Mechanical performance and sustainability of GGBS-blended cementitious mortars for resilient construction

Background Cement production is a significant source of global CO 2 emissions, driving the need for sustainable alternatives in construction. Ground granulated blast-furnace slag (GGBS) has emerged as a promising supplementary cementitious material; however, its performance across wide replacement ranges and its combined environmental and economic implications remain insufficiently characterised, particularly in hot and arid climatic contexts such as the Gulf region. Methods Nine mortar mixes incorporating GGBS as a partial replacement for ordinary Portland cement (OPC) were prepared at replacement levels ranging from 5% to 100%. Compressive and flexural strength were assessed at 7, 14, and 28 days of curing. Life cycle assessment (LCA) and life cycle cost (LCC) analyses were conducted to evaluate the environmental and economic performance of each mix over its service life. Results Replacement levels between 20% and 30% yielded optimal compressive strength, surpassing the OPC control at 28 days. Higher replacement levels enhanced flexural strength, though the highest recorded values require further validation. LCA results confirmed a progressive reduction in CO 2 emissions with increasing GGBS content, while LCC analysis demonstrated improved cost efficiency relative to the OPC reference. Discussion A 30% GGBS replacement level is identified as the optimal balance between mechanical performance, environmental benefit, and economic efficiency. These findings support the adoption of GGBS-blended mortars as viable, sustainable alternatives to conventional OPC-based construction materials in the Gulf region and comparable climatic environments.