Influence of Alccofine 1203 Addition on the Compressive Strength of Ordinary Portland Cement and Portland Composite Cement Mortar Cubes

https://doi.org/10.46610/JoCCS.2026.v011i03.005

Abstract

The production of Ordinary Portland Cement (OPC) is energy-intensive and contributes to a large amount of carbon dioxide emissions in the world. This has led to the search for supplementary cementitious materials (SCMs) that can partially replace cement without loss of strength. The present study investigates experimentally the effect of Alccofine 1203, an ultra-fine slag-based SCM, on the compressive strength of cement mortar cubes made with two commercially available binders, Ordinary Portland Cement (OPC, 43 grade) and Portland Composite Cement (PCC). Alccofine was used to replace cement at 0%, 5%, 10%, and 15% by weight in a 1:3 (cement: sand) mortar mix with a water-cement ratio of 0.485. Forty-eight cube specimens of 2 in × 2 in × 2 in were cast, cured in fresh water, and tested in compression at 3, 7, and 28 days. The results indicate that at 28 days the compressive strength increased with Alccofine content up to 10% replacement, after which it declined slightly at 15%, while every replacement level remained above the control; at 3 days, the 5% and 15% PCC mixes and the 15% OPC mix were below their controls. The highest 28-day compressive strength was 27.50 MPa for OPC mortar and 25.50 MPa for PCC mortar at 10% Alccofine replacement, compared to 19.00 MPa and 17.00 MPa for the respective plain controls. The improvement is attributed to the pozzolanic reactivity and fine particle packing of Alccofine, which densifies the microstructure and expedites the formation of calcium silicate hydrate (C-S-H) gel. The study concludes that 10% is the optimum Alccofine replacement level for both OPC and PCC mortars under the tested conditions, which provides a pragmatic route to more sustainable, higher-strength cementitious mortar.