Preventive
measures against corrosion of reinforcing steel require
making the concrete dense by adding pozzolanic
materials, such as fly ash, silica fu
me, Superpozz, blast furnace slag, etc. to Portland ce
ment. In order to obtain the desired strength and durability of concrete, it is desirable to
monitor the concentration of the pozzolan in the blended ce
ment concrete. Addition of pozzolan to blended ce
ment changes the overall concentration of calciu
m and silicon in the blended ce
ment concrete. The resulting variation in calciu
m and silicon ga
mma-ray yield ratio fro
m blended ce
ment concrete has found to have an inverse correlation with concentration of fly ash, silica fu
me, Superpozz, blast furnace slag in the blended ce
ment concrete.
For experimental verification of the correlation, intensities of calcium and silicon prompt gamma-ray due to capture of thermal neutrons in blended cement concrete samples containing 5–80 % (by weight of cement) silica fume, fly ash and Superpozz were measured. The gamma-ray intensity ratio was measured from 6.42 MeV gamma-rays from calcium and 4.94 MeV gamma-ray from silicon. The experimentally measured values of calcium to silicon gamma-ray yield ratio in the fly ash, silica fume and Superpozz cement concrete specimens agree very well with the results of the Monte Carlo simulations.