Potential use of Triassic basalts and Middle Cretaceous limestone as cementitious components in Portland cement

In the Moroccan cement industry, searching for alternatives to clinker using noncalcined mineral additions has become a significant focus to reduce energy consumption and greenhouse gas emissions and produce cement with a low environmental impact. This study examines the effects of incorporating Triassic basalts and Liassic limestone on the mechanical properties of mortars, as well as cement color, water demand, setting time, and durability of cement – based composites. The pozzolanic activity of basalt, calculated from chemical composition and amorphous phase content, is proposed as an intrinsic index of pozzolanic activity. The pozzolanic activity strength index was evaluated as the ratio of the compressive strength of the blended basalt – limenstone/cement mortar to that of a control Portland cement. Mortars with 10–15% of El Hajeb basalt and 19–24% limestone exhibited optimal mechanical performance at early (2 d) and long-term (28 d) stages, while improving setting times. Additionally, these combinations offer improved environmental and economic benefits for the production of pozzolanic CEMIV and CEMII composite cements, which comply with international standards (ASTM C618, 2022; EN 197-5, 2021; and NM 10, 01, 004, 2019).