Flexural behaviour of plain and reinforced lightweight aggregate concrete beams up to 600°C

Abstract

Flexural tests were conducted on concrete and reinforced concrete beams (50 × 75 × 846 mm) made of lightweight aggregate and ordinary portland cement as part of a general investigation of the properties of concrete at elevated temperature. The beams were tested at steady states of temperature in the range 20 to 600°C. The performances of the beams were compared at different temperatures by measuring the changes of their properties. The properties investigated were loss of weight, thermal movements, ultimate strength, and flexural rigidity under uniform distribution of temperature within the specimens. The performance of reinforced concrete beams shows continous deterioration of flexural properties at elevated temperature. Plain concrete, on the other hand, lose in strength and rigidity at temperatures below 100°C and gain strength at higher temperature.