The American Concrete Institute (ACI) has released a paper which summarises an investigation into the bond and crack behaviour of reinforced infra-lightweight concrete (ILC). The study also assessed the flexural behaviour of ILC beams.
Called Structural Behaviour of Reinforced Infra-Lightweight Concrete (ILC), the paper says ILC is a high-performance lightweight-aggregate concrete (HPLWAC) with a dry density of less than 800 kg/m3 (50 lb/ft3).
“Such low density means low thermal conductivity (increased thermal resistance [R-value]) and thus allows for monolithic and fair-faced concrete structures without any additional heat insulation,” the document adds.
The experimental tests included 60 reinforced ILC specimens (plus reinforced normal concrete [NC] specimens for reference) for each type: pullout test, tension stiffening test and beam test. Lightweight concrete with such low densities shows a linear-elastic behaviour and is brittle.
Research findings indicate rigid bond properties that bring about favourable crack behaviour.
According to ACI: “The paper describes calculation models for bond, cracks, and bending considering such material behaviour. The theoretical and experimental research presented herein also gives insight into the ductility of ILC beams.”
Alex Hückler and Mike Schlaich wrote this paper.