to investigate the effects of temperature on tdr measured dielectric constant and electrical conductivity the cured concrete specimens from both mixtures were sealed and stored for 24 hours in temperature controlled room of 4 u00b0 c and 40 u00b0 c respectively and then allowed to return to ordinary laboratory room temperature as the mixture temperature was being restored to room temperature tdr and thermocouple readings were taken to monitor the change of dielectric constant and electrical conductivity with temperature the measured values of dielectric constant and electrical conductivity for the two mixtures are normalized by those at room temperature 22 u00b0 c and are plotted in fig8 and 9 fig8 and 9 show that both the dielectric constant and electrical conductivity increase linearly with temperature within the temperature range of the study the effect of temperature on electrical conductivity measurement is much more significant than that of dielectric constant as indicated by the steeper slope in fig9 from these observations the following temperature compensation factors eq 8 are recommended to compensate for the effects of temperature on tdr measured dielectric constant and electrical conductivity tcf k a 1 0 0019 u00b7 t 0 952 u2062 u2062 tcf ec b 1 0 0247 u00b7 t 0 453 8 the results of compressive strength obtained from concrete cylinder testing are shown in fig1 and 11 there is significant about 20 although not unreasonable scatter of results which is possibly due to effects of sampling disturbance and curing process the phenomena are common when evaluating concrete strength from cylinder samples hyperbolic curves give good fit to the data and can be used.