Investigating supplementary cementitious materials' effects on stabilized aggregate performance, behaviour, and design aspects

Abstract

Supplementary Cementitious Materials (SCMs) have been widely accepted in the concrete industry due to their varied advantages. However, the same reflects little in the case of Cementitious Stabilized Aggregates (CSA). The present work focuses on the potential and practical application of SCMs in CSA based on laboratory-based growth and performance analysis followed by their design aspects and economic advantages. Fly ash and Crushed Granulated Blast Furnace Steel Slag (GBFS) were chosen at 30% and 50% by weight of cement as partial replacement to cementitious material to prepare a cementitious stabilized mix of aggregates. Mechanical and microstructural properties were then assessed through critical tests like Unconfined Compression Strength (UCS), Flexural Strength (FS), Flexural Modulus (FM) and Thermogravimetric Analysis (TGA) over subsequent curing periods. Results from these tests revealed improved performance on including SCMs in significant proportion when compared to cement mix of aggregates. Power-law relationships proved optimal for comprehending strength and stiffness growth in CSA. Mixes with SCMs exhibited higher growth coefficients and growth rates for UCS, FS and FM. TGA data showed higher bound water loss %, indicating increased hydration for SCMs mixes. Composite pavement design revealed a 5 mm increase in the bituminous layer for cement-fly ash mix, while it remained unchanged for cement and cement-GBFS mix. Economic analysis demonstrated SCM cost savings of 6% to 16% in the CSA layer in mixes with SCMs.