A series of tests was performed to investigate salient mechanical properties of concrete in which Portland Cement (PC) was replaced by different combinations of low energy-demanding materials. Binary or ternary combinations of Pulverised Fuel Ash (PFA), Metakaolin (MK) and reactive magnesia (MgO) were tested at various percentages. The results showed that mixes combining the above materials at the right proportions i.e. MK up to a maximum of 20%, PFA up to 20% and 5-10% MgO, show good potential for replacing high proportions of PC (up to 50%), giving good quality concrete in terms of strength and durability, with improved environmental ...