Browsing by Author "Nyangi, Patrice"

Now showing 1 - 1 of 1

Chemical Characterization of Pumice Material Sourced from Mbeya, Tanzania
(MUST, 2025-02) Nyangi, Patrice
Pumice, a lightweight volcanic material abundantly available in Mbeya, Tanzania, is underutilized and often discarded following excavation activities. In most construction projects within the region, conventional materials like clay soil, river sand, normal-weight aggregates, and cement are pre-dominantly used, leaving the potential of pumice largely unexploited. This study presents a comprehensive chemical characterization of pumice sourced from two locations, MUST main campus (Sample A) and Wimba (Sample B), to assess its suitability as a supplementary cementitious material (SCM). Energy Dispersive X-ray Fluorescence (EDXRF) analysis revealed that Sample A contained 70.3% SiO₂, 17.9% Al₂O₃, and 3.53% Fe₂O₃, while Sample B had 71.3% SiO₂, 17.3% Al₂O₃, and 3.38% Fe₂O₃. The combined SiO₂, Al₂O₃, and Fe₂O₃ content for both samples exceeded the 70% ASTM C618 threshold for pozzolanic materials, confirming strong pozzolanic properties. Additionally, K₂O was 5.21% in Sample A and 5.05% in Sample B, while CaO was 0.667% and 0.763%, respectively.SO₃ was detected at 0.448% (Sample A) and 0.482% (Sample B), and TiO₂ at 0.528% and 0.507%, respectively. Na₂O and MgO were not detected. The high levels of SiO₂ and Al₂O₃ suggest strong pozzolanic properties, while the low CaO content indicates that pumice would function primarily as a pozzolanic additive rather than a primary binder. Consequently, these findings confirm that pumice is better suited as a supplementary cementitious material (SCM) and filler rather than a complete replacement for cement. By partially replacing cement with pumice, it could be possible to reduce the carbon footprint, contributing to more sustainable construction practices.