Title:
Sustainable Improvement of Recycled Fine Aggregate Using Chemical Pre-soaking and Plant-Based Organic Additives (Prepublished)
Author(s):
Anila C Shaju, Praveen Nagarajan, Sudhakumar J, and Blessen S. Thomas
Publication:
Materials Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
bio-additives; calcium silicate hydrates (C-S-H); construction and demolition waste; recycled fine aggregate; silica fume; sodium silicate
DOI:
10.14359/51749324
Date:
11/12/2025
Abstract:
The growing generation of construction and demolition waste necessitates the development of effective recycling strategies to address environmental concerns. This study investigated the replacement of natural fine aggregate (NFA) with recycled fine aggregate (RFA) at 0, 50, and 100% using two treatment methods: (i) sodium silicate (SS)–silica fume (SF) pre-soaking treatment (SS-T) and (ii) organic treatment (OA-T) with bio-additives derived from Persea macranta, Haritaki, and Ciccus glauca roxb. A quantitative comparison of the aggregate and mortar quality was conducted for each method. The combined application of SST and OT demonstrated an 85% improvement in workability and a 68% reduction in water absorption for RFA. Mortar experiments revealed up to 76% improvement in compressive and flexural strengths compared with untreated RFA mortar. Microstructural analyses (SEM, EDS, XRD, and FT-IR) confirmed the enhanced bond strength and mineral composition. This study highlights the potential of SST and OT to produce durable, high-performance RFA mortars using locally available, economical bio-additives.