Shear behaviour of lightweight aggregate concrete beams using palm-oil by-products as coarse aggregate

One of the main concerns of engineers to design a structural member using structural lightweight concrete is the shear performance of this concrete due to its lower tensile strength. This research presents an experimental investigation on the shear behaviour of reinforced palm-oil by-product lightweight concrete beams without shear links. The used by-products are wastes from oil palm industry i.e., oil palm shell (OPS) and oil-palm-boiler clinker (OPBC). They used as coarse aggregate in the concrete mixture while normal sand was used as fine aggregate. Nine reinforced OPS and OPS-OPBC lightweight concrete beams were prepared and their structural performance in terms of shear behaviour have been investigated. Three sets of the lightweight aggregate concretes with the maximum oven dry density less than 2000 kg/m(3) were designed and each set contained three concrete mixes of grades 25, 35, and 45. The results of this study show that the OPS concrete beams have lower ultimate capacity in comparison with blended coarse aggregates (OPS-OPBC) concrete beams. The contribution of OPBC aggregate in the OPS concrete improved the structural performance and the failure nature of the beams, significantly. It was found that from the existing prediction models for estimating shear capacity of concrete beams, the shear capacity can be predicted about 10% underestimate and up to 60% overestimate.

Automated summary

The research investigated the shear behavior of reinforced lightweight concrete beams made from oil palm shell (OPS) and oil-palm-boiler clinker (OPBC) as coarse aggregates. The study found that the inclusion of OPBC aggregates improved the shear performance and failure nature of OPS concrete beams, compared to OPS alone. Prediction models for shear capacity of concrete beams were found to have inaccuracies, with potential underestimations of up to 10% and overestimations of up to 60%.