Fresh, mechanical, and short-term durability performance of green self-compacting concrete incorporating ternary cementitious systems with nanosilica

Abstract

This study presents a comprehensive experimental investigation into the processing, fresh, mechanical, short-term durability, and sustainability properties of self-compacting concrete (SCC) produced using a ternary supplementary cementitious material (SCM) system comprising fly ash and ground granulated blast-furnace slag (GGBS), with and without nanosilica (NS) at a 1% replacement level. A polycarboxylate ether (PCE)-based superplasticiser was used to produce seven mixes at a fixed water-to-binder ratio of 0.38. Fresh properties were analysed through slump flow, T500, V-funnel, L-box, J-ring and sieve segregation tests per EFNARC 2005. Hardened properties included compressive strength at 7, 28, 56 and 90 d, split tensile, flexural strength and static modulus of elasticity. Durability was assessed via RCPT, chloride migration coefficient (NT Build 492), water absorption, sorptivity, ISAT-10 and accelerated carbonation. Sustainability indices (CO2 emissions, embodied energy) were computed from life cycle inventory data. The SCC-F15G15 + NS ternary blend exhibited a compressive strength of 49.3 MPa at 28 d, chloride migration coefficient of 7.2 × 10−12 m2 s−1 and 21% lower CO2 emissions than the control. One-way ANOVA with Tukey HSD post-hoc analysis confirmed highly significant effects (p < 0.001) of SCM type and dosage on all measured properties. The findings support adoption of ternary SCM systems with nanosilica as a high-performance, sustainable alternative in SCC production within a 90 d observation period.