Author(s)

Seke Vangu Max^1,2*, Clement Nzau Umba Di Mbudi³, Makanzu Imwangana Fils^3,4,5, Seke Makunga Daudet⁶, Efoto Eale Louis¹

¹Department of Physics and Technology, Faculty of Science and Technology, University of Kinshasa, Kinshasa, The Democratic Republic of the Congo.
²Faculties of Engineering & Architecture, Kongo University, Mbanza-Ngungu, The Democratic Republic of the Congo.
³Department of Geosciences, Faculty of Sciences and Technologies, University of Kinshasa, Kinshasa, The Democratic Republic of the Congo.
⁴Centre of Research on Geology and Mining, Laboratory of Geomorphology and Remote Sensing, Kinshasa, The Democratic Republic of the Congo.
⁵National Institute of Building and Public Works, INBTP, Kinshasa, The Democratic Republic of the Congo.
⁶Sibanye-StillWater Ltd., Johannesburg, South Africa.

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

Pozzolan, Cement, Alite, Nyiragongo, ASR (Alkali-Silica Reaction)

Max, S. , Mbudi, C. , Fils, M. , Daudet, S. and Louis, E. (2023) Influence of the Partial Substitution of Industrial Clinker by Volcanic Lava Powder from Nyiragongo Volcano on the Physical Properties of Mortars. Journal of Minerals and Materials Characterization and Engineering, 11, 172-196. doi: 10.4236/jmmce.2023.115014.