Long-term performance of lightweight aggregate reinforced concrete beams

The results of long-term sustained flexural loading tests of 17 large scale reinforced concrete beams fabricated with lightweight aggregate (LWAC) having a density of 1800 kg/m(3) are presented. Deflections, strains and crack widths were recorded over a period of 30 years. Subsequently, each beam was tested to failure. The observations are compared to US, European and Chinese standard provisions for long-term concrete behaviour and LWAC concrete design. The dominant conclusion drawn from this study is that, accounting for reduced material properties, the long-term behaviour of LWAC exhibits no differences from that of normal weight concrete (NWC). Existing provisions for addressing long-term behaviour of NWC may be applied to LWAC and remain suitably conservative. Experimental results confirmed the beneficial effects of the presence of compression reinforcement or a wider compression flange (tee beam). Creep effects on deflection and compression strains were more pronounced that those on maximum measured crack width. The paper presents extensive data accumulated over the 30 year long-term load study reported. (C) 2020 Elsevier Ltd. All rights reserved.