Low weight, self-levelling, high workability and thermal insulating properties make lightweight foamed concrete (LWFC) an attractive substitute for normal weight concrete (NWC). The unfamiliarity of LWFC and paucity of design guidance pose concern for its use in structural application. One…
Low weight, self-levelling, high workability and thermal insulating properties make lightweight foamed concrete (LWFC) an attractive substitute for normal weight concrete (NWC). The unfamiliarity of LWFC and paucity of design guidance pose concern for its use in structural application. One such concern is the bonding of steel reinforcement within LWFC. The bond behaviour of deformed steel reinforcement (rebar), embedded in LWFC and NWC was tested using [1] pull-out (PO) and the beam-end (BE) tests . The concretes used for testing were a reference NWC 3 and LWFC with casting densities of 1200, 1400 and 1600 kg/m . The nominal diameters of rebar used were Y10, Y12 and Y20 at embedded lengths of 3, 4 and 5 nominal bar diameters. Characterization of these materials included compressive strength, Young’s modulus, tensile splitting strength and wedge splitting fracture energy. The bond-slip envelopes of the denser LWFC yield significant bond stress magnitudes, but lack the ductility in failure observed in the NWC tests. The least dense LWFC exhibits ductility during failure, but lacks sufficient bonding stress magnitude. A significant difference in bond behaviour is observed between the results of the PO tests and the BE tests. The interaction of LWFC fracture and rebar bond mechanisms in the BE tests in the presence of shear and bending moment, is the direct cause, and the relatively low fracture toughness leads to low apparent bond resistance. Through this understanding, material improvement is envisaged by inclusion of aggregate to increase cracking tortuosity and thereby fracture energy of LWFC, in order to improve rebar bond in LWFC.