Partial Replacement of Portland Cement by Granulated Cupola Slag – Sustainable Option for Concrete of Low Permeability

Abstract

This paper presents the results of investigation on the potentials of cupola slag as a partial replacement option for ordinary Portland cement (OPC) in applications requiring low permeable concrete. The chemical analysis of granulated cupola furnace slag (GCFS), its fineness, bulk density, specific gravity, and the standard consistency and setting times of binary OPC and GCFS pastes were conducted. Furthermore, concrete mixes of 0.55 water/cement ratio were produced using 1:2:4 ratio (volume basis) at 0%, 5%, 10% and 15% replacement levels of OPC by GCFS and the workability and permeability of the fresh concrete were determined. Thirty six (36) standard 150mm cubes were cast from the various concrete mixes, cured for 7, 21 and 28 days and crushed to determine their compressive strengths. The results of the tests showed that within the OPC replacement range investigated, the compressive strength of concrete progressively increased at all curing ages as the replacement level of OPC increased and attained a maximum value of 29.8 N/mm² at 28 days for 15% OPC replacement, which amounted to a 31.9% increase above the compressive strength of the reference concrete. In addition, the porosity of concrete decreased as the replacement level of OPC by GCFS increased. The chemical analysis of GCFS also indicated that it has pozzolanic properties. The above results indicate the suitability of granulated cupola furnace slag for use in concrete for which reduced permeability is an essential performance requirement.

Keywords: cupola slag, low permeable concrete, compressive strength, chemical analysis, sustainable