▁( E ls a ▁& ▁S ven ▁Th ys ell ▁Foundation ▁for ▁Const ruction ▁Engineering ▁Research ) ▁of ▁Sweden . ▁ ▁Chem istry ▁Through ▁the ▁use ▁of ▁po zz ol ans ▁in ▁concrete , ▁por ous ▁( re active ) ▁Port land ite ▁can ▁be ▁transformed ▁into ▁hard ▁and ▁imper me able ▁( rel atively ▁non - re active ) ▁comp ounds , ▁rather ▁than ▁the ▁por ous ▁and ▁soft ▁relatively ▁re active ▁calci um ▁carbon ate ▁produced ▁using ▁ordinary ▁c ement . ▁Many ▁of ▁the ▁end ▁products ▁of ▁po zz olan ic ▁chem istry ▁exhib it ▁a ▁hard ness ▁greater ▁than ▁ 7 . 0 ▁on ▁the ▁Moh s ▁scale . ▁ ▁E MC ▁Activ ation ▁is ▁a ▁process ▁which ▁increases ▁a ▁po zz olan ' s ▁chemical ▁aff inity ▁for ▁po zz olan ic ▁re actions . ▁This ▁leads ▁to ▁faster ▁and ▁greater ▁strength ▁development ▁of ▁the ▁resulting ▁concrete , ▁at ▁higher ▁replacement ▁r ati os , ▁than ▁un tre ated ▁po zz ol ans . ▁ ▁These ▁highly ▁re active ▁po zz ol ans ▁can ▁yield ▁further ▁stabil isation ▁benefits ▁upon ▁the ▁po zz olan ic ▁reaction - path ways . ▁ ▁In ▁concrete ▁( including ▁con cre tes ▁with ▁E MC s ), ▁Port land ▁c ement ▁comb ines ▁with ▁water ▁to ▁produce ▁a ▁stone - like ▁material ▁through ▁a ▁complex ▁series ▁of ▁chemical ▁re actions , ▁whose ▁mechan isms ▁are ▁still ▁not ▁fully ▁understood . ▁That ▁chemical ▁process , ▁called ▁min eral ▁hyd r ation , ▁forms ▁two