Supplementary cementitious materials (SCMs) have been widely used to enhance both the microscopic and macroscopic properties of the Portland cement (PC)-SCM composite matrix. Few studies have been undertaken to establish the gel/space ratio of meta-illite calcined clay (MCC) and rice husk ash (RHA)-based high-performance concrete (HPC) mortar. This experimental paper describes a conventional degree of hydration (non-evaporable water) and porosity routes of establishing a link amid the gel/space ratio and compressive strength of a sieved mortar from Class 1 (50-75 MPa) HPC at an early age. Using the non-evaporable water method, this paper predicted the gel/space ratio of the hardened MCC/RHA-based HPC mortars and curved fitted into Powers' exponent equation. The results from this study revealed that MCC or RHA additions (5-30% by weight of PC) to the PC-SCM matrix led to a moderate decline in the compressive strength of the low water-binder ratio (W/B) HPC mortar. The modification aimed at void volume (superabsorbent polymers, SAP, and air) applying Bolomey's formula and Powers' gel/space ratio developed a suitable fitting into the Powers' model. This experimental procedure shows feasibility to predict the MCC and RHA outcome on the compressive strength of HPC.
Keywords: Powers’ model; gel/space ratio; high-performance concrete; meta-illite calcined clay; rice husk ash; superabsorbent polymers.