Computation of buildup factor for studying piling up of photons in flyash concretes

Six concrete mixtures were prepared with 0%, 20%, 30%, 40%, 50% and 60% of flyash replacing the cement content and having constant water to cement ratio. In the lower energy region and with low Z interaction medium, photons pile up resulting in peak around 100 keV; predominantly less than this value. Buildup factor can describe it effectively and it was computed in the energy range of 0.015 MeV to 15 MeV. Mechanical strength results of the specimens assert improvement with age and results of buildup factor show no significant effect of flyash substitution of cement on it.