Experimental and numerical study on behaviour of fibre reinforced lightweight hollow core slabs under different flexure to shear ratios

Abstract

The current work explores the behaviour of fibre-reinforced lightweight hollow core slabs (FR-LWHCS) intending to develop sustainable construction solutions. The FR-LWHCS investigated in this work contains sintered fly ash aggregate (SFA) as coarse aggregate. Due to the use of SFA, the behaviour of LWHCS is expected to be different from the hollow core slabs (HCS) constructed using normal density concrete. FR-LWHCS are tested at different shear span to depth (a/d) ratios of 3.5, 7 and 10 to understand the shear and flexure behaviour. Twelve full-scale hollow core slab (HCS) specimens of 3400 mm length, 600 mm width, and 150 mm thickness are tested. FR-LWHCS consists of monofilament macro synthetic fibre dosages of 0.4 %, and 0.6 %, along with fibrillated micro fibre of 0.02 % dosage. The digital image correlation (DIC) technique is adopted to understand the strain profile on the HCS at different levels of loading. The numerical analysis is performed using a commercially available finite element software and is corroborated with experimental findings and parametric studies have been performed. Both LWHCS and normal HCS specimens failed in shear, flexural-shear and flexure modes at a/d ratios of 3.5, 7 and 10, respectively. The addition of fibres increased the peak load by 65 % compared to control LWHCS specimens tested at an a/d ratio of 3.5. The use of fibres increased strain energy absorption and changed the failure to less brittle mode at all a/d ratios. The fibre reinforced specimens have nearly 3.5 times, 2.5 times and 1.3 times the strain energy absorption of the control LWHCS when tested at a/d ratio 3.5, 7 and 10 respectively.