Behaviour of clamp-enhanced palm tendons reinforced concrete

Abstract

Recent studies on affordability and sustainability of building materials have shown that broom fibres derived from the leaflets of oil palm tree have impressive tensile strength but poor bond strength with concrete. Although bonding has been reported to be improved when the fibres are combined in the form of tendons, the bond-slip failure between the tendons and concrete still compromises composite performance. This study, therefore, investigates the use of hose clamps in increasing slip resistance between oil palm broom fibres (OPBF) tendons and concrete matrix. A total of 64 concrete samples comprising of 46 beams (100x100x500 mm) reinforced with varying areas of OPBF tendons and 18 bond pull – out samples were prepared. The tendon reinforcements were fitted with hose clamps to improve the bond strength between the concrete and the reinforcement. Spacing between hose clamps was chosen as 45 mm and 85 mm. The flexural strength of the beams was tested under 4-point bending at 28, 56 and 112 days. Test results show improvement in the flexural capacity of the beams as a result of increased slip resistance induced by the hose clamps. Finite element modelling of the behaviour of the OPBF-tendon reinforced concrete was carried out and recommendations were made after ensuring that the ultimate and serviceability limit states are satisfied.