Alkali Silica Reactivity in Cement Composite with Ferronickel Slag Aggregates: A Regression Analysis and 3D Visualisation Approach

Abstract The utilisation of industrial by-products and waste materials as supplementary materials in cement-based composites offers a sustainable approach towards reducing environmental impact and optimising resource utilisation in construction. This study investigates the potential use of ferronickel slag (FNS) aggregates in cement mortar, focusing on their influence on alkali silica reactivity (ASR) and mechanical properties. The compressive strength of mortar mixes was evaluated at different water to cement ratio, with varying proportions of FNS as a replacement for natural sand. The results revealed that a 50% replacement of standard sand with FNS aggregates yielded the highest compressive strength, reaching a maximum of 59.49 MPa. Full replacement with FNS aggregates ASR expansion tests indicated that FNS aggregates are highly reactive in NaOH solutions, with expansion levels exceeding ASTM limits. However, innocuous expansion was observed in water and Ca(OH)₂ environments, highlighting their stabilizing effect. Regression analysis showed that use of FNS aggregates present challenges in strongly alkaline environments, they hold significant potential for enhancing the mechanical properties of cement mortar, particularly when used in balanced proportions.