In order to meet the above permeability criterion, larger than 140 in/hour (0.1 cm/sec ), selecting
coarse aggregate with proper void content is very important. Based on the present study, the void
content of raw coarse aggregate should be higher than 35%. In the present study, a raw coarse
aggregate, #4RG, had void content of 38.5%. The void content of the PCPC made with this
aggregate was 25.3%, decreased approximate 10% when compared with raw aggregate. After
replacing 7% of the coarse aggregate with sand (for strength and durability improvement), the
corresponding PCPC had another deduction in the void content by 10%. As a result, the PCPC
mix (Mix 2A: #4 RG with 7% sand) had void content of 18.5% and permeability of 140 in./hour
(0.1 cm/sec ). This sequential deduction of void content may provide engineers with an insight to
aid selection of raw aggregate materials in PCPC mix design.