Title:
Self-Healing Capability of Ambient Cured High Calcium Based Alkali-Activated Engineered Composites (Prepublished)
Author(s):
Khandaker M. Anwar Hossain and Dhruv Sood
Publication:
Materials Journal
Volume:
Issue:
Appears on pages(s):
Keywords:
akali activated engineered composite; industrial wastes; fiber; microstructure; powder form reagents; self-healing; strain hardening; strength
DOI:
10.14359/51750609
Date:
3/25/2026
Abstract:
The self-healing performance of zero cement-based one-part ambient cured alkali-activated engineered composites (AAECs) using 2% v/v polyvinyl alcohol (PVA) fibers and silica sand was evaluated. The variables in the study were: binary (fly ash class C ‘FA-C’ and ground granulated blast furnace slag ‘GGBFS’)/ternary (FA-C, fly ash class F ‘FA-F’ and (GGBFS) combination of precursors, two types of powder form alkaline reagents (type 1- calcium hydroxide: sodium meta-silicate = 1:2.5 and type 2 - calcium hydroxide; sodium sulfate = 2.5:1) and different pre-loading strain levels (0%, 0.5%, and 1%). The performance was based on the recovery of compressive/tensile strength, tensile strain hardening properties, crack-sealing, and microstructural characteristics after 365 days of water curing compared to conventional engineered cementitious composites (ECCs). All AAECs (binary/ternary or reagent type 1/2) exhibited enhanced/comparable self-healing performance compared to ECCs at both 0.5% and 1% pre-loading strain levels exhibiting maximum recovery of tensile strength, tensile strain capacity, stress index, tensile ductility and tensile elasticity up to 115%, 184%, 130%, 236% and 123%, respectively through preserving strain hardening and micro-cracking characteristics with up to 96% recovery of compressive strength. This was attributed to ongoing alkali activation and pozzolanic reactions forming C-S-H/C-A-S-H in binary with additional N-C-A-S-H in ternary and calcite binding phases leading to matrix densification, crack-sealing, and improved PVA fibre-matrix bonding as per SEM-EDS and XRD analyses. Generally, all the AAECs exhibited the ability of recovering properties and composites with reagent 2, demonstrating superior self-healing characteristics compared to their reagent 1 counterparts by achieving complete or higher recovery of tensile strength/strain capacities compared to their virgin counterparts. This study confirmed the viability of producing cement-free ambient-cured self-consolidating AAECs with powder form reagents having satisfactory strength, strain hardening, and self-healing characteristics for durable, sustainable construction.