Influence of the Partial Substitution of Industrial Clinker by Volcanic Lava Powder from Nyiragongo Volcano on the Physical Properties of Mortars

This study evaluates the pozzolanicity of Nyiragongo volcano lava flows in Congo by an indirect method using mortars with different rock powder proportions. The clinker used is a locally produced alite clinker, whose chemical and mineralogical composition was determined XRF, Bogue Taylor formulas. were collected from 2002, 2010 2021 eruption sites, characterized CIPW normative mineralogy geomechanical tests. results show that rocks are ultrabasic, silica- alkali-rich, contain minerals like nepheline, wollastonite leucite. They satisfy natural pozzolan criterion, have pozzolanic activity indices above 70%. These also high RC LA resistances, ranging 190 MPa to 45 MPa, 18% 32.6%, respectively. addition reduces mechanical resistances increases setting times, except for 5% replacement rate, which speeds up hardening. can be as produce CEM II/B-P 32.5 cement.