Flexural Behaviour of Steel Fibre Reinforced Aerated Concrete Beam

Abstract

Lighweight concrete can be made used either using foamed concrete or aertaed concrete. Aerated concrete is gaining importance due to lot of advantages like reduced dead weight, economy in construction, good thermal and acoustaical insulation. Aerated concrete can be made using aluminium powder or hydrogen peroxide to introduce air bubbles in concrete which forms isolated air voids resulting in lightweight. Commercialy aerated concrete is used as building blocks for infill walls of framed structure. Research focus is now towards expanding the use of this material for use in precast structural members. Aerated concrete using aluminium powder as aerating agent and reinfored with steel fibres was used in this project. Aluminium powder reacts with lime and liberates hydrogen gas which is the reason for the air voids in the concrete. The aerated concrete was cured in steam curing chamber at 100 C for 24 hours. This paper deals with the optimization of steel fibre reinforced aerated concrete to be used as beam members in the place of conventioanl concrete. The density of the aerated concrete that was achieved in this work was 967 kg/m3. The compressive strength of the concrete was 22.12 MPa and the flexural strength was 3.12 MPa. Durability tests like sorptivity test, carbonation test and sorptivity test were carried out to study the durability characteristics. The experiments were designed using central composite design of Response surface methodology. Trials were carried out based on the designed combimnations. Finally an optimized mix proportion was obtained for maximum strength and minium sorptivity. Beam members were casted for the optimized mix ratio and tested for flexural strength and deflection. The results show that the stell fibre reinforced beam can be used as a structural member. The precast industries can use this product advantageously to manufacture other structural members also after carrying out appropriate tests.