Evaluating residual compressive strength of post-fire concrete using Raman Spectroscopy

•Raman bands at 1083, 709 and 276 cm−1 relate to changes in compressive strength.•Ratio 1083/709 cm−1 correlated to the compression strength of the concrete.•Decline in strength around a critical peak ratio of 8.78.•Indirect evaluation of the temperature the concrete.•Raman to provide in-situ non-destructive testing of fire damaged concrete.