where VT is the void content (%), T is the theoretical density of PGC computed on an air free basis (kg/m3), D is the density of PGC (kg/m3), MS is the total mass of all material batched (kg), VS is the sum of absolute volumes of component ingredients in the batch (m3).
After the void content test, the cylindrical specimens were placed in the PVC pipe and tightened by circular clamps. The water permeability of PGC was tested using the constant head method [21] and [22] and the schematic diagram of the experimental test set-up is shown in Fig. 3. The permeability test was carried out when a steady state flow was reached. The coefficients of water permeability (k) were the average of three samples and calculated following Darcy’s law as shown in the following equation: