A Study on the Application of Gamma Transmission Techniques on the Quality Control of Sandcrete Block

This study considered the setup of gamma transmission facility to develop a methodology for determining the amount of cement in sandcrete block. Twelve block samples was moulded in varying sand/cement ratio. The 12 samples each were measured both in volume, masses and density. Each of the samples went through a destructive test to determine the compressive strength via strength test machine. Also each of the sample went through a non destructive gamma ray transmission (GRT) test, where gamma count was taken both before and after crushing. The linear & mass attenuation co-efficient U & U (cm2/g) was determined by (1) The incident gamma ray intensity,(2) the attenuation gamma ray intensity and (3) the background intensity. We realized that the cement weight concentration against the mass attenuation co-efficient has a linear corelation of 0.97, while the compressive strength of the same samples against cement concentration also give a linear correlation of 0.96 except for lower cement values of 7.35 and 9.37wt% which deviates from the straight line. Its deduced that there is a remarkable relationship between mass attenuation coefficient, compressive strength and cement concentration, thus mass attenuation coefficient against compressive strength has a linear correlation of 0.985. Conclusively, it was noted that gamma transmission technique is non-destructive, fast and cost effective compared to the conventional method.