposed slab, the predictions of which are found to agree satisfactorily with experimental data and can be applied to practical engineering design.